Expert Panel on Integrated Guidelines for Cardiovascular Health and Risk Reduction in Children and Adolescents: Summary Report
Atherosclerotic cardiovascular disease (CVD) remains the leading cause of death in North Americans, but manifest disease in childhood and adolescence is rare. By contrast, risk factors and risk behaviors that accelerate the development of atherosclerosis begin in childhood, and there is increasing evidence that risk reduction delays progression toward clinical disease. In response, the former director of the National Heart, Lung, and Blood Institute (NHLBI), Dr Elizabeth Nabel, initiated development of cardiovascular health guidelines for pediatric care providers based on a formal evidence review of the science with an integrated format addressing all the major cardiovascular risk factors simultaneously. An expert panel was appointed to develop the guidelines in the fall of 2006.
The goal of the expert panel was to develop comprehensive evidence-based guidelines that address the known risk factors for CVD (Table 1-1) to assist all primary pediatric care providers in both the promotion of cardiovascular health and the identification and management of specific risk factors from infancy into young adult life. An innovative approach was needed, because a focus on cardiovascular risk reduction in children and adolescents addresses a disease process (atherosclerosis) in which the clinical end point of manifest CVD is remote. The recommendations, therefore, need to address 2 different goals: the prevention of risk-factor development (primordial prevention) and the prevention of future CVD by effective management of identified risk factors (primary prevention).
The evidence review also required an innovative approach. Most systematic evidence reviews include 1 or, at most, a small number of finite questions that address the impact of specific interventions on specific health outcomes, and a rigorous literature review often results in only a handful of in-scope articles for inclusion. Typically, evidence is limited to randomized controlled trials (RCTs), systematic reviews, and meta-analyses published over a defined time period. There is a defined format for abstracting studies, grading the evidence, and presenting of results. The results of the review lead to the conclusions, independent of interpretation.
By contrast, given the scope of the charge to the expert panel, this evidence review needed to address a broad array of questions concerning the development, progression, and management of multiple risk factors extending from birth through 21 years of age, including studies with follow-up into later adult life. The time frame extended back to 1985, ∼5 years before the review for the last NHLBI guideline addressing lipids in children published in 1992.1 This evidence is largely available in the form of epidemiologic observational studies (rather than RCTs) that, therefore, must be included in the review. In addition, the review required critical appraisal of the body of evidence that addresses the impact of managing risk factors in childhood on the development and progression of atherosclerosis. Because of known gaps in the evidence base relating risk factors and risk reduction in childhood to clinical events in adult life, the review must include the available evidence that justifies evaluation and treatment of risk factors in childhood. The process of identifying, assembling, and organizing the evidence was extensive, the review process was complex, and the conclusions could only be developed by interpretation of the body of evidence. Even with inclusion of every relevant study from the evidence review, there were important areas in which the evidence was inadequate. When this occurred, recommendations were made on the basis of a consensus of the expert panel. The schema used in grading the evidence appears in Tables 1-2 and 1-3; expert consensus opinions are identified as grade D.
The NHLBI expert panel integrated guidelines for cardiovascular health and risk reduction in children and adolescents contain recommendations based on the evidence review and are directed toward all primary pediatric care providers: pediatricians, family practitioners, nurses and nurse practitioners, physician assistants, and registered dietitians. The full report contains complete background information on the state of the science, methodology of the evidence review and the guideline-development process, summaries of the evidence reviews according to risk factor, discussion of the expert panel's rationale for recommendations, and >1000 citations from the published literature and is available at www.nhlbi.nih.gov/guidelines/cvd_ped/index.htm. The complete evidence tables will be available as a direct link from that site. This summary report presents the expert panel's recommendations for patient care relative to cardiovascular health and risk-factor detection and management with only the references cited in the text provided. It begins with a state-of-the-science synopsis of the evidence, which indicates that atherosclerosis begins in childhood, and the extent of atherosclerosis is linked directly to the presence and intensity of known risk factors. This is followed by a cardiovascular health schedule (Section 3), which summarizes the expert panel's age-based recommendations according to risk factor in a 1-page periodic table. Risk factor specific sections follow, with the graded conclusions of the evidence review, normative tables, and age-specific recommendations. These recommendations are often accompanied by supportive actions, which represent expert consensus suggestions from the panel provided to support implementation of the recommendations. The summary report will be released simultaneously with online availability of the full report with references for each section and the evidence tables at www.nhlbi.nih.gov/guidelines/cvd_ped/index.htm.
It is the hope of the NHLBI and the expert panel that these recommendations will be useful for all those who provide cardiovascular health care to children.
2. STATE OF THE SCIENCE: CARDIOVASCULAR RISK FACTORS AND THE DEVELOPMENT OF ATHEROSCLEROSIS IN CHILDHOOD
Atherosclerosis begins in youth, and this process, from its earliest phases, is related to the presence and intensity of the known cardiovascular risk factors shown in Table 1-1. Clinical events such as myocardial infarction, stroke, peripheral arterial disease, and ruptured aortic aneurysm are the culmination of the lifelong vascular process of atherosclerosis. Pathologically, the process begins with the accumulation of abnormal lipids in the vascular intima, a reversible stage, progresses to an advanced stage in which a core of extracellular lipid is covered by a fibromuscular cap, and culminates in thrombosis, vascular rupture, or acute ischemic syndromes.
Evidence Linking Risk Factors in Childhood to Atherosclerosis at Autopsy
Atherosclerosis at a young age was first identified in Korean and Vietnam War casualties. Two major contemporary studies, the Pathobiological Determinants of Atherosclerosis in Youth (PDAY) study2 and the Bogalusa Heart Study,3 subsequently evaluated the extent of atherosclerosis in children, adolescents, and young adults who died accidentally. The Bogalusa study3 measured cardiovascular risk factors (lipid levels, blood pressure [BP], BMI, and tobacco use) as part of a comprehensive school-based epidemiologic study in a biracial community. These results were related to atherosclerosis measured at autopsy after accidental death. Strong correlations were shown between the presence and intensity of risk factors and the extent and severity of atherosclerosis. In the PDAY study,2 risk factors and surrogate measures of risk factors were measured after death in 15- to 34-year olds who died accidentally of external causes. Strong relationships were found between atherosclerotic severity and extent, and age, non–high-density lipoprotein (HDL) cholesterol, HDL cholesterol, hypertension (determined by renal artery thickness), tobacco use (thiocyanate concentration), diabetes mellitus (DM) (glycohemoglobin), and (in men) obesity. There was a striking increase in both severity and extent as age and the number of risk factors increased. By contrast, the absence of risk factors was shown to be associated with a virtual absence of advanced atherosclerotic lesions, even in the oldest subjects in the study.
Evidence Linking Risk Factors in Childhood to Atherosclerosis Assessed Noninvasively
Over the last decade, measures of subclinical atherosclerosis have developed, including the demonstration of coronary calcium on electron beam computed tomography imaging, increased carotid intima-media thickness (CIMT) assessed with ultrasound, endothelial dysfunction (reduced arterial dilation) with brachial ultrasound imaging, and increased left ventricular mass with cardiac ultrasound. These measures have been assessed in young people with severe abnormalities of individual risk factors:
In adolescents with a marked elevation of low-density lipoprotein (LDL) cholesterol level caused by familial heterozygous hypercholesterolemia, abnormal levels of coronary calcium, increased CIMT, and impaired endothelial function have been found.
Children with hypertension have been shown to have increased CIMT, increased left ventricular mass, and eccentric left ventricular geometry.
Children with type 1 DM (T1DM) have significantly abnormal endothelial function and, in some studies, increased CIMT.
Children and young adults with a family history of myocardial infarction have increased CIMT, higher prevalence of coronary calcium, and endothelial dysfunction.
Endothelial dysfunction has been shown by ultrasound and plethysmography in association with cigarette smoking (passive and active) and obesity. In obese children, improvement in endothelial function occurs with regular exercise.
Left ventricular hypertrophy at levels associated with excess mortality in adults has been found in children with severe obesity.
Four longitudinal studies have found relationships of risk factors measured in youth (specifically LDL cholesterol, non-HDL cholesterol and serum apolipoproteins, obesity, hypertension, tobacco use, and DM) with measures of subclinical atherosclerosis in adulthood. In many of these studies, risk factors measured in childhood and adolescence were better predictors of the severity of adult atherosclerosis than were risk factors measured at the time of the subclinical atherosclerosis study.
Evidence Linking Risk Factors in Childhood to Clinical CVD
The most important evidence relating risk in youth to clinical CVD is the observed association of risk factors for atherosclerosis to clinically manifest cardiovascular conditions. Genetic disorders related to high cholesterol are the biological model for risk-factor impact on the atherosclerotic process. With homozygous hypercholesterolemia, in which LDL cholesterol levels exceed 800 mg/dL beginning in infancy, coronary events begin in the first decade of life and life span is severely shortened. With heterozygous hypercholesterolemia, in which LDL cholesterol levels are minimally 160 mg/dL and typically >200 mg/dL and total cholesterol (TC) levels exceed 250 mg/dL beginning in infancy, 50% of men and 25% of women experience clinical coronary events by the age of 50. By contrast, genetic traits associated with low cholesterol are associated with longer life expectancy. In the PDAY study,2 every 30 mg/dL increase in non-HDL cholesterol level was associated with a visible incremental increase in the extent and severity of atherosclerosis. In natural-history studies of DM, early CVD mortality is so consistently observed that the presence of DM is considered evidence of vascular disease in adults. Consonant with this evidence, in 15- to 19-year olds in the PDAY study, the presence of hyperglycemia was associated with the demonstration of advanced atherosclerotic lesions of the coronary arteries. In the PDAY study, there was also a strong relationship between abdominal aortic atherosclerosis and tobacco use. Finally, in a 25-year follow-up, the presence of the metabolic syndrome risk-factor cluster in childhood predicted clinical CVD in adult subjects at 30 to 48 years of age.4
The Impact of Racial/Ethnic Background and Socioeconomic Status in Childhood on the Development of Atherosclerosis
CVD has been observed in diverse geographic areas and all racial and ethnic backgrounds. Cross-sectional research in children has found differences according to race and ethnicity and according to geography for prevalence of cardiovascular risk factors; these differences are often partially explained by differences in socioeconomic status. No group within the United States is without a significant prevalence of risk. Several longitudinal cohort studies referenced extensively in this report (Bogalusa Heart Study,3 the PDAY study,2 and the Coronary Artery Risk Development in Young Adults [CARDIA] study5) have included racially diverse populations, and other studies have been conducted outside the United States. However, longitudinal data on Hispanic, Native American, and Asian children are lacking. Clinically important differences in prevalence of risk factors exist according to race and gender, particularly with regard to tobacco-use rates, obesity prevalence, hypertension, and dyslipidemia. Low socioeconomic status in and of itself confers substantial risk. However, evidence is not adequate for the recommendations provided in this report to be specific to racial or ethnic groups or socioeconomic status.
