Attention-deficit-hyperactivity disorder increases risk of bone fracture: a population-based cohort study

Abstract

Aim: Attention-deficit-hyperactivity disorder (ADHD) is a disorder that is associated with accidental injuries. The aim of this study was to evaluate the relationship between ADHD and bone fracture in children.

Method: The study cohort comprised 3640 children (2874 males, 766 females; mean age 8y 5mo, SD 3y) with ADHD (International Classification of Diseases, Ninth Revision) who were matched to children without ADHD at a ratio of 1:4 (n=14 560; 11 496 males, 3064 females; mean age 8y 5mo, SD 3y). A Cox proportional hazard regression analysis was conducted to estimate how ADHD affected the risk of bone fracture.

Results: The incidence of fracture among the ADHD cohort was 197.67 per 10,000 person-years, and was 1.3-fold greater than in the comparison cohort (147.54 per 10,000 person-years). The risk in children with ADHD was higher than that in children without ADHD (p value for log-rank test < 0.001). After adjusting for potential confounding factors, the ADHD cohort was 1.32 times more likely to have bone fracture accidents than the comparison cohort (hazard ratio, 1.32; 95% confidence interval 1.17-1.49).

Interpretation: Children with ADHD have a higher risk of experiencing bone fracture accidents than do children without ADHD.