Evacuation and Risk of Hypertension After the Great East Japan Earthquake

On March 11, 2011, the Great East Japan Earthquake, registering 9.0 on the Richter scale, occurred in Japan. The earthquake provoked the subsequent tsunami that struck the Fukushima Daiichi Nuclear Power Plant (NPP), located on the east coast of Honshu. More than 160 000 residents of the Fukushima prefecture, many living in the areas surrounding the NPP, were forced to evacuate from their homes because of radiation hazards from the nuclear accident. Many epidemiological studies have previously reported that cardiovascular diseases (CVD) and related deaths tend to occur more frequently after large disasters, such as earthquakes, tsunamis, and hurricanes. For instance, compared with those in the previous years, the weekly occurrences of CVD, including out-of-hospital cardiac arrest, heart failure, acute coronary syndrome, and stroke, were significantly increased after the Great East Japan Earthquake. Because hypertension is closely related to the incidence of CVD, increased blood pressure (BP) is likely to be one important factor in the increase of CVD occurrences after a disaster. Although the acute effects of a disaster on increased BP have Abstract—On March 11, 2011, the Great East Japan Earthquake occurred in Japan, with a nuclear accident subsequently occurring at the Fukushima Daiichi Nuclear Power Plant. The disaster forced many evacuees to change particular aspects of their lifestyles. This study assessed the hypothesis that evacuation may have increased the risk of hypertension among residents in Fukushima. A longitudinal study examined data collected from 31 252 Japanese participants aged 40 to 74 years sourced from general health checkups conducted in 13 communities between 2008 and 2010. Follow-up examinations were conducted from 2011 through 2013. A total of 21 989 participants (follow-up proportion, 70.4%) received follow-up examinations. Mean blood pressure significantly increased in both evacuees and nonevacuees after the disaster, with greater changes in blood pressure among the former. The changes in systolic and diastolic blood pressure among the evacuees and nonevacuees were +5.8/3.4 versus +4.6/2.1 mm Hg (P<0.01/P<0.0001) for men and +4.4/2.8 versus +4.1/1.7 mm Hg (P=0.33/P<0.0001) for women, respectively. Evacuation was associated with an increased risk of hypertension among men, and the age-adjusted hazard ratios of evacuation for incidence of hypertension were 1.24 (95% confidence interval, 1.11–1.39; P<0.001) for men and 1.05 (95% confidence interval, 0.94–1.17; P=0.37) for women, respectively. For men, after adjustment for confounding variables, the hazard ratio slightly decreased to 1.20, but the association was essentially unchanged. Blood pressure increased among residents, especially evacuees, in the evacuation zone of Fukushima prefecture after the Great East Japan Earthquake. Evacuation may be associated with an increased risk of hypertension among men in the 2 years after the disaster. (Hypertension. 2016;68:558-564. DOI: 10.1161/HYPERTENSIONAHA.116.07499.)