OBJECTIVES: This study examined racial/ethnic, socioeconomic, and geographic disparities in children's exposure to environmental tobacco smoke (ETS) or secondhand smoke in the home.
METHODS: The 2007 National Survey of Children's Health (N = 90 853) was used to calculate the prevalence of children's exposure to ETS. State-level data on home smoking ban from the 2006–2007 Current Population Survey–Tobacco Use Supplement were used to supplement analyses. Logistic regression was used to estimate adjusted odds of exposure.
RESULTS: In 2007, 7.6% of US children, or 5.5 million children, lived in households where someone smoked inside the home. The prevalence varied from a low of 1.1% for Utah and 1.9% for California to a high of 17.9% for West Virginia and 17.6% in Kentucky. After adjustment for sociodemographic factors, children in Ohio, West Virginia, Kentucky, and Pennsylvania had 12 times higher odds and those in Wisconsin, Missouri, Delaware, and the District of Columbia had 10 times higher odds of being exposed to ETS than children in Utah. Compared with children from higher socioeconomic backgrounds, Hispanic ethnicity, and non–English-speaking households, children from lower socioeconomic backgrounds had 7.3 to 10.6 times higher adjusted odds; non-Hispanic white, black, American Indian, and mixed-race children had 2.0 to 2.6 times higher odds; and children from English-speaking households had 4.1 times higher odds of ETS exposure.
CONCLUSIONS: Considerable disparities exist in children's exposure to ETS, with geographic pattern strongly related to home smoking ban. Greater exposure to ETS among children in several states and disadvantaged socioeconomic groups is likely to exacerbate existing health disparities.
- children's exposure to ETS
- secondhand smoke
- geographic disparity
- socioeconomic status
- home smoking ban
- United States
WHAT'S KNOWN ON THIS SUBJECT:
Exposure to ETS causes respiratory problems in children and is associated with increased risk for sudden infant death syndrome, respiratory infections, ear problems, and childhood asthma. Few studies have examined detailed racial/ethnic, socioeconomic, and state-level disparities in children's exposure to ETS.
WHAT THIS STUDY ADDS:
In 2007, 7.6% of US children—5.5 million—were exposed to ETS in homes, and 19.1 million (26.2%) children lived in households with a smoker. Considerable disparities exist in children's exposure to ETS, with geographic pattern strongly related to home smoking ban.
Exposure to environmental tobacco smoke (ETS) or secondhand smoke can have serious health consequences for children.1,2 Studies have shown that secondhand smoke exposure causes respiratory problems in children and is associated with increased risk for sudden infant death syndrome, acute respiratory infections, ear problems, and more frequent and severe asthma attacks in children.1,2 For children, most of the exposure to tobacco smoke occurs in the home,1 and presence of a smoker in the home or a parent who smokes has been shown to be a strong predictor of adolescent smoking behavior.3,4
Current cigarette smoking rates have declined substantially across most age, gender, racial/ethnic, and socioeconomic groups in the United States during the past 3 decades.5 Rates of parental smoking and smoking in the home have also declined, although only a few studies have examined detailed social and geographic disparities in these smoking outcomes, particularly at the national level.6,–,8 Only 1 previous study examined state-level differences in childhood exposure to secondhand smoke at home, albeit indirectly, by using survey data on ETS from the mid-1990s.7 Lack of information on children's exposure to household smoke is partly because periodic national health surveys, such as the National Health and Nutrition Examination Surveys and the National Health Interview Surveys, do not collect data on ETS routinely.9,10 Because of small sample sizes and/or a lack of geographic identifiers, these surveys also do not permit state-specific estimates.9,10 The newly released 2007 National Survey of Children's Health (NSCH), with its large sample size and extensive demographic, socioeconomic, geographic, and health data, offers an opportunity to estimate ETS exposure rates among children at the state level while simultaneously taking into account geographic differences in sociodemographic characteristics.11,12
Given the harmful health effects of ETS exposure among children, it is important to know, by using latest statistics, which states or demographic groups have relatively high rates of exposure. Such information is vital to the design and implementation of effective tobacco control programs at both the national and state levels aimed at curbing smoking rates in general and reducing children's exposure to secondhand smoke in particular. The purpose of this study was (1) to provide the latest prevalence estimates of children's exposure to smoking inside the home across major racial/ethnic and socioeconomic groups and in the 50 states and the District of Columbia by using the 2007 NSCH and (2) to examine the extent of social and geographic disparities in children's exposure to secondhand smoke after controlling for relevant characteristics.
