Effects of Overweight on Risk of Thyroid Nodules in Children and Adolescents: The Fukushima Health Management Survey.

CONTEXT: Examining how overweight/obesity impacts thyroid nodule development in children and adolescents by sex and age can speculate on the mechanism. OBJECTIVE: We examined whether overweight in children and adolescents are associated with thyroid nodule development by sex and age. DESIGN: Approximately 300,000 participants who underwent thyroid ultrasonography in the Fukushima Health Management Survey after a nuclear accident were enrolled. Those without nodules in the initial two examinations (1-3 and 4-5 years postaccident) were prospectively assessed for nodule development in the third examination (6-7 years postaccident) relative to baseline overweight status, with an average follow-up of 4.2 years. SETTING: A population-based prospective cohort study. PARTICIPANTS: The first and second thyroid examinations involved 299,939 and 237,691 participants, respectively, excluding those with thyroid nodules. After the third examination, 184,519 participants were finalized for analysis. MAIN OUTCOME MEASURES: Multivariable-adjusted odds ratios of new detected thyroid nodules for overweight participants compared with normal-weight participants. RESULTS: New thyroid nodules were detected in 660 participants. Being overweight was positively associated with thyroid nodules. The adjusted odds ratio (95% confidence interval) of thyroid nodules for overweight participants compared with other participants was 1.27 (1.04-1.57). Additionally, the multivariable-adjusted odds ratios for males and females with overweight were 1.21 and 1.32, respectively, and those for different age groups (0-9, 10-14, and 15-19 years) ranged from 1.17 to 1.75. CONCLUSIONS: Being overweight was associated with thyroid nodules in children and adolescents, mostly adolescent females, regardless of their proximity to the nuclear power plant.

Prevalence of thyroid diffuse goiter and its association with body mass index and the presence of cysts and nodules in children and adolescents: the Fukushima Health Management Survey.

The main cause of diffuse thyroid goiter is autoimmune chronic thyroiditis, otherwise known as Hashimoto's thyroiditis. Thyroid hormones play pivotal roles in growth and development during childhood. However, the prevalence of diffuse goiter and the relationships between diffuse goiter, thyroid volume, cysts and nodules, and anthropometric measurements in children are not well known. Among 789,459 participants who participated in thyroid ultrasound examinations, 320,206 participants (male: 161,728; female: 158,478) aged 1-23 years were analyzed. Logistic regression analyses were conducted to calculate the odds ratios of the standard deviation score of body mass index (BMI-SDS), the SDS of bilateral width multiplied thickness area (BWTAR-SDS) as a provisional determination of thyroid volume, and the presence of nodules or cysts for positive diffuse goiter compared with negative diffuse goiter after correction for sex and age. The prevalence of diffuse goiter increased in a female-dominant manner with aging. Compared with the absence of diffuse goiter, the age- and sex-adjusted odds ratios (95% confidence intervals) for BMI-SDS (1 SD), BWTAR-SDS (1 SD), cysts, and nodules were 1.24 (1.21-1.27), 3.21 (3.13-3.29), 0.53 (0.50-0.58), and 1.38 (1.17-1.64), respectively. The odds ratios of nodules for positive diffuse goiter were 4.18 (1.08-16.08), 1.76 (1.01-3.07), 1.80 (1.32-2.45), and 1.34 (1.08-1.67) in the age groups 1-7, 8-11, 12-15, and 16-23 years, respectively. The age-dependent increase in the prevalence of diffuse goiter was independently associated with increased BMI and positive prevalence of nodules in young individuals.

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.

Relationship between evacuation after the Great East Japan Earthquake and new-onset hyperuricemia: A 7-year prospective longitudinal study of the Fukushima Health Management Survey.