The Impact of Risk-Factor Clustering in Childhood on the Development of Atherosclerosis
From a population standpoint, clustering of multiple risk factors is the most common association with premature atherosclerosis. The pathologic studies reviewed above clearly showed that the presence of multiple risk factors is associated with striking evidence of an accelerated atherosclerotic process. Among the most prevalent multiple-risk combinations are the use of tobacco with 1 other risk factor and the development of obesity, which is often associated with insulin resistance, elevated triglyceride levels, reduced HDL cholesterol levels, and elevated BP, a combination known in adults as the metabolic syndrome. There is ample evidence from both cross-sectional and longitudinal studies that the increasing prevalence of obesity in childhood is associated with the same obesity-related risk-factor clustering seen in adults and that it continues into adult life. This high-risk combination is among the reasons that the current obesity epidemic with its relationship to future CVD and DM is considered one of the most important public health challenges in contemporary society. One other prevalent multiple-risk combination is the association of low cardiorespiratory fitness (identified in 33.6% of adolescents in the National Health and Nutrition Examination Surveys [NHANES] from 1999 to 20026) with overweight and obesity, elevated TC level and systolic BP, and a reduced HDL cholesterol level.
Risk-Factor Tracking From Childhood Into Adult Life
Tracking studies from childhood to adulthood have been performed for all the major risk factors.
Obesity tracks more strongly than any other risk factor; among many reports from studies that have demonstrated this fact, one of the most recent is from the Bogalusa study,7 in which >2000 children were followed from initial evaluation at 5 to 14 years of age to adult follow-up at a mean age of 27 years. On the basis of BMI percentiles derived from the study population, 84% of those with a BMI in the 95th to 99th percentile as children were obese as adults, and all of those with a BMI at the >99th percentile were obese in adulthood. Increased correlation is seen with increasing age at which the elevated BMI occurs.
For cholesterol and BP, tracking correlation coefficients in the range of 0.4 have been reported consistently from many studies, correlating these measures in children 5 to 10 years of age with results 20 to 30 years later. These data suggest that having cholesterol or BP levels in the upper portion of the pediatric distribution makes having them as adult risk factors likely but not certain. Those who develop obesity have been shown to be more likely to develop hypertension or dyslipidemia as adults.
Tracking data on physical fitness are more limited. Physical activity levels do track but not as strongly as other risk factors.
By its addictive nature, tobacco use persists into adulthood, although ∼50% of those who have ever smoked eventually quit.
T1DM is a lifelong condition.
The insulin resistance of T2DM can be alleviated by exercise, weight loss, and bariatric surgery, but the long-term outcome of those with T2DM diagnosed in childhood is not known.
As already discussed, risk-factor clusters such as those seen with obesity and the metabolic syndrome have been shown to track from childhood into adulthood.
CVD Prevention Beginning in Youth
The rationale for these guidelines comes from the following evidence.
Atherosclerosis, the pathologic basis for clinical CVD, originates in childhood.
Risk factors for the development of atherosclerosis can be identified in childhood.
Development and progression of atherosclerosis clearly relates to the number and intensity of cardiovascular risk factors, which begin in childhood.
Risk factors track from childhood into adult life.
Interventions exist for the management of identified risk factors.
The evidence for the first 4 bullet points is reviewed in this section, and the evidence surrounding interventions for identified risk factors is addressed in the risk-factor–specific sections of the guideline to follow.
It is important to distinguish between the goals of prevention at a young age and those at older ages in which atherosclerosis is well established, morbidity may already exist, and the process is only minimally reversible. At a young age, there have historically been 2 goals of prevention: (1) prevent the development of risk factors (primordial prevention); and (2) recognize and manage those children and adolescents who are at increased risk as a result of the presence of identified risk factors (primary prevention). It is well established that a population that enters adulthood with lower risk will have less atherosclerosis and will collectively have lower CVD rates. This concept is supported by research that has found that (1) societies with low levels of cardiovascular risk factors have low CVD rates and that changes in risk in those societies are associated with a change in CVD rates, (2) in adults, control of risk factors leads to a decline in morbidity and mortality from CVD, and (3) those without childhood risk have minimal atherosclerosis at 30 to 34 years of age, absence of subclinical atherosclerosis as young adults, extended life expectancy, and a better quality of life free from CVD.
The Pathway to Recommending Clinical Practice-Based Prevention
The most direct means of establishing evidence for active CVD prevention beginning at a young age would be to randomly assign young people with defined risks to treatment of cardiovascular risk factors or to no treatment and follow both groups over sufficient time to determine if cardiovascular events are prevented without undue increase in morbidity arising from treatment. This direct approach is intellectually attractive, because atherosclerosis prevention would begin at the earliest stage of the disease process and thereby maximize the benefit. However, this approach is as unachievable as it is attractive, primarily because such studies would be extremely expensive and would be several decades in duration, a time period in which changes in environment and medical practice would diminish the relevance of the results.
The recognition that evidence from this direct pathway is unlikely to be achieved requires an alternative stepwise approach in which segments of an evidence chain are linked in a manner that serves as a sufficiently rigorous proxy for the causal inference of a clinical trial. The evidence reviewed in this section provides the critical rationale for cardiovascular prevention beginning in childhood: atherosclerosis begins in youth; the atherosclerotic process relates to risk factors that can be identified in childhood; and the presence of these risk factors in a given child predicts an adult with risk if no intervention occurs. The remaining evidence links pertain to the demonstration that interventions to lower risk will have a health benefit and that the risk and cost of interventions to improve risk are outweighed by the reduction in CVD morbidity and mortality. These issues are captured in the evidence reviews of each risk factor. The recommendations reflect a complex decision process that integrates the strength of the evidence with knowledge of the natural history of atherosclerotic vascular disease, estimates of intervention risk, and the physician's responsibility to provide both health education and effective disease treatment. These recommendations for those caring for children will be most effective when complemented by a broader public health strategy.
The Childhood Medical Office Visit as the Setting for Cardiovascular Health Management
One cornerstone of pediatric care is placing clinical recommendations in a developmental context. Those who make pediatric recommendations must consider not only the relation of age to disease expression but the ability of the patient and family to understand and implement medical advice. For each risk factor, recommendations must be specific to age and developmental stage. The Bright Futures concept of the American Academy of Pediatrics8 (AAP) is used to provide a framework for these guidelines with cardiovascular risk-reduction recommendations for each age group.
This document provides recommendations for preventing the development of risk factors and optimizing cardiovascular health, beginning in infancy, that are based on the results of the evidence review. Pediatric care providers (pediatricians, family practitioners, nurses, nurse practitioners, physician assistants, registered dietitians) are ideally positioned to reinforce cardiovascular health behaviors as part of routine care. The guideline also offers specific guidance on primary prevention with age-specific, evidence-based recommendations for individual risk-factor detection. Management algorithms provide staged care recommendations for risk reduction within the pediatric care setting and identify risk-factor levels that require specialist referral. The guidelines also identify specific medical conditions such as DM and chronic kidney disease that are associated with increased risk for accelerated atherosclerosis. Recommendations for ongoing cardiovascular health management for children and adolescents with these diagnoses are provided.
A cornerstone of pediatric care is the provision of health education. In the US health care system, physicians and nurses are perceived as credible messengers for health information. The childhood health maintenance visit provides an ideal context for effective delivery of the cardiovascular health message. Pediatric care providers provide an effective team educated to initiate behavior change to diminish risk of CVD and promote lifelong cardiovascular health in their patients from infancy into young adult life.
4. FAMILY HISTORY OF EARLY ATHEROSCLEROTIC CVD
A family history of CVD represents the net effect of shared genetic, biochemical, behavioral, and environmental components. In adults, epidemiologic studies have found that a family history of premature coronary heart disease in a first-degree relative (heart attack, treated angina, percutaneous coronary catheter interventional procedure, coronary artery bypass surgery, stroke, or sudden cardiac death in a male parent or sibling before the age of 55 years or a female parent or sibling before the age of 65 years) is an important independent risk factor for future CVD. The process of atherosclerosis is complex and involves many genetic loci and multiple environmental and personal risk factors. Nonetheless, the presence of a positive parental history has been consistently found to significantly increase baseline risk for CVD. The risk for CVD in offspring is strongly inversely related to the age of the parent at the time of the index event. The association of a positive family history with increased cardiovascular risk has been confirmed for men, women, and siblings and in different racial and ethnic groups. The evidence review identified all RCTs, systematic reviews, meta-analyses, and observational studies that addressed family history of premature atherosclerotic disease and the development and progression of atherosclerosis from childhood into young adult life.
Conclusions and Grading of the Evidence Review for the Role of Family History in Cardiovascular Health
Evidence from observational studies strongly supports inclusion of a positive family history of early coronary heart disease in identifying children at risk for accelerated atherosclerosis and for the presence of an abnormal risk profile (grade B).
For adults, a positive family history is defined as a parent and/or sibling with a history of treated angina, myocardial infarction, percutaneous coronary catheter interventional procedure, coronary artery bypass grafting, stroke, or sudden cardiac death before 55 years in men or 65 years in women. Because the parents and siblings of children and adolescents are usually young themselves, it was the panel consensus that when evaluating family history of a child, history should also be ascertained for the occurrence of CVD in grandparents, aunts, and uncles, although the evidence supporting this recommendation is insufficient to date (grade D).
Identification of a positive family history for cardiovascular disease and/or cardiovascular risk factors should lead to evaluation of all family members, especially parents, for cardiovascular risk factors (grade B).
Family history evolves as a child matures, so regular updates are a necessary part of routine pediatric care (grade D).
Education about the importance of accurate and complete family health information should be part of routine care for children and adolescents. As genetic sophistication increases, linking family history to specific genetic abnormalities will provide important new knowledge about the atherosclerotic process (grade D).
Recommendations for the use of family history in cardiovascular health promotion are listed in Table 4-1.
5. NUTRITION AND DIET
The 2010 Dietary Guidelines for Americans (DGA)8 include important recommendations for the population aged 2 years and older. In 1992, the National Cholesterol Education Program (NCEP) Pediatric Panel report1 provided dietary recommendations for all children as part of a population-based approach to reducing cardiovascular risk. Evidence relative to diet and the development of atherosclerosis in childhood and adolescence was identified by the evidence review for this guideline and, collectively, provides the rationale for new dietary prevention efforts initiated early in life.
This new pediatric cardiovascular guideline not only builds on the recommendations for achieving nutrient adequacy in growing children as stated in the 2010 DGA but also adds evidence regarding the efficacy of specific dietary changes in reducing cardiovascular risk from the current evidence review for use by pediatric care providers in the care of their patients. Because the focus of these guidelines is on cardiovascular risk reduction, the evidence review specifically evaluated dietary fatty acid and energy components as major contributors to hypercholesterolemia and obesity, as well as dietary composition and micronutrients as they affect hypertension. New evidence from multiple dietary trials that addressed cardiovascular risk reduction in children has provided important information for these recommendations.