The data for this study came from the 2007 NSCH.11,–,13 The survey was conducted by the Centers for Disease Control and Prevention's National Center for Health Statistics, with funding and direction from the Health Resources and Services Administration's Maternal and Child Health Bureau.11,12 The purpose of the survey was to provide national and state-specific prevalence estimates for a variety of children's health and well-being indicators.11,12 The survey also included an extensive array of questions about the family, including parental health, stress and coping behaviors, family activities, and parental concerns about their children.11,12
The 2007 NSCH was a telephone survey conducted between April 2007 and July 2008.10,11 It had a total sample size of 91 642 children from birth through 17 years of age, including a sample of ∼1800 children per state.13 A random-digit-dial sample of households with children who were younger than 18 years was selected from each of the 50 states and the District of Columbia. One child was selected from all children in each identified household to be the subject of the survey. Interviews were conducted in English, Spanish, and 4 Asian languages. The respondent was the parent or guardian who knew most about the child's health status and health care. The interview completion rate, measuring the percentage of completed interviews among known households with children, was 66.0%.12,13 Substantive and methodologic details of the survey are described elsewhere.13 The National Center for Health Statistics Research Ethics Review Board approved all data collection procedures. Verbal informed consent for survey participation was obtained, informing respondents of the voluntary nature of the survey and confidentiality protection of their responses.13
The dependent variable, exposure to ETS or secondhand smoke, was derived from the following questions asked of parents: “Does anyone in your household use cigarettes, cigars, or pipe tobacco?” “Does anyone smoke inside child's home?” Analysis was conducted for 90 853 children who were younger than 18 years and for whom this information was available.12
Besides state of residence (including the 50 states and the District of Columbia), we considered the following variables as covariates: child's age (0–5, 6–8, 9–11, 12–14, and 15–17 years), gender, race/ethnicity (non-Hispanic white, non-Hispanic black, Hispanic, American Indian, Asian, Pacific Islander, non-Hispanic mixed race, and other), household composition (2-parent biological or step-families, single mother, and other), metropolitan/nonmetropolitan residence, primary language spoken at home (English or any other language), household poverty status measured as a ratio of family income to federal poverty level (FPL; <100%, 100%–199%, 200%–399%, and ≥400%), and parental education (<12, 12, 13–15, and ≥16 years).1,6,7
Approximately 0.7% of the observations had missing data on household smoking, which were excluded from the analysis. Nine percent of the observations had missing income data, which were imputed by a multiple imputation technique.13 For all other demographic covariates, there were few or no missing cases, which were excluded from the multivariate analyses.
State-level data on home smoking ban for adults aged ≥18 years were derived from the 2006–2007 Current Population Survey–Tobacco Use Supplement to supplement analyses of the NSCH data.14 Home smoking ban was based on the question, “Which statement best describes the rules about smoking inside your home: (1) no one is allowed to smoke anywhere inside your home; (2) smoking is allowed in some places or at some time inside your home; (3) smoking is permitted anywhere inside your home.” The percentage of adults with the response “no one is allowed to smoke anywhere inside the home” represented the rate of home smoking ban. Home smoking ban was defined as a household-imposed ban and applied to all people in the household.
Estimates of the percentage of children who were exposed to secondhand smoke were computed for all 50 states and the District of Columbia. The χ2 statistic was used to test the overall association between each covariate, including state of residence, and exposure. The t statistic was used to test the difference in prevalence between any 2 states or sociodemographic groups. Multivariate logistic regression models were used to derive the odds and adjusted prevalence of exposure for each state in 2007 after controlling for selected sociodemographic factors. To account for the complex sample design of the NSCH, we used SUDAAN software15 to conduct regression analyses and to determine prevalence estimates and corresponding SEs.
