OBJECTIVE: To determine sociodemographics, patterns of comorbidity, and function of US children with reported epilepsy/seizure disorder.
METHODS: Bivariate and multivariable cross-sectional analysis of data from the National Survey of Children’s Health (2007) on 91 605 children ages birth to 17 years, including 977 children reported by their parents to have been diagnosed with epilepsy/seizure disorder.
RESULTS: Estimated lifetime prevalence of epilepsy/seizure disorder was 10.2/1000 (95% confidence interval [CI]: 8.7–11.8) or 1%, and of current reported epilepsy/seizure disorder was 6.3/1000 (95% CI: 4.9–7.8). Epilepsy/seizure disorder prevalence was higher in lower-income families and in older, male children. Children with current reported epilepsy/seizure disorder were significantly more likely than those never diagnosed to experience depression (8% vs 2%), anxiety (17% vs 3%), attention-deficit/hyperactivity disorder (23% vs 6%), conduct problems (16% vs 3%), developmental delay (51% vs 3%), autism/autism spectrum disorder (16% vs 1%), and headaches (14% vs 5%) (all P < .05). They had greater risk of limitation in ability to do things (relative risk: 9.22; 95% CI: 7.56–11.24), repeating a school grade (relative risk: 2.59; CI: 1.52–4.40), poorer social competence and greater parent aggravation, and were at increased risk of having unmet medical and mental health needs. Children with prior but not current seizures largely had intermediate risk.
CONCLUSIONS: In a nationally representative sample, children with seizures were at increased risk for mental health, developmental, and physical comorbidities, increasing needs for care coordination and specialized services. Children with reported prior but not current seizures need further study to establish reasons for their higher than expected levels of reported functional limitations.
- ADHD —
- attention-deficit/hyperactivity disorder
- ASD —
- autism spectrum disorder
- CI —
- confidence interval
- MADDSP —
- Metropolitan Atlanta Developmental Disabilities Surveillance Program
- NSCH —
- National Survey of Children’s Health
- RR —
- relative risk
What’s Known on This Subject:
Epilepsy/seizure disorder is known to be associated with a range of mental health and neurodevelopmental comorbidities, based on clinical studies, and on population studies largely conducted outside the United States.
What This Study Adds:
In a nationally representative sample of US children, estimated prevalence of reported lifetime epilepsy/seizure disorder was 1%, and of current epilepsy/seizure disorder was 6.3/1000. Developmental, mental health, and physical comorbidities are common, warranting enhanced surveillance, and an integrated service approach.
Epilepsy/seizure disorder is the most common childhood neurologic condition,1 and a major public health concern.2 Children diagnosed with epilepsy face considerable challenges. The seizures themselves, especially when poorly controlled, may be disabling and interfere with the child’s ability to learn, whereas secondary influences, such as stigma and lack of knowledge about the condition can negatively affect social and psychological function.3–5 In addition, children with epilepsy frequently exhibit comorbidities that affect developmental progress and emotional health, including attention-deficit/hyperactivity disorder (ADHD),6–8 learning disabilities,9–11 depression, and anxiety.1,12–16 Knowledge of the epidemiology of childhood epilepsy and of current functioning of children with this condition will help inform the development of systems of care that move beyond a narrow focus on seizure control to address implications of the condition for the child’s social, emotional, and developmental well-being.3
Most studies of childhood epilepsy in the United States have been conducted on subjects recruited from general and specialist medical settings, so may be biased toward inclusion of children with the most complex clinical pictures.17 Population-based studies, with subjects recruited from nonmedical community-based settings have generally been based on local samples,2 with limited ability to examine a wide range of potential comorbidities and functional attributes, or have been conducted outside the United States.18 Identifying and characterizing the full range of comorbidities in people with epilepsy has been identified as a National Institute of Neurologic Disorders and Stroke Epilepsy Research Benchmark.19 To address this gap in knowledge, we used data from the 2007 National Survey of Children’s Health (NSCH) to estimate the prevalence of reported epilepsy/seizure disorder for US children, and to examine comorbid mental health/developmental disorders, physical health conditions, and child and family functioning. To our knowledge, this is the first national study to estimate prevalence of reported epilepsy/seizure disorder in US children and to examine patterns of reported comorbidity.