Conclusions and Grading of the Evidence Review for Diet and Nutrition in Cardiovascular Risk Reduction
The expert panel concluded that there is strong and consistent evidence that good nutrition beginning at birth has profound health benefits and the potential to decrease future risk for CVD. The expert panel accepts the 2010 DGA8 as containing appropriate recommendations for diet and nutrition in children aged 2 years and older. The recommendations in these guidelines are intended for pediatric care providers to use with their patients to address cardiovascular risk reduction. The conclusions of the expert panel's review of the entire body of evidence in a specific nutrition area with grades are summarized. Where the evidence is inadequate yet nutrition guidance is needed, recommendations for pediatric care providers are based on a consensus of the expert panel (grade D). The age- and evidence-based recommendations of the expert panel follow.
In accordance with the Surgeon General's Office, the World Health Organization, the AAP, and the American Academy of Family Physicians, exclusive breastfeeding is recommended for the first 6 months of life. Continued breastfeeding is recommended to at least 12 months of age with the addition of complementary foods. If breastfeeding per se is not possible, feeding human milk by bottle is second best, and formula-feeding is the third choice.
Long-term follow-up studies have found that subjects who were breastfed have sustained cardiovascular health benefits, including lower cholesterol levels, lower BMI, reduced prevalence of type 2 DM, and lower CIMT in adulthood (grade B).
Ongoing nutrition counseling has been effective in assisting children and families to adopt and sustain recommended diets for both nutrient adequacy and reducing cardiovascular risk (grade A).
Within appropriate age- and gender-based requirements for growth and nutrition, in normal children and in children with hypercholesterolemia intake of total fat can be safely limited to 30% of total calories, saturated fat intake limited to 7% to 10% of calories, and dietary cholesterol limited to 300 mg/day. Under the guidance of qualified nutritionists, this dietary composition has been shown to result in lower TC and LDL cholesterol levels, less obesity, and less insulin resistance (grade A). Under similar conditions and with ongoing follow-up, these levels of fat intake might have similar effects starting in infancy (grade B). Fats are important to infant diets because of their role in brain and cognitive development. Fat intake for infants younger than 12 months should not be restricted without medical indication.
The remaining 20% of fat intake should comprise a combination of monosaturated and polyunsaturated fats (grade D). Intake of trans fats should be limited as much as possible (grade D).
For adults, the current NCEP guidelines9 recommend that adults consume 25% to 35% of calories from fat. The 2010 DGA supports the Institute of Medicine recommendations for 30% to 40% of calories from fat for ages 1 to 3 years, 25% to 35% of calories from fat for ages 4 to 18 years, and 20% to 35% of calories from fat for adults. For growing children, milk provides essential nutrients, including protein, calcium, magnesium, and vitamin D, that are not readily available elsewhere in the diet. Consumption of fat-free milk in childhood after 2 years of age and through adolescence optimizes these benefits without compromising nutrient quality while avoiding excess saturated fat and calorie intake (grade A). Between the ages of 1 and 2 years, as children transition from breast milk or formula, reduced-fat milk (ranging from 2% milk to fat-free milk) can be used on the basis of the child's growth, appetite, intake of other nutrient-dense foods, intake of other sources of fat, and risk for obesity and CVD. Milk with reduced fat should be used only in the context of an overall diet that supplies 30% of calories from fat. Dietary intervention should be tailored to each specific child's needs.
Optimal intakes of total protein and total carbohydrate in children were not specifically addressed, but with a recommended total fat intake of 30% of energy, the expert panel recommends that the remaining 70% of calories include 15% to 20% from protein and 50% to 55% from carbohydrate sources (no grade). These recommended ranges fall within the acceptable macronutrient distribution range specified by the 2010 DGA: 10% to 30% of calories from protein and 45% to 65% of calories from carbohydrate for children aged 4 to 18 years.
Sodium intake was not addressed by the evidence review for this section on nutrition and diet. From the evidence review for the “High BP” section, lower sodium intake is associated with lower systolic and diastolic BP in infants, children, and adolescents.
Plant-based foods are important low-calorie sources of nutrients including vitamins and fiber in the diets of children; increasing access to fruits and vegetables has been shown to increase their intake (grade A). However, increasing fruit and vegetable intake is an ongoing challenge.
Reduced intake of sugar-sweetened beverages is associated with decreased obesity measures (grade B). Specific information about fruit juice intake is too limited for an evidence-based recommendation. Recommendations for intake of 100% fruit juice by infants was made by a consensus of the expert panel (grade D) and are in agreement with those of the AAP.
Per the 2010 DGA, energy intake should not exceed energy needed for adequate growth and physical activity. Calorie intake needs to match growth demands and physical activity needs (grade A). Estimated calorie requirements according to gender and age group at 3 levels of physical activity from the dietary guidelines are shown in Table 5-2. For children of normal weight whose activity is minimal, most calories are needed to meet nutritional requirements, which leaves only ∼5% to 15% of calorie intake from extra calories. These calories can be derived from fat or sugar added to nutrient-dense foods to allow their consumption as sweets, desserts, or snack foods (grade D).
Dietary fiber intake is inversely associated with energy density and increased levels of body fat and is positively associated with nutrient density (grade B); a daily total dietary fiber intake from food sources of at least age plus 5 g for young children up to 14 g/1000 kcal for older children and adolescents is recommended (grade D).
The expert panel supports the 2008 AAP recommendation for vitamin D supplementation with 400 IU/day for all infants and children.10 No other vitamin, mineral, or dietary supplements are recommended (grade D). The new recommended daily allowance for vitamin D for those aged 1 to 70 years is 600 IU/day.
Use of dietary patterns modeled on those shown to be beneficial for adults (eg, Dietary Approaches to Stop Hypertension [DASH] pattern) is a promising approach to improving nutrition and decreasing cardiovascular risk (grade B).
All diet recommendations must be interpreted for each child and family to address individual diet patterns and patient sensitivities such as lactose intolerance and food allergies (grade D).
Graded, age-specific recommendations for pediatric care providers to use in optimizing cardiovascular health in their patients are summarized in Table 5-1. The Cardiovascular Health Integrated Lifestyle Diet (CHILD-1) is the first stage in dietary change for children with identified dyslipidemia, overweight and obesity, risk-factor clustering, and high-risk medical conditions that might ultimately require more intensive dietary change. CHILD-1 is also the recommended diet for children with a positive family history of early cardiovascular disease, dyslipidemia, obesity, primary hypertension, DM, or exposure to smoking in the home. Any dietary modification must provide nutrients and calories needed for optimal growth and development (Table 5-2). Recommended intakes are adequately met by a DASH-style eating plan, which emphasizes fat-free/low-fat dairy and increased intake of fruits and vegetables. This diet has been modified for use in children aged 4 years and older on the basis of daily energy needs according to food group and is shown in Table 5-3 as an example of a heart-healthy eating plan using CHILD-1 recommendations.
6. PHYSICAL ACTIVITY
Physical activity is any bodily movement produced by contraction of skeletal muscle that increases energy expenditure above a basal level. Physical activity can be focused on strengthening muscles, bones, and joints, but because these guidelines address cardiovascular health, the evidence review concentrated on aerobic activity and on the opposite of activity: sedentary behavior. There is strong evidence for beneficial effects of physical activity and disadvantageous effects of a sedentary lifestyle on the overall health of children and adolescents across a broad array of domains. Our review focused on the effects of activity on cardiovascular health, because physical inactivity has been identified as an independent risk factor for coronary heart disease in adults. Over the last several decades, there has been a steady decrease in the amount of time that children spend being physically active and an accompanying increase in time spent in sedentary activities. The evidence review identified many studies in youth ranging in age from 4 to 21 years that strongly linked increased time spent in sedentary activities with reduced overall activity levels, disadvantageous lipid profiles, higher systolic BP, higher levels of obesity, and higher levels of all the obesity-related cardiovascular risk factors including hypertension, insulin resistance, and type 2 DM.
Conclusions and Grading of the Evidence Review for Physical Activity
The expert panel felt that the evidence strongly supports the role of physical activity in optimizing cardiovascular health in children and adolescents.
There is reasonably good evidence that physical activity patterns established in childhood are carried forward into adulthood (grade C).
There is strong evidence that increases in moderate-to-vigorous physical activity are associated with lower systolic and diastolic BP, decreased measures of body fat, decreased BMI, improved fitness measures, lower TC level, lower LDL cholesterol level, lower triglyceride level, higher HDL cholesterol level, and decreased insulin resistance in childhood and adolescence (grade A).
There is limited but strong and consistent evidence that physical exercise interventions improve subclinical measures of atherosclerosis (grade B).
Physical activity patterns, dietary choices, and smoking behaviors cluster together (grade C).
There is no evidence of harm associated with increased physical activity or limitation of sedentary activity in healthy children (grade A).
There is strong evidence that physical activity should be promoted in schools (grade A).
There is less specific information on the type and amount of physical exercise required for optimum cardiovascular health. Reported activity interventions ranged from 20 to 60 minutes, 2 to 5 times per week in children aged 3 to 17 years and included a wide variety of dynamic and isometric exercises. Extrapolating from these interventions, which occurred in supervised settings, to the real world of childhood and adolescence, the expert panel recommends at least 1 hour of moderate-to-vigorous activity every day of the week for children older than 5 years (Table 6-1). In agreement with the “Physical Activity Guidelines Advisory Committee Report, 2008”11 from the Department of Health and Human Services, the expert panel recommends that activity be vigorous on 3 days/week (www.health.gov/paguidelines). In working with children and families, the expert panel suggested that moderate-to-vigorous activity could be compared with jogging or playing baseball and that vigorous physical activity could be compared with running, playing singles tennis, or playing soccer. Similarly, reducing sedentary time is convincingly associated with a favorable cardiovascular profile, and the expert panel agreed with the AAP recommendation for limiting leisure screen time to <2 hours/day.
7. TOBACCO EXPOSURE
Tobacco dependence is responsible for ∼4 million deaths worldwide annually, and in utero exposure to tobacco products, involuntary tobacco smoke exposure (secondhand smoke), and tobacco use directly impair health in fetuses, infants, children, and adolescents. On the basis of an analysis of published causes of death, tobacco use is the leading actual cause of death in the United States. The evidence that cigarette use is harmful and addictive is unequivocal. In childhood, nicotine is highly addicting; symptoms of tobacco dependence have been found after brief intermittent use. Cigarette use among high school students declined from 1997 to 2003. Rates were stable from 2003 to 2007 with >20% of high school students reporting daily smoking. From a public health standpoint, the need to reduce tobacco exposure is compelling, and a role for pediatric health care providers is essential.
