Radiation occupational health interventions offered to radiation workers in response to the complex catastrophic disaster at the Fukushima Daiichi Nuclear Power Plant

Factors affecting the changes in body mass index among emergency workers at the Fukushima Daiichi Nuclear Power Plant

Understanding the effects of lifestyle and radiation on health is important for the health management of disaster recovery workers. International research has demonstrated the relationship between natural disasters and diseases. The lifestyle and working conditions following the Great East Japan Earthquake potentially increased the incidence of cardiovascular disease and obesity among affected individuals. The aim of this study was to analyze the body mass index (BMI) of 1,341 emergency workers who responded to the accident at the Fukushima Daiichi Nuclear Power Plant. The BMI of each emergency worker was measured immediately after the accident and compared with that measured at the initial survey conducted 5 yr later to determine the effect of lifestyle habits on BMI. Awareness of the frequency of eating out and caloric intake helped maintain their BMI, while evacuation contributed to the increase in BMI. Prevention of obesity, which can trigger or exacerbate certain health conditions, such as heat exhaustion, infection, and cerebro-cardiovascular disease, requires diet counseling, with a focus on maintaining adequate caloric intake; moreover, special consideration should be provided to evacuated workers.

Influence of post-disaster evacuation on childhood obesity and liver dysfunction: The Fukushima Health Management Survey

BACKGROUND

After the Great East Japan Earthquake and subsequent Fukushima Daiichi Nuclear Power Plant accident in 2011, the Fukushima Prefectural Government launched a long-term health management survey for the population of Fukushima. Results of the Comprehensive Health Check (CHC) showed that some children aged 6-15 years, who resided in the evacuation area at the time of the disaster, had obesity, hyperlipidemia, liver dysfunction, and/or renal dysfunction from as early as 2011. The aim of the present study was to determine the long-term trend of obesity and hepatic enzyme abnormalities in Fukushima children.

METHODS

We evaluated the changes in body mass index standard deviation score (BMI-SDS), aspartate aminotransferase, alanine aminotransferase, and gamma-glutamyl transpeptidase from 2011 to 2018.

RESULTS

Obesity (BMI-SDS ≥ 2) was significantly associated with hepatobiliary enzyme abnormalities. The mean BMI-SDS was significantly higher in 2011 after the disaster, but then soon showed a gradual decrease. The frequency of obesity did not increase significantly after the disaster. There were no significant differences in the prevalence of hepatobiliary enzyme abnormalities in the children aged 6-15 years of either sex from 2011 to 2018.

CONCLUSIONS

In the present study, we found that the increase in the mean BMI-SDS after the disaster was temporary, suggesting that the frequency of obesity and liver dysfunction might not have been significantly influenced by the disaster.

Obesity and glucose metabolism abnormalities by post-disaster evacuation

BACKGROUND

The objectives of this study were to determine the longer-term trends in childhood obesity and glucose metabolism abnormalities among residents of Fukushima Prefecture 5 years after the Great East Japan Earthquake.

METHODS

We evaluated the changes in height, weight, body mass index (BMI), BMI SD score, fasting plasma glucose (FPG) concentration, and hemoglobin A1c (HbA1c) among elementary and junior high school residents who had lived in the evacuation zone between 2011 and 2015.

RESULTS

Of the residents, 11,112 received health checks in 2011, while in 2012, 2013, 2014, and 2015, 5,737, 4522, 4297 and 3405 received health checks, respectively. The mean BMI SD score for all participants in 2011 was 0.149, and this score gradually decreased from 2011 to 2015. FPG levels and HbA1c levels for all participants with a BMI value +2SD or more in 2011 were higher than those in residents with a BMI value of less than +2SD. The frequency of participants with a FPG level of 126 mg/dl or more and the frequency of participants with a HbA1c level of 6.5% or more in 2011 were higher than those in 2012, 2013, and 2015.