Table 1 shows the prevalence of ETS exposure by state and sociodemographic factors. In 2007, 7.6% of US children lived in households where someone smoked inside the home. This prevalence varied from a low of 1.1% for Utah and 1.9% for California to a high of 17.9% for West Virginia and 17.6% in Kentucky. Ohio, Oklahoma, Mississippi, District of Columbia, Pennsylvania, Missouri, and Tennessee also had a high prevalence that ranged from 13.2% to 16.4%. The prevalence was generally higher in the Midwestern and Southern states than in the Western states (Fig 1).
Exposure to secondhand smoke was greater among older than among younger children; the prevalence ranged from 4.9% for children who were younger than 6 years to 11.6% for adolescents aged 15 to 17 years. Exposure to secondhand smoke varied significantly by race/ethnicity. More than 10% of black, American Indian, and mixed-race children lived in households where someone smoked in the home, compared with 1.6% of Asian children, 2.6% of Hispanic children, and 8.0% of non-Hispanic white children. The prevalence of exposure to secondhand smoke at home exceeded 12% for children in low-education and low-income families, for children who lived in nonmetropolitan areas, and for children in single-mother and step-family households.
Because states vary substantially in their racial/ethnic and socioeconomic composition, the adjusted odds ratios and prevalence in Table 1 are more appropriate for state comparisons. The adjustment for socioeconomic factors reduced geographic disparities and accounted for a 56% reduction in the variance of state-specific prevalence estimates. Specifically, children in Ohio, West Virginia, Kentucky, and Pennsylvania had 12 times higher odds and those in Wisconsin, Missouri, Delaware, and District of Columbia (adjusted prevalence: >10.2%) had 10 times higher odds of being exposed to secondhand smoke than children in Utah (adjusted prevalence: 1.3%). The other states that showed at least 75% higher adjusted odds of exposure (with an adjusted prevalence higher than the national prevalence) than Utah include Arkansas, Louisiana, North Carolina, Nebraska, New Jersey, New York, Ohio, and Texas (Table 1).
After adjustment for state of residence and socioeconomic factors, non-Hispanic white, black, American Indian, and mixed-race children had 2.0 to 2.6 times higher odds of exposure to secondhand smoke at home than Hispanic children. Children below the FPL had 7.3 times higher adjusted odds of being exposed to secondhand smoke than children with family incomes at ≥400% of the FPL. Children with parental education of <12 years had 10.6 times higher adjusted odds of exposure than children whose parents had a college degree. Children from English-speaking households had 4.1 times higher odds of exposure from secondhand smoke than children from non–English-speaking households.
Disparities in Risks for ETS Exposure Among Children Who Lived in Households With a Smoker
Overall, 19.1 million (26.2%) US children who were younger than 18 years lived in households where someone smoked either inside or outside the home or both. Of these children, 29.0% were exposed to ETS at the national level (Table 2). Geographic, racial/ethnic, and socioeconomic patterns in ETS exposure among children from only households with a smoker were similar to those in overall ETS exposure rates estimated for all children. The prevalence of ETS exposure among children from smoking households varied from a low of 9.8% in California and 9.9% in Utah to a high of 52.3% for the District of Columbia and 46.8% for West Virginia. Prevalence also exceeded 40% for Ohio, Kentucky, Pennsylvania, and Wisconsin.
The adjusted odds of ETS exposure, estimated only among smoking households, were 5.5 to 6.5 times higher among children in West Virginia, Wisconsin, Pennsylvania, Ohio, and Kentucky than children in Utah (Table 2). Fifty percent of black children and more than one-third of children from low-income and low-education families in smoking households were exposed to ETS. Their adjusted odds of ETS exposure were 3.0 to 3.6 times higher than those for Hispanic children and children from high-income and high-education households.
Using a large, nationally representative cross-sectional survey—the 2007 NSCH—we examined the extent to which children's exposure to tobacco smoke inside the home varied across the 50 states and the District of Columbia and among various racial/ethnic and socioeconomic groups. We found that 7.6% of US children (5.5 million children) in 2007 were exposed to ETS in homes. Among 19.1 million US children who lived in households with at least 1 smoker, the risk for ETS exposure was even higher, 29%. Considerable social and geographic disparities exist in the reported exposure, with children from some ethnic minority groups and socioeconomically disadvantaged groups being particularly vulnerable to greater exposure. Children in low-income and low-education households had 7.3 and 10.6 times higher odds of being exposed to secondhand smoke than children from high-income and high-educational attainment households, respectively. Children from English-speaking households and non-Hispanic white, black, American Indian, and mixed-race children were substantially more likely to be exposed to smoking inside the home. Moreover, children in West Virginia, Kentucky, Ohio, Pennsylvania, Wisconsin, Missouri, Delaware, and the District of Columbia were at a considerably increased risk for exposure.
