Risk-taking, coordination and upper limb fractures in children: a population based case-control study.

The aim of this population based case-control study was to examine the association between risk-taking behaviour, motor coordination and upper limb fractures in children aged 9-16 years. A total of 321 fracture cases and 321 randomly selected individually matched controls were studied. The number for different types of upper limb fractures was 91 for hand, 190 for wrist and forearm and 40 for upper arm. Risk-taking behaviour was determined by a 5-item interview-administered questionnaire. Motor coordination was assessed by the 8-point movement ABC that tests manual dexterity, ball skills as well as static and dynamic balance. Bone mass was assessed by dual energy X-ray absorptiometry (DXA) and metacarpal morphometry. In general, there was heterogeneity by fracture site with regard to associations. Risk-taking behaviour was associated with hand fracture risk but not other fracture sites for downhill cycling behaviour (OR: 2.0/category, 95% CI: 1.1-3.7), dare behaviour (OR: 3.3/category, 95% CI: 1.1-10.0) and total risk-taking score (OR: 2.6/category, 95% CI: 1.3-5.7). Conversely, coordination measures were associated with wrist and forearm fractures only: cutting/threading (OR: 1.2/unit, 95% CI: 1.0-1.4); flower trail (OR: 1.2/unit, 95% CI: 1.0-1.4) and dynamic balance score (OR: 1.1/unit, 95% CI: 1.0-1.2). Backward stepwise analysis selected total risk taking score for hand fracture, and dynamic balance score for wrist and forearm fracture. None of the risk-taking or coordination scores were associated with upper arm fractures. These associations were unchanged following adjustment for bone mass. In conclusion, the propensity to take risks is most strongly associated with hand fracture risk while dynamic balance is most strongly associated with wrist and forearm fracture risk in children. These results inform the development of fracture prevention strategies in children.