CONCLUSIONS

These results suggest that a number of pediatric residents suffered from obesity and glucose metabolism abnormalities. However, the longer-term observations indicated an improvement in obesity and glucose metabolism abnormalities. There was a strong association observed between obesity and glucose metabolism, thus, it is important to continue with health checks for children with obesity and strive to improve their health.

Contribution of radiation education to anxiety reduction among Fukushima Daiichi Nuclear Power Plant workers: a cross sectional study using a text mining method

The purpose of this study is to investigate the frequency of education, knowledge of radiation and workplace anxiety of Fukushima Daiichi Nuclear Power Plant (FDNPP) workers and to analyze what type of words are used for anxiety with a text mining method. An original questionnaire survey was given to FDNPP workers, and a text mining method was used to extract information from free-entry fields. The questionnaires were collected from 1135 workers (response rate: 70.8%). It was found that when workers receive education on radiation, the increased knowledge helps to reduce their anxiety. Among the 1135 workers, 92 of 127 completed the free-entry field with valid entries. Seventy-one words were extracted by the text mining method. The words used differed depending on the degree of anxiety. The text mining method revealed information about the presence or absence of radiation anxiety and the subjects' working environment and background.

High-dose radiation exposure and hypothyroidism: aetiology, prevention and replacement therapy

Without any doubt, high dose radiation exposure can induce hypothyroidism. However, there are open questions related to the mechanisms of its induction, corresponding dose thresholds and possible countermeasures. Therefore, this review addresses the aetiology, prevention and therapy of radiation induced hypothyroidism. External beam radiotherapy with several 10 Gy to the head and neck region and radioiodine therapy with several 100 Gy thyroid absorbed dose can destroy the thyroid gland and can induce autoantibodies against thyroid tissue. According to recent literature, clinical hypothyroidism is observed at threshold doses of ∼10 Gy after external beam radiotherapy and of ∼50 Gy after radioiodine therapy, children being more sensitive than adults. In children and adolescents exposed by the Chernobyl accident with mean thyroid absorbed doses of 500-800 mGy, subclinical hypothyroidism has been detected in 3%-6% of the cases with significant correlation to thyroid absorbed doses above 2.5 Gy. In case of nuclear emergencies, iodine thyroid blocking (ITB) is the method of choice to keep thyroid absorbed doses low. Large doses of stable iodine affect two different steps of internalization of radioiodine (transport and organification); perchlorate affecting the transport only may be an alternative to iodine. Administered before radioiodine incorporation, the effect of 100 mg iodide or more is still about 90% after 1 days, 80% after 2 days, and 50% or less after 3 days. If administered (too) late after exposure to radioiodine, the theoretically expected protective effect of ITB is about 50% after 6 h, 25% after 12 h, and about 6% after 24 h. In case of repeated or continuous exposure, repeated administration of 50 mg of iodide daily is indicated. If radiation-induced hypothyroidism cannot be avoided, thyroid hormone replacement therapy with individualized dosing and regular monitoring in order to maintain thyroid-stimulating hormone levels within the normal range ensures normal life expectancy.

Identifying Candidate Biomarkers of Ionizing Radiation in Human Pulmonary Microvascular Lumens Using Microfluidics-A Pilot Study

The microvasculature system is critical for the delivery and removal of key nutrients and waste products and is significantly damaged by ionizing radiation. Single-cell capillaries and microvasculature structures are the primary cause of circulatory dysfunction, one that results in morbidities leading to progressive tissue and organ failure and premature death. Identifying tissue-specific biomarkers that are predictive of the extent of tissue and organ damage will aid in developing medical countermeasures for treating individuals exposed to ionizing radiation. In this pilot study, we developed and tested a 17 µL human-derived microvascular microfluidic lumen for identifying candidate biomarkers of ionizing radiation exposure. Through mass-spectrometry-based proteomics, we detected 35 proteins that may be candidate early biomarkers of ionizing radiation exposure. This pilot study demonstrates the feasibility of using humanized microfluidic and organ-on-a-chip systems for biomarker discovery studies. A more elaborate study of sufficient statistical power is needed to identify candidate biomarkers and test medical countermeasures of ionizing radiation.

