Leveraging existing databases to study vehicle crashes in a combat occupational cohort: Epidemiologic methods

Background: The US military is a large, well-defined occupational cohort offering tremendous opportunities to study risk factors for important health outcomes. This article describes our nested case-control methods to evaluate risk factors for fatal motor vehicle crashes (MVC) within all Service branches in a 1991 Gulf War era cohort. Methods: We identified 1,343 cases of fatal MVC between 1991 and 1995 that were also included in the Department of Transportation's Fatality Analysis Reporting System database and, using risk set sampling, selected 13,430 controls. Our final analytic dataset consisted of 980 male driver cases and 12,807 controls linked to multiple databases. Results: Cases were disproportionately younger, less educated, not married, enlisted, and deployed to the Gulf War, compared to controls. Conclusions: The ability to leverage multiple databases to study risk factor s for fatal MVC is clearly advantageous and could eventually lead to the reduction of fatalities in similar occupational cohorts.