A clinical practice guideline update from the US Public Health Service published in May 200812 systematically reviewed almost 9000 publications and concluded that smoking prevention and cessation interventions are effective in adults. These same methods should be safely applicable in childhood and adolescence, because behavioral interventions to alter smoking behaviors have little if any morbidity and because morbidity with pharmacologic treatment is limited. Physicians who care for children are well positioned to provide prevention and treatment interventions for their patients. Youth interventions must target parents as well as children, because parental smoking is both a risk factor for child smoking and provides secondhand smoke exposure to fetuses and children. The evidence review assessed prevention and treatment interventions in each of these areas.
Conclusions and Grading of the Evidence on Preventing Tobacco Exposure
Among all the known risk factors for CVD, the dichotomy between known benefits of risk elimination and the paucity of evidence for effective interventions to achieve risk reduction in pediatric care provider settings is greatest for tobacco exposure. The quality of the evidence regarding the harm of smoking and the benefits of avoiding passive smoke exposure, smoking prevention, and smoking cessation is uniformly grade A. That evidence grades in the recommendations are less than grade A reflects the lack of existing evidence on interventions that impact smoking behaviors in specific pediatric age groups as opposed to the collective evidence.
Good-quality interventions in pediatric care settings to decrease children's environmental smoke exposure have had mixed results (grade B).
Intervention studies to prevent smoking initiation have had moderate success, although long-term results are limited (grade B).
Practice-based interventions to achieve smoking cessation in adolescents have had moderate success with limited long-term follow-up (grade B).
School-based smoking-prevention programs have been moderately successful with limited long-term follow-up (grade B).
Although the evidence base for effective office-based approaches to tobacco interventions is moderate and mixed, the evidence that cigarette use is harmful and addictive is unequivocal. The need to reduce tobacco exposure is so compelling that a role for pediatric health care providers is essential. The lack of harm associated with such interventions and the importance of communicating the message of risk associated with tobacco provides the rationale for “strongly recommend” despite the lack of conclusive evidence that office-based interventions reliably reduce tobacco initiation or smoking cessation. Physicians and nurses who care for children are well positioned to provide intervention to patients who smoke. The expert panel feels that such providers should routinely identify patients who smoke by using the medical history (Table 7-1). Patients should be explicitly informed about the addictive and adverse health effects of tobacco use. By using the 5 A's (ask, advise, assess, assist, and arrange), providers can assess readiness to quit and assist in providing resources to support smoking-cessation efforts. Information about telephone quit lines (eg, 1-800-QUIT-NOW), community cessation programs, and pharmacotherapy should also be made available.
As described, practice-based interventions to decrease environmental smoke exposure have had mixed results. Nonetheless, the expert panel believes that pediatric care providers should identify parents and other caregivers who smoke and explicitly recommend that children not be exposed to tobacco smoke in the home, in automobiles, or in any other space where exposure can occur. For the parent who smokes, information provided should include statements about health benefits to the individual, child, and/or fetus and referral to smoking-cessation care providers.
8. HIGH BP
In 2004, an NHLBI task force published “The Fourth Report on the Diagnosis, Evaluation, and Treatment of High Blood Pressure in Children and Adolescents.”13 This report included a complete review of the current evidence on this subject and detailed recommendations for managing BP throughout childhood. These recommendations were used as the basis for these guidelines, considered complete until 2003 when the review for the report ended. Therefore, this evidence review for BP for these guidelines was limited to studies published between January 1, 2003, and June 30, 2007, with the addition of selected studies through June 30, 2008, identified by the expert panel as having met all the criteria for inclusion. Repeating the review performed by the task force was not felt to be necessary, given the short time since publication of that report, or a judicious use of the resources available for development of these guidelines. Recommendations regarding BP are all graded as expert opinion (grade D), because they are based on the expert consensus conclusions of this NHLBI task force.
Conclusions of the Evidence-Review Update for High BP (2003–2008)
The evidence review for the defined time period resulted in no major changes in the approach to BP evaluation and management.
According to epidemiologic surveys of children and adolescents over the past 20 years, BP levels have been increasing, and the prevalence of hypertension and prehypertension are also increasing, explained partially by the rise in obesity rates.
Prehypertension progresses to hypertension at a rate of ∼7% per year; hypertension persists in almost one-third of boys and one-fourth of girls on 2-year longitudinal follow-up.
Breastfeeding and supplementation of formula with polyunsaturated fatty acids in infancy are both associated with lower BP at follow-up.
A DASH-style diet, which is rich in fruits, vegetables, low-fat or fat-free dairy products, whole grains, fish, poultry, beans, seeds, and nuts and lower in sweets and added sugars, fats, and red meats than the typical American diet, is associated with lower BP. The CHILD-1 combined with the DASH eating plan described in “Diet and Nutrition” is an appropriate diet for children that meets the DASH study and 2010 DGA nutrient goals.
Lower dietary sodium intake is associated with lower BP levels in infants, children, and adolescents.
Losartan, amlodipine, felodipine, fosinopril, lisinopril, metoprolol, and valsartan can be added to the list of medications that are tolerated over short periods and can reduce BP in children from ages 6 to 17 years but are predominantly effective in adolescents. For black children, greater doses of fosinopril might be needed for effective BP control. Medications are shown in Table 8-5.
In 1 study of small-for-gestational-age infants, a nutrient-enriched diet that promoted rapid weight gain was associated with higher BP on follow-up in late childhood. This potential risk should be considered when such diets are selected in the clinical setting.
In another study, transcendental meditation effectively lowered BP in nonhypertensive adolescents.
In “The Fourth Report on the Diagnosis, Evaluation, and Treatment of High Blood Pressure in Children and Adolescents,”13 an NHLBI task force provided an algorithm and flow diagram to assist clinicians in identifying hypertension in children. For these guidelines, the task force's recommendations are stratified here to provide an age-appropriate approach congruent with other risk-factor recommendations in other sections, and this is also reflected in a series of revised algorithms (Table 8-1 and Figs 8-1 and 8-2). Conditions under which children younger than 3 years should have BP measured are shown in Table 8-2. The BP norms for age, gender, and height are shown in Tables 8-3 and 8-4 and were taken directly from the NHLBI task force's report. Age-specific percentiles of BP measurements from birth to 12 months are provided in the “Report of the Fourth Task Force on Blood Pressure Control in Children.” For all age groups the assessment of left ventricular mass by echocardiography is recommended as the best method of assessing hypertensive target organ disease; this testing should be performed for patients with stage 2 hypertension and those with persistent stage 1 hypertension. Elevated left ventricular mass might be useful in establishing the need for pharmacologic treatment of hypertension. In Table 8-5, the medications used to achieve BP control in children and adolescents are listed. At present, there are no data to support the use of specific antihypertensive agents for specific age groups.
9. LIPIDS AND LIPOPROTEINS
Since the last NHLBI guidelines for lipid management in children and adolescents were published in 1992,1 both the knowledge base surrounding dyslipidemia in childhood and the clinical picture have changed. A series of critical observational studies have found a clear correlation between lipoprotein disorders and the onset and severity of atherosclerosis in children, adolescents, and young adults. A major increase in the prevalence of obesity has led to a much larger population of children with dyslipidemia. At the time of the original guidelines, the focus was almost exclusively on identification of children with an elevated LDL cholesterol level. Since then, the predominant dyslipidemic pattern in childhood is a combined pattern associated with obesity, moderate-to-severe elevation in triglyceride level, normal-to-mild elevation in LDL cholesterol level, and a reduced HDL cholesterol level. Both dyslipidemic patterns have been shown to be associated with initiation and progression of atherosclerotic lesions in children and adolescents as demonstrated by pathology and imaging studies. Identification of children with dyslipidemias, which place them at increased risk for accelerated early atherosclerosis, must include a comprehensive assessment of serum lipid and lipoprotein levels.
The evidence review for lipids and lipoproteins addressed the association between dyslipidemia and atherosclerosis in childhood, lipid assessment in childhood and adolescence with tables of normative results provided, the dyslipidemias, dietary treatment of dyslipidemia, and medication therapy.
Conclusions and Grading of the Evidence Review for Lipid Assessment in Childhood and Adolescence
Combined evidence from autopsy studies, vascular studies, and cohort studies strongly indicates that abnormal lipid levels in childhood are associated with increased evidence of atherosclerosis (grade B).
The evidence review supports the concept that early identification and control of dyslipidemia throughout youth and into adulthood will substantially reduce clinical CVD risk beginning in young adult life. Preliminary evidence in children with heterozygous familial hypercholesterolemia with markedly elevated LDL cholesterol levels indicates that earlier treatment is associated with reduced subclinical evidence of atherosclerosis (grade B).
Multiple prospective screening cohort studies have demonstrated the normal lipid and lipoprotein distributions in childhood, adolescence, and young adult life (Tables 9-1 and 9-2) (grade B). Cohort studies have also demonstrated significant tracking of elevated lipid levels from childhood into adulthood. Lipid and lipoprotein results in childhood are predictive of future adult lipoprotein profiles; the strongest statistical correlation occurs between results in late childhood and in the third and fourth decades of life (grade B).
TC and LDL cholesterol levels decrease as much as 10% to 20% or more during puberty (grade B). On the basis of this normal pattern of change in lipid and lipoprotein levels with growth and maturation, 10 years of age (range: 9–11 years) is a stable time for lipid assessment in children (grade D). For most children, this age range will precede the onset of puberty.
Significant evidence exists to indicate that using family history of premature CVD or cholesterol disorders as the primary factor in determining lipid screening for children misses ∼30% to 60% of children with dyslipidemias, and accurate and reliable measures of family history are not available (grade B). In the absence of a clinical or historic marker, identification of children with lipid disorders that predispose them to accelerated atherosclerosis requires universal lipid assessment (grade B).
Non-HDL cholesterol level has been identified as a significant predictor of the presence of atherosclerosis, as powerful as any other lipoprotein cholesterol measure in children and adolescents. For both children and adults, non-HDL cholesterol level seems to be more predictive of persistent dyslipidemia and, therefore, atherosclerosis and future events than TC, LDL cholesterol, or HDL cholesterol levels alone. A major advantage of non-HDL cholesterol is that it can be accurately calculated in a nonfasting state and is therefore practical to obtain in clinical practice. The expert panel felt that non-HDL cholesterol should be added as a screening tool for identification of a dyslipidemic state in childhood (grade B).
In terms of other lipid measurements, (1) most but not all studies have found that measurement of apolipoprotein B and apolipoprotein A-1 for universal screening provides no additional advantage over measuring non-HDL cholesterol, LDL cholesterol, and HDL cholesterol levels, (2) measurement of lipoprotein(a) is useful in the assessment of children with both hemorrhagic and ischemic stroke, (3) in offspring of a parent with premature CVD and no other identifiable risk factors, elevations of apolipoprotein B, apolipoprotein A-1, and lipoprotein(a) have been noted, and (4) measurement of lipoprotein subclasses and their sizes by advanced lipoprotein testing has not been found to have sufficient clinical utility in children at this time (grade B).