KMRC011, an agonist of toll-like receptor 5, mitigates irradiation-induced tissue damage and mortality in cynomolgus monkeys

In the study here, the potential applicability of KMRC011 - an agonist of toll-like receptor-5 - as a countermeasure for radiation toxicities was evaluated. Following a single 5.5 Gy total body irradiation (TBI, surface absorbed dose = 7 Gy) of Co⁶⁰ γ-rays, mortality rates and degrees of pathological lesions that developed over 80 days were compared in monkeys that received TBI only and a group that was injected once with KMRC011 (10 μg/kg) after TBI. Compared to the TBI-only hosts (80%), the death rate was significantly improved by the use of KMRC011 (40%), all deaths in both groups occurred in the period from Days 19-24 post-TBI. Further analysis of monkeys that survived until the end of the experiment showed that AST and ALT levels were elevated only in the TBI group, and that radiation-induced tissue damage was alleviated by the KMRC011 injection. Additionally, expression of cell death-related proteins was lower in tissues from the KMRC011-treated hosts than in those in the TBI-only group. Other measured parameters, including body weight, food uptake, and hematological values did not significantly differ between the two groups over the entire period. The results of this study, thus demonstrate that KMRC011 could potentially be used as a medical countermeasure for the treatment of acute radiation exposure.

Roles of Fibroblasts in Microenvironment Formation Associated with Radiation-Induced Cancer

In tumor tissues, activated stromal fibroblasts, termed cancer-associated fibroblasts (CAFs), exhibit similar characteristics to myofibroblasts. CAFs promote cancer cell differentiation and invasion by releasing various factors, such as growth factors, chemokines, and matrix-degrading proteases, into neighboring tumor cells. However, the roles of tumor microenvironment in case of radiation-induced carcinogenesis remain poorly understood. We recently revealed that mitochondrial oxidative stress causes tumor microenvironment formation associated with radiation-induced cancer. Repeated low-dose fractionated radiation progressively damages fibroblast mitochondria and elevates mitochondrial reactive oxygen species (ROS) levels. Excessive mitochondrial ROS activate transforming growth factor-beta (TGF-β) signaling, thereby inducing fibroblasts activation and facilitating tumor microenvironment formation. Consequently, radiation affects malignant cancer cells directly and indirectly via molecular alterations in stromal fibroblasts, such as the activation of TGF-β and angiogenic signaling. This review summarizes for the first time the roles of mitochondrial oxidative stress in microenvironment formation associated with radiation-induced cancer. This review may help us understand the risks of exposure to low-dose radiation. The cross talk between cancer cells and stromal fibroblasts contributes to the development and progression of radiation-induced cancer.

Influence of post-disaster evacuation on childhood obesity and hyperlipidemia

BACKGROUND

The objectives of this study were to determine the longer-term trends in childhood obesity and hyperlipidemia among residents of Fukushima Prefecture 5 years after the Great East Japan Earthquake.

METHODS

We evaluated the changes in height, weight, body mass index (BMI) standard deviation score (BMI-SDS), low-density lipoprotein-cholesterol (LDL-CHO), high-density lipoprotein-cholesterol (HDL-CHO), and triglyceride (TG) in residents aged 7-15 years who had lived in the evacuation zone between 2011 and 2015.

RESULTS

(i) the mean BMI SDS in all residents in 2011 was 0.113, and the mean BMI-SDS in all residents gradually decreased from 2011 to 2015; (ii) serum LDL-CHO levels and TG levels in all residents with a BMI value ≧ 2SD in 2011 were higher than those in residents with a BMI value <2SD; (iii) the frequency of residents with an LDL-CHO level ≥ 140 mg/dl in 2012, 2013, and 2014 did not decrease in comparison with that in 2011, whereas the frequency of residents with an LDL-CHO level of  ≥ 140 mg/dl in 2015 was lower than that in 2011. The frequency of residents with a TG level ≥ 120 mg/dl increased over the 5 years.

