EXTERNAL AND INTERNAL EXPOSURE TO FUKUSHIMA RESIDENTS

Varying Cellular Immune Response against SARS-CoV-2 after the Booster Vaccination: A Cohort Study from Fukushima Vaccination Community Survey, Japan

Booster vaccination reduces the incidence of severe cases and mortality related to COVID-19, with cellular immunity playing an important role. However, little is known about the proportion of the population that has achieved cellular immunity after booster vaccination. Thus, we conducted a Fukushima cohort database and assessed humoral and cellular immunity in 2526 residents and healthcare workers in Fukushima Prefecture in Japan through continuous blood collection every 3 months from September 2021. We identified the proportion of people with induced cellular immunity after booster vaccination using the T-SPOT.COVID test, and analyzed their background characteristics. Among 1089 participants, 64.3% (700/1089) had reactive cellular immunity after booster vaccination. Multivariable analysis revealed the following independent predictors of reactive cellular immunity: age < 40 years (adjusted odds ratio: 1.81; 95% confidence interval: 1.19-2.75; p-value: 0.005) and adverse reactions after vaccination (1.92, 1.19-3.09, 0.007). Notably, despite IgG(S) and neutralizing antibody titers of ≥500 AU/mL, 33.9% (349/1031) and 33.5% (341/1017) of participants, respectively, did not have reactive cellular immunity. In summary, this is the first study to evaluate cellular immunity at the population level after booster vaccination using the T-SPOT.COVID test, albeit with several limitations. Future studies will need to evaluate previously infected subjects and their T-cell subsets.

Loss of participation among evacuees aged 20-37 years in the disaster cohort study after the Great East Japan Earthquake

The present study aimed to clarify the characteristics of young evacuees who had missed the Comprehensive Health Check of the Fukushima Health Management Survey (FHMS) after the Great East Japan Earthquake in 2011. The FHMS has been conducted as a prospective cohort study to evaluate the 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 evacuees aged between 20 and 37 years in 2011 who evacuated due to the Fukushima Daiichi Nuclear Power Plant accident. The characteristics of subjects who did not participate after the second survey year were identified with a multivariate logistic regression model. The participation rate was estimated at 26.6% (9720 among 36,502 residents) and 15.6% (5691 residents) in 2011 and 2012, respectively. The logistic regression model revealed the following characteristics at baseline as independent predictors of non-participation after the second year of the survey: age ≤ 24 years (adjusted odds ratio 2.11, 95% CI 1.84-2.42), 25-29 years of age (1.28, 1.13-1.45), men (1.52, 1.38-1.69), evacuation outside the municipality but within Fukushima prefecture (1.54, 1.40-1.70), evacuation outside the Fukushima prefecture (1.40, 1.21-1.63), anemia (1.23, 1.06-1.43), smoking habit (1.34, 1.21-1.48), and drinking habit (1.20, 1.09-1.32). A medical history of heart disease showed opposite odds ratios, which indicate the association with continuous participation (0.43, 0.26-0.72, respectively). We observed deteriorated participation in the prospective study of the Comprehensive Health Check of the FHMS among evacuees of a younger age group, men, those evacuated outside their municipalities, and those with history of anemia, smoking and drinking habits. Hence, the cohort study may have missed certain population groups with worse health behaviors. 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.

Tailoring Digital Tools to Address the Radiation and Health Information Needs of Returnees after a Nuclear Accident

Digital tools are increasingly used for health promotion, but their utility during recovery from a nuclear disaster has yet to be established. This study analysed differences in knowledge, attitude, and practice (KAP) toward digital tools for radiation protection and health promotion, and preferences for specific application functions, among cohorts living within and outside areas affected by the Fukushima Daiichi nuclear power station (FDNPS) accident. A needs assessment was conducted by internet survey, and responses from those affected (N = 86) and not affected (N = 253) were compared and quantified by an adjusted odds ratio (aOR), using logistic regression analyses. KAP toward the radiation-related application in the affected group had an aOR of 1.95 (95% confidence interval (CI) = 1.12–3.38) for knowledge, and 5.71 (CI = 2.55–12.8) for practice. Conversely, toward the health-related application, the aOR of the affected group was 0.50 (CI = 0.29–0.86). The preference in the affected group was significantly lower for two application functions related to radiation measurement and two health-related functions (one about the effects of radiation in general and another about personal health advice in general): aOR range 0.43–0.50. Development of specific applications incorporating the findings from this survey was intended to foster a locally appropriate eHealth environment during recovery from the FDNPS accident.

