Long-Term Effects of the 2011 Japan Earthquake and Tsunami on Incidence of Fatal and Nonfatal Myocardial Infarction

Abstract

This study aimed to examine the long-term effects of the 2011 Japan earthquake and tsunami on the incidence of fatal and nonfatal myocardial infarction (MI). In the present study, the incidence of 2 types of cardiac events was comprehensively recorded. The study area was divided into 2 zones based on the severity of tsunami damage, which was determined by the percentage of the inundated area within the residential area (<10%, low-impact zone and ≥10%, high-impact zone). The standardized incidence ratio (SIR) and 95% CI for both types of cardiac events during the disaster year and the postdisaster years were determined in each zone. During the 4-year period after the disaster, the SIRs for nonfatal MI did not change to a statistically significant extent in either zones. For fatal MI, the SIR was stable during the study period in the low-impact zone. However, in the high-impact zone, the SIR was significantly elevated in the disaster year of 2011 (1.80 [95% CI 1.32 to 2.28]), and this increase was sustained for the following 3years (2012, 2.06 [1.55 to 2.57]; 2013, 1.99 [1.49 to 2.48]; 2014, 2.12 [1.62 to 2.63]). The SIRs for fatal MI for the 4 postdisaster years in the municipal areas were significantly correlated with the percentage of the inundated area (r= 0.83; p <0.001) and the number of deaths due to the tsunami (r= 0.77; p <0.005) but not with the maximum seismic intensity (r= 0.43; p= 0.12). In conclusion, these results suggest that the devastating tsunami was associated with a continual increase in the incidence of fatal MI among disaster survivors.