The 2007 NSCH was conducted as a module of the State and Local Area Integrated Telephone Survey by the National Center for Health Statistics. The study used a stratified random-digit-dial sampling design to achieve a nationally representative sample of 91 642 parents of children 0 to 17 years of age. One child was randomly selected from each household and interviews were conducted with the parent or guardian who knew most about the child’s health and health care. Interviews lasting ∼30 minutes were conducted in English and Spanish. The overall weighted response rate was 51.2% (American Association of Public Opinion Rate 4).
The sample for this study included 91 605 children ages birth to 17 with nonmissing data on the question about lifetime epilepsy/seizure disorder. There is some variability in the final study sample for each different comorbid condition/functioning indicator owing to missing data, and because certain measures were not relevant and/or not asked for infants or very young children. Questions about learning disability were asked only of children ages 3 to 17 years, questions about severe headaches were asked only of children ages 6 to 17 years, and questions about oral health problems were asked only of children ages 1 to 17 years. Height/weight data were restricted to children ages 10 and older because of concerns about the validity of parent report for younger ages.20 School functioning and social competence were measured only for children ages 6 to 17. Questions about mental health treatment were asked only of children older than 24 months, and special education services only of children aged 6 to 17 years.
To produce population-based estimates, data records for each interview were assigned a sampling weight. NSCH sampling weights adjust for stratification by geographic area and various forms of nonresponse, including poststratification to match population control totals on key demographic variables obtained from Census Bureau data. Further details on the design and operation of NSCH are reported elsewhere.20 This study was granted exempt status by the University of California Los Angeles Institutional Review Board.
Lifetime Epilepsy or Seizure Disorder
Parents were asked if a doctor or health care provider ever told them that their child had epilepsy or seizure disorder, and if so, if their child currently had epilepsy or seizure disorder. Children were categorized as never diagnosed with epilepsy/seizure disorder, currently diagnosed, or previously but not currently diagnosed.
Mental Health and Developmental Indicators
Children were identified as having comorbid mental health/developmental disorders if the parent reported that the child currently had depression, anxiety, attention-deficit disorder/ADHD, conduct problems, learning disability, developmental delay, or autism/autism spectrum disorder (ASD).
Physical Health Indicators
Measures of physical health included parent report of a child currently having a hearing or vision problem and currently having asthma. Additional measures included a health care provider telling the parent the child had migraine headaches in the past year; hay fever/respiratory allergy, food/digestive allergy, or eczema/skin allergy; and 3 or more ear infections. Obesity was defined as a BMI in the 95th percentile and above according to Centers for Disease Control and Prevention growth charts.20 Oral health problems were assessed by parent report of whether the child had decayed teeth or cavities, broken teeth, or bleeding gums in the past 6 months.
Functional Health Indicators
Parents reported an activity restriction (yes/no) if the child was “limited or prevented in any way in his/her ability to do the things most children of the same age can do.” School functioning was assessed by parent report of whether the child had ever repeated a grade, and contact in the past year by the school about problems. Social competence was measured by parent ratings of how often the child shows respect for teachers and neighbors; gets along well with other children; tries to understand others’ feelings; and tries to resolve conflicts with classmates, family, and friends. Items were summed to create a composite following criteria established by previous research21; scores <12 on the 16-point scale identified children with low social competence. The Aggravation in Parenting scale22 measures stress in parenting through 3 items where parents rate how often the child was much harder to care for than other children; does things that really bothers them; and how often they felt angry with him or her. Items were summed to create a scale ranging from 0 to 12, and scores above 6 (corresponding with an answer of “sometimes” for each item) identified parents with high aggravation.