Rahim MH, Nordin R, Mohamed F, Abu-Samah A, Abdullah NF. Ionizing Radiation Monitoring Technology at the Verge of Internet of Things

As nuclear technology evolves, and continues to be used in various fields since its discovery less than a century ago, radiation safety has become a major concern to humans and the environment. Radiation monitoring plays a significant role in preventive radiological nuclear detection in nuclear facilities, hospitals, or in any activities associated with radioactive materials by acting as a tool to measure the risk of being exposed to radiation while reaping its benefit. Apart from in occupational settings, radiation monitoring is required in emergency responses to radiation incidents as well as outdoor radiation zones. Several radiation sensors have been developed, ranging from as simple as a Geiger-Muller counter to bulkier radiation systems such as the High Purity Germanium detector, with different functionality for use in different settings, but the inability to provide real-time data makes radiation monitoring activities less effective. The deployment of manned vehicles equipped with these radiation sensors reduces the scope of radiation monitoring operations significantly, but the safety of radiation monitoring operators is still compromised. Recently, the Internet of Things (IoT) technology has been introduced to the world and offered solutions to these limitations. This review elucidates a systematic understanding of the fundamental usage of the Internet of Drones for radiation monitoring purposes. The extension of essential functional blocks in IoT can be expanded across radiation monitoring industries, presenting several emerging research opportunities and challenges. This article offers a comprehensive review of the evolutionary application of IoT technology in nuclear and radiation monitoring. Finally, the security of the nuclear industry is discussed.

Health management and care following the Fukushima nuclear power plant accident: overview of Fukushima Health Management Survey

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.

The Clinicopathological Results of Thyroid Cancer With BRAFV600E Mutation in the Young Population of Fukushima

BACKGROUND

Thyroid ultrasound screening for children aged 0 to 18 years was performed in Fukushima following the accident at the Fukushima Daiichi Nuclear Power Plant. As a result, many thyroid cancer cases were detected. To explore the carcinogenic mechanisms of these cancers, we analyzed their clinicopathological and genetic features.

METHODS

We analyzed 138 cases (52 males and 86 females) who had undergone surgery between 2013 and 2016 at Fukushima Medical University Hospital. Postoperative pathological diagnosis revealed 136 (98.6%) cases of papillary thyroid cancer (PTC).

RESULTS

The BRAFV600E mutation was detected using direct DNA sequencing in 96 (69.6%) of the thyroid cancer cases. In addition, oncogenic rearrangements were detected in 23 cases (16.7%). Regarding chromosomal rearrangements, 8 (5.8%) RET/PTC1, 6 (4.3%) ETV6(ex4)/NTRK3, 2 (1.4%) STRN/ALK, and 1 each of RET/PTC3, AFAP1L2/RET, PPFIBP/RET, KIAA1217/RET, ΔRFP/RET, SQSTM1/NTRK3 and TPR/NTRK1 were detected. Tumor size was smaller in the BRAFV600E mutation cases (12.8 ± 6.8 mm) than in wild-type BRAF cases (20.9 ± 10.5 mm). In the BRAFV600E mutation cases, 83 (86.5%) showed lymph node metastasis, whereas 26 (61.9%) of the wild-type BRAF cases showed lymph node metastasis.

CONCLUSIONS

The BRAFV600E mutation was mainly detected in residents of Fukushima, which was different from post-Chernobyl PTC cases with RET/PTC3 rearrangement. PTC with the BRAFV600E mutation was smaller but was shown in the high rate of central cervical lymph node metastasis than the wild-type BRAF PTC in the young population of Fukushima.

External Radiation Dose, Obesity, and Risk of Childhood Thyroid Cancer After the Fukushima Daiichi Nuclear Power Plant Accident: The Fukushima Health Management Survey

BACKGROUND

The 2011 Great East Japan Earthquake led to a nuclear accident at Fukushima Daiichi Nuclear Power Plant. This study examines the associations of radiation dose and lifestyle factors with incidence of thyroid cancer in Fukushima.

METHODS

We designed a prospective study with 300,473 participants aged 18 years or younger, who underwent thyroid examinations from October 2011. Follow-up surveys were conducted through June 2017, and 245,530 participants (123,480 men and 122,050 women, 82% follow-up) received follow-up examinations. Fukushima Prefecture was divided into five areas based on individual external radiation dose. We calculated relative risks and 95% confidence intervals (CIs) for thyroid cancer in each area, with area of lowest dose as reference, using age-adjusted Poisson regression models. We also calculated risks associated with overweight and obesity.

RESULTS

The incidence per 100,000 for Groups A (highest dose), B, C, D, and E (lowest dose) were 13.5, 19.2, 17.3, 9.0, and 8.3, respectively. Compared with Group E, the age-adjusted risks (95% CIs) were 1.62 (0.59, 4.47) for group A, 2.32 (0.86, 6.24) for group B, 2.21 (0.82, 5.94) for group C, and 1.02 (0.36, 2.86) for group D. Obesity was positively associated with thyroid cancer incidence; the multivariable-adjusted risk of thyroid cancer was 2.23 (1.01, 4.90) for obese individuals compared with nonobese individuals.

