Age-based variability in the association between restraint use and injury type and severity in multi-occupant crashes

• Published in: Annals of epidemiology Vol. 76; pp. 114 - 120.e2
• Main Authors: Benedetti, Marco H., Humphries, Kayleigh D., Codden, Rachel, Sagar, Shraddha, Kufera, Joseph A., Cook, Lawrence J., Norris, Jesse, Stamatiadis, Nikiforos, Vesselinov, Roumen, Zhu, Motao
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01-12-2022
• Subjects: Abbreviated Injury Scale; Accidents, Traffic; Adolescent; Adult; Aged; Fatal and severe injury; Humans; Matched cohort design; Motor vehicle crash; Older adult occupants; Risk; Seat belt use; Seat Belts; Torso injury; Wounds and Injuries - epidemiology; Wounds and Injuries - etiology; Young Adult; Par; RR; Codes; CI; ICD; Older adult occupants; Motor vehicle crash; Fatal and severe injury; Seat belt use; Torso injury; Matched cohort design; mvc; Fars; MAIS
• DOI: 10.1016/j.annepidem.2022.10.003
• EISSN: 1873-2585
• ISSN: 1047-2797

•We analyzed fatal, severe, and torso injuries using linked crash and hospital data.•We utilized a matched cohort design to control for potential unmeasured confounding.•Seatbelts were highly protective for fatal and MAIS3+ injuries in all age groups.•Seatbelt protection for MAIS3+ and torso injuries attenuated with age.•Injury prevention can be further tailored to vulnerable populations like older adults.
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.
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.
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.
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.