Long-term effects of radiation exposure on mental health symptoms and concern among Fukushima nuclear plant workers: The Fukushima NEWS Project Study

The Fukushima nuclear power plant workers suffered tremendous stress due to the accident, and a part of them were exposed to high levels of radiation. This study included 1,157 workers and level of radiation exposure was assessed in 2012, one year after the disaster. Mental health symptoms (post-traumatic stress response PTSR and general psychological distress GPD) and three types of concern (work, life, or health-related) were assessed annually from 2012 to 2014. The relationships between high radiation exposure (≥50 millisievert mSv) and mental health symptoms and concern over time were analyzed using mixed-effects longitudinal beta regression and logistic regression models. A total of 352 workers were exposed to 50 mSv radiation or more (30.4%). None of the changes over time in PTSR and GPD were significantly affected by high radiation exposure. Scores for job- or life-related concern were also not significantly affected. Only scores for health-related concern were significantly elevated by high radiation exposure in 2012 (β=4.49, p=0.03), and the impact continued until 2014. Neither PTSR nor GPD was elevated by high radiation exposure among the workers. However, the workers with high radiation exposure continued to worry about their health in later years.