Service Use and Access Indicators
Parents reported whether their child received preventive medical care at least 1 time in the past 12 months, and mental health treatment or counseling. Children ages 6 to 17 years were coded as receiving special education if parents reported an Individualized Educational Program (IEP). Children were coded as having an unmet health need if their parent reported that during the past 12 months, the child needed health care but care was delayed or not received. The medical home variable was constructed by researchers at the Child and Adolescent Health Measurement Initiative.23 The following criteria must be met for presence of a medical home: (1) having a personal doctor or nurse, (2) having a usual place for sick/well care, (3) presence of family-centered care, (4) no trouble obtaining needed referrals, and (5) receipt of needed care coordination.
Study covariates included household income in relation to the federal poverty level, family structure, race/ethnicity, highest parent education, child age in years, and child gender. Missing data on household income were imputed following routines from National Center for Health Statistics.20
All statistical analyses were performed using Stata (version 11.0; Stata Corp, College Station, TX). Survey estimation procedures were applied and the Taylor-series linearization method adjusted the standard errors for the complex survey design. We present prevalence estimates for comorbid conditions, functioning, and service use by epilepsy/seizure disorder status (never diagnosed, current epilepsy/seizure disorder, previously diagnosed). Bivariate associations were examined using χ2 tests with post hoc pairwise comparisons between selected categories. Regression models added controls for sociodemographics. Relative risks were estimated using generalized linear models with a Poisson distribution and log link.24
Prevalence and Sociodemographics of Epilepsy/Seizure Disorder
The estimated lifetime prevalence of epilepsy/seizure disorder was 10.2 per 1000 (95% confidence interval [CI]: 8.7–11.8), or 1%, and current epilepsy/seizure disorder was 6.3 per 1000 (95% CI: 4.9–7.8), or 0.6%. After adjustment for sociodemographics, lifetime epilepsy/seizure disorder was more common in children from families with income <100% federal poverty level (relative risk [RR]: 1.95; CI: 1.16–3.27) (Table 1). There was no relationship between childhood epilepsy and family structure, race/ethnicity, or parent educational level. Prevalence of lifetime epilepsy/seizure disorder (and also current epilepsy, data not shown) increased with age. Epilepsy/seizure disorder was more common in boys (RR: 1.38; CI: 1.03–1.84).
Epilepsy/Seizure Disorder Comorbidity
Compared with children never diagnosed, children with current epilepsy/seizure disorder were more likely to experience mental health and developmental comorbidities (Table 2). Depression (8% vs 2%), anxiety (17% vs 3%), ADHD (23% vs 6%), conduct problems (16% vs 3%), learning disability (56% vs 7%), developmental delay (51% vs 3%), and autism/ASD (16% vs 1%) were all significantly more likely in children with current epilepsy (P < .05). Each of these conditions was also reported more frequently in children with previously but not currently diagnosed epilepsy/seizure disorder (eg, depression [7% vs 2%], developmental delay [17% vs 3%], autism/ASD [7% vs 1%]).
Compared with children never diagnosed, children with current epilepsy/seizure disorder were more likely to experience a range of physical health comorbidities including hearing or vision problems (22% vs 2%), asthma (18% vs 9%), headaches (14% vs 5%), allergies (43% vs 26%), ear infections (11% vs 6%), and poor oral health (Table 3). Children with a former epilepsy/seizure disorder diagnosis also had elevated risks. Epilepsy/seizure disorder status was not associated with obesity.
Epilepsy/Seizure Disorder and Function
Compared with children never diagnosed, children with current epilepsy/seizure disorder were more likely to have limited activity (RR: 9.22; CI: 7.56–11.24), grade repetition (RR: 2.59; CI: 1.52–4.42), school problems (RR: 1.63; CI: 1.26–2.10), low social competence (RR: 2.16; CI: 1.61–2.90), and high levels of parent aggravation (RR: 2.46; CI: 1.54–3.93) after adjustment for sociodemographics (Table 4). Children previously but not currently diagnosed with epilepsy/seizure disorder also had greater risks of poorer function across all domains, in each case with an intermediate level of risk (eg, activity limitation [RR: 2.92; CI: 2.14–4.00], grade repetition [RR: 1.55; CI: 1.05–2.27], high parent aggravation [RR: 2.19; CI: 1.44–3.32]).
