EFFECTIVENESS OF SAFETY-BELT USE - A STUDY USING HOSPITAL-BASED DATA FOR NONFATAL MOTOR-VEHICLE CRASHES

To evaluate the effectiveness of safety-belt use in reducing the likel ihood of a serious injury, we analyzed data from the Iowa Safety Restr aint Assessment study collected from 893 front-seat passenger car occu pants treated for nonfatal injuries in the emergency department of 16 Iowa hospitals from November 1987 through March 1988. Data analyzed in cluded demographic information, motor-vehicle and crash-related inform ation, and medical information collected on all driver-seat and right- front-seat occupants. Logistic regression analyses were used to assess outcomes for front-seat occupants who did or did not use safety belts , while controlling for confounder variables. The crude odds of being seriously injured (Injury Severity Score greater than or equal to 9) w ere greater for those who were not using safety belts than for those w ho were (4.4 to 1, respectively) at the time of the crash. The odds of a serious injury for people not using safety belts versus those using safety belts was greater in larger cars than in small cars. We conclu ded that the use of safety belts reduces the number and seriousness of injuries for cars of all sizes; however, car size may influence the e ffectiveness of safety-belt use in preventing a serious injury. The li mitations of this study (including small sample size, the lack of deta iled vehicle and crash information, and the lack of injury outcome inf ormation for all of each vehicle's passengers) underscore the need for further research into the role of vehicle size and mass in the effect iveness of safety restraint systems in nonfatal and fatal crashes or f atal combined with nonfatal crashes.