Congenital hypothyroidism and risk of subsequent autism spectrum disorder and attention‐deficit/hyperactivity disorder in Taiwan

Aim Evidence suggests an association between maternal hypothyroidism and risk of attention‐deficit/hyperactivity disorder (ADHD) or autism spectrum disorder (ASD) in offspring. We examined the risk of ASD and ADHD in individuals with congenital hypothyroidism (CHT). Methods A nationwide population‐based cohort study enrolled a total of 1260 children younger than 12 years with a confirmed diagnosis of CHT and no prior diagnosis of any neurodevelopmental disorders, selected from the National Health Insurance Research Database of Taiwan between 1998 to 2013. In addition, 12,600 controls matched for sex, age, and residence were selected. Cox proportional hazards analysis was used to investigate the association among CHT, ASD, and ADHD. Results Children with CHT were associated with a higher incidence of ASD (7.1‰ vs 1.3‰, P < 0.001) and ADHD (39.7‰ vs 18.7‰, P < 0.001) than the control group. Cox regression analyses demonstrated that children with CHT were associated with elevated risks of ASD (hazard ratio [HR], 4.72 [95% confidence interval (CI), 2.08–10.70]) and ADHD (HR, 2.03 [95% CI, 1.49–2.77]), after adjusting for demographic data and family history of major psychiatric disorders, compared with the control group. Conclusion Children with CHT were associated with approximately a two‐fold increased risk of ADHD and a four‐fold increased risk of ASD than the control group. Our study highlights the need for future research to elucidate the potential pathophysiology among CHD, ASD, and ADHD.