Children's exposure to ETS has declined over time. According to the 1994 National Health Interview Survey, 35% of children lived in homes where someone smoked in the home on a regular basis, compared with our estimate of 7.6% in 2007.6 Decreases in parental smoking, increases in household smoking restrictions, and a greater awareness of adverse health effects of ETS have been suggested as possible factors for this sharp decline.1 The declining trend in childhood exposure to ETS has clearly followed the trends in rates of home smoking ban, which have increased consistently from 43% in 1992–1993 to 61% in 1998–1999 to 77.8% in 2006–2007.14 Geographic patterns in ETS seem to have changed very little over time, however. A 1997 Centers for Disease Control and Prevention study, which indirectly derived childhood ETS exposure from the Behavioral Risk Factor Surveillance System and Current Population Survey, found higher prevalence of ETS in Kentucky, West Virginia, Tennessee, District of Columbia, and Ohio and lowest prevalence in Utah and California.7 These patterns are consistent with the most recent pattern shown in our study.
Geographic patterns in children's exposure to smoking in the home were strongly related to those in home smoking ban (Fig 1). West Virginia, Kentucky, and Ohio, which topped the list with the highest secondhand smoke exposure rates, also happened to be the states with the lowest rates of home smoking ban in 2006–2007. Similarly, Utah, California, Oregon, and Washington, with the lowest secondhand smoke exposure rates, rank at the top among the states with the highest home smoking ban rates. The correlation coefficient between these 2 state-level variables was −0.91.
Racial/ethnic and socioeconomic patterns in childhood exposure to ETS reported in our study are consistent with those noted previously.1,6 In the 1994 National Health Interview Survey, white and black children had higher exposure rates than Hispanic children, and children with lower household socioeconomic status (SES) had substantially higher exposure rates than children from higher SES backgrounds6; however, despite that rates of ETS exposure fell substantially for all racial/ethnic and socioeconomic groups between 1994 and 2007, the socioeconomic gradients in ETS exposure seemed to be steeper in our study, because the rate of exposure for children in the lower SES households declined at a slower pace than for children in the higher SES groups. Similar temporal patterns have also been noted for smoking in the general population, where men and women in the higher education and income groups have experienced more rapid declines in their smoking rates over time than their lower SES counterparts.5
Because parental smoking behavior has been shown to influence adolescents' smoking behavior,3,4 it is important to encourage parents and other adults in the household to quit smoking. Parental smokers with younger and adolescent children should be especially encouraged to stop smoking, given the serious health risks associated with children's exposure to ETS in the home and a strong likelihood of adolescents' taking up smoking themselves if exposed to smoking at home.3,4,6 Although all children would benefit from a smoke-free home environment, parents of children in certain demographic groups, such as those in black, American Indian, and low-SES households and in the Midwestern and Southern states, may especially be targeted for smoking cessation efforts and reduced ETS exposure.
