Medical conditions and the risk of motor vehicle crashes in men

Objective: To determine whether men aged 45 to 70 years with any medical condition are at an increased risk of involvement as drivers in police-reported motor vehicle crashes. Design: Case-control study. Setting: Province-wide population-based sampling. Participants: A total of 2504 drivers randomly selected from those involved as a driver in a motor vehicle crash (cases) and 2520 men not involved in a crash (controls) during a 6-month period. Data Collection: The Societe de l'assurance automobile du Quebec (SAAQ) computerized files provided data on crashes, age, and medical conditions. A mailed questionnaire elicited information on usual mileage and driving conditions. Results: Data from the SAAQ files were obtained for all 5024 drivers. The overall response rate to the mailed survey was 35.5% with no statistically significant differences in the distribution of characteristics between respondents and nonrespondents. There was no increase in crude (odds ratio, 0.99; 95% confidence interval, 0.85-1.17) or age-adjusted risk of crashes for men with a medical condition in the entire sample of subjects (N = 5024). Among respondents to the mailed questionnaire only, men with a medical condition showed no increased crude risk of crashes (odds ratio, 0.99; 95% confidence interval, 0.76-1.27); no difference was observed after adjustment for age, mileage driven, driver behaviors, and sociodemographic characteristics (odds ratio, 0.91; 95% confidence interval, 0.64-1.31). Conclusions: Unlike previous studies, the risk estimate was derived from a population-based sample of drivers and adjusted for age, mileage driven, driver behaviors, and sociodemographic characteristics in multivariate analyses. The adjusted estimates failed to show an increased risk of motor vehicle crashes for drivers with a medical condition.