INTRODUCTION: On March 11, 2011, the Great East Japan Earthquake occurred in Japan, with a nuclear accident subsequently occurring at the Fukushima Daiichi Nuclear Power Plant. The disaster forced many evacuees to change particular aspects of their lifestyles. However, the effect of evacuation on the new-onset of hyperuricemia have not been sufficiently elucidated. This study assessed the association between evacuation and new-onset hyperuricemia after the earthquake based on the Fukushima Health Management Survey from a lifestyle and socio-psychological perspective. MATERIALS AND METHODS: This is a 7-year prospective longitudinal study included 18,140 residents (6,961 men and 11,179 women) with non-hyperuricemia who underwent both the Comprehensive Health Check and the Mental Health and Lifestyle Survey in fiscal year 2011. Associations between new-onset hyperuricemia and lifestyle- and disaster-related factors, including evacuation, were estimated using a Cox proportional hazards regression model analysis. Hyperuricemia was defined as uric acid levels > 7.0 mg/dL for men and > 6.0 mg/dL for women. RESULTS: During a median follow-up of 4.3 years, 2,996 participants (1,608 men, 23.1%, 1,388 women, 12.4%) newly developed hyperuricemia. Significant associations were observed between evacuation and onset of hyperuricemia in women (adjusted hazard ratio 1.18, 95% confidence interval, 1.05-1.32, p = 0.007), but not in men (adjusted hazard ratio 1.11, 95% confidence interval, 0.99-1.24, p = 0.067). DISCUSSION: Evacuation after a natural disaster is an independent risk factor for the new-onset of hyperuricemia in women. The possibility of hyperuricemia developing in response to natural disasters should be considered.

Blood data trends of children in Fukushima after the Great East Japan Earthquake: Fukushima health management survey.

BACKGROUND: After the Great East Japan Earthquake on March 11, 2011 and the subsequent accident at the Tokyo Electric Power Company-operated Daiichi Nuclear Power Plant, the Fukushima Prefecture government initiated the Fukushima Health Management Survey (FHMS) to assess the long-term health effects of the disaster on Fukushima residents. The blood tests of children aged ≤15 years between 2011 and 2012 did not reveal any changes regarding peripheral blood data; however, long-term monitoring is still necessary. Therefore, this study aimed to investigate the long-term health status of children aged ≤15 years who had evacuated the Fukushima Prefecture. METHODS: From 2011 to 2018, 71,250 evacuees aged 15 years or younger participated in the FMHS and were subjected to blood tests. By analyzing the data of the comprehensive health check survey managed by the FHMS, we examined the changes in hemoglobin (Hb) levels, white blood cell (WBC) counts, including fractions, and platelet (PLT) counts among children from 2011 to 2018. RESULTS: Minor fluctuations in Hb levels, PLT counts, and WBC counts were observed during the study period, but the central 95% intervals of distribution of the laboratory values were generally within previously reported reference intervals. In particular, there was no increase in the proportions of patients with anemia, polycythemia, or deviating WBC counts. CONCLUSION: From 2011 to 2018, there was no increase in the percentages of children with anemia, polycythemia, or deviating WBC counts among the Fukushima Prefecture evacuees.

Eight-Year Trends in the Effect of the Great East Japan Earthquake on Obstetrics Outcomes: A Study from the Fukushima Health Management Survey.

Information regarding the longitudinal effects of natural/environmental disasters on obstetrics outcomes is limited. This study aimed to analyze the longitudinal changes in obstetrics outcomes over 8 years after the Great East Japan Earthquake and the Fukushima power plant accident. We used data from the first 8 years of the Pregnancy and Birth Survey by the Fukushima prefectural government, launched in 2011. We compared data on obstetrics outcomes by year and divided Fukushima Prefecture into six districts based on administrative districts. Longitudinal changes in the occurrence of preterm birth before 37 gestational weeks, low birth weight, and anomalies in newborns were accessed using the Mantel-Haenszel test for trends in all six districts. Overall, 57,537 participants were included. In 8 years, maternal age, conception rate after sterility treatment, and cesarean section delivery incidence increased. Although significant differences were observed in preterm birth and low birth weight occurrence among districts, there was no significant trend in the occurrence of preterm birth, low birth weight, and anomalies in newborns in all six districts of Fukushima Prefecture. The Great East Japan Earthquake and Fukushima power plant accident were associated with increased cesarean section delivery incidence but had no significant adverse effects on obstetrics outcomes.

Confounding factors and biases involved in regional differences in the detection rate of thyroid cancer in the second-round Thyroid Ultrasound Examination: the Fukushima Health Management Survey.

In response to concerns about health due to radiation exposure, the Fukushima Prefecture launched the Thyroid Ultrasound Examination program for residents aged 0-18 years at the time of the earthquake. Herein, we considered the confounding factors involved in the regional differences in the development of thyroid cancer. In this study, the 242 065 individuals who participated in both first- and second-round surveys were classified into four groups by address according to their air radiation dose. The number of participants diagnosed as malignant or suspicious for malignancy by cytological examination were 17, 38, 10 and 4 with detection rates of 53.8, 27.8, 21.7 and 14.5 per 100 000 participants in Regions 1, 2, 3 and 4, respectively. Sex (P = 0.0400), age at the time of the primary examination (P < 0.0001) and interval between the first- and second-round surveys (P < 0.0001) were significantly different among the four regions, and these were suspected to be confounding factors affecting regional differences in malignant nodule detection rates. In addition, significant regional differences were observed in the participation rate in the confirmatory examination (P = 0.0037) and the fine needle aspiration cytology implementation rate (P = 0.0037), which could be potential biases. No significant regional differences in the detection of malignant nodules were found in the multivariate logistic regression analysis after adjusting for the survey interval alone or for sex, age and survey interval. The confounding factors and biases identified in this study that may have important impacts on thyroid cancer detection rate should be fully considered in future studies.

