title: Attention-deficit-hyperactivity disorder increases risk of bone fracture: a population-based cohort study.
abstract: OBJECTIVE
  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.
  
  
  METHODS
  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).
  
  
  CONCLUSIONS
  Children with ADHD have a higher risk of experiencing bone fracture accidents than do children without ADHD.
authors.affiliation: Department of Paediatrics, China Medical University Hospital, China Medical University, Taichung, Taiwan; Graduate Institute of Integrated Medicine, College of Chinese Medicine, China Medical University, Taichung, Taiwan.
authors.forename: I-Ching
authors.initials: IC
authors.lastname: Chou
authors.forename: Che-Chen
authors.initials: CC
authors.lastname: Lin
authors.forename: Fung-Chang
authors.initials: FC
authors.lastname: Sung
authors.forename: Chia-Hung
authors.initials: CH
authors.lastname: Kao
mesh_terms: D000293:Adolescent; D001289:Attention Deficit Disorder with Hyperactivity / Q000150:complications*; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D005260:Female; D050723:Fractures, Bone / Q000453:epidemiology*; D006801:Humans; D015994:Incidence; D008297:Male; D016016:Proportional Hazards Models; D012306:Risk; D013624:Taiwan / Q000453:epidemiology