Bicycle helmet use four years after the introduction of helmet legislation in Alberta, Canada.

BACKGROUND Bicycle helmets reduce fatal and non-fatal head and face injuries. This study evaluated the effect of mandatory bicycle helmet legislation targeted at those less than 18 years old on helmet use for all ages in Alberta. METHODS Two comparable studies were conducted two years before and four years after the introduction of helmet legislation in Alberta in 2002. Bicyclists were observed in randomly selected sites in Calgary and Edmonton and eight smaller communities from June to October. Helmet wearing and rider characteristics were recorded by trained observers. Poisson regression adjusting for clustering by site was used to obtain helmet prevalence (HP) and prevalence ratio (PR) (2006 vs. 2000) estimates. RESULTS There were 4002 bicyclists observed in 2000 and 5365 in 2006. Overall, HP changed from 75% to 92% among children, 30% to 63% among adolescents and 52% to 55% among adults. Controlling for city, location, companionship, neighborhood age proportion <18, socioeconomic status, and weather conditions, helmet use increased 29% among children (PR = 1.29; 95% CI: 1.20-1.39), over 2-fold among adolescents (PR 2.12; 95% CI: 1.75-2.56), and 14% among adults: (PR = 1.14; CI: 1.02-1.27). CONCLUSIONS Bicycle helmet legislation was associated with a greater increase in helmet use among the target age group (<18). Though HP increased over 2-fold among adolescents to an estimated 63% in 2006, this percentage was approximately 30% lower than among children <13.