Seven-year incidence of new-onset hypertension by frequency of dairy intake among survivors of the Great East Japan Earthquake

Survivors of natural disasters are at a high risk of cardiovascular disease. Behavioral risk factors, including modifiable diet, need to be identified. Thus far, the association between dairy intake and new-onset hypertension among these survivors is unknown. Therefore, we investigated this relationship. We conducted a longitudinal cohort study of 4475 survivors of the Great East Japan Earthquake in 2011 who participated in a 7-year follow-up survey. New-onset hypertension was assessed using annual health checkup data. Information on the frequency of dairy intake was obtained using a self-report questionnaire. The hazard ratio for developing hypertension according to the frequency of dairy intake was calculated using Cox proportional hazards regression models. The total number of person-years observed was 20,042, with a median follow-up of 5.4 years. During the observation period, 1554 individuals developed hypertension. The multivariable-adjusted hazard ratios of new-onset hypertension were significantly lower in those who consumed dairy products once per day (0.82, 95% confidence interval 0.71–0.94) and twice or more times per day (0.84, 95% confidence interval 0.71–0.99) than in nonconsumers; the inverse linear trend was marginally significant (P = 0.083). This association was not affected by lipid metabolism and was consistent across subgroups by sex, age, behavioral factors, cardiometabolic factors, and housing type due to the disaster. A higher frequency of dairy intake was associated with a lower risk of new-onset hypertension in community-dwelling survivors of earthquakes and tsunamis. Dietary guidance involving dairy intake could reduce the risk of developing hypertension among these survivors.