Is atopy in early childhood a risk factor for ADHD and ASD? a longitudinal study.

OBJECTIVE

Previous studies have found a temporal concordance in the increased prevalence of atopic diathesis/atopic diseases, attention-deficit hyperactivity disorder (ADHD), and autistic spectrum disorder (ASD) worldwide. But, the temporal association among these 3 distinct diseases is unknown.

METHOD: 14,812 atopic subjects diagnosed with any atopic disease (asthma, atopic dermatitis, allergic rhinitis, or allergic conjunctivitis) before the age of 3 (atopic cohort) and 6944 non-atopic subjects with no lifetime atopic disease (non-atopic cohort), born between 1997 and 2000, were enrolled and followed to December 31, 2010 to identify the development of ADHD and ASD.

RESULTS

The presence of any atopic disease in early childhood increased the risk of developing ADHD (hazard ratio [HR]: 1.97) and ASD (HR: 3.40) in later life. Greater numbers of atopic comorbidities (4 comorbidities: ADHD: HR: 2.53; ASD: HR: 4.29) were significantly related to a greater risk of developing ADHD and ASD.

DISCUSSION: Atopic diathesis in early childhood elevated the risk of developing ADHD and ASD in later life, with the dose-dependent relationship of more atopic comorbidities with a greater likelihood of ADHD and ASD.