Multivariate Analysis of Restraint Use and Injury Severity among Older Child Passengers in the US

This study focuses on older child passengers between the ages of 9 and 12.

The objective of this study is to evaluate the relationship between restraint use and injury severity in older child passengers in the United States between 1991 and 2005. Secondary data analysis was performed using the NHTSA NASS-CDS data system.

Restraint use was compared with injury severity along with other potential risk factors, potential confounders and effect modifiers, which included seating position, crash type, vehicle type, age, height, and weight. Descriptive statistics were obtained to characterize the study population, and stratified analysis and multivariate logistic regression were utilized to assess the association between restraint use and injury severity while controlling for confounders and effect modifiers.

Overall, descriptive statistics demonstrated that no restraint and serious injury are positively associated with a crude OR=4.74; 95% CI=2.6, 8.7. Seating position, vehicle type, and weight were significantly associated with restraint use. Also, crash type was significantly associated with serious injury. Study results showed that among children between the ages of 9 and 12 who were unrestrained, after controlling for crash type and vehicle type, the odds of experiencing a serious injury was higher than for those restrained, adjusted Mantel-Haenszel OR=4.53.

These findings combined with past literature, suggest that there is a strong relationship between restraint use and injury severity that is maintained even when controlled for significant cofactors. However, it is suggested that the protective effects of restraints could be further enhanced to protect older child passengers.