A population-based study on the immediate and prolonged effects of the 1999 Taiwan earthquake on mortality

PURPOSE: To investigate the patterns of immediate seismic deaths and post-earthquake mortality changes in the disaster area after the September 21, 1999 Taiwan earthquake. METHODS: We used the data of 1826 seismic deaths to elucidate the immediate seismic effects on mortality patterns, and to determine the association between seismic death rates and house damage among 23 townships in the disaster area. We used standardized mortality ratios (SMRs) to estimate the changes in mortality of all natural causes (ICD-9: 1-799) in the 12 months after the earthquake. RESULTS: For the 1826 seismic deaths, two leading causes of death were asphyxiation and intracranial injury and the death rates were higher among the female and elderly population. Township-specific seismic death rates were proportional to the proportion of completely collapsed houses. SMRs decreased six months after the earthquake for all residents and female adults aged 45 years and over. CONCLUSIONS: The immediate effects of the Taiwan earthquake included a higher proportion of female and elderly seismic deaths and an association between seismic death rates and earthquake damages in the disaster area. The prolonged effect of the earthquake on mortality in the post-earthquake year was a decrease in mortality for all residents except male adults.