Association between relocation and changes in cardiometabolic risk factors: a longitudinal study in tsunami survivors of the 2011 Great East Japan Earthquake

Abstract

Objectives: The aim of this study is to determine changes in atherosclerotic cardiovascular risk factors with and without serious disaster-related mental and socioeconomic problems represented by relocation (REL).

Design: A longitudinal survey.

Setting: Multiphasic health check-ups for the general population affected by the 2011 Great East Japan Earthquake and Tsunami.

Participants: A total 6528 disaster survivors in heavily tsunami-damaged municipalities were recruited. Two sequential surveys were conducted and the data were analysed.

Main outcome measures: Multiphasic health check-ups including investigation of lifestyle and psychological and socioeconomic measures were performed in two sequential phases (8 and 18 months) after the disaster for tsunami survivors with REL (n=3160) and without REL (n=3368). Longitudinal changes in cardiometabolic risk factors between the two phases were compared in the REL and non-REL groups.

Results: In sex/age-adjusted analysis, we found increases in body weight and waist circumference between the two phases that were significantly greater in the REL group than in the non-REL group (body weight:+0.31 (0.23∼0.39) versus -0.24 (-0.32∼-0.16) kg, p<0.001; waist circumference:+0.58 (0.48∼0.68) versus+0.05 (-0.05∼0.15) cm, p<0.001)). A decrease in serum HDLC levels was found and again was significantly greater in the REL group than in the non-REL group (-0.65 (-0.96∼-0.34) versus -0.09 (-0.39∼0.21) mg/dL, p=0.009). In addition, deterioration in physical activity, mental health and socioeconomic status was more prevalent in the REL group than in the non-REL group (all p<0.001).

Conclusions: This study suggests that relocation after the devastating tsunami was related to weight gain and decreasing HDLC among survivors, and this change was associated with prolonged psychological distress and socioeconomic problems after the disaster.

Keywords: EPIDEMIOLOGY; PREVENTIVE MEDICINE; PUBLIC HEALTH.

Figure 1

Map of the study area. The black square shows the study area along the Pacific Ocean coast that was affected by the tsunami. The municipalities included in our study were Yamada, Otsuchi and Rikuzentakata. The epicentre of the earthquake is marked as a dot.

Figure 2

Flow chart of the study phase and the procedure used to select participants for the study. The survey in 2011 (phase 1) was conducted 6 months after the disaster (from September to December 2011). The original cohort consisted of 10 196 participants in phase 1. The next survey (phase 2) was carried out 18 months after the disaster (from September to December 2012). The average period between phase 1 and phase 2 was 11 months. We excluded a total of 2689 persons who did not participate in the phase 2 survey and 979 persons who lacked at least one variable used for analysis. We finally used data from 6528 participants for analysis.

Figure 3

Comparison of sex-adjusted and age-adjusted mean changes in body weight (3A), waist circumference (3B) and serum HDLC level (3C) between phase 1 and phase 2 surveys for the REL and non-REL groups. Adjusted mean and 95% CI. HDLC, high-density lipoprotein cholesterol; REL, relocation group; non-REL, non-relocation group.