Extent of Flood Damage Increased Cerebrovascular Disease Incidences in Iwate Prefecture after the Great East Japan Earthquake and Tsunami of 2011

Abstract

Background: Several studies have reported on increases in the incidence of cardiovascular and cerebrovascular diseases after huge earthquakes. An increase in the incidence of cerebrovascular diseases was observed after the Great East Japan Earthquake and Tsunami of 2011. To assess whether tsunami damage or the earthquake was responsible for this trend, we assessed the relative impact of earthquake magnitude and flood damage on cerebrovascular disease. Methods: A total of 12 coastal municipalities facing the epicenter were divided into 4 flood severity groups according to the percentage of people living in the flooded areas (<20, 20-40, 40-60, and ≥60%) and 3 groups according to the Japanese Meteorological Agency seismic intensity of the main shock (<4.5, 4.5-5.0 and ≥5.0). The standard incidence ratios (SIRs) of cerebrovascular diseases in the first 4 weeks after the disaster compared with the same periods in 2008−2010 were calculated for each flood severity group and each earthquake severity group. Odds ratios (ORs) of disease incidence and the adjusted ORs for seismic intensity (using the Mantel-Haenszel method) between the higher (≥40%) and the lower flooded area (<40%) were compared with the same periods in 2008−2010. Likewise, ORs and adjusted ORs for flood severity in the high seismic intensity area (≥4.9) were compared with those in the low seismic intensity area (<4.9). Results: SIRs increased with the increased flood severity: 0.94 (0.59-1.30) at <20%, 1.02 (0.70-1.34) at 20-40%, 1.26 (0.66-1.86) at 40-60% and 1.98 (1.25-2.72) at ≥60%. However, SIRs did not increase with increased seismic intensity: 0.95 (0.60-1.29) at <4.5, 1.52 (1.07-1.98) at 4.5-5.0 and 1.17 (0.80-1.54) at ≥5.0. ORs and adjusted ORs for seismic intensity in the high flood area compared with the low flood area were significant: 1.68 (1.07-2.65) and 1.78 (1.08-2.96), respectively. However, ORs and adjusted ORs for flood severity in the high seismic intensity area compared with the low intensity area were not significant: 1.33 (0.82-2.17) and 1.19 (0.62-2.31), respectively. Conclusions: Cerebrovascular disease incidences after the Great East Japan Earthquake and Tsunami of 2011 increased because of tsunami damage and not because of the earthquake magnitude.

Noncommunicable Diseases After the Great East Japan Earthquake: Systematic Review, 2011–2016

“…Increase of the patients and exacerbation of their symptoms was strongly related to the degree of tsunami damage. 74,75 The number of patients who had seizures also increased significantly during the 2 months after the GEJE. Shibahara expected that the lack of anticonvulsant therapy would contribute to worsening of their symptoms.…”

“…[71][72][73][74][75][76][77] The number of patients who developed some cerebrovascular disease, such as cerebral infarction, cerebral hemorrhage, subarachnoid hemorrhage, and seizures increased after the GEJE. 71,72,[74][75][76][77] Those patients were especially male, 75 years of age and older, and had sustained tsunami damage or injury. Increase of the patients and exacerbation of their symptoms was strongly related to the degree of tsunami damage.…”

Changes in Cognitive Functions in the Elderly Living in Temporary Housing after the Great East Japan Earthquake

“…Therefore, we are now planning to perform future studies to elucidate these issues. In addition, cerebral circulation could affect cognitive impairment because Omama et al reported that the occurrence of cerebral infarction among elderly men was more than doubled after the disaster [ 14 , 15 ].…”

Association between the extent of house collapse and urine sodium-to-potassium ratio of victims affected by the 2011 Great East Japan Earthquake and Tsunami: a cross-sectional study

“…After the 2011 Great East Japan Earthquake (GEJE), a high incidence of CVDs, such as stroke [ 10 ], heart failure [ 11 , 12 ], and acute myocardial infarction [ 12 , 13 ], was observed in the acute phase. The incidence of stroke [ 10 , 14 ] or heart failure [ 12 ] was particularly high in areas that were badly flooded by the tsunami due to the 2011 GEJE, and the incidence of acute myocardial infarction positively correlated with the seismic scale of the earthquake [ 12 ]. Furthermore, the increase in the incidence of fatal myocardial infarction [ 15 ] or acute decompensated heart failure [ 16 ] was sustained 3 years after the 2011 GEJE.…”