The Great East Japan Earthquake and suicide: The long-term consequences and underlying mechanisms.

How and why do major natural disasters affect suicide? This study revisits this question by focusing on the Great East Japan Earthquake (GEJE) in March 2011 as a historically important natural disaster. Using an event-study analysis, we assessed how the GEJE changed the suicide rates in the regions affected by it and whether its effect persisted, attenuated, or escalated over time. In addition, we explored the political and social channels underlying the relationship between the GEJE and suicide. Using prefecture-level data, our analysis reveals that suicide by men aged 40-64 years and 65 years and over showed a large decline in the GEJE-affected prefectures in the years following the earthquake, and this decline attenuated over time. Furthermore, following the GEJE, government spending increased while divorce rates decreased in the affected prefectures, both of which were correlated with male suicide rates. These findings indicate that suicide after major natural disasters is preventable when political and social reactions to disasters provide a safety net, especially for men.

Heat-related mortality and ambulance transport after a power outage in the Tokyo metropolitan area.

Background: Air conditioners can prevent heat-related illness and mortality, but the increased use of air conditioners may enhance susceptibility to heat-related illnesses during large-scale power failures. Here, we examined the risks of heat-related illness ambulance transport (HIAT) and mortality associated with typhoon-related electricity reduction (ER) in the summer months in the Tokyo metropolitan area. Methods: We conducted event study analyses to compare temperature-HIAT and mortality associations before and after the power outage (July to September 2019). To better understand the role of temperature during the power outage, we then examined whether the temperature-HIAT and mortality associations were modified by different power outage levels (0%, 10%, and 20% ER). We computed the ratios of relative risks to compare the risks associated with various ER values to the risks associated without ER. Results: We analyzed the data of 14,912 HIAT cases and 74,064 deaths. Overall, 93,200 power outage cases were observed when the typhoon hit. Event study results showed that the incidence rate ratio was 2.01 (95% confidence interval [CI] = 1.42, 2.84) with effects enduring up to 6 days, and 1.11 (95% CI = 1.02, 1.22) for mortality on the first 3 days after the typhoon hit. Comparing 20% to 0% ER, the ratios of relative risks of heat exposure were 2.32 (95% CI = 1.41, 3.82) for HIAT and 0.95 (95% CI = 0.75, 1.22) for mortality. Conclusions: A 20% ER was associated with a two-fold greater risk of HIAT because of summer heat during the power outage, but there was little evidence for the association with all-cause mortality.