Purpose: Previous studies have shown older adults receive relatively less protection from seat belts against fatal injuries, however it is unknown how seat belt protection against severe and torso injury changes with age. We estimated age-based variability in seat belt protection against fatal injuries, injuries with maximum abbreviated injury scale greater than two (MAIS 3+), and torso injuries. Methods: We leveraged the Crash Outcome Data Evaluation System to analyze binary indicators of fatal, MAIS 3+, and torso injuries. Using a matched cohort design and conditional Poisson regression, we estimated age-based relative risks (RR) of the outcomes associated with seat belt use. Results: Our results suggested that seat belts were highly protective against fatal injuries for all ages. For ages 16–30, seat belt use was associated with 66% lower risk of MAIS3+ injury (RR 0.34, 95% CI 0.30, 0.38) for occupants of the same vehicle, whereas for ages 75 and older, seat belt use was associated with 38% lower risk of MAIS3+ injury (RR 0.62; 95% CI 0.45, 0.86) for occupants in the same vehicle. The association between restraint use and torso injury also attenuated with age. Conclusions: In multi-occupant crashes, seat belts were highly protective against fatal and MAIS3+ injury, however seat belt protection against MAIS3+ and torso injury attenuated with age.
|Journal||Annals of Epidemiology|
|State||Published - Dec 2022|
Bibliographical noteFunding Information:
The critical finding of this work was that seat belt protection against MAIS 3+ injury and torso injuries attenuated with age. Our findings with respect to MAIS 3+ injuries contrasted with Noh et al., who found that seat belt offered the greatest protection against severe injury for those aged 65 and older  . We found the opposite: seat belts exhibited the strongest protection against MAIS 3+ injuries among younger occupants, and the protection attenuated with age. Echoing previous calls to action by, for example, Carter et al. (2014)  , the implications of our findings with respect to MAIS 3+ and torso injury are twofold. First, our results, like studies that found age-based variability in injury severity by age, underscore the need for accurate human conceptual models for all ages and body types. This assertion has been supported by studies of belt positioning [ 50 , 51 ], body scans  , and comparison of postmortem subjects to crash-test dummies  . Second, injury prevention systems in motor vehicles should continue to be refined towards vulnerable populations such as older adults.
- Fatal and severe injury
- Matched cohort design
- Motor vehicle crash
- Older adult occupants
- Seat belt use
- Torso injury
ASJC Scopus subject areas