Impact of Lifestyle and Psychosocial Factors on the Incidence of Hepatobiliary Enzyme Abnormalities After the Great East Japan Earthquake: Seven-Year Follow-up of the Fukushima Health Management Survey.

OBJECTIVE: Residents who lived near the Fukushima Power Plant accident were forced to change their lifestyle after the 2011 accident. This study aimed to elucidate the association of resident lifestyle and psychological factors with onset of hepatobiliary enzyme abnormalities (HEA) after the accident. METHODS: This longitudinal study included 15705 residents who underwent a comprehensive health check, as well as a mental health and lifestyle survey between June 2011 and March 2012. Follow-up surveys were conducted between June, 2012 and March 2018. Risk factors for new HEA onset were evaluated using the Cox proportional hazards model, moreover, population attributable risks for new HEA onset were calculated. RESULTS: HEA developed in 29.7% of subjects. In addition to metabolic factors such as overweight, hyperglycemia, and hyperlipidemia; there were differences in alcohol intake, evacuation, unemployment, educational background, and psychological distress between subjects with and without HEA onset. After we adjusted for potential confounding factors, an association of being overweight, hypertension, and dyslipidemia, as well as alcohol consumption, evacuation, and psychological distress with increased risk of HEA onset was realized. Among these identified risk factors, evacuation accounted for the greatest share. CONCLUSIONS: Metabolic characteristics and disaster-related lifestyle aspects, including mental status, were risk factors for HAE onset after the Fukushima Power Plant accident.

Sterilization efficacy of a new water-free breast milk pasteurizer.

BACKGROUND: Breast milk, nature's optimum source of nutrition for infants, can contain undesirable microorganisms that cause severe morbidity. After an outbreak of multidrug-resistant Escherichia coli among neonates receiving breast milk donated by another mother in our neonatal intensive care unit (NICU), we were motivated to develop a high-grade breast milk pasteurizer (BMP) designed to thaw and pasteurize breast milk at 63°C for 30 min in a sealed bag without having to open the bag or immerse it in water. METHODS: Pre-existing bacteria and spiked cytomegalovirus (CMV) were measured pre- and post-pasteurization in frozen breast milk donated by mothers of children admitted to the NICU. RESULTS: Among 48 breast milk samples (mean ± standard deviation [SD]), pre-existing bacterial counts of 5.1±1.1 × 104 colony forming units (cfu)/mL decreased to less than 10 cfu/mL (below detection level) in 45 samples after pasteurization for 30 min. In three samples, 10-110 cfu/mL persisted. As no CMV was detected in any of the 48 samples, CMV at ≥5 × 104 pfu/mL was spiked into 11 breast milk samples. After just 10 min of pasteurization, infectious CMV was not detected (threshold <50 pfu/mL) in any sample. CONCLUSION: A new BMP was shown to pasteurize milk effectively with more than a 3-log reduction of microorganisms. Compared to conventional pasteurizers, this device reduces the effort involved in pasteurizing breast milk, avoids various contamination risks, and may reduce the risk of infectious disease transmission via breast milk.

Asian-type DEL (RHD*DEL1) with an allo-anti-D: A paradoxical observation in a healthy multiparous woman.