Obesity is commonly associated with a combined dyslipidemia pattern with mild elevation in TC and LDL cholesterol levels, moderate-to-severe elevation in triglyceride level, and a low HDL cholesterol level. This is the most common dyslipidemic pattern seen in childhood, and lipid assessment in overweight and obese children identifies an important proportion of those with significant lipid abnormalities (grade B).
Dyslipidemias can be acquired genetically but also secondary to specific conditions such as DM, nephrotic syndrome, chronic renal disease, postorthotopic heart transplant, history of Kawasaki disease with persistent coronary involvement, chronic inflammatory disease, hypothyroidism, and other causes, as outlined in Table 9-3. There is impressive evidence for accelerated atherosclerosis both clinically and as assessed with noninvasive methods in some of these conditions, which have been designated accordingly as special risk diagnoses for accelerated atherosclerosis (Table 9-7); management of these conditions is described in “DM and Other Conditions Predisposing to the Development of Accelerated Atherosclerosis.” Lipid evaluation for these patients contributes to risk assessment and identifies an important proportion of those with dyslipidemia (grade B).
The complete phenotypic expression of some inherited disorders such as familial combined hyperlipidemia may be delayed until adulthood. Therefore, evaluation of children and adolescents from high-risk families with familial combined hyperlipidemia (Table 9-4) should begin in childhood and continue through adulthood (per NCEP adult treatment guidelines) and will lead to early detection of those with abnormalities (grade B).
Age-specific recommendations for lipid assessment are outlined in Table 9-5. Specific management for children with identified dyslipidemia is outlined in the algorithms in Figs 9-1 and 9-2. Definitions of the risk factors and special risk conditions for use with the recommendations and in the algorithms appear in Tables 9-6 and 9-7. The first step proposed for management of children with identified lipid abnormalities is a focused intervention on diet and physical activity.
Conclusions and Grading of the Evidence Review for Dietary Management of Dyslipidemia
A diet with total fat at 25% to 30% of calories, saturated fat at <10% of calories, and cholesterol intake at <300 mg/day, as recommended by the original NCEP Pediatric Panel,1 has been shown to safely and effectively reduce the levels of TC and LDL cholesterol in healthy children (grade A). There is some evidence that this is also the case when the diet begins in infancy and is sustained throughout childhood and into adolescence (grade B). The CHILD-1, described in “Nutrition and Diet,” has this composition.
In children with identified hypercholesterolemia and an elevated LDL cholesterol level, a more stringent diet with saturated fat at ≤7% of calories and dietary cholesterol limited to 200 mg/day has been shown to be safe and modestly effective in lowering the LDL cholesterol level (grade A) (CHILD-2–LDL; Table 9-8).
The use of dietary adjuncts such as plant sterol or stanol esters up to 20 g/day can safely enhance LDL cholesterol–lowering effects short-term in children with familial hypercholesterolemia (grade A). However, long-term studies on the safety and effectiveness of plant sterol and stanol esters have not been completed. Their use, therefore, is usually reserved for children with primary elevations of their LDL cholesterol level who do not achieve LDL cholesterol goals with dietary treatment alone. Such an approach might lower the LDL cholesterol level sufficiently to avoid the necessity of drug treatment. Food products that contain plant stanol esters, such as some margarines, are marketed directly to the general public. In 2 short-term trials, they have been shown to be safe and have minimal LDL-lowering effects in healthy children (grade B).
Evidence for the use of other dietary supplements is insufficient for any recommendation (no grade).
In children with an elevated triglyceride level, reduction of simple carbohydrate intake and weight loss are associated with decreased triglyceride levels (grade B). Reduction of simple carbohydrate intake needs to be associated with increased intake of complex carbohydrates and reduced saturated-fat intake. When triglyceride elevation is associated with obesity, decreased calorie intake and increased activity levels are of paramount importance. The CHILD-2–TG (shown in Table 9-8) is recommended as the primary diet therapy in this setting.
A behavioral approach that engages the child and family delivered by a registered dietitian has been shown to be the most consistently effective approach for achieving dietary change (grade B).
The approach to management of dyslipidemias is staged, as in the original NCEP Pediatric Panel recommendations.1 For all children with identified dyslipidemia in whom the response to a low-fat/low-saturated-fat/low-cholesterol diet has not been evaluated, the CHILD-1 (described in “Nutrition and Diet”) is recommended as the first step; implementation should be guided by a registered dietitian. For obese children with identified dyslipidemia, additional age- and BMI-specific recommendations that address calorie restriction and increased activity appear in “Overweight and Obesity.” If, after a 3-month trial of the CHILD-1/lifestyle management, fasting-lipid-profile (FLP) findings exceed the therapeutic goals listed in Tables 9-1 and 9-2, then the lipid parameter-specific diet changes outlined in Table 9-8 are recommended. Dyslipidemia management is also outlined in the algorithms in Figs 9-1 and 9-2.
Conclusions and Grading of the Evidence Review for Use of Medication to Treat Dyslipidemia
When medication is recommended, it should always be in the context of the complete cardiovascular risk profile of the patient and in consultation with the patient and the family. Note that, in the following section, values given are in mg/dL; to convert to SI units, divide the results for TC, LDL cholesterol, HDL cholesterol, and non-HDL cholesterol by 38.6; for triglycerides, divide by 88.6.
Decisions regarding the need for medication therapy should be based on the average of results from at least 2 FLPs obtained at least 2 weeks but no more than 3 months apart (grade C) (Fig 9-1).
The cut points used to define the level at which drug therapy should be considered from the 1992 NCEP pediatric guidelines1 have been used as the basis for multiple drug safety and efficacy trials in dyslipidemic children (grade B):
LDL cholesterol ≥ 190 mg/dL after a 6-month trial of lifestyle management (CHILD-1 → CHILD-2–LDL) for children aged 10 years or older.
LDL cholesterol 160 to 189 mg/dL after a 6-month trial of lifestyle/diet management (CHILD-1 → CHILD-2–LDL) in a child aged 10 years or older with a positive family history of premature CVD/events in first-degree relatives (Table 9-6) or at least 1 high-level risk factor or risk condition or at least 2 moderate-level risk factors or risk conditions (Tables 9-6, 9-7, and 9-12; Fig 9-1).
LDL cholesterol 130 to 190 mg/dL in a child aged 10 years or older with a negative family history of premature CVD in first-degree relatives and no high- or moderate-level risk factor or risk condition: management should continue to focus on lifestyle changes (CHILD-1 → CHILD-2–LDL) based on lipid-profile findings (Fig 9-1) plus weight management if the BMI is at the ≥85th percentile.
The goal of LDL-lowering therapy in childhood and adolescence is to decrease the LDL cholesterol level to the <95th percentile (≤130 mg/dL).
Children with homozygous familial hypercholesterolemia and extremely elevated LDL cholesterol levels (>500 mg/dL) have undergone effective LDL-lowering therapy with biweekly LDL apheresis under the care of lipid specialists in academic medical centers (grade C).
Multiple cohort studies have found that the benefits of LDL-lowering therapy in children at high risk for accelerated atherosclerosis (such as those with chronic kidney disease, T1DM or T2DM, Kawasaki disease with coronary aneurysms, or post–cardiac transplantation) should be considered for initiation of medication therapy (grade C) (see “DM and Other Conditions Predisposing to the Development of Accelerated Atherosclerosis”).
Bile acid sequestrants are medications that bind bile salts within the intestinal lumen and prevent their enterohepatic reuptake in the terminal ileum, which results in a depletion of bile salts in the liver and signals for increased production. Because bile salts are synthesized from intracellular cholesterol in the liver, the intracellular pool of cholesterol becomes depleted, which signals increased production of LDL receptors and increased clearance of circulating LDL cholesterol to replenish the intracellular cholesterol pool for increased production of bile salts. Studies of bile acid sequestrants in children and adolescents aged 6 to 18 years with LDL cholesterol levels from 131 to 190 mg/dL have resulted in TC reduction of 7% to 17% and reduction of LDL cholesterol of 10% to 20%, sometimes with a modest elevation in triglyceride level. Bile acid sequestrants commonly cause adverse gastrointestinal effects that can significantly affect compliance. However, they are safe and moderately effective (grade A).
Statin medications inhibit hydroxymethylglutaryl coenzyme A reductase, which is a rate-limiting enzyme in the endogenous cholesterol-synthesis pathway. This inhibition results in a decrease in the intracellular pool of cholesterol, which signals upregulation of LDL receptors and increased clearance of circulating LDL cholesterol. As a group, statins have been shown to reduce LDL cholesterol in children and adolescents with marked LDL cholesterol elevation or familial hypercholesterolemia (defined as elevated LDL cholesterol in the child in conjunction with a family history of elevated LDL cholesterol and/or atherosclerosis or CAD) when used from 8 weeks to 2 years for children aged 8 to 18 years. The lower LDL cholesterol level for eligibility into the statin trials was ≥190 or ≥160 mg/dL with ≥2 additional risk factors after a trial period on diet. Trial subjects were monitored carefully throughout treatment; adverse effects on growth, development, or sexual maturation were not seen, and adverse-event profiles and efficacy were similar to those in studies of adults (grade A).
Adverse effects from statins are rare at standard doses but include myopathy and hepatic enzyme elevation. In a meta-analysis of statin use in children, evidence of hepatic enzyme elevation and muscle toxicity did not differ between the statin and placebo groups. Routine monitoring of hepatic enzymes and clinical assessment for muscle toxicity are strongly recommended for children and adolescents on statin therapy (Table 9-12). The risk of adverse events increases with use of higher doses and interacting drugs; the latter occurs primarily with drugs that are metabolized by the cytochrome P-450 system, which is the primary mode of metabolism for the majority of statins. Drugs that potentially interact with statins include fibrates, azole antifungal agents, macrolide antibiotics, antiarrhythmic agents, and protease inhibitors (grade A).
Bile acid–binding sequestrants may be used in combination with a statin for patients who fail to meet LDL cholesterol target levels with either medication alone. One pediatric study assessed this combination and found no increase in adverse effects. The efficacy of the 2 agents together seems to be additive (grade B).
There is limited published experience in children of use of niacin and fibrates, which have been useful in treating adult patients with combined dyslipidemias. Efficacy and safety data are limited, and no data are available regarding newer formulations. In adults, cholesterol absorption inhibitors have been advocated as an adjunct to statin therapy for patients who do not reach LDL cholesterol therapeutic targets. Because their action is independent of and complementary to that of statins, the LDL cholesterol–lowering effect is additive. No pediatric studies of monotherapy with cholesterol absorption inhibitors had been published during the time period for this evidence review. The use of niacin, fibrates, and cholesterol absorption inhibitors should be instituted only in consultation with a lipid specialist (grade C).
Medication therapy is rarely needed for children with elevated triglyceride levels that respond well to weight loss and lifestyle changes (grade B) (Fig 9-2; Table 9-8). When triglyceride levels exceed 500 mg/dL, patients are at risk for pancreatitis and require care in consultation with a lipid specialist (grade B). In adults, use of ω-3 fish oil has been shown to lower the triglyceride level by 30% to 40% and to raise the HDL level by 6% to 17%. Experience with fish oil in children has been limited to small case series, and no safety concerns identified; there have been no RCTs of fish oil in children (grade D).
