#97 Population-based case-control study of injury risk factors in the northridge earthquake.

摘要

PURPOSE: Earthquakes pose a persistent but unpredictable health threat, causing many injuries and damage throughout the world each year. Researchers have identified personal, structural, and geophysical characteristics as risk factors for injuries, but no studies have examined these factors simultaneously.METHODS: A population-based case-control study was conducted to examine the role of age, gender, building characteristics, and ground movement on the risk of injury in the 1994 Northridge Earthquake. Cases were all earthquake-related fatal and hospital-admitted injuries that occurred in buildings in Los Angeles County (N = 102). Two sets of controls were drawn from a population-based random survey of LA County residents who reported no injury in the earthquake. The first control group was matched to cases by age and gender. The second control group was matched on closest location to the case during the earthquake. Information about buildings was obtained by linkage to building damage files. Ground motion was determined by geomapping case and control locations onto isoseismal maps. Conditional logistic regression was used to estimate risk ratios.RESULTS: Individuals over age 65 had a 2.9 times higher risk of injury than younger people (95% CI = 1.2-7.4), and women had a 2.4 times greater risk than men (95% CI = 1.2-5.1). Location in multiple-unit residential and commercial structures at the time of the earthquake were each associated with higher risk of injury than location in single-unit residential structures, but the exact estimate varied depending on the control group used. With every increase in ground motion of 10%g, risk of injury increased 2.2-fold (95% CI = 1.6-3.3).CONCLUSION: Controlling for other factors, we found that individual, building, and seismic characteristics were independently predictive of increased injury risk. Prevention and preparedness efforts should focus on each of these as potential points of intervention.