BACKGROUND: The DEL phenotype is the D variant expressing the least amounts of D antigen per red cell. Asian-type DEL (RHD:c:1227G > A) is the most prevalent DEL in East Asia without any anti-D alloimmunization reported before. We investigated the first observation of an anti-D in any DEL phenotype, reported in the Japanese language at a 1987 conference, only 3 years after the discovery of DEL. METHODS: We contacted the proband 35 years after the initial report. Standard hemagglutination, adsorption/elution, and flow cytometry tests were performed, as was nucleotide sequencing for the RHD, RHCE, and HLA class I and class II genes. RESULTS: The healthy multiparous Japanese woman, a regular blood donor, still had the anti-D of titer 8 representing an alloantibody by standard serologic methods. Unexpectedly, she carried an Asian-type DEL without any additional RHD gene variation. All 12 HLA alleles identified were known in the Japanese population. Interestingly, one of her HLA-DRB1 and a variant of her HLA-DQB1 alleles had previously been associated with anti-D immunization. CONCLUSION: We described an allo-anti-D, maintained for more than three decades, in an Asian-type DEL. The combination of two implicated HLA alleles were rare and could have contributed to the anti-D immunization. Continued monitoring of anti-D immunization events in patients with DEL is warranted, and we discuss possible mechanisms for further study. As only this single observation has been recognized in the last 35 years, the current recommendation is affirmed: Individuals with Asian-type DEL should be treated as Rh D-positive for transfusion and Rh immune prophylaxis purposes.

Ultrasonography-based reference values for the cross-sectional area of the thyroid gland in children and adolescents: The Fukushima Health Management Survey.

We previously described the thyroid volume, which was calculated by measuring the thyroid width, thickness, and longitudinal length using ultrasonography, in children and adolescents. We have proposed a simplified method for quantitatively assessing the thyroid size, to overcome the inaccuracy and challenges in measuring the longitudinal length of the thyroid. Based on measurements of 317,847 (girls: 156,913, boys: 160,934) children and adolescents, we calculated sex-specific means and standard deviations of thyroid width and thickness, and of the cross-sectional area computed by multiplying them, for every age and 0.1 m2 of body surface area, after ensuring normal distribution with Box-Cox transformation. Multivariate regression analysis revealed that female sex, age, and body surface area were independently associated with areas of each thyroid lobe. Our novel method may be useful in quantitatively assessing the thyroid size, and appropriately diagnosing pathological conditions, such as hypoplasia, atrophy, and enlargement of the thyroid gland, in children and adolescents.

Longitudinal Trends in Blood Pressure Associated with The Changes in Living Environment Caused by the Great East Japan Earthquake: The Fukushima Health Management Survey.

The Great East Japan Earthquake occurred on 11 March 2011, forcing Fukushima Prefecture residents to change their living environment. Such sudden changes possibly have long-term effects on cardiovascular-related diseases. We therefore sought to identify temporal relationships between living environment changes and blood pressure levels over three years following the earthquake. Participants included 14,941 men and 21,533 women aged 16 years or older who answered self-administered questionnaires, including questions on living environment changes at baseline (2012). Blood pressure levels were measured each year from 2012 to 2015. Linear mixed-effects models were used to analyze associations between living environment changes and blood pressure levels. Men with changes in living environment (i.e., those living in shelters or in temporary housing, rental apartments, relatives' houses, or others) showed significantly higher diastolic blood pressure levels than those who lived in their home at baseline (77.3 mmHg vs. 77.8 mmHg; p < 0.001). The time-dependent effect of diastolic blood pressure levels associated with living environment was not statistically significant, indicating a sustained difference in diastolic blood pressure associated with living environment changes at baseline after three years. The effect of living environment changes on diastolic blood pressure increment was also evident in men without antihypertensive medication use during the study period and in men who were current drinkers at baseline. There were no associations between living environment changes and diastolic blood pressure levels among women. Sudden changes in living environment due to the disaster had an impact on the long-term effects of higher diastolic blood pressure among middle-aged men.

Predicting neonatal mortality with a disseminated intravascular coagulation scoring system.

BACKGROUND: Although disseminated intravascular coagulation (DIC) is a critical disease, its mortality in neonates is hard to predict. The aim of this study was to investigate underlying conditions associated with neonatal DIC to see if a scoring system could predict mortality. METHODS: We retrospectively evaluated the DIC scores of neonates diagnosed on or after the second day of life, in conjunction with underlying conditions associated with DIC. The diagnosis of DIC was made according to Japan Society of Obstetrical, Gynecological & Neonatal Hematology (JSOGNH) 2016 neonatal DIC criteria. RESULTS: Among 23 neonates with DIC, 8 had gastrointestinal perforation with necrotizing enterocolitis and 6 had congenital heart disease. Although factors such as birth weight, gestational age, D-dimer, and fibrinogen were not predictive of mortality, median PT-INR differed significantly between the two groups (survived 1.69 vs died 2.37, P = 0.004). Furthermore, median DIC scores differed significantly by survival outcome (P = 0.013). CONCLUSION: DIC scores based on JSOGNH 2016 neonatal DIC criteria are predictive of mortality in infants diagnosed with DIC on or after the second day of life.

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.