CONCLUSION

Regional differences in radiation dose were not associated with increased risk of thyroid cancer among children in Fukushima within 4 to 6 years after the nuclear power plant accident. Obesity may be an important factor for further follow-up in Fukushima.

Cryptorchidism after the Fukushima Daiichi Nuclear Power Plant accident:causation or coincidence?

Cryptorchidism (undescended testes) is among the most common congenital diseases in male children. Although many factors have been linked to the incidence of cryptorchidism, and testicular androgen plays a key role in its pathogenesis, the cause remains unknown in most cases. Recently, a Japanese group published a speculative paper entitled, "Nationwide increase in cryptorchidism after the Fukushima nuclear accident." Although the authors implicated radionuclides emitted from the Fukushima accident as contributing to an increased incidence of cryptorchidism, they failed to establish biological plausibility for their hypothesis, and glossed over an abundance of evidence and expert opinion to the contrary. We assessed the adequacy of their study in terms of design setting, data analysis, and its conclusion from various perspectives. Numerous factors must be considered, including genetic, environmental, maternal/fetal, and social factors associated with the reporting of cryptorchidism. Other investigators have established that the doses of external and internal radiation exposure in both Fukushima prefecture and the whole of Japan after the accident are too low to affect testicular descent during fetal periods;thus, a putative association can be theoretically and empirically rejected. Alternative explanations exist for the reported estimates of increased cryptorchidism surgeries in the years following Japan's 2011 earthquake, tsunami, and nuclear crisis. Data from independent sources cast doubt on the extent to which cryptorchidism increased, if at all. In any case, evidence that radionuclides from the Fukushima Daiichi Nuclear Power Plant could cause cryptorchidism is lacking.

Risk Perception and Anxiety Regarding Radiation after the 2011 Fukushima Nuclear Power Plant Accident: A Systematic Qualitative Review

The purpose of this study was to provide a review of the publications of the risk perceptions or anxiety regarding radiation among people living in Japan after the 2011 Fukushima nuclear power plant accident. Two database (MEDLINE and PsycINFO) and hand-searched the references in identified publications were searched. For each identified publication, the measurements and time related-change of risk perception and anxiety regarding radiation were summarized. Twenty-four publications were identified. Quantitative measures of risk perception or anxiety were roughly divided into two types: single-item Likert scales that measure anxiety about radiation; and theoretical, or model-based measures. Rates of Fukushima residents with radiation-related anxiety decreased from 2012 to 2015. Factors governing risk perception or radiation-related anxiety were summarized by demographics, disaster-related stressors, trusted information, and radiation-related variables. The effects of risk perception or anxiety regarding radiation were summarized as severe distress, intention to leave employment or not to return home, or other dimensions. This review provides summary of current findings on risk perception or anxiety regarding radiation in Japan after the accident. Further researches are needed about detailed statistical analysis for time-related change and causality among variables.

Japanese Food Data Challenge the Claimed Link between Fukushima's Releases and Recently Observed Thyroid Cancer Increase in Japan

Internal, high-dose exposure with radioiodine is known to increase the risk for thyroid cancer in children and adolescents. Ingestion of contaminated food is generally regarded a dominant route of internal exposure. We analyzed the huge data set of the post-Fukushima food monitoring campaign and deployed a conservative model for the estimation of the doses to the general public in a worst-case scenario. Our data suggest that the committed equivalent ingestion doses to the thyroids of the affected Japanese public, even in the utmost conservative approach, remained below the limit on ingestion of radioiodine in foodstuffs and beverages of 50 mSv (as thyroid equivalent dose). This level of 50 mSv is also the intervention level for the administration of stable iodine, mainly after inhalation. Our study hence suggests that, based on the food data, the internal exposure of Japanese residents was too low to cause a statistically discernible increase in thyroid cancer, even if the contribution from inhalation is taken into account. The data also indicate that the governmental efforts in the food monitoring campaign were successful and cut the thyroid doses to the public by a factor of approximately 3 compared to a scenario without any monitoring.

Risk Communication Strategies: Lessons Learned from Previous Disasters with a Focus on the Fukushima Radiation Accident

PURPOSE OF THE REVIEW

It has been difficult to both mitigate the health consequences and effectively provide health risk information to the public affected by the Fukushima radiological disaster. Often, there are contrasting public health ethics within these activities which complicate risk communication. Although no risk communication strategy is perfect in such disasters, the ethical principles of risk communication provide good practical guidance.

FINDINGS

These discussions will be made in the context of similar lessons learned after radiation exposures in Goiania, Brazil, in 1987; the Chernobyl nuclear power plant accident, Ukraine, in 1986; and the attack at the World Trade Center, New York, USA, in 2001. Neither of the two strategies is perfect nor fatally flawed. Yet, this discussion and lessons from prior events should assist decision makers with navigating difficult risk communication strategies in similar environmental health disasters.