title: Prevalence of attention-deficit/hyperactivity disorder in patients with pediatric allergic disorders: a nationwide, population-based study.
abstract: BACKGROUND
  Allergic disorders are common, chronic conditions in pediatric populations. The characteristic symptoms of allergic disorders mainly include bronchial asthma (BA), allergic rhinitis (AR), and atopic dermatitis (AD), all of which may disturb sleep, leading to daytime inattention, irritability, and hyperactivity, which are also components of attention-deficit/hyperactivity disorder (ADHD). Conflicting data exist in the literature regarding the relationship between ADHD and allergic disorders. The aim of this nationwide, population-based study is to examine the prevalence and risk of developing ADHD among allergic patients in a pediatric group.
  
  
  METHODS
  Data from a total of 226,550 pediatric patients under 18 years of age were collected from Taiwan's National Health Insurance Research Database recorded from January 1 to December 31, 2005 and analyzed. We calculated the prevalence of allergic diseases based on various demographic variables, including ADHD. We also used multivariable logistic regression to analyze the risk factors of ADHD.
  
  
  RESULTS
  In 2005, the period prevalence rates of allergic disorders and ADHD in persons under the age of 18 were 21.5% and 0.6%, respectively. Pediatric patients with allergic disorder(s) had a substantially increased rate of developing ADHD (p < 0.001) in terms of period prevalence and odds ratio (OR). This significance existed across various demographic groups regardless of age, gender, location, or degree of urbanization of their residence. BA and AR, but not AD, were determined to be risk factors for ADHD. Co-morbidities of allergic disorders, including AR+AD, AR+BA and AR+BA+AD, but not BA+AD, were also determined to increase the risk of ADHD.
  
  
  CONCLUSIONS
  Allergic disorders appear to increase the risk of ADHD in pediatric patients. Our detailed analysis shows that the main contributing factor is AR. Co-morbidity with AD, BA, and BA+AD in AR patients further increases the risk of ADHD.
authors.affiliation: Division of Immunology and Nephrology, Department of Pediatrics, Taichung Veterans General Hospital, Taichung City, Taiwan.
authors.forename: Ching-Shan
authors.initials: CS
authors.lastname: Shyu
authors.forename: Heng-Kuei
authors.initials: HK
authors.lastname: Lin
authors.forename: Ching-Heng
authors.initials: CH
authors.lastname: Lin
authors.forename: Lin-Shien
authors.initials: LS
authors.lastname: Fu
mesh_terms: D000293:Adolescent; D001249:Asthma / Q000453:epidemiology*; D001289:Attention Deficit Disorder with Hyperactivity / Q000453:epidemiology* / Q000276:immunology; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D003876:Dermatitis, Atopic / Q000453:epidemiology*; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D016017:Odds Ratio; D015995:Prevalence; D012221:Rhinitis, Allergic, Perennial / Q000453:epidemiology*; D012306:Risk; D013624:Taiwan / Q000453:epidemiology