T-Cell-Replete Haploidentical Hematopoietic Stem Cell Transplantation for a Patient With Tcf3-Hlf-Positive Acute Lymphoblastic Leukemia Extramedullary Relapse After Unrelated Bone Marrow Transplantation.

TCF3-HLF-positive B-cell precursor acute lymphoblastic leukemia (BCP-ALL) has an extremely poor prognosis. A 2-year-old boy with TCF3-HLF-positive BCP-ALL had an isolated extramedullary relapse in multiple bones after allogeneic hematopoietic stem cells transplantation (HSCT) from a human leukocyte antigen-matched unrelated donor. In this study, he received a T-cell-replete haploidentical HSCT (TCR-haplo-HSCT) from his father when in nonremission state, which resulted in a sustained complete remission for over 3 years. Immune therapies for patients with an extramedullary relapse of TCF3-HLF-positive BCP-ALL have been attempted; however, long-term efficacies of these therapies remain unknown. Our TCR-haplo-HSCT may be an effective therapeutic option for such patients.

Psychological burden predicts new-onset diabetes in men: A longitudinal observational study in the Fukushima Health Management Survey after the Great East Japan earthquake.

Background: The burden of psychological distress and post-traumatic stress disorder (PTSD) has been suggested as a factor in developing type 2 diabetes mellitus. However, longitudinal features in psychological distress- and PTSD-related new-onset diabetes mellitus have not been thoroughly evaluated. Methods: The association between probable depression and probable PTSD and the risk of developing new-onset diabetes mellitus was evaluated in a 7-year prospective cohort of evacuees of the Great East Japan Earthquake in 2011. Probable depression was defined as a Kessler 6 scale (K6) ≥ 13 and probable PTSD as a PTSD Checklist-Stressor-Specific Version (PCL-S) ≥ 44. Results: The log-rank test for the Kaplan-Meier curve for new-onset diabetes mellitus was significant between K6 ≥ 13 vs. < 13 and PCL-S ≥ 44 vs. < 44 in men but not in women. In men, both K6 ≥ 13 and PCL-S ≥ 44 remained significant in the Cox proportional hazards model after multivariate adjustment for established risk factors and disaster-related factors, including evacuation, change in work situation, sleep dissatisfaction, and education. Conclusion: The post-disaster psychological burden of probable depression and probable PTSD was related to new-onset diabetes in men but not in women. In post-disaster circumstances, prevention strategies for new-onset diabetes might consider sex differences in terms of psychological burden.

Effects of External Radiation Exposure on Perinatal Outcomes in Pregnant Women After the Fukushima Daiichi Nuclear Power Plant Accident: the Fukushima Health Management Survey.

BACKGROUND: This study aimed to investigate the effects of maternal exposure to external radiation on perinatal outcomes among women who experienced the Fukushima Daiichi Nuclear Disaster (FDND) using the Fukushima Health Management Survey (FHMS). METHODS: Data from the Pregnancy and Birth Survey and Basic Survey in the FHMS were combined to analyze external maternal radiation exposure following the FDND, and the relationship between radiation dose and perinatal outcomes was analyzed using binomial logistic regression analysis. Missing dose data were supplemented using multiple imputation. RESULTS: A total of 6,875 individuals responded to the survey. Congenital anomalies occurred in 2.9% of patients, low birth weight (LBW) in 7.6%, small for gestation age (SGA; <10th percentile) in 8.9%, and preterm birth in 4.1%. The median maternal external radiation dose was 0.5 mSv (maximum, 5.2 mSv). Doses were classified as follows: <1 mSv (reference), 1 to <2 mSv, and ≥2 mSv. For congenital anomalies, the crude odds ratio for 1 to <2 mSv was 0.81 (95% confidence interval [CI], 0.56-1.17) (no participants with congenital anomaly were exposed to ≥2 mSv). At 1 to <2 mSv and ≥2 mSv, the respective adjusted odds ratios were 0.91 (95% CI, 0.71-1.18) and 1.21 (95% CI, 0.53-2.79) for LBW, 1.14 (95% CI, 0.92-1.42) and 0.84 (95% CI, 0.30-2.37) for SGA, and 0.91 (95% CI, 0.65-1.29) and 1.05 (95% CI, 0.22-4.87) for preterm birth. CONCLUSION: External radiation dose due to the FDND was not associated with congenital anomalies, LBW, SGA, or preterm birth.

External Doses Available for Epidemiological Studies Related to the Fukushima Health Management Survey: First 4-month Individual Doses and Municipality-average Doses for the First Year.

