Cataract in atomic bomb survivors

Purpose: Ophthalmologic examinations were conducted on atomic bomb (A‐bomb) survivors 55 years after exposure.

Materials and methods: A‐bomb survivors who had been exposed before 13 years of age at the time of the bombings in 1945 or who had been examined in a previous study between 1978 and 1980. The examinations, conducted between June 2000 and September 2002, included slit‐lamp examination, digital photography and a cataract grading system for three parts of the lens (nucleus, cortex and posterior subcapsule) as an outcome variable. Proportional odds logistic regression analysis was conducted using the lowest grading class as a reference and included explanatory variables such as age, sex, city, dose and various cataract‐related risk factors. When the grades in an individual differed, the worst grade was used.

Results: Results indicate that odds ratios (ORs) at 1 Sv were 1.07 (95% confidence intervals [CI] 0.90, 1.27) in nuclear colour, 1.12 (95% CI 0.94, 1.30) in nuclear cataract, 1.29 (95% CI 1.12, 1.49) in cortical cataract and 1.41 (95% CI 1.21, 1.64) in posterior subcapsular cataract. The same was true after excluding 13 people whose posterior subcapsular cataracts had been previously detected.

Conclusion: Significant radiation effects were observed in two types of cataracts in A‐bomb survivors.     

Cardiovascular disease among atomic bomb survivors

Abstract

Purpose: The profile of cardiovascular disease in Japan has been different from that in Western countries. Hypertension was the major cause not only for hemorrhagic stroke but also for ischemic stroke and heart disease in the past, and the influence of hypertension has decreased with calendar years because of reduced salt intake and westernization of lifestyle, and also improved medical care. The health status of atomic bomb survivors has reflected this profile as well as radiation effects. It is also likely that this cohort has been affected by the difficult conditions experienced in the aftermath of the war and atomic bombings. In this article, we tried to make a consistent interpretation of epidemiological findings of atomic bomb radiation effects on cardiovascular disease.

Conclusion: Among the atomic bomb survivors, radiation exposure was associated with some cardiovascular diseases that are often associated with hypertension, and dose response appeared to be primarily non-linear among those who were exposed at younger ages. These effects are thought to reflect the nature of whole body irradiation. But, some findings remain inconsistent, possibly because of possible misclassification in death certificate diagnoses in the Life Span Study as well as selected information from the Adult Health Study which was limited to participants, focused on specific outcomes, and gathered in selected periods of follow-up. Therefore, a comprehensive and balanced interpretation of the results from both groups is necessary.     

Radiation dose and cataract surgery incidence in atomic bomb survivors, 1986-2005

Purpose: To examine the incidence of clinically important cataracts in relation to lens radiation doses between 0 and approximately 3 Gy to address risks at relatively low brief doses. Materials and Methods: Informed consent was obtained, and human subjects procedures were approved by the ethical committee at the Radiation Effects Research Foundation. Cataract surgery incidence was documented for 6066 atomic bomb survivors during 1986-2005. Sixteen risk factors for cataract, such as smoking, hypertension, and corticosteroid use, were not confounders of the radiation effect on the basis of Cox regression analysis. Radiation dose-response analyses were performed for cataract surgery incidence by using Poisson regression analysis, adjusting for demographic variables and diabetes mellitus, and results were expressed as the excess relative risk (ERR) and the excess absolute risk (EAR) (ie, measures of how much radiation multiplies [ERR] or adds to [EAR] the risk in the unexposed group). Results: Of 6066 atomic bomb survivors, 1028 underwent a first cataract surgery during 1986-2005. The estimated threshold dose was 0.50 Gy (95% confidence interval [CI]: 0.10 Gy, 0.95 Gy) for the ERR model and 0.45 Gy (95% CI: 0.10 Gy, 1.05 Gy) for the EAR model. A linear-quadratic test for upward curvature did not show a significant quadratic effect for either the ERR or EAR model. The linear ERR model for a 70-year-old individual, exposed at age 20 years, showed a 0.32 (95% CI: 0.17, 0.52) excess risk at 1 Gy. The ERR was highest for those who were young at exposure. Conclusion: These data indicate a radiation effect for vision-impairing cataracts at doses less than 1 Gy. The evidence suggests that dose standards for protection of the eye from brief radiation exposures should be 0.5 Gy or less. ? RSNA, 2012 Supplemental material: http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.12111947/-/DC1.     

