Objective: To develop national and state level estimates for preventable bicycle related head injuries (BRHIs) and associated direct and indirect health costs from the failure to use bicycle helmets. Methods: Information on the effectiveness and prevalence of use of bicycle helmets was combined to estimate the avoidable fraction, that is, the proportion of BRHIs that could be prevented through the use of bicycle helmets. The avoidable fraction multiplied by the expected number of BRHIs gives an estimate of the number of preventable cases. Direct and indirect health costs are estimated from a social perspective for the number of preventable BRHIs to assess potential cost savings that would be achieved if all riders wore helmets.Results: Approximately 107 000 BRHIs could have been prevented in 1997 in the United States. These preventable injuries and deaths represent an estimated $81 million in direct and $2.3 billion in indirect health costs. Estimates range from 200 preventable BRHIs and $3 million in health costs in Wyoming (population 480 000) to 13 700 preventable BRHIs and $320 million in health costs in California (population 32.3 million). Conclusions: A number of successful approaches to increasing bicycle helmet use exist, including mandatory use laws and community based programs. The limited use of these strategies may be related to the fact that too little information is available to state agencies about the public health and economic burden of these preventable injuries. In conjunction with information on program costs, our estimates can assist state planners in better quantifying the number of preventable BRHIs and the costs and benefits of helmet promotion programs. E ach year in the US, nearly 700 persons die from bicycle crashes 1 and 567 000 more are treated in emergency departments.2 About two thirds of these fatalities and one third of these injuries are related to a head injury.3 4 Although bicycle helmets substantially reduce the risk such injuries, [5][6][7] the majority of bicyclists do not always wear helmets. One reason for the limited use of successful strategies to increasing bicycle helmet use 10 may be related to the dearth of information at the state level about the public health burden and associated health costs of these preventable injuries. This information could demonstrate to decision makers that promoting helmet use could be a cost saving investment. Accordingly, we report national and state specific estimates of preventable bicycle related head injuries (BRHIs) and the associated health costs for 1997. We also discuss methodological issues and data gaps encountered in developing these estimates.
METHODSWe use four steps in the estimation process (fig 1). State level population estimates are multiplied by the corresponding national death, hospitalization, and emergency department visit rates to generate the expected number of cases. The proportion of cases that could be prevented-the avoidable fraction-is estimated by combining information on helmet effectiveness and prevalenc...