Age-Based Recommendations for Medication Therapy of Children with Dyslipidemia
The age-specific recommendations for pharmacologic management of dyslipidemia are summarized in Table 9-9. Children Younger Than 10 Years
Children younger than 10 years should not be treated with a medication unless they have a severe primary hyperlipidemia or a high-risk condition that is associated with serious medical morbidity (homozygous hypercholesterolemia/LDL cholesterol level of ≥400 mg/dL; primary hypertriglyceridemia with a triglyceride level of ≥500 mg/dL; evident CVD in the first 2 decades of life; post–cardiac transplantation) (grade C).
Children Aged 10 to 21 Years
Decisions regarding the need for medication therapy should be based on the average of results from at least 2 FLPs obtained at least 2 weeks but no more than 3 months apart (grade C) (Fig 9-1).
Children with an average LDL cholesterol level of ≥250 mg/dL or average triglyceride level of ≥500 mg/dL should be referred directly to a lipid specialist (grade B).
Children with lipid abnormalities should have a detailed family history taken and be assessed for causes of hyperlipidemia, additional risk factors, and risk conditions (grade C) (Tables 9-3, 9-6, and 9-7).
Children with lipid abnormalities (other than an LDL cholesterol level of ≥250 mg/dL or triglyceride level of >500 mg/dL) should be managed initially for 3 to 6 months with diet changes (CHILD-1 → CHILD-2–LDL or CHILD-2–TG) (Table 9-8) on the basis of specific lipid profile findings (Figs 9-1 and 9-2); if the BMI is at the ≥85th percentile, add increased physical activity, reduced screen time, and calorie restriction. Assessment for associated secondary causes (Table 9-3), additional risk factors, or high-risk conditions (Tables 9-6 and 9-7) is recommended. Children at high risk who are unlikely to achieve lipid targets with this strategy alone (severe primary dyslipidemia, post–cardiac transplantation) should concomitantly be considered for initiation of medication therapy (grade C) (see “DM and Other Conditions Predisposing to the Development of Accelerated Atherosclerosis”).
Children with an average LDL cholesterol level of ≥250 mg/dL should be referred directly to a lipid specialist (grade B).
If the LDL cholesterol level remains ≥190 mg/dL after a 6-month trial of lifestyle/diet management (CHILD-1 → CHILD-2–LDL) for children aged 10 years and older, statin therapy should be considered (grade A) (Fig 9-1; Table 9-11 and 9-12).
If the LDL cholesterol level remains ≥130 to <190 mg/dL in a child aged 10 years or older with a negative family history of premature CVD in first-degree relatives and no high- or moderate-level risk factor or risk condition (Tables 9-6 and 9-7), management should continue to be focused on diet changes (CHILD-2–LDL) on the basis of lipid profile findings (Fig 9-1) plus weight management if BMI is at the ≥85th percentile. Pharmacologic therapy is not generally indicated, but treatment with bile acid sequestrants might be considered, the latter in consultation with a lipid specialist (grade B).
If the LDL cholesterol level remains ≥160 to 189 mg/dL after a trial of lifestyle/diet management (CHILD-1 → CHILD-2–LDL) in a child aged 10 years or older with a positive family history of premature CVD/events in first-degree relatives (Table 9-6) or at least 1 high-level risk factor or risk condition or at least 2 moderate-level risk factors or risk conditions (Tables 9-6 and 9-7), then statin therapy should be considered (grade B) (Fig 3; Table 27).
If the LDL cholesterol level remains ≥130 to 159 mg/dL after a trial of lifestyle/diet management (CHILD-1 → CHILD-2–LDL) in a child aged 10 years or older with at least 2 high-level risk factors or risk conditions or at least 1 high-level risk factor or risk condition together with at least 2 moderate-level risk factors or risk conditions (Tables 21 and 22), then statin therapy should be considered (grade C) (Fig 9-1; Table 9-12).
For children aged 8 or 9 years with an LDL cholesterol level persistently ≥190 mg/dL after a trial of lifestyle/diet management (CHILD-1 → CHILD-2–LDL), together with multiple first-degree family members with premature CVD/events, or the presence of at least 1 high-level risk factor or risk condition or the presence of at least 2 moderate-level risk factors or risk conditions (Fig 9-1) (Tables 9-6 and 9-7), statin therapy might be considered (grade B) (Table 9-12)).
Statin use should begin with the lowest available dose given once daily. If LDL cholesterol target levels are not achieved with at least 3 months of compliant use, then the dose may be increased by 1 increment (usually 10 mg). If LDL cholesterol target levels are still not achieved with at least 3 months of compliant use, then the dose may be further increased by 1 increment. The risk and effectiveness of dose escalation have been explored in several of the clinical trials of statins in children, and no additional safety issues have been identified (grade B). Alternatively, a second agent such as a bile acid sequestrant or cholesterol absorption inhibitor may be added under the direction of a lipid specialist (grade B) (Table 9-12).
Children taking a statin should have routine clinical monitoring for symptoms of muscle toxicity and assessment of hepatic transaminases and creatine kinase (grade A) (Table 9-12).
Pediatric care providers should be on the alert for, and children and their families should be counseled about, potential medication interactions (grade D) (Table 9-12).
Females taking a statin should be counseled about risks associated with pregnancy and appropriate contraception strategies if indicated. Use of oral contraceptives in combination with statins is not contraindicated (grade D) (Table 9-12).
Children with elevated triglyceride or non-HDL cholesterol after control of LDL cholesterol are managed on the basis of lipid levels (Fig 9-2):
Children with average fasting triglyceride levels of ≥500 mg/dL or any single measurement of ≥1000 mg/dL related to a primary hypertriglyceridemia should be treated in conjunction with a lipid specialist; the CHILD-2–TG (Table 9-8) should be started, and use of fish oil, fibrate, or niacin to prevent pancreatitis should be considered (grade D) (Fig 9-2) (Tables 9-10 and 9-11).
Children with fasting triglyceride levels of ≥200 to 499 mg/dL after a trial of lifestyle/diet management with CHILD-1 → CHILD-2–TG (Table 9-8) should have non-HDL recalculated and be managed to a goal level of <145 mg/dL (grade D).
Children with fasting triglyceride levels of ≥200 to 499 mg/dL, non-HDL levels of >145 mg/dL, after a trial of lifestyle/diet management with CHILD-1 → CHILD-2–TG (Table 9-8) and increased fish intake, may be considered for fish-oil supplementation (grade D) (Table 9-10).
Children aged 10 years or older with non-HDL cholesterol levels of ≥145 mg/dL after the LDL cholesterol goal has been achieved may be considered for further intensification of statin therapy or additional therapy with a fibrate or niacin in conjunction with referral to a lipid specialist (grade D) (Fig 9-1) (Tables 9-10 and 9-11).
Children with severe or complex mixed dyslipidemias, particularly when multiple medications are being considered, should be referred for consultation with a lipid specialist (grade D) (Figs 9-1 and 9-2).
10. OVERWEIGHT AND OBESITY
The dramatic increases in childhood overweight and obesity in the United States since 1980 are an important public health focus. Despite efforts over the last decade to prevent and control obesity, recent reports from the National Health and Nutrition Examination Survey14 show sustained high prevalence; 17% of children and adolescents have a BMI at the >95th percentile for age and gender. The presence of obesity in childhood and adolescence is associated with increased evidence of atherosclerosis at autopsy and of subclinical measures of atherosclerosis on vascular imaging. Because of its strong association with many of the other established risk factors for cardiovascular disease, obesity is even more powerfully correlated with atherosclerosis; this association has been shown for BP, dyslipidemia, and insulin resistance in each of the major pediatric epidemiologic studies. Of all the risk factors, obesity tracks most strongly from childhood into adult life. Improvement in weight status and decrease in body fatness have been shown to be associated with improvement in all the obesity-related risk factors and in subclinical vascular changes. Higher BMI during childhood is directly associated with increased coronary heart disease in adult life. Extrapolation from current data suggests that adolescent obesity will likely increase adult coronary heart disease by 5% to 16% over the next 25 years with >100 000 excess cases of coronary heart disease attributable to increased obesity in childhood. The evidence review included RCTs, systematic reviews, meta-analyses, and observational studies that assessed the prevention and treatment of overweight and obesity in childhood and adolescence.
Identification of Overweight and Obese Children and Adolescents
To identify overweight and obesity in children living in the United States, BMI percentile distributions relative to gender and age on the Centers for Disease Control and Prevention (CDC) 2000 growth charts15 are now the preferred reference. The CDC growth charts were not developed as a health-related standard. Instead, the growth charts present percentiles of the BMI distribution derived from measurements taken during several National Health and Nutrition Examination Surveys as points of reference. Although the charts were published in 2000, they include selected data from the 1963 through 1980 surveys and, thus, are not representative of the US population in 2000. These BMI percentile growth charts provide the best reference data available for describing normal growth in US children. They are, however, a screening tool and not an instrument for the diagnosis of overweight and obesity.
An expert committee jointly convened by the American Medical Association (AMA), the CDC, and the Maternal and Child Health Bureau (MCHB) of the Health Resources and Services Administration (US Department of Health and Human Services)16 recently recommended that BMI be used to assess weight-for-height relationships in children. This conclusion was reached because BMI can be easily calculated from height and weight, correlates strongly with direct measures of body fat (especially at higher BMI values), associates only weakly with height, and identifies those with the highest body fat correctly with acceptable accuracy, particularly above the 85th BMI percentile. Pediatric care providers need a feasible standard for identifying overweight and obesity in their patients, because parents recognize a child's overweight status in fewer than half of the cases. The AMA/CDC/MCHB expert committee16 defined a BMI at the ≥95th percentile as obese and a BMI between the 85th and 94th percentiles as overweight; children in the latter BMI category have a great deal of variation with respect to prediction of future risk. The expert panel for these guidelines concluded that BMI is a sufficient measure for screening children and adolescents to identify those who need evaluation for cardiovascular risk factors associated with body adiposity. The expert panel also concluded that the scientific evidence linking elevated BMI to cardiovascular risk factors and morbidity is strong and well supported.
The expert panel therefore recommends that children and adolescents aged 2 to 18 years with a BMI at the ≥95th percentile be described as “obese” and identified as needing assessment for cardiovascular risk factors. For children with a BMI that falls between the 85th and 95th percentiles, the term “overweight” should be used, and the position of the child's BMI on the growth chart should be used to express concern regarding weight-for-height disproportion. It is important to follow the pattern of growth over time by using these cut points to identify children who require more frequent follow-up and further assessment rather than to assign a diagnosis. Some might feel that “obese” is an unacceptable term for children and parents, so as with all health conditions, the practitioner is encouraged to use descriptive terminology that is appropriate for each child and family and to provide a thorough explanation and discussion. Each patient and family should be considered on an individual basis in deciding how best to convey the seriousness of this issue and to develop management plans.