Epilepsy/Seizure Disorder and Service Use and Access
Compared with children never diagnosed, children with current epilepsy/seizure disorder were more likely to access mental health treatment (RR: 3.07; CI: 2.25–4.20) and special education services (RR: 6.39; CI: 5.44–7.50) (Table 5). They were reported to be as likely to attend preventive health visits as children never diagnosed, less likely to report receiving care in a medical home (RR 0.72; CI: 0.54–0.96), and more likely to report unmet needs for care coordination, medical care, and mental health services. Children with a former epilepsy/seizure disorder diagnosis also had elevated unmet care coordination needs.
The estimated lifetime prevalence of epilepsy/seizure disorder among children in the United States in 2007 was 10.2 per 1000 (1%). Prevalence of current epilepsy/seizure disorder was 6.3 per 1000, corresponding to just over 450 000 children ages birth to 17 years nationwide. Children with current seizures are at increased risk for mental health, developmental, and physical comorbidities, as well as functional disabilities. They are less likely to receive care in a medical home, and are at increased risk for having unmet needs for medical and mental health services. Children reported to have previous but not current epilepsy/seizure disorder also had more reported comorbidities and functional limitations, but at lower levels than children with active seizure disorders.
Direct comparison with other prevalence studies is hampered by different methods of case ascertainment, study samples (local versus national), case definitions, and cohort ages. These estimates are slightly higher than the 6.0 to 7.7 per 1000 lifetime prevalence of childhood epilepsy among 10-year-olds from the 1995 Metropolitan Atlanta Developmental Disabilities Surveillance Program (MADDSP),2 and prevalences reported from other developed countries, possibly reflecting a broader case definition.25–32 Consistent with prior studies, epilepsy was more prevalent in boys,2 and in lower-income families,33–35 yet there were no differences based on race/ethnicity or household educational level. The prevalence of current epilepsy/seizure disorder was higher in older age cohorts. Lack of data on age of onset of seizures precluded separation of incident cases, expected to decrease with age,36,37 from prevalent cases in each age group.
Our study reports the most comprehensive analysis to date of comorbidities in a nationally representative sample of US children with epilepsy. Compared with MADDSP (1995), which reported 35% prevalence of any of 4 comorbid developmental disabilities (mental retardation, cerebral palsy, visual or hearing impairment) among children with lifetime epilepsy,2 we observed a 50% prevalence of developmental delay and 56% prevalence of learning disabilities among children with current epilepsy/seizure disorder. Rates of learning disability among children with epilepsy have varied in the literature from 25% to 76%,10,11,38 depending on case definitions and populations studied. Consistent with prior studies, we also observed a strong association between epilepsy and autism/ASD, and a weaker association with ADHD, suggesting a need for investigation of potential common genetic and environmental etiologic factors.39–41 Observed associations with depression and anxiety are consistent with current literature.1,12–14,16,42 Qualitative studies show parents of children with epilepsy to be largely aware of their children’s emotional and behavioral difficulties, but are frustrated with inadequate services5 and stigma associated with accessing mental health care, particularly among minority families.43 Reported unmet needs, and lack of a medical home approach, suggest that the existing system of care is not fully responsive to these issues.
Physical health associations of epilepsy/seizure disorder have not been well studied. Reported associations with asthma, allergies, and ear infections could reflect common etiologic factors (eg, immune-mediated response, environmental triggers, genetic predisposition), but must be interpreted with caution, as parents may have preferential recall for these conditions, especially if related to seizure onset or exacerbations, or frequent contact with physicians more likely to assign these diagnoses. Our study confirmed reported associations with headaches.44–46 Researchers have suggested that migraine and epileptic attacks could represent a clinical continuum resulting from altered cortical hyperexcitability.47 Children with a prior history of seizures who have continuing headaches could be an important population to study in relation to this hypothesis.
Most prior studies of school performance in childhood epilepsy have relied on subjects recruited from medical settings, with almost all showing increased likelihood of academic difficulties.9,38,48,49 High rates of school problems and grade repetition in our community-based sample support calls for further study of possible neuropsychological deficits, including declines in processing speed50 and vulnerabilities in working memory in children with seizures.51 One study suggests there may be a “window” early after onset of seizures to ameliorate impact on school performance.52 We also need more information on specific contributors to problems with social competence, and ways to compensate for or adapt to these deficits.
