A cross-sectional survey of blood pressure of a coastal city's resident victims of the 2011 Tohoku tsunami.

Background: Blood pressure (BP) increase as a reaction to major disasters has been well documented; however, the impact has been underdocumented for tsunamis. This study aimed to confirm whether different levels of flooding/inundation and other damage caused by the 2011 Tohoku (northeast Japan) tsunami were associated with BP among resident victims in Higashi-Matsushima, Miyagi.

Methods: Cross-sectional household screening was conducted 7-19 weeks after the disaster in administrative areas totally or partially flooded by the tsunami. Systolic and diastolic BP (SBP/DBP) were measured in 4,311 residents.

Results: There was a degree-dependent association between SBP/DBP and flooding height above sea level among victims not on antihypertensive medication (P < 0.01 for both). Disruption of the gas supply was also significantly associated with SBP/DBP (P < 0.01 for both). Among individuals on antihypertensive medication, the discontinuation of medication was associated with SBP/DBP (P < 0.01 for both). After adjusting for confounding and multiplicity, a matched case-control analysis did not identify any significant associations between the tsunami or lifeline indicators and high BP (SBP ≥160mm Hg or DBP ≥100mm Hg).

Conclusions: This study suggests that after a major tsunami, resident victims in areas highly inundated by flood waters and those with disrupted gas supply are more likely to have higher BP and thus might warrant getting BP screening earlier than other residents. Those with hypertension should be given assistance to resume or commence antihypertensive medication as soon as possible to reduce the risk of cardiovascular morbidity and mortality.