Back to Annual Meeting Page		American Public Health Association 133rd Annual Meeting & Exposition December 10-14, 2005 Philadelphia, PA

Abstract #121761

Tom Rice, MPH, PhD¹, Craig Anderson, DHSc, PhD², and Jess Kraus, PhD¹. (1) Southern California Injury Prevention Research Center, University of California, Los Angeles, 10911 Weyburn Ave, Suite 200, Los Angeles, CA 90024, 310-794-2725, tr@ucla.edu, (2) Department of Emergency Medicine, University of California Irvine, 101 The City Drive, Building 200, Suite 715, Orange, CA 92868

Background / Objectives

Most studies of the effectiveness of seat belts in preventing fatal injuries among vehicle occupants have considered seating position only as a dichotomy (front vs. rear). In the current study, we estimated seat belt effectiveness and allowed the estimates to vary across individual seating positions. We extended the matched-pair methods employed in several recent studies to estimate risk ratios using matched sets of vehicle occupants.

Method

A matched-set cohort study was conducted using FARS data on occupants of multiple-occupancy vehicles involved in crashes during the years 1994 through 2003. Conditional Poisson and estimating equation regression methods were applied to the data.

Results

Identified in FARS were 97,771 occupants who were riding in 39,169 cars or light trucks. Overall, seat belt use greatly reduced the estimated risk of death (RR 0.33, 95% CI 0.32-0.35). All first and second row passengers had lower estimated risks of death than drivers. Average estimated seat belt effectiveness for occupants of vehicles that overturned (RR 0.22, 95% CI 0.21-0.24) was greater than for that for occupants of vehicles that did not overturn (RR 0.48, 95% CI 0.46-0.51)(LR p<0.005).

Discussion

The findings from this study clarify the effectiveness of seat belt use controlling for numerous crash, vehicle, and occupant characteristics. They demonstrate how effectiveness varies for different seating positions and for different crash types. They also highlight the low prevalence of seat belt use among rear seat occupants.

Learning Objectives:

• Identify the methodologic challenges in studying the effect of seat belts on occupant death risk
• Describe a matched-set cohort study
• Describe how the risk of death is influenced by seating position and seat belt use among occupants of passenger vehicles involved in severe crashes

Keywords: Motor Vehicles, Methodology

Presenting author's disclosure statement:

I wish to disclose that I have NO financial interests or other relationship with the manufactures of commercial products, suppliers of commercial services or commercial supporters.