Five-year blood pressure trajectories of survivors of the tsunami following the Great East Japan Earthquake in Iwate.

Whether tsunami survivors who suffered substantial damage experienced increases in blood pressure (BP) immediately after the disaster and in the medium to long term is unclear. We divided tsunami survivors into groups, those who relocated (substantial damage) and those who did not (little damage) and compared the BP trajectories between the groups over the first 5 years after the disaster. Of the 42,831 residents, 3914 were assessed from 2010 to 2015. Subgroup analysis was performed among the 2037 subjects with no information on antihypertensive medications between 2010 and 2015 (no antihypertensive medication group). The BP trajectories in the relocation and no relocation groups were compared using linear mixed models. The multivariate-adjusted mean systolic BP (SBP) values for all subjects significantly decreased after the disaster in both the group who relocated (2010: 130.6 mmHg, 2015: 124.8 mmHg) and the group who did not relocate (2010: 130.7 mmHg, 2015: 126.7 mmHg). The interaction between relocation and time points on SBP was significant (P = 0.017). In the no antihypertensive medication group, the SBP values in the subgroup who relocated were significantly lower in the second, third, and fifth years after the disaster than those in the subgroup who did not relocate. It was concluded that the SBP values of survivors of the tsunami caused by Great East Japan Earthquake decreased in the medium to long term after the disaster, and the group who relocated had a larger decrease in SBP than the group who did not relocate.