Muneaki Matsuo

Background In children, relationships between developmental disorders such as attention‐deficit hyperactivity disorder (ADHD) and autism spectrum disorder and allergic diseases remain controversial, because these diseases show age‐ and sex‐related differences. A proper understanding of the relationships between developmental disorders and allergic diseases should improve medical care for both diseases. We confirmed the prevalence of allergic diseases in elementary school‐age children with developmental disorders by grade and sex. Methods The subjects were 446 lower grade and 312 upper grade elementary school‐age children who had visited our hospital. The prevalence of allergic diseases among subjects with and without developmental disorders by grade and sex was examined using the diagnostic names on medical records. Results The prevalence of allergic diseases was significantly higher in lower grade boys and girls with developmental disorders than in those without developmental disorders (boys: OR 3.22, 95%; CI 1.49–6.95; girls: OR: 3.87, 95% CI: 1.27–11.82). The prevalence of allergic diseases was significantly higher in higher grade boys with developmental disorders than in those without developmental disorders (OR: 3.46, 95% CI: 1.59–7.53). Multiple logistic regression analysis in lower grades revealed that ADHD correlated with bronchial asthma (adjusted OR: 3.72, 95% CI: 1.42–9.69) and that autism spectrum disorder correlated with atopic dermatitis (adjusted OR: 4.26, 95% CI: 1.36–13.36). Analyses of children in the upper grades showed that ADHD correlated with atopic dermatitis (adjusted OR: 5.06, 95% CI: 1.28–20.05). Conclusions Elementary school‐age children with developmental disorders were more likely to have allergic diseases. The types of allergic diseases related to developmental disorders differed by grade and sex.