Response to: 'Helmet use and risk of head injuries in alpine skiers and snowboarders: changes after an interval of one decade'.

BACKGROUND In a previous study, we concluded that a safety helmet can reduce the risk for head injury by 60%. Other studies reported similar effects, resulting in a general recommendation to wear a helmet while skiing or snowboarding. AIM To determine the effect of the expected increased helmet wear on the risk of head injury one decade after the recommendation. METHODS Ski patrols reported injury cases in major Norwegian alpine ski resorts. Injury type, helmet use and other risk factors were recorded. A multiple logistic regression analysis was used to assess the relation between individual risk factors and the risk of head injuries by comparing head injured skiers (cases) with skiers and snowboarders who reported other injuries (controls). RESULTS Helmet use was associated with improved odds for head injuries (OR: 0.45, 95% CI 0.34 to 0.60; p<0.001) in 2002; this effect was attenuated in 2010 (OR: 0.79, 95% CI 0.63 to 0.98; p=0.02), and not significant in 2011 (OR: 0.80, 95% CI 0.60 to 1.06; p=0.12). For potentially severe head injuries, the protective effect of using a helmet was better sustained over the observation period, from an OR of 0.44 (95% CI 0.28 to 0.68, p<0.001) in 2002 to an OR of 0.74 (95% CI 0.57 to 0.97, p=0.02) in 2010 and 0.67 (95% CI 0.47 to 0.96; p=0.03) in 2011. CONCLUSIONS We observed an unexpected reduction in the protective effect of a skiing helmet. This may be due to new skiing trends in the alpine resorts.