Comparison of cardiovascular mortality in the great East Japan and the great Hanshin-Awaji earthquakes-a large-scale data analysis of death certificates

Abstract

Background: Large earthquakes have been associated with cardiovascular disease (CVD) mortality. In Japan, the 1995 Great Hanshin-Awaji (H-A) Earthquake was an urban-underground-type earthquake, whereas the 2011 Great East Japan (GEJ) Earthquake was an ocean-trench type. In the present study, we examined how these different earthquake types affected CVD mortality. Methods and Results: We examined death certificate data from 2008 to 2012 for 131 municipalities in Iwate, Miyagi, and Fukushima prefectures (n=320,348) and from 1992 to 1996 for 220 municipalities in Hyogo, Osaka, and Kyoto prefectures (n=592,670). A Poisson regression model showed significant increases in the monthly numbers of acute myocardial infarction (AMI)-related deaths (incident rate ratio [IRR] GEJ=1.34, P=0.001; IRR of H-A=1.57, P<0.001) and stroke-related deaths (IRR of GEJ=1.42, P<0.001; IRR of H-A=1.33, P<0.001) after the earthquakes. Two months after the earthquakes, AMI deaths remained significant only for H-A (IRR=1.13, P=0.029). When analyzing the standardized mortality ratio (SMR) after the earthquakes using the Cochran-Armitage trend test, seismic intensity was significantly associated with AMI mortality for 2 weeks after both the GEJ (P for trend=0.089) and H-A earthquakes (P for trend=0.005). Conclusions: Following the GEJ and H-A earthquakes, there was a sharp increase in CVD mortality. The effect of the disaster was sustained for months after the H-A earthquake, but was diminished after the GEJ Earthquake.