High-sodium diets in Japanese evacuation centers increase blood pressures of evacuees.

Aims: High blood pressure after a natural disaster is tentatively considered to be due to elevation of sympathetic nerve activity. A volcano in Japan erupted on March 31, 2000, and people living in the vicinity of the volcano were evacuated to safe shelters. We found that many evacuees developed high blood pressure while staying at evacuation centers. The aim of this study was to investigate why their blood pressures stayed elevated. Methods and Subjects: Sixty-five evacuees, who were staying evacuation centers for 4 months, were examined for blood pressure, urinary sodium excretion, urinary potassium excretion, and plasma and urinary catecholamines. Results: Associations were found between systolic blood pressure and sodium excretion (r = 0.311, p < 0.05) and between systolic blood pressure and the ratio of urinary sodium to urinary potassium (r = 0.320, p < 0.05). However, no association was found between blood pressure and plasma and urinary catecholamines (NE, DHPG and MHPG). Conclusion: High sodium consumption was thought to be an important factor in the elevation of blood pressure of the evacuees after acute phase reactions.