Cyclist head and facial injury risk in relation to helmet fit: a case-control study

INTRODUCTION: We examined the effect of bicycle helmet fit and position on head and facial injuries. METHODS: Cases were helmeted cyclists with a head (n=297) or facial (n=289) injury. Controls were helmeted cyclists with other injuries, excluding the neck. Participants were interviewed in seven Alberta emergency departments or by telephone; injury data were collected from charts. Missing values were imputed using chained equations and custom prediction imputation models. RESULTS: Compared with excellent helmet fit, those with poor fit had increased odds of head injury (odds ratio [OR] = 3.38, 95% confidence interval [CI]: 1.06-10.74). Compared with a helmet that stayed centred, those whose helmet tilted back (OR = 2.90, 95% CI: 1.54-5.47), shifted (OR = 1.91, 95% CI: 1.01-3.63) or came off (OR = 6.72, 95% CI: 2.86-15.82) had higher odds of head injury. A helmet that tilted back (OR = 4.81, 95% CI: 2.74-8.46), shifted (OR = 1.83, 95% CI: 1.04-3.19) or came off (OR = 3.31, 95% CI: 1.24-8.85) also increased the odds of facial injury. CONCLUSION: Our findings have implications for consumer and retail education programs.