Obese drivers at greater risk for fatal injury in car crashes

Obese drivers are up to 78 percent more likely to die in a car crash than normal-weight drivers, according to a recent study from UC Berkeley’s Safe Transportation and Research Education Center (SafeTREC), a research center affiliated with the UC Berkeley School of Public Health and the Institute of Transportation Studies

Given the rising rate of obesity in the U.S. population, the ability of passenger vehicles to protect overweight or obese occupants may have increasingly important public health implications, the researchers noted.

“This study highlights yet another negative consequence of obesity,” said study coauthor Thomas Rice, a research epidemiologist with SafeTREC.

Researchers reviewed data on accidents recorded in the Fatality Analysis Reporting System, managed by the National Highway Traffic Safety Administration. Using information on 41,283 collisions, the researchers selected accidents in which the vehicles involved were the same size. They then used height and weight statistics from the drivers’ licenses to categorize them in terms of their body mass index (BMI). The study also recorded information on seat-belt use, time of day of the crash, driver sex, driver alcohol use, air bag deployment, and collision type.

Drivers with a BMI under 18 and those between 25 and 29.9 had death rates about the same as people of normal weight, the researchers found. But among the obese, the higher the BMI, the more likely a driver was to die in a crash.

A BMI of 30 to 34.9 was linked to a 21 percent increase in risk of death, and a number between 35 and 39.9 to a 51 percent increase. Drivers with a BMI above 40 were 81 percent more likely to die than those of normal weight in similar crashes. Obese women were more likely to die than obese men.

Authors found these risks remained for drivers wearing seat belts and when the airbag deployed. While increased comorbidities are a probable contributor, researchers also suggest that “it may be the case that passenger vehicles are well designed to protect normal-weight vehicle occupants but are deficient in protecting overweight or obese occupants.”

“Vehicle designers are teaching to the test –designing so that crash-test dummies do well,” said Rice. “But crash-test dummies are typically normal size adults and children. They’re not designed to account for our nation’s changing body types.”

The study was published online in the Emergency Medicine Journal.

By Linda Anderberg