A NEW study using Mendelian randomisation (MR) has revealed a potential causal link between attention-deficit hyperactivity disorder (ADHD) and childhood allergic diseases. While previous observational studies have reported associations between these conditions, this is the first investigation to use genetic evidence to explore whether ADHD may directly increase the risk of allergies in children.
Researchers conducted a two-sample bidirectional MR analysis, drawing on large-scale genome-wide association studies (GWAS) involving 38,691 individuals with ADHD and 5,337 with childhood allergy. The primary analysis method, inverse-variance weighting, indicated that ADHD is significantly associated with an increased risk of allergic diseases in children, with an odds ratio of 1.14 and a p-value of 0.017. This means children with ADHD may be 14% more likely to develop allergies than those without the condition.
To explore possible biological mechanisms, the team also conducted a two-step MR mediation analysis to assess whether gut microbiota or serum metabolites might play a mediating role. However, no evidence was found to support their involvement in the pathway linking ADHD and allergy. This suggests that the relationship may be due to a direct neuroimmune interaction rather than being mediated by gut-related factors.
The findings provide genetic evidence supporting the theory that the nervous and immune systems may interact more closely in children with ADHD, influencing their susceptibility to allergic responses. This insight has important clinical implications. Early identification and monitoring of allergic diseases in children diagnosed with ADHD could lead to more effective management and prevention strategies.
Overall, this study represents a significant advance in understanding the link between neurodevelopmental and immunological conditions. By using robust genetic methods, it strengthens the argument for a direct, biological connection between ADHD and allergy, and paves the way for future research into shared pathways and targeted interventions.
Reference
Liu M et al. Attention-Deficit Hyperactivity Disorder and Childhood Allergy: Evidence From Mendelian Randomization. Child Care Health Dev. 2025;51(4):e70135.
