Following the accident at Fukushima Daiichi nuclear power plant, Fukushima Prefecture is conducting the Fukushima Health Management Survey, which has been contracted out to Fukushima Medical University. The purpose of this survey is to investigate the exposure doses and health conditions of the residents of Fukushima Prefecture in order to prevent, diagnose, and treat diseases at an early stage, and to maintain and improve the health of residents in the future.

This survey consists of a basic survey to estimate external exposure doses and detailed surveys to investigate health conditions. The detailed surveys comprise: (i) thyroid ultrasound examination; (ii) comprehensive health check; (iii) mental health and lifestyle survey; and (iv) pregnancy and birth survey.

In the basic survey, the external exposure dose was estimated for >466,000 people during the first 4 months after the accident; it was estimated to be <5 mSv for 99.8% of residents.

The thyroid ultrasound examination included four rounds of echo examinations covering approximately 380,000 children aged <18 years at the time of the accident in each round. The first, second, third, and fourth examinations identified 116, 71, 31, and 21 children with thyroid cancer/suspected cancer, respectively. The Fukushima Prefectural Oversight Committee analysed the results from the first and second examinations, and evaluated that ‘the detected increased rate is unlikely to be the impact of radiation’. However, the Oversight Committee is deliberating the future direction of thyroid examination, taking into consideration the advantages and disadvantages of the examination as well as ethical viewpoints.

In the comprehensive health check, approximately 210,000 people in the evacuation area were examined, and increased rates of lifestyle-related diseases [e.g. obesity, hypertension, diabetes, and dyslipidaemia (low high-density-lipoprotein cholesterol)] were confirmed. In the mental health and lifestyle survey, approximately 210,000 people, including residents in the evacuation area, were examined. A deterioration in general mental health was found for the period immediately after the accident across a wide range of age groups, and although recovery was seen over the years, the rate of mental health issues remains above the national average. The pregnancy and birth survey revealed that the pre-term birth rate, low-birthweight rate, and rate of congenital anomalies did not differ from the national average.

The purpose of Fukushima Health Management Survey is not only to collect data on the health of the residents of Fukushima Prefecture, but to provide direct support to residents regarding the health issues clarified by the survey. Moreover, various initiatives are being implemented in cooperation with various local government authorities with the aim of maintaining and promoting the health of the residents.