Almost 40% of children in our study previously diagnosed with epilepsy/seizure disorder were not reported by parents to currently have the condition. Although these data could reflect a true remission of seizure activity, they could result from an initial “misdiagnosis” of epilepsy/seizure disorder, inclusion of some children with single febrile seizures, or variation in interpretations of the terms “current” versus “ever” having seizures. Other studies have reported children with a history of prior epilepsy to have worse behavior problems, lower social competency, slower processing speeds, and worse reading and spelling abilities.53,54 It is not possible within the limitations of the NSCH dataset to answer the important question of whether it is only those children who have additional neurologic conditions (eg, cerebral palsy), who have increased risks of comorbidities and functional limitations, even if seizures are reported to resolve. Our finding of higher frequency of comorbidities compared with children never reported to have seizures suggests that children with a previous history of epilepsy remain a clinically important, potentially vulnerable group that warrants further longitudinal study.
Adults with epilepsy have high reported rates of mental health and developmental comorbidities, including learning disability,11 anxiety,55,56 depression, and suicidal ideation57,58; and physical comorbidities including severe headaches, asthma, heart disease,59 and arthritis.60 High rates of unemployment61 and lower educational achievement62 are reported frequently. Pathways to poorer adult functioning have been attributed to the effects of recurrent seizures, medications, and social stigma, but altered neurodevelopment of the brain starting very early in the life course may play a role.63 More research is needed to determine whether early intervention to address cumulative comorbidities could disrupt what appear to be complex and continuing pathways to poorer health outcomes in adulthood.
Study limitations include reliance on parent report, susceptible to recall bias and inaccuracies, for assigning children to diagnostic categories, and the cross-sectional nature of the data that preclude any inferences about direction of observed associations. Parent report has been widely used in the literature to give valid estimates of childhood neurodevelopmental conditions,64–66 and our estimated prevalences were in the same general range as those obtained from MADDSP using different methods of case ascertainment.2 Our study lacked data on different subtypes of epilepsy/seizure disorder (eg, absence, Lennox Gastaut), etiology, frequency or duration of seizures, age at onset or remission, use of medications or other treatment modalities, or whether children had seen a neurologist, or were diagnosed with additional neurologic conditions. We could not exclude children who had received a “misdiagnosis” of epilepsy or seizure disorder; however, the strengths of this study, including the large, nationally representative nature of the study sample, coupled with rich data on a wide range of potential comorbid conditions and measures of child and family function, balance if not outweigh these potential shortcomings. The findings likely reflect patterns of morbidity encountered by community-based pediatricians in daily practice.
The estimated 1% prevalence of lifetime epilepsy/seizure disorder for the US child population is slightly higher than prior estimates. High levels of developmental and mental health comorbidities reported for children with current epilepsy/seizure disorder underscore the need for a proactive approach to the prevention of comorbidities, and a more structured approach to early detection and management.67 Further study of the pathophysiologic processes contributing to the development of comorbid conditions may provide clues to the etiology of individual epilepsy/seizure disorders. Children with reported previous but not current epilepsy appear to continue to manifest higher rates of neurodevelopmental comorbidities and as a clinical populations are in need of more detailed characterization.
Dr Halfon was supported in part by funding from the Maternal and Child Health Bureau of the Health Resources and Services Administration for the University of California Los Angeles National Center for Education in Maternal and Child Health Alliance for Information on Maternal and Child Health Child and Adolescent Policy Center.
- Accepted October 13, 2011.
- Address correspondence to Shirley A. Russ, MD, MPH, University of California Los Angeles Center for Healthier Children, Families, and Communities, 10990 Wilshire Blvd, Suite 900, Los Angeles, CA 90024. E-mail:
FINANCIAL DISCLOSURE: The authors have indicated they have no financial relationships relevant to this article to disclose.
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- Copyright © 2012 by the American Academy of Pediatrics