Conclusions of the Evidence Review on Prevention of Overweight and Obesity With Diet or Combined Diet and Physical Activity Interventions
The expert panel concluded that there is good evidence that the dietary behavior of children can safely be improved with interventions that result in lower saturated fat intake, reduced intake of sweetened beverages, and increased fruit and vegetable consumption. In a small number of studies, these changes were associated with lower BMI. No evidence that diets of this kind are harmful was identified. Most studies also had specific interventions aimed at changing physical activity behaviors, so it is difficult to separate benefits related to diet change alone. Although calorie balance is generally seen as a key issue for weight control, intervention studies that addressed both diet and physical activity had mixed results, perhaps because most of them offered relatively weak interventions at the community level rather than targeting individual at-risk youths.
The guideline recommendations for diet and nutrition for children at elevated cardiovascular risk (CHILD-1) (Table 5-1; “Nutrition and Diet”) specifically address optimizing the diet in each of these areas as well as increasing intake of whole grains and matching energy intake to growth and expenditure. For healthy children, implementation of the CHILD-1 dietary recommendations with monitoring of BMI and dietary intake over time should be all that is needed from a nutritional standpoint to prevent obesity. No additional recommendations are indicated on the basis of this evidence review.
Conclusions of the Evidence Review on Prevention of Overweight and Obesity With Physical Activity
A moderate number of RCTs have evaluated the effect of interventions that addressed only physical activity and/or sedentary behavior on prevention of overweight and obesity. In a small number of these studies, the intervention was effective. It should be noted that these successful interventions often addressed reduction in sedentary behavior rather than attempts to increase physical activity. In a majority of the studies there was no significant difference in body-size measures. Sample sizes were often small, and follow-up was often short (frequently <6 months). It is suggested that gender-specific programs might be more successful in changing activity behavior. Overall, the expert panel concluded that on the basis of the evidence review, increasing activity in isolation is of little benefit in preventing obesity. By contrast, the review suggests that reducing sedentary behavior might be beneficial in preventing the development of obesity. The activity recommendations in the guideline specifically address limiting sedentary behavior and increasing physical activity in all children. Guidance on amounts and intensity of physical activity and limitations on sedentary screen time are provided in the recommendations in “Physical Activity.” On the basis of this evidence review, no additional specific recommendations addressing physical activity in preventing obesity are indicated.
Summary of the Evidence Review of Children at Increased Risk for Overweight and Obesity
Certain populations of children who are of normal weight are at risk for developing overweight and obesity as they grow older. Observational studies have identified risk factors that put these children at greater risk; however, research is lacking regarding an appropriate intervention. Despite that fact, epidemiologic associations suggest that primary care providers should be alert to increasing BMI trends and excessive weight gain beyond what is anticipated for height increase when dealing with these children and consider intervention before the child becomes overweight.
Observational studies have identified sample populations that are at special risk for obesity:
children with a BMI between the 85th and 95th percentiles;
children in whom there is a positive family history of obesity in 1 or both parents;
early onset of increasing weight beyond that appropriate for increase in height, which can be identified early (beginning in the first year of life);
excessive increase in weight during adolescence, particularly in black girls; and
children who have been very active and then become inactive or adolescents who are inactive in general (an example would be a child who previously participated in organized sports and has stopped, particularly in adolescence).
No RCTs that addressed these populations were identified. Despite this fact, the expert panel believes that lifestyle recommendations with a goal of prevention of excessive weight gain are needed for normal-weight children with characteristics consistent with special risk for development of overweight and obesity. The diet and activity recommendations proposed for children at elevated cardiovascular risk (“Nutrition and Diet”; “Physical Activity”) should be vigorously reinforced in these children. In any child, the development of a BMI between the 85th and 95th percentile should be taken as a sign that increased attention to diet and activity as well as BMI-specific follow-up is indicated.
Conclusions and Grading of the Evidence Review on Treatment of Obesity
There is good evidence for the effectiveness of combined weight-loss programs that included behavior-change counseling, negative energy balance through diet, and increased physical activity in addressing obesity in children older than 6 years with a BMI at the ≥95th percentile and no comorbidities (grade A). However, such programs have been effective primarily in a comprehensive weight-loss program or in research settings; only a small number have been shown to be effective in primary care settings.
No data were identified on weight-loss programs for children younger than 6 years.
No single negative-energy diet plan was identified from the evidence review. Dietary plans should be determined for each child on the basis of baseline body size, energy requirements for growth, and physical activity level (grade D).
Increasing dietary fiber from corn bran, wheat flour, wheat bran, oat flakes, corn germ meal, or glucomannan does not significantly improve weight loss (grade A).
Various diets, including low-glycemic-load diets, low-carbohydrate diets, fiber supplements, and protein-sparing modified fasts, have not been adequately studied as to their effects on obesity in children and adolescents.
For children aged 6 to 12 years:
Family-based programs in research settings that addressed both diet and activity have been shown to be effective at initiating and sustaining weight loss over a follow-up of 10 years (grade A).
The greatest weight loss is achieved when parents are the focus of the intervention (grade A).
Comprehensive programs in research settings were effective at achieving weight loss in the short-term (grade A).
The greatest weight change was achieved when the adolescent was the primary focus of the intervention (grade B).
Behavior-change programs that involved peers resulted in more sustained weight loss (grade B).
In overweight and obese youth, the combination of diet and a specific physical activity intervention that reduced sedentary activity and/or increased physical activity was universally more effective at achieving decreases in weight and BMI as well as decreases in body fat compared with an isolated diet intervention:
In both children and adolescents, exercise training improved weight loss and body composition (decreasing fat mass and reducing visceral fat), decreased insulin resistance, reduced BP, normalized dyslipidemia, and normalized subclinical measures of atherosclerosis (grade A).
In children aged 7 to 12 years, reduction in sedentary activity independent of increasing physical activity produced weight loss (grade B). In this age group, reductions in sedentary activity were effectively accomplished by rewarding children for time spent being physically active with TV-viewing time (grade B).
Girls did not respond as well as boys to combined treatments that both reduced sedentary behaviors and increased physical activity (grade B).
For adolescents with or without significant comorbidities and a BMI at the >95th percentile and for adolescents with a BMI of >35 who have failed to lose weight in a comprehensive lifestyle weight-loss program, addition of medication under the care of a physician experienced in managing weight loss with medication can be safe and effective in achieving weight loss with follow-up of 4 to 12 months. However, long-term safety and efficacy data are not available:
In adolescents with severe obesity and insulin resistance, the addition of metformin to a comprehensive lifestyle weight-loss program improved fasting insulin levels and significantly reduced weight and BMI (grade B). (Metformin is currently approved by the US Food and Drug Administration [FDA] for pediatric patients aged 10 years or older with T2DM but is not approved for weight loss for either children or adults.)
For obese adolescents older than 12 years, the addition of orlistat to a comprehensive lifestyle weight-loss program improved weight loss and BMI (grade A); however, use of this medication had a high rate of adverse gastrointestinal effects. (Orlistat [under the trade name Xenical (Roche Pharmaceuticals, Nutley, NJ)] is approved by the FDA for weight loss in pediatric patients 12 years of age and older in conjunction with a reduced-calorie diet. In August 2009, the FDA released an early communication about an ongoing safety review regarding reports of liver-related adverse events in some patients taking orlistat. In May 2010, the orlistat labeling was updated to incorporate safety information pertaining to the occurrence of rare postmarketing cases of severe liver injury, including hepatic failure that resulted in liver transplant or death.)
Dropout rates are substantial for all weight-treatment programs.
No studies defining an appropriate rate for weight loss in any age group were identified by the guidelines evidence review. The 2010 DGA8 recommends slowing weight gain while allowing normal growth and development. For those with a BMI at the >95th percentile without comorbidities, both the AMA/CDC/MCHB expert committee and the AAP16 recommend weight maintenance resulting in decreasing BMI as age increases. With a BMI at the >95th percentile with comorbidities, the AMA/CDC/MCHB expert committee and the AAP16 recommend gradual weight loss not to exceed 1 lb/month in children aged 2 to 11 years or 2 lb/week in adolescents (no grade).
For adolescents with a BMI far above 35 and associated comorbidities, bariatric surgery on a research protocol in conjunction with a comprehensive lifestyle weight-loss program improved weight loss, BMI, and other outcomes such as insulin resistance, glucose tolerance, and cardiovascular measures in small case series (grade D).
The recommendations for management of overweight and obesity are listed in Table 10-1.
11. DM AND OTHER CONDITIONS PREDISPOSING TO THE DEVELOPMENT OF ACCELERATED ATHEROSCLEROSIS
DM is an established risk factor for early CVD. Metabolically, DM is characterized by hyperglycemia caused by defects in insulin secretion (T1DM) and insulin function and/or secretion (T2DM). Both T1DM and T2DM are associated with vascular disease. Results of autopsy and noninvasive imaging studies suggest that the extent of vascular involvement reflects the duration of the disease and the severity of the chronic metabolic derangement. The epidemiologies of the 2 types differ significantly. T1DM presents at a younger age; 25% of patients are diagnosed between the ages of 5 and 10 years and another 40% between the ages of 10 and 15 years. If not treated adequately, the degree of hyperglycemia is severe, and patients are highly symptomatic. By contrast, with T2DM, the majority of patients present in adult life, but a small and growing number present in adolescence, and most are relatively asymptomatic with only mild-to-moderate hyperglycemia in combination with obesity. Regardless of these differences, children with DM, type 1 or 2, are at significantly increased risk for accelerated atherosclerosis and early CVD.
In certain other pediatric disease states, the process of atherosclerosis is dramatically accelerated with clinical coronary events occurring in childhood and very early adult life. These conditions were the subject of a recent guideline from the American Heart Association (AHA).17 The expert panel elected to use the AHA guideline as a template for developing recommendations for children with conditions such as DM that predispose them to very accelerated atherosclerosis, because the evidence review identified only a small number of studies that addressed these conditions in an RCT.
Conclusions of the Evidence Review for DM and Other Predisposing Conditions
Children with DM, T1DM or T2DM, represent the prototype of the child at special risk for accelerated atherosclerosis and early clinical CVD. To maximize identification of T2DM in childhood and adolescence, the screening algorithm from the American Diabetes Association18 is recommended for screening in all children (Table 11-1).
Limited high-quality studies that addressed cardiovascular risk reduction in children with conditions predisposing them to accelerated atherosclerosis were found, so the expert panel elected to modify the recommendations of an expert pediatric panel convened by the AHA that published its recommendations for risk-factor management in 2006; these recommendations have been endorsed by the AAP and are included in the guideline database for these guidelines.17
The authors of the AHA statement recommended specific risk identification and management stratified according to risk on the basis of defined other conditions that parallel the recommendations for adults with DM or other CVD equivalents. For those in the high-risk category (Table 11-2), the disease process has been associated with clinical coronary disease before 30 years of age. For those in the moderate-risk category, the disease process has been shown to be associated with pathologic, physiologic, or subclinical evidence of accelerated atherosclerosis.
