Car occupant death according to the restraint use of other occupants: a matched cohort study.

CONTEXT A car occupant could be killed if struck by another occupant who was catapulted forward, backward, or sideways in a crash. OBJECTIVE To estimate the association between death of a car occupant (the target) and restraint use by other occupants. DESIGN Matched-pair cohort study comparing the outcomes of 2 target occupants in the same passenger car that crashed. SETTING United States traffic crashes in 1988-2000, using data from the Fatality Analysis Reporting System. SUBJECTS Target pairs, at least 1 of whom died: 61 834 front-seat pairs, 5278 rear-seat pairs, and 21 127 pairs on the left or right side. MAIN OUTCOME MEASURES Adjusted risk ratio (RR) for death within 30 days of a crash. RESULTS The risk of death was greater for a restrained front target occupant in front of an unrestrained occupant compared with a restrained front target in front of a restrained occupant (adjusted RR, 1.20; 95% confidence interval [CI], 1.10-1.31). For a restrained rear target occupant behind an unrestrained occupant compared with a restrained rear target occupant behind a restrained occupant, the adjusted RR was 1.22 (95% CI, 1.10-1.36). For a restrained side target occupant sitting next to an unrestrained occupant compared with a restrained side target occupant sitting next to a restrained occupant, the adjusted RR was 1.15 (95% CI, 1.08-1.22). Among unrestrained target occupants, the adjusted RRs were, for front targets, 1.04 (95% CI, 0.97-1.12), rear targets, 1.22 (95% CI, 1.10-1.36), and side targets, 0.85 (95% CI, 0.80-0.92). CONCLUSION Persons who wish to reduce their risk of death in a crash should wear their own restraint and should ask others in the same car to use their restraints.