Prevalence of non-communicable diseases among healthy male decontamination workers after the Fukushima nuclear disaster in Japan: an observational study

Low-dose radiation exaggerates HFD-induced metabolic dysfunction by gut microbiota through PA-PYCR1 axis

Co-exposure of High-fat-diet (HFD) behavior and environmental low-dose radiation (LDR) is common among majority occupational workers, but the synergism of this co-exposure in metabolic health is poorly understood. This study aimed to investigate the impact of gut microbiota and its metabolites on the regulation of HFD accompanied by LDR-associated with metabolic dysfunction and insulin resistance. Here, we reported that Parasutterella was markedly elevated in the gut microbiota of mice in co-exposure of HFD and LDR, accompanied by increased pyrrolidinecarboxylic acid (PA) level in both intestine and plasma. Transplantation of fecal microbiota from mice with co-exposure HFD and LDR with metabolic dysfunction resulted in increased disruption of metabolic dysfunction, insulin resistance and increased PYCR1 (Pyrroline-5-carboxylate reductase 1) expression. Mechanistically, intestinal barrier was damaged more serious in mice with co-exposure of HFD and LDR, leading high PA level in plasma, activating PYCR1 expression to inhibit insulin Akt/mTOR (AKT kinase-transforming protein/Serine threonine-protein kinase) signaling pathway to aggravate HFD-induced metabolic impairments. This study suggests a new avenue for interventions against western diet companied with low dose radiation exposure-driven metabolic impairments.

Symposium on disaster-related deaths after the Fukushima Daiichi Nuclear Power Plant accident

Disaster deaths can be classified into direct and indirect deaths. Direct deaths are those caused by the direct physical effects of disasters, such as earthquakes, tsunamis, and radiation exposure. Indirect deaths are those caused by secondary health effects such as emergency evacuation, relocation, evacuation environment, disruption of health care delivery services, and psychosocial effects. In addition, in Japan, the term disaster-related deaths refers to indirect deaths in accordance with the disaster condolence payments system, which provides relief for bereaved families. On 11 March 2011, the Great East Japan Earthquake exposed several issues related to disaster-related deaths in Japan. Therefore, on 1 February 2022, a symposium on disaster-related deaths hosted by this study was held on the website. The symposium discussed the issues and challenges associated with disaster-related deaths for future disaster preparedness. The authors introduced the concept of 'shaking' at the symposium by defining 'shaking' as 'the repeated changes in the social and living environment that worsen health conditions, regardless of the disaster'. It was also pointed out that vulnerable populations are more likely to experience more pronounced health effects. This generalised concept of 'shaking' associated with disaster-related deaths suggests that it is important to anticipate disasters before they occur to take specific preventive measures, targeted at vulnerable populations. This study found that disaster-related deaths in Japan create several problems in terms of future radiation disaster preparedness and medical countermeasures. In the future, there will be a need to examine the relevance of the issues of disaster-related deaths identified as a result of this symposium for future radiation disaster preparedness.

Comparison of mortality patterns after the Fukushima Daiichi Nuclear Power Plant radiation disaster and during the COVID-19 pandemic

The initial health impact caused by radiation disasters can be broadly classified into direct and indirect effects. Though no direct health hazards caused by radiation, such as acute radiation injury, were observed following the Fukushima Daiichi nuclear power plant accident, indirect deaths have been reported, including those caused by initial emergency evacuation and relocation, medical disruption, and psychological and social health effects. However, these indirect health effects have not been prioritised for addressal. We evaluated the radiation disaster experience with that of the coronavirus disease (COVID-19) pandemic that emerged while facing the challenges from the radiation disaster. Most of the health effects of COVID-19 are directly associated with infection, but indirect health effects of various scales and entities have been reported. The two disasters have similarities in terms of the strain on community healthcare and the large number of deaths. Adapting the measures implemented in the acute to subacute phases of the COVID-19 disaster to radiation disasters may help improve management following future radiation disasters. Based on the experience and findings during the COVID-19 pandemic, the pattern of deaths in radiation disasters can be divided into five major groups: direct deaths, and four indirect patterns of deaths due to a deteriorating supply-demand balance (a hospital-level problem), collapse of the healthcare system (a community-level problem), death due to neglect alongside underlying disease, and diseases other than direct invasion. From the similarities between the two disasters, three main issues should be prioritised as initial emergency evacuation measures in a radiation disaster: emergency exposure medicine, the establishment of a medical system, and protection of death with dignity. The validity of these priority issues needs to be verified in future research.