Association of allergic diseases and attention-deficit/hyperactivity (ADHD) disorder in children: a large-scale cohort study.

BACKGROUND

The burden of attention-deficit/hyperactivity disorder (ADHD) has increased during the last few decades, as in allergic disorders. In some observational studies, ADHD has been linked to allergic diseases, but the evidence remains limited.

OBJECTIVE

The aim of this study was to investigate whether allergic disorders are associated with ADHD in a large cohort of patients.

MATERIAL AND

METHODS

Data from this cohort were retrieved from 860,089 children aged 5-16 years, collected from the pediatric database of Health Services in İzmir, Turkey, between January 1, 2013 and December 31, 2023, and analyzed. The person-years and the association between allergic disorders (including respiratory, skin, and other allergies, such as food and drug allergies as well as anaphylaxis) and ADHD were estimated using relative risks.

RESULTS

The incidence of allergic disorders in the last 11 years was 7.9% (68,351 cases). Respiratory allergies (61,728; 6.8%) were the most common one, followed by skin allergies (7,152; 0.9%). The incidence of ADHD was determined as 5.3% and, as expected, was more common in boys (7.2%). The total number of patients with allergic diseases diagnosed prior to ADHD was 64,137 (7.5%), and the most common were respiratory allergies (57,905; 6.7%) and skin allergies (6,602; 0.8%). The other allergy group comprised 1,878 (0.2%) cases. The relative risk estimations showed a positive association between allergy groups and ADHD (relative risk [RR] 1.99, 95% Confidence Interval [CI] 1.96-2.02) for both genders.

CONCLUSION

An association is observed between allergic disorders and ADHD. Understanding the link and relationship between allergic disorders and the development of ADHD will lead to earlier diagnosis and better treatment of allergic children with neurodevelopmental symptoms. To establish this association more robustly, further population-based cohorts are required.