Organ doses to atomic bomb survivors during photofluorography, fluoroscopy and computed tomography

Doses to the salivary glands, thyroid gland, breast, lung, stomach and colon during mass radiological gastric screening, mass radiographic chest screening, upper gastrointestinal series and computed tomography were determined by exposing a female human phantom to simulated radiological X-ray examinations as performed in community hospitals. The doses were measured using thermoluminescent dosimeters, and the results will be used to document organ doses received by participants in the Atomic Bomb Casualty Commission/Radiation Effects Research Foundation Adult Health Study.     

Present status and self-reported diseases of the Korean atomic bomb survivors: a mail questionnaire survey

Many Koreans were forced to move to Japan while Korea was occupied by Japan. Consequently, when the atomic bombs were dropped on Hiroshima and Nagasaki an estimated 40,000 Koreans died and 30,000 survived. In 2004, 2,235 Koreans were registered as A-bomb survivors in South Korea. A mail questionnaire survey to evaluate the present status and self-reported diseases of the Korean survivors was conducted. In total, 1,256 questionnaires were returned and analysed. The most frequent chronic diseases reported by Korean survivors were hypertension (40.1 per cent), peptic ulcer disease (25.7 per cent), anaemia (23.3 per cent) and cataracts (23.1 per cent). The most frequent malignant diseases were stomach cancer (1.9 per cent), colon cancer (0.5 per cent) and leukaemia/multiple myeloma (0.4 per cent). This study suggests that further investigations are needed into the health concerns of the survivors and into health protection measures.     

Organ doses received by atomic bomb survivors during radiological examinations at the Radiation Effects Research Foundation

When evaluating the risks of oncogenesis and cancer mortality following exposure to the radiations of the atomic bombs (A-bombs), the medical X-ray doses received by the A-bomb survivors must also be estimated and considered. Using a human phantom, dosimetry was performed to estimate the X-ray doses received by A-bomb survivors during medical examinations at the Radiation Effects Research Foundation (RERF) as part of the long-term follow-up on the Adult Health Study (AHS). These examinations have been estimated to represent nearly 45% of the survivors' cumulative medical irradiation dose. Doses to the salivary glands, thyroid gland, lung, breast, stomach and colon were measured using thermoluminescent dosimeters. The results, which are reported here, will aid in estimating organ doses received by individual AHS participants.     

Derivation of low-dose extrapolation factors from analysis of curvature in the cancer incidence dose response in Japanese atomic bomb survivors

Purposes : To assess the degree of overestimation in low-dose cancer risk when models linear in dose are fitted to cancer data. Materials and methods : Examination of the quadratic and the linear coefficients (in dose) in the Japanese atomic bomb survivor cancer incidence data, based on follow-up to 1987 and taking separate account of random errors in DS86 neutron and DS86 gamma dose estimates and systematic errors in Hiroshima DS86 neutron dose estimates. Results : When the 0-4 Gy dose range is used, the low-dose extrapolation factor for all solid tumours, assessing the degree to which low-dose cancer risks are overestimated by fitting a model linear in dose, is 1.06 (95% CI 0.78, 1.62) and so is not significantly different from 1; the associated ratio of the quadratic to the linear coefficients is 0.06 Sv -1 (95% CI - 0.22, 0.67). The best estimate of the low-dose extrapolation factor for leukaemia is 2.47 (95% CI 1.24, > 1000). The ratio of the quadratic to the linear coefficients is 1.81 Sv -1 (95% CI 0.21, > 1000). When various types and groupings of solid tumours are considered there is not generally any strong evidence for upward curvature; for only two out of the six solid tumour groupings are there indications of appreciable upward curvature in the dose response, and in no instance is this statistically significant. Consideration of a lower dose range (0-2 Gy rather than 0-4 Gy) results in the low-dose extrapolation factor for solid tumours increasing to 1.21 (95% CI 0.81, 2.45), with corresponding increases for solid tumour subtypes; the corresponding quantity for leukaemia decreases to 1.73 (95% CI 0.79, 147.67). Three out of the six solid tumour subtypes now show appreciable upward curvature. If there is additional adjustment of the Hiroshima neutron dose estimates over the 0-2 Gy dose range, the low-dose extrapolation factor for all solid tumours increases still further, to 1.43 (95% CI 0.97, 2.72), whereas for leukaemia this quantity is further reduced, to 1.58 (95% CI 0.90, 10.58). Conclusions : There is marked upward curvature in the dose response for leukaemia. For solid tumours there is little indication of upward curvature in the dose response over the 0-4 Gy dose range, although over the 0-2 Gy dose range and after adjustment of Hiroshima DS86 neutron dose estimates the upward curvature is more pronounced. Uncertainties in the likely adjustments to the Hiroshima DS86 neutron dose estimates imply that these findings should be treated with caution.     

Serum TSH, thyroglobulin, and thyroidal disorders in atomic bomb survivors exposed in youth: 30-year follow-up study

Follow-up examinations to determine the frequency of thyroidal disorders were conducted by the Radiation Effects Research Foundation (RERF) on individuals in Hiroshima and Nagasaki who were less than 20 yr of age at the time of exposure to the atomic bomb. Concentrations of serum thyroid stimulating hormone (TSH), thyroglobulin (TG), and anti-TG antibody 30 yr after exposure were also determined. Nontoxic uninodular goiter was found in 13 cases of the 100 + rad exposed group (n = 477) and in three cases of the nonexposed group (n = 501). The prevalence in the 100+ rad exposed group was significantly higher (chi-squared = 6.584, p less than 0.01). Thyroid cancer was found in eight exposed cases, all of whom were in the 100+ rad group, and the prevalence was significantly greater (chi-squared = 7.919, p less than 0.01). Regardless of the presence or absence of thyroid disorders, serum TSH and TG levels were not statistically different between the 100 rad + exposed and nonexposed groups. Although hypothyroidism was found in 23 of the total cases, there was no correlation between its development and exposure to ionizing irradiation.     

Derivation of low-dose extrapolation factors from analysis of curvature in the cancer incidence dose response in Japanese atomic bomb survivors

PURPOSES: To assess the degree of overestimation in low-dose cancer risk when models linear in dose are fitted to cancer data. MATERIALS AND METHODS: Examination of the quadratic and the linear coefficients (in dose) in the Japanese atomic bomb survivor cancer incidence data, based on follow-up to 1987 and taking separate account of random errors in DS86 neutron and DS86 gamma dose estimates and systematic errors in Hiroshima DS86 neutron dose estimates. RESULTS: When the 0-4Gy dose range is used, the low-dose extrapolation factor for all solid tumours, assessing the degree to which low-dose cancer risks are overestimated by fitting a model linear in dose, is 1.06 (95% CI 0.78, 1.62) and so is not significantly different from 1; the associated ratio of the quadratic to the linear coefficients is 0.06 Sv(-1) (95% CI -0.22, 0.67). The best estimate of the low-dose extrapolation factor for leukaemia is 2.47 (95% CI 1.24, > 1,000). The ratio of the quadratic to the linear coefficients is 1.81 Sv(-1) (95% CI 0.21, > 1,000). When various types and groupings of solid tumours are considered there is not generally any strong evidence for upward curvature; for only two out of the six solid tumour groupings are there indications of appreciable upward curvature in the dose response, and in no instance is this statistically significant. Consideration of a lower dose range (0-2Gy rather than 0-4 Gy) results in the low-dose extrapolation factor for solid tumours increasing to 1.21 (95% CI 0.81, 2.45), with corresponding increases for solid tumour subtypes; the corresponding quantity for leukaemia decreases to 1.73 (95% CI 0.79, 147.67). Three out of the six solid tumour subtypes now show appreciable upward curvature. If there is additional adjustment of the Hiroshima neutron dose estimates over the 0-2 Gy dose range, the low-dose extrapolation factor for all solid tumours increases still further, to 1.43 (95% CI 0.97, 2.72), whereas for leukaemia this quantity is further reduced, to 1.58 (95% CI 0.90, 10.58). CONCLUSIONS: There is marked upward curvature in the dose response for leukaemia. For solid tumours there is little indication of upward curvature in the dose response over the 0-4 Gy dose range, although over the 0-2 Gy dose range and after adjustment of Hiroshima DS86 neutron dose estimates the upward curvature is more pronounced. Uncertainties in the likely adjustments to the Hiroshima DS86 neutron dose estimates imply that these findings should be treated with caution.     

Long-lasting alterations of the immune system by ionizing radiation exposure: implications for disease development among atomic bomb survivors

PURPOSE: The immune systems of the atomic-bomb (A-bomb) survivors were damaged proportionately to irradiation levels at the time of the bombing over 60 years ago. Although the survivor's immune system repaired and regenerated as the hematopoietic system has recovered, significant residual injury persists, as manifested by abnormalities in lymphoid cell composition and function. This review summarizes the long-lasting alterations in immunological functions associated with atomic-bomb irradiation, and discusses the likelihood that damaging effects of radiation on the immune system may