BACKGROUND: One of the components of the Fukushima Health Management Survey (FHMS) is the Basic Survey, which estimates individual external doses for the first 4 months after the 2011 nuclear power plant accident. However, external exposure continues long-term. According to estimations by international organizations, the external dose during the first year accounts for a significant part of the long-term dose. Thus, the present study was intended to estimate the first-year doses by extrapolating the Basic Survey results. METHODS: For most municipalities of non-evacuated areas, ambient dose rate had been continuously measured for at least one designated point in each municipality after the accident. In the present study, a municipality-average dose received by residents for a period was assumed to be proportional to the ambient dose measured at the designated point of that municipality during the same period. Based on this assumption, 4-month municipality-average doses calculated from the Basic Survey results were extrapolated to obtain first-year doses. RESULTS: The extrapolated first-year doses for 49 municipalities in the non-evacuated areas had a good correlation with those estimated by UNSCEAR, although the extrapolated doses were generally higher (slope of the regression line: 1.23). The extrapolated municipality-average doses were in reasonable agreement (within 30%) with personal dosimeter measurements, suggesting that the extrapolation was reasonable. CONCLUSION: The present paper reports the first 4-month average doses for all 59 municipalities of Fukushima Prefecture and the extrapolated first-year doses for 49 municipalities. The extrapolated doses will be the basis for future epidemiological studies related to the FHMS.

A Comprehensive Review of the Progress and Evaluation of the Thyroid Ultrasound Examination Program, the Fukushima Health Management Survey.

The Great East Japan Earthquake on March 11, 2011, and the subsequent tsunami caused an accident at the Fukushima Daiichi Nuclear Power Plant, in which extensive damage to the nuclear power reactors resulted in massive radioactive contamination. Fukushima Prefecture implemented the Thyroid Ultrasound Examination (TUE) program as part of the Fukushima Health Management Survey project in response to residents' anxieties about health risks due to radiation exposure for residents aged 0-18 years at the time of the nuclear accident. This program consisted of the primary examination and the confirmatory examination. In the primary examination, thyroid nodules and cysts were examined using portable ultrasound apparatuses. The confirmatory examination was performed to have clinical or cytological diagnosis. As of June 30, 2021, 116, 71, 31, 36, and 9 examinees in the first, second, third, and fourth round of surveys, and the survey at age 25 years, respectively, were determined to have nodules cytologically diagnosed as malignant or suspicious for malignancy. The confirmatory examination of the fourth-round survey and the primary and confirmatory examination of fifth-round survey are currently in progress. Together with the low thyroid absorbed radiation dose estimated in the United Nations Scientific Committee on the Effects of Atomic Radiation 2020 report, our results suggested that the increased incidence of childhood thyroid cancer in Fukushima Prefecture was not caused by radiation exposure, but rather by the highly sensitive detection method. As detailed in this review, there were ongoing challenges in our program, such as actions against the risk of overdiagnosis and psychological support for participants and their families.

Achievements and Current Status of the Fukushima Health Management Survey.

The Fukushima Health Management Survey (FHMS) was established in response to the Fukushima Daiichi Nuclear Power Plant accident on March 11, 2011. The primary objectives of the study are to monitor residents' long-term health and promote their future well-being, and to determine the health effects of long-term low-dose radiation exposure. This special issue summarizes the results and current status of the FHMS and discusses the challenges and future directions of the FHMS. The FHMS, a cohort study of all people who were residents in Fukushima Prefecture at the time of the accident, consists of a Basic Survey, Thyroid Ultrasound Examination, Comprehensive Health Check, Mental Health and Lifestyle Survey, and Pregnancy and Birth Survey. The radiation exposure was estimated based on the behavioral records examined using the Basic Survey. Although the response rate was low in the Basic Survey, the representativeness of the radiation exposure data was confirmed using additional surveys. There appears to be no relationship between the radiation exposure and risk of thyroid cancer, although more thyroid cancer cases were detected than initially expected. The ongoing Comprehensive Health Check and Mental Health and Lifestyle Survey have provided evidence of worsening physical and mental health status. The Pregnancy and Birth Survey showed rates of preterm delivery, low birth weight, and congenital abnormalities similar to the national average. Considering the above evidence, the Fukushima Prefectural Government decided to end the Pregnancy and Birth Survey at the end of March 2021, as recommended by the Prefectural Oversight Committee. The framework of the FHMS has not changed, but the FHMS needs to adapt according to the survey results and the changing needs of the eligible residents and municipalities.