Comparison of injuries of belted occupants among different BMI categories in frontal crashes

Previous studies have shown that occupants with obesity are at a greater risk of fatality and serious injury than other occupants in motor vehicle crashes. To provide a more complete description of the most frequent injuries and the most frequently injured body regions for occupants with obesity. Sampled cases (n = 13,470) representing ~4.7 million adult occupants involved in frontal crashes (between 2000 and 2015) were selected from the U.S. National Automotive Sampling System—Crashworthiness Data System database. A retrospective cohort study was performed to study the effect of BMI on the risk of injury to different body regions and to identify the most frequent injuries to occupants with different BMIs. Lastly, in-depth crash analysis cases from the U.S. Crash Injury Research and Engineering Network (CIREN) database were studied to elucidate the source of the most common injuries to occupants with obesity. Occupants with obesity experienced a higher risk of upper extremity (4.79 vs 2.92%), lower extremity (8.37 vs 3.23%), and spine (1.53 vs 1.09%) injuries than other occupants. After adjusting for other variables, the risks of spinal, thoracic, and extremities injuries were found to be affected by the BMI class. Seven out of the ten most common injuries sustained by occupants with obesity were lower extremity injuries, and talus fractures were the most common overall. Direct loading through the plantar surface of the foot by the vehicle toe pan was found to be a likely cause of many of those injuries based on CIREN cases. The injuries of occupants with obesity are different than other occupants which can be attributed to their different interaction with the seat belt and vehicle interior. The findings of this study should be considered for designing restraint systems to protect occupants with obesity in car crashes.