Given that a child who is younger than 18 years, on average, makes 2 primary care visits per year for preventive medical care12 and a child who is younger than 2 years makes 4.5 doctor visits per year,16 pediatricians, family physicians, and other primary care providers are in a key position to provide education and counseling to parents during such visits on the dangers of household smoking and children's ETS exposure and advising them to stop smoking.17 There is evidence to suggest that such education and counseling efforts may be effective intervention strategies for reducing tobacco use among adults6,17; however, a national study in 2001 found that only approximately half of all parents who visited a pediatrician or family practitioner for their child's primary care were asked about smoking status of household members.17 Even fewer parents were asked regarding rules about smoking in the home.17 Fewer than half of parental smokers reported being counseled by pediatricians and family practitioners about harmful health effects of secondhand smoke or received advice to quit smoking.17
A few potential limitations of our study should be noted. First, our dependent variable is based on the assumption that presence of someone who smokes inside the home necessarily results in exposure of children to secondhand smoke.1,2 This is, however, a fairly reasonable assumption given that home is the predominant location of exposure for children. Second, our measure of exposure in the home does not fully capture total exposure to secondhand smoke because it does not include potential exposure to secondhand smoke at other sites, such as vehicles, playgrounds, restaurants, and malls. Third, our exposure measure does not include duration or intensity (or number of smokers or number of cigarettes smoked in the household) of exposure.6 Fourth, because all NSCH data were based on parental reports, the prevalence of household smoking and ETS exposure in the home may be underreported; however, previous research showed that questionnaire-based surveys of the general population provide a reliable estimate of smoking status when cotinine measurement is used for validation, without systematic differentials in underreporting by socioeconomic groups.18,19 The amount of misclassification (proportion of self-reported nonsmokers with increased cotinine levels indicative of active smoking) is found to be very low in most population-based studies.20
Documenting geographic and social-group disparities in exposure to household smoking is essential to tracking the nation's progress toward reducing the excess morbidity and mortality burden associated with tobacco use and toward meeting the overall health objective of reducing and/or eliminating health inequities across population subgroups.1,21 Given the substantial adverse health effects of ETS, marked racial/ethnic, socioeconomic, and geographic disparities in exposure to secondhand smoke shown here are likely to exacerbate health inequalities among children. The revised national target for reducing the childhood exposure to tobacco smoke at home has been set at 6% for the year 2010.22 Our findings suggest that, to meet this objective, considerable effort is needed at the national and state levels to reduce exposure among children in a number of racial/ethnic and socioeconomic groups as well as in the majority of states. Although public health campaigns and educational efforts may be needed to promote smoke-free homes, anti-smoking policies that place greater smoking restrictions or legislate against smoking in cars, playgrounds, restaurants, and other public places to reduce further adult smoking prevalence and children's exposure to secondhand smoke can be launched at the national, state, and local levels.1,6,22
- Accepted March 31, 2010.
- Address correspondence to Gopal K. Singh, PhD, Maternal and Child Health Bureau, Health Resources and Services Administration, US Department of Health and Human Services, 5600 Fishers La, Room 18-41, Rockville, MD 20857. E-mail:
The views in this article are those of the authors and do not necessarily represent the views of the Health Resources and Services Administration or the US Department of Health and Human Services.
FINANCIAL DISCLOSURE: The authors have indicated they have no financial relationships relevant to this article to disclose.
- ETS =
- environmental tobacco smoke •
- NSCH =
- National Survey of Children's Health •
- FPL =
- federal poverty level •
- SES =
- socioeconomic status
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Food Allergies: Myths and Realities: A recent study commissioned by the federal government and reported on in The New York Times (Kolata G, May 11, 2010) reveals that a number of research studies on food allergies are poorly done, and are rife with misdiagnoses and tests that give misleading results. While 30 percent of the population believes they have a food allergy, only about 8 percent of children and less than 5 percent of adults actually do, according to Dr Marc Riedl, one of the study's authors who is an allergist and immunologist at University of California, Los Angeles. More than 12 000 articles were reviewed for this study and yet only 72 met study criteria—having sufficient data for analysis and using rigorous tests for diagnoses. The study, published in The Journal of the American Medical Association (Chafen JJ, Newberry SJ, Riedl MA, et al. Diagnosing and managing common food allergies. JAMA. 2010;303(18):1848–1856), will hopefully help the National Institute of Allergy and Infectious Diseases (NIAID) as they develop better guidelines for diagnosing and treating food allergies, a project currently in progress. Authors of the study and experts working on the new guidelines note that even the idea that breast-fed babies have fewer allergies or that babies should avoid eggs in their first year of life lack strong evidence. Dr Matthew J. Fenton, who is overseeing the national guidelines project for the NIAID, recommends that doctors not use either the skin-prick test or an IgE antibody test as the sole reason to believe these patients have a food allergy, given that these antibodies can be transient and inconsequential. Confirming the diagnosis with alternative methods such as a food challenge test is certainly a better way to diagnose a food allergy—although a food challenge can be quite time consuming and may scare patients if they are asked to consume a food they suspect they are allergic to. Thus we are itching to read the new guidelines on food allergies as soon as they become available.
Noted by JFL, MD
- Copyright © 2010 by the American Academy of Pediatrics