摘要：Objectives . We examined the role of body mass index (BMI) and other factors in driver deaths within 30 days after motor vehicle crashes. Methods . We collected data for 22 107 drivers aged 16 years and older who were involved in motor vehicle crashes from the Crashworthiness Data System of the National Automotive Sampling System (1997–2001). We used logistic regression and adjusted for confounding factors to analyze associations between BMI and driver fatality and the associations between BMI and gender, age, seatbelt use, type of collision, airbag deployment, and change in velocity during a crash. Results . The fatality rate was 0.87% (95% confidence interval [CI]=0.50, 1.24) among men and 0.43% (95% CI=0.31, 0.56) among women involved as drivers in motor vehicle crashes. Risk for death increased significantly at both ends of the BMI continuum among men but not among women ( P <.05). The association between BMI and male fatality increased significantly with a change in velocity and was modified by the type of collision, but it did not differ by age, seatbelt use, or airbag deployment. Conclusions . The increased risk for death due to motor vehicle crashes among obese men may have important implications for traffic safety and motor vehicle design. Motor vehicle crashes are the leading cause of injury-related death in the United States and accounted for more than 42000 deaths in 2002. 1 , 2 Injury pattern and severity of injury due to motor vehicle crashes depend on a complex interaction of biomechanical factors; changes in velocity during a crash, seat-belt use, airbag deployment, and type of collision all play a role. 3 However, the role of body habitus, or body shape, in those interactions is not well understood. The current Federal Motor Vehicle Safety Standards provide protection primarily for the mid-size male (body mass index [BMI]=24.3 kg/m2), 4 but this standard may apply to fewer people today. During the past 2 decades, more Americans have become obese or extremely obese: a study conducted in 2000 reported that 30.4% of American adults had a BMI of 30 kg/m2 or greater, and 4.9% had a BMI of 40 kg/m2 or greater. 5 , 6 Mock et al. 7 used a nationally representative sample and found a linear increasing association between BMI and risk for death due to motor vehicle crashes after they adjusted for several confounding factors. The authors speculated that increased comorbidity was the cause. In contrast, Arbabi et al. 3 found a nonlinear association between BMI and motor vehicle crash mortality: normal-weight (BMI <25 kg/m2) and obese (BMI ≥ 30 kg/m2) people had an increased risk for death compared with overweight (BMI=25–29.9 kg/m2) people. This is possibly because of increased insulating tissue without a significant increase in mass—the cushion effect—among the overweight group. Women, however, may not be subjected to the same increased risk. 8 Fat deposits and distribution (e.g., subcutaneous fat vs visceral fat and waist vs hip girths) differ between men and women, and body shape affects women’s all-cause mortality risk more than it affects men’s. 9 – 12 Yet, the role of obesity, gender, and other risk factors for crash fatality is not known. We conducted this study to clarify the effects of BMI on driver motor vehicle crash fatality and thereby inform Federal Motor Vehicle Safety Standards and other standards. Accordingly, we assessed whether the association between BMI and motor vehicle crash fatality differed by other risk factors, such as gender, age, seatbelt use, airbag deployment, type of collision, and changes in velocity (km/hr) during the crash. We used a nationally representative sample of police-reported automobile crashes.
