Loss of participation among young adults in the prospective disaster cohort study of the Comprehensive Health Check in the Fukushima Health Management Survey after the Great East Japan Earthquake

Abstract

Abstract Background The present study aimed to clarify the characteristics of young evacuees who had missed the Comprehensive Health Check of the Fukushima Health Management Survey after the Great East Japan Earthquake in 2011. Methods The Fukushima Health Management Survey has been conducted as a prospective cohort study to evaluate health status of evacuees annually after the great earthquake in 2011. This study focused on the annual participation rate in the Comprehensive Health Check of young evacuees aged between 20 and 37 years who had been evacuated due to the Fukushima Daiichi Nuclear Power Plant accident. Exploratorily, we compared the characteristics of subjects who participated in 2011 only with those who had in both 2011 and after 2012. Results The participation rate was estimated at 26.6% (9,720 among 36,502 residents) and 15.6% (5,691 residents) in 2011 and 2012, respectively. Multivariate analysis revealed the following characteristics in 2011 as independent predictors of non-participation after the second year of the survey: age ≤ 24 years (adjusted odds ratio 2.07, 95% confidence interval: 1.82–2.36), 25–29 years of age (1.25, 1.12–1.41), men (1.51, 1.37–1.66), evacuation outside the municipality but within Fukushima Prefecture (1.52, 1.38–1.67), evacuation outside the Fukushima Prefecture (1.29, 1.14–1.46), smoking habit (1.33, 1.21–1.46), and drinking habit (1.19, 1.09–1.30). A medical history of heart disease and a body mass index ≤ 18.5 kg/m2 showed opposite odds ratios which indicates the association with continuous participation (0.48, 0.30–0.76, 0.84, 0.73–0.97, respectively). Conclusions We observed deteriorated participation in the prospective study of the Comprehensive Health Check of the Fukushima Health Management Survey among evacuees of a younger age group, men, those evacuated outside their municipalities, and those with smoking and drinking habits. Hence, the cohort study may have missed certain population groups indifferent to disaster-related health problems. Thus, it is necessary to consider various measures to increase the participation rate in the disaster cohort study to understand the long-term health effects of disasters on younger residents in evacuation zones.