Increased fracture risk among children diagnosed with attention- deficit/hyperactivity disorder: a large matched cohort study.

To analyse the risk of fractures among children with attention-deficit/hyperactivity disorder (ADHD) compared with matched children without ADHD; and to evaluate the impact of pharmacological treatment. This registry-based cohort study included 31,330 children diagnosed with ADHD and a comparison group of 62,660 children matched by age, sex, population sector and socioeconomic status. Demographic and clinical information was extracted from the electronic database of Meuhedet, a health maintenance organization. Fracture events between 2-18 years of age were identified by coded diagnoses. The overall fracture incidence rate was 334 per 10,000 patient-years (PY) in the ADHD group and 284 per 10,000 PY in the comparison group (p < 0.001). Among boys, the fracture incidence rates were 388 per 10,000 PY and 327 per 10,000 PY (p < 0.001), for the respective groups. Among girls, the rates were lower in both groups compared to boys, but higher in the ADHD compared to the matched group (246 vs 203 per 10,000 PY, p < 0.001). Among the children with ADHD, the hazard ratios (HR) to have a fracture were similar in boys (1.18, 95%CI 1.15-1.22, p < 0.001) and girls (1.22, 95%CI 1.16-1.28, p < 0.001). Children with ADHD were also at increased risk for two and three fractures; the hazard ratios (HRs) were 1.32 (95%CI 1.26-1.38, p < 0.001) and 1.35 (95%CI 1.24-1.46, p < 0.001), respectively. In a multivariable model of the children with ADHD, pharmacological treatment was associated with reduced fracture risk (HR 0.90, 95%CI 0.82-0.98, p < 0.001) after adjustment for sex, resident socioeconomic status and population sector.   Conclusion: Children with ADHD had greater fracture risk than a matched group without ADHD. Pharmacological treatment for ADHD may decrease this risk. What is Known: • Children with attention-deficit/hyperactivity disorder (ADHD) may be more prone to injuries and fractures than children without ADHD. What is New: • Children with ADHD were 1.2 times more likely to have a fracture than children with similar characteristics, without ADHD. The increased risk for fractures was even greater for two and three fractures (hazard ratios 1.32 and 1.35, respectively). • Our study suggests a positive effect of pharmacological treatment for ADHD in reducing fracture risk.