CONCLUSIONS

These results suggest that a number of pediatric residents suffered from obesity and hyperlipidemia. Furthermore, the long-term observation indicated an improvement in obesity, although the improvement in lipid abnormalities was delayed compared with that in obesity. Thus, it is necessary to continue with health checks for these residents with obesity and/or hyperlipidemia.

Non-communicable diseases in decontamination workers in areas affected by the Fukushima nuclear disaster: a retrospective observational study

OBJECTIVES

To assess the prevalence of non-communicable diseases (NCDs), and whether NCDs were treated or not, among hospitalised decontamination workers who moved to radio-contaminated areas after Japan's 2011 Fukushima Daiichi Nuclear Power Plant disaster.

METHODS

We retrospectively extracted records of decontamination workers admitted to Minamisoma Municipal General Hospital between 1 June 2012 and 31 August 2015, from hospital records. We investigated the incidence of underlying NCDs such as hypertension, dyslipidaemia and diabetes among the decontamination workers, and their treatment status, in addition to the reasons for their hospital admission.

RESULTS

A total of 113 decontamination workers were admitted to the hospital (112 male patients, median age of 54 years (age range: 18-69 years)). In terms of the demographics of underlying NCDs in this population, 57 of 72 hypertensive patients (79.2%), 37 of 45 dyslipidaemic patients (82.2%) and 18 of 27 hyperglycaemic patients (66.7%) had not been treated for their NCDs before admission to the hospital.

CONCLUSIONS

A high burden of underlying NCDs was found in hospitalised decontamination workers in Fukushima. Managing underlying diseases such as hypertension, hyperlipidaemia and diabetes mellitus is essential among this population.

The longitudinal mental health impact of Fukushima nuclear disaster exposures and public criticism among power plant workers: the Fukushima NEWS Project study

BACKGROUND

The Fukushima Daiichi and Daini Nuclear Power Plant workers experienced multiple stressors as both victims and onsite workers after the 2011 Great East Japan Earthquake and subsequent nuclear accidents. Previous studies found that disaster-related exposures, including discrimination/slurs, were associated with their mental health. Their long-term impact has yet to be investigated.

METHOD

A total of 968 plant workers (Daiichi, n = 571; Daini, n = 397) completed self-written questionnaires 2-3 months (time 1) and 14-15 months (time 2) after the disaster (response rate 55.0%). Sociodemographics, disaster-related experiences, and peritraumatic distress were assessed at time 1. At time 1 and time 2, general psychological distress (GPD) and post-traumatic stress response (PTSR) were measured, respectively, using the K6 scale and Impact of Event Scale Revised. We examined multivariate covariates of time 2 GPD and PTSR, adjusting for autocorrelations in the hierarchical multiple regression analyses.

RESULTS

Higher GPD at time 2 was predicted by higher GPD at time 1 (β = 0.491, p < 0.001) and discrimination/slurs experiences at time 1 (β = 0.065, p = 0.025, adjusted R 2 = 0.24). Higher PTSR at time 2 was predicted with higher PTSR at time 1 (β = 0.548, p < 0.001), higher age (β = 0.085, p = 0.005), and discrimination/slurs experiences at time 1 (β = 0.079, p = 0.003, adjusted R 2 = 0.36).

CONCLUSIONS

Higher GPD at time 2 was predicted by higher GPD and discrimination/slurs experience at time 1. Higher PTSR at time 2 was predicted by higher PTSR, higher age, and discrimination/slurs experience at time 1.

