Association of attention-deficit/hyperactivity disorder and atopic diseases: a case-control study

Background: Data on the association between attention-deficit/hyperactivity disorder (ADHD) and atopic diseases have been inconclusive. We assessed whether children using ADHD medication are more likely to receive drug treatment for asthma, allergic rhinitis, and/or eczema than children not using ADHD medication. Methods: We conducted a retrospective nested case-control study among children between 6 and 12 years of age using the IADB.nl prescription database. Cases were defined as children with at least two prescriptions of methylphenidate within 12 months. Cases were matched to four controls on age, sex, and area code. We further assessed the exposure of parental use of medication for ADHD and atopic diseases as a predicting parameter on receiving ADHD medication in childhood. Conditional logistic regression analysis was applied to obtain odds ratios and corresponding 95 % confidence intervals (CI). Results: We identified 4257 children, drug-treated for ADHD, and 17,028 controls. Drug treatment for asthma, allergic rhinitis, and eczema were more common in cases than controls with odds ratios of 1.4 (95 % CI 1.3-1.6), 1.4 (95 % CI 1.1-1.8) and 1.3 (95 % CI 1.1-1.5), respectively. Association of parental use of medication for atopy on receiving ADHD medication in the offspring (OR: 1.1: 95 % CI 1.0-1.2) was higher in cases compared to controls, but lower than the association between medication for atopy and ADHD in the child (OR: 1.4: 95 % CI 1.2-1.5) (p = 0.006). Conclusion: This study provides further evidence on the hypothesis that ADHD is associated with atopic diseases. Our results suggest that the association may have a genetic component.