Age gradient in the cost-effectiveness of bicycle helmets

Objectives. This study analyzed the reduction in risk of head injuries asso ciated with use of bicycle helmets among persons ages 3 to 70 and the cost- effectiveness of helmet use based on this estimated risk reduction. Methods. To derive our cost-effectiveness estimates, we combined injury inc idence data gathered through a detailed and comprehensive injury registrati on system in Norway, acute medical treatment cost information for the Norwe gian health service, and information reported in the scientific literature regarding the health protective effects of helmet use. The analysis include d all cases of head injuries reported through the registration system from 1990 through 1996. We performed an age-stratified analysis to determine the incidence of bicycle-related head injuries, the 5-year reduction in absolu te risk of injury, the number needed to treat, and the cost-effectiveness o f helmet use. To test the robustness of the findings to parameter assumptio ns, we performed sensitivity analysis. Results. The risk of head injury was highest among children aged 5 to 16. T he greatest reduction in absolute risk of head injury, 1.0 to 1.4% over 5 y ears estimated helmet Lifetime, occurred among children who started using a helmet between the ages of 3 and 13. Estimates indicate that it would cost approximately U.S.$2200 in bicycle helmet expenses to prevent any one uppe r head injury in children ages 3-13. In contrast, it would cost U.S.$10,000 -25,000 to avoid a single injury among adults. Conclusions. Bicycle safety helmets appear to be several times more cost-ef fective for children than adults, primarily because of the higher risk of h ead injury among children. Programs aiming to increase helmet use should co nsider the differences in injury risk and cost-effectiveness among differen t age groups and target their efforts accordingly. (C) 2000 American Health Foundation and Academic Press.