Revisiting the health effects of psychological stress-its influence on susceptibility to ionizing radiation: a mini-review

Both psychological stress (PS) and ionizing radiation (IR) cause varied detrimental effects on humans. There has been no direct evidence so far showing PS alone could cause cancer; however, long-lasting PS may affect our overall health and ability to cope with cancer. Due to their living conditions and occupations, some people may encounter concurrent exposure to both PS and IR to a high extent. In addition to possible health effects resulting directly from exposure to IR on these people, fear of IR exposure is also a cause of PS. The question of whether PS would influence susceptibility to IR, radiocarcinogenesis in particular, is of great concern by both the academic world and the public. Recently, investigations using animal PS models demonstrated that PS could modulate susceptibility to IR, causing increased susceptibility to radiocarcinogenesis in Trp53-heterozygous mice, hematological toxicity in peripheral blood and elevated chromosome aberration (dicentrics) frequency in splenocytes of Trp53-wild-type mice. To actively reduce health risk from exposure to IR, further studies are needed to cumulate more evidence and provide insights into the mechanisms underlying the alterations in susceptibility due to PS modulation. This mini-review gives a general overview of the significance of PS effects on humans and experimental animals, with a special focus on summarizing the latest weight-of-evidence approaches to radiobiological studies on PS-induced alterations in susceptibility in experimental animal models. The susceptibility being investigated is mainly in the context of the impact of the modulatory effect of PS on radiocarcinogenesis; we seek to improve understanding of the combined effects of exposure to both PS and IR in order to facilitate, via active intervention, strategies for radiation risk reduction.

THE BASIC DATA FOR RESIDENTS AGED 15 YEARS OR YOUNGER WHO RECEIVED A COMPREHENSIVE HEALTH CHECK IN 2011-2012 AS A PART OF THE FUKUSHIMA HEALTH MANAGEMENT SURVEY AFTER THE GREAT EAST JAPAN EARTHQUAKE

AIM

To assist in the long-term health management of residents and evaluate the health impacts after the Tokyo Electric Power Company's Fukushima Daiichi Nuclear Power Plant accident in Fukushima Prefecture, the Fukushima prefectural government decided to implement the Fukushima Health Management Survey. This report describes the results for residents aged 15 years or younger who received health checks and evaluates the data obtained from 2011 and 2012.

METHODS

The target group consisted of residents aged 15 years or younger who had lived in the evacuation zone. The health checks were performed on receipt of an application from any of the residents. The checks, which included the measurements of height, weight, blood pressure, biochemical laboratory findings, and peripheral blood findings, were performed as required.

RESULTS

1) A total of 17,934 (64.5%) and 11,780 (43.5%) residents aged 15 years or younger received health checks in 2011 and 2012, respectively. 2) In both years, a number of male and female residents in the 7-15 year age group were found to suffer from obesity, hyperlipidemia, hyperuricemia, or liver dysfunction. Furthermore, pediatric aged 15 years or younger were commonly observed to suffer from hypertension or glucose metabolic abnormalities. 3) A comparison of data from 2012 and 2011 demonstrated that both males and females frequently showed increased body height and decreased body weight in 2012. The prevalence of hypertension, glucose metabolic abnormalities, or high γ-GTP values in males and females in the 7-15 year age group in 2012 was lower than that in 2011. However, the prevalence of hyperuricemia among residents in the 7-15 year age group was higher in 2012 than in 2011.

CONCLUSIONS

These results suggested that some residents aged 15 years or under who had lived in the evacuation zone had developed obesity, hyperlipidemia, hyperuricemia, liver dysfunction, hypertension, or glucose metabolic abnormalities. Therefore, we think that it is necessary to continue the health checks for these residents in order to ameliorate these lifestyle-related diseases.

Public health activities for mitigation of radiation exposures and risk communication challenges after the Fukushima nuclear accident

Herein we summarize the public health actions taken to mitigate exposure of the public to radiation after the Fukushima accident that occurred on 11 March 2011 in order to record valuable lessons learned for disaster preparedness. Evacuations from the radiation-affected areas and control of the distribution of various food products contributed to the reduction of external and internal radiation exposure resulting from the Fukushima incident. However, risk communication is also an important issue during the emergency response effort and subsequent phases of dealiing with a nuclear disaster. To assist with their healing process, sound, reliable scientific information should continue to be disseminated to the radiation-affected communities via two-way communication. We will describe the essential public health actions following a nuclear disaster for the early, intermediate and late phases that will be useful for radiological preparedness planning in response to other nuclear or radiological disasters.