Association of Anemia with Neurodevelopmental Disorders in a Nationally Representative Sample of US Children.

Objective: To examine the associations of anemia with autism spectrum disorder (ASD), attention deficit hyperactivity disorder (ADHD), and learning disability in US children.

Study Design: We included children and adolescents aged 3-17 years from the National Health Interview Survey (NHIS), 1997-2018. Information about physician-diagnosed history of anemia, ASD, ADHD, and learning disability was reported by a parent or guardian. Multiple logistic regression with sample weights was used to estimate the ORs and 95% CIs of neurodevelopmental disorders according to the presence of anemia.

Results: Of the total population of 213 893 children aged 3-17 years (mean age [SE], 10.01 [0.01] years), 2379 were reported to have a diagnosis of anemia, for a weighted prevalence of 1.06% (95% CI, 1.01-1.12). The prevalence of ASD was 1.94% (95% CI, 1.20-2.68) among children with anemia and 1.07% (95% CI, 1.01-1.14) among those without anemia. The corresponding prevalences were 12.24% (95% CI, 10.47-14.00) and 7.73% (95% CI, 7.58-7.88) for ADHD and 15.03% (95% CI, 13.08-16.99) and 7.75% (95% CI, 7.39-7.70) for learning disability, respectively. Compared with those without anemia, children with anemia were more likely to have neurodevelopmental disorders, with an aOR of 2.07 (95% CI, 1.39-3.08) for ASD, 1.84 (95% CI, 1.55-2.19) for ADHD, and 2.22 (95% CI, 1.90-2.60) for learning disability.

Conclusions: In a nationally representative sample of US children, we found significant associations between anemia and neurodevelopmental disorders including ASD, ADHD, and learning disability. Further investigation is warranted to assess the causality and elucidate the underlying mechanisms.