The expert panel believes that these recommendations should be used for the management of children and adolescents with DM and other predisposing conditions as outlined in the algorithm in Fig 11-1 and in Tables 11-2 and 11-3. With the growing evidence of vascular disease in children with T2DM, the expert panel felt that it was prudent to include both T1DM and T2DM in the high-risk category. With increasing evidence of vascular dysfunction in children with HIV infection and nephrotic syndrome, these 2 conditions have been added to the selected disease settings in the moderate-risk category. Patients in the high-risk category require intensive management with more aggressive goals for therapy than those in the moderate-risk category, as outlined in the algorithm.
12. RISK-FACTOR CLUSTERING AND THE METABOLIC SYNDROME
Traditional cardiovascular risk factors such as obesity, hypertension, and dyslipidemia demonstrate clustering in youth. Risk behaviors such as smoking, suboptimal diet, and sedentary behavior also demonstrate clustering, as do advantageous diet and exercise habits. Becoming obese increases the prevalence of the risk-factor cluster in adults called the metabolic syndrome. The metabolic syndrome is defined as ≥3 of the following risk factors: elevated waist circumference, triglyceride levels, BP, and/or fasting glucose level and reduced HDL cholesterol level. In the United States, the metabolic syndrome is said to affect between 34% and 39% of adults, including 7% of men and 6% of women in the 20- to 30-year-old age group. The expert panel reviewed all the RCTs, systematic reviews, meta-analyses, and observational studies that addressed the childhood association between the risk-factor cluster known as the metabolic syndrome and the development of atherosclerosis, and the identification and management of the cluster in children and adolescents.
There is a lack of consensus on how to define metabolic syndrome in youth, which has led to widely varying estimates of its frequency. A recent analysis of National Health and Nutrition Examination Survey data from 1999 to 200219 yielded prevalence estimates for all teens from 2.0% to 9.4% and for obese teens from 12.4% to 44.2%. Regardless of the definition used, the prevalence of the metabolic syndrome risk-factor cluster is higher in older (12- to 14-year-old) compared with younger (8- to 11-year-old) children. The specific etiology of metabolic syndrome is unknown; however, it is most likely caused by the expression of various genotypes modified by environmental interactions and mediated through abdominal obesity and insulin resistance. Longitudinal studies of cohorts in which the metabolic syndrome cluster was present in childhood identified an increased incidence of both T2DM and clinical cardiovascular events over a follow-up period of 25 years.4 A strong association between obesity with or without elevated insulin levels and/or hypertension in early childhood and subsequent development of the metabolic syndrome constellation in adulthood has been consistently demonstrated. Treatment of cardiovascular risk-factor clustering in youth has not been thoroughly evaluated, but maintenance of low levels of cardiovascular risk factors starting in childhood is associated with a lower prevalence of CVD and increased longevity in adult life.
RECOMMENDATIONS FOR MANAGEMENT OF RISK-FACTOR CLUSTERING AND THE METABOLIC SYNDROME
The metabolic-syndrome concept is important, because it identifies a common multiple cardiovascular-risk phenotype in pediatrics. However, the absence of a defined etiology, the lack of consensus on definition, and the paucity of high-level evidence addressing management in childhood led the expert panel to conclude that the metabolic syndrome should not be considered as a separate risk factor in childhood and adolescence. Prevention of obesity is the most important strategy for lowering the prevalence of metabolic syndrome in adults, and this seems strongly applicable in childhood (see “Overweight and Obesity”). Given the strong relationship of obesity and physical inactivity to the metabolic syndrome and insulin resistance, the expert panel makes the following recommendations. Because of the paucity of evidence available, the recommendations are a consensus of the expert panel (grade D).
The presence of any combination of multiple risk factors should prompt intensification of therapy with an emphasis on lifestyle modification to address individual metabolic syndrome risk-factor levels.
The presence of obesity should prompt specific evaluation for all other cardiovascular risk factors including family history of premature CVD, hypertension, dyslipidemia, DM, and tobacco exposure.
The coexistence of obesity with any other major cardiovascular risk factor should be recognized by clinicians as a setting in which:
intensive weight reduction should be undertaken per the recommendations in “Overweight and Obesity,” along with management of identified risk factors including initiation of pharmacologic therapy, per the risk-factor–specific sections in these guidelines (“High BP”; “Lipids and Lipoproteins”; “DM and Other Conditions Predisposing to the Development of Accelerated Atherosclerosis”; “Tobacco Exposure”); and
prompt evaluation for DM, liver-function abnormalities, left ventricular hypertrophy, and sleep apnea should be undertaken.
These recommendations are supported by the knowledge that cardiovascular morbidity has a continuous relationship across the risk-distribution spectrum and that a youth with multiple borderline risk factors might, in fact, have risk equivalent to a person with extreme abnormality of a single major risk factor. A presentation such as this should lead to intense nutrition and exercise management with close follow-up, and if lifestyle intervention is unsuccessful, consideration should be given to endocrine referral. Table 12-1 provides definitions of component risk-factor levels for evaluating children with multiple cardiovascular risk factors.
13. PERINATAL FACTORS
Increasing evidence links prenatal exposures to adverse health outcomes. Perinatal risk reduction is an area in which pediatric care providers can potentially be effective, because they are often the only physicians whom a mother sees between pregnancies. The expert panel identified 3 potential areas for consideration: maternal obesity; choice of neonatal feeding method; and maternal smoking cessation. Maternal obesity is associated with gestational DM, higher birth weight, childhood obesity measured by increased BMI, and increased risk of the metabolic syndrome and T2DM in offspring. However, the expert panel could not identify any prepregnancy or postpartum studies that addressed maternal obesity in a pediatric care setting, and more general approaches to preventing or treating obesity in women of reproductive age are beyond the scope of this report. A detailed discussion of childhood obesity itself is the subject of “Overweight and Obesity.” With regard to choice of neonatal feeding method, the cardiovascular advantages of breastfeeding as the primary source of nutrition for infants are emphasized in “Nutrition and Diet.” Therefore, the evidence review for this section is focused on maternal smoking cessation.
Conclusions and Grading of the Evidence Review on Maternal Smoking Cessation
The expert panel found that strong evidence supports a benefit for interventions directed at maternal smoking cessation during pregnancy (grade A). Weaker evidence suggests that these interventions do not prevent relapse after delivery. Trials of cessation in the postpartum period, which would be the most applicable to pediatric providers, have been limited in number and suggest that for maternal smoking cessation to be sustained, specific continued support in the pediatric care setting is required.
No smoking-cessation interventions have resulted in any reported adverse effects related to the interventions (no grade).
The expert panel believes that pediatric care providers can play a role in helping mothers to remain smoke-free or to quit smoking in the interpregnancy interval. For most women, this interval will extend to the early first trimester of any subsequent pregnancy. The pediatric well-child schedule calls for ∼10 visits in the first 2 years of life, and mothers attend most of those visits, so the pediatric care provider usually sees women in this period more than any other health care professional. Pediatric care providers often have a sustained relationship with the mother and her infant, and many already advocate for parental smoking cessation in their efforts to promote a smoke-free environment for children. Pediatric providers and/or their staff need to be trained to either deliver or refer to a long-term maternal smoking-cessation program (no grade).
Recommendations for maternal smoking cessation are listed in Table 13-1.
- Accepted September 8, 2011.
- Address correspondence to Janet M. de Jesus, MS, RD, 31 Center Dr, Building 31, Room 4A17, MSC 2480, Bethesda, MD 20892. E-mail:
FINANCIAL DISCLOSURE: Dr Daniels has served as a consultant for Abbott Laboratories, Merck, and Schering-Plough and has received funding/grant support for research from the National Institutes of Health (NIH); Dr Gidding has served as a consultant for Merck and Schering-Plough and has received funding/grant support for research from GlaxoSmithKline; Dr Gillman has given invited talks for Nestle Nutrition Institute and Danone and has received funding/grant support for research from Mead Johnson, Sanofi-Aventis, and the NIH; Dr Gottesman has served on the Health Advisory Board, Child Development Council of Franklin County, was a consultant to Early Head Start for Region 5B, has written for iVillage and taught classes through Garrison Associates for the State of Ohio, Bureau of Early Intervention Services and Help Me Grow program, and has received funding/grant support for research from the NIH; Dr Kwiterovich has served as a consultant or advisory board member for Merck, Schering-Plough, Pfizer, Sankyo, LipoScience, and Astra Zeneca, has served on speaker's bureaus for Merck, Schering-Plough, Pfizer, Sankyo, Kos, and Astra Zeneca, and has received funding/grant support for research from Pfizer, Merck, GlaxoSmithKline, Sankyo, and Schering-Plough; Dr McBride has served as a consultant or advisory board member for Bristol-Myers Squibb and Merck and has served on speaker's bureaus for Kos, Merck, and Pfizer but declares no relevant relationships since July 2007; Dr McCrindle has been a consultant for Abbott, Bristol-Myers Squibb, Daichii Sankyo, and Roche, owns stock in CellAegis and reports funding/grant support for research from Astra Zeneca, Sankyo, Merck, Schering-Plough, and the NIH; Dr Urbina reports funding/grant support for research from Merck, Schering-Plough, Sankyo, and the NIH; and Dr VanHorn has provided advice to Chartwells School Food Service and has received funding/grant support for research from General Mills and the NIH. Drs Benuck, Christakis, Dennison, O'Donnell, Rocchini, and Washington have indicated they have no financial relationships relevant to this article to disclose.
Funded by the National Institutes of Health (NIH).
- CVD —
- cardiovascular disease
- NHLBI —
- National Heart, Lung, and Blood Institute
- RCT —
- randomized controlled trial
- PDAY —
- Pathobiological Determinants of Atherosclerosis in Youth
- BP —
- blood pressure
- HDL —
- high-density lipoprotein
- DM —
- diabetes mellitus
- CIMT —
- carotid intima-media thickness
- LDL —
- low-density lipoprotein
- T1DM —
- type 1 diabetes mellitus
- T2DM —
- type 2 diabetes mellitus
- TC —
- total cholesterol
- AAP —
- American Academy of Pediatrics
- DGA —
- Dietary Guidelines for Americans
- NCEP —
- National Cholesterol Education Program
- DASH —
- Dietary Approaches to Stop Hypertension
- CHILD —
- Cardiovascular Health Integrated Lifestyle Die
- FLP —
- fasting lipid profile
- CDC —
- Centers for Disease Control and Prevention
- AMA —
- American Medical Association
- MCHB —
- Maternal and Child Health Bureau
- FDA —
- Food and Drug Administration
- AHA —
- American Heart Association
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- Copyright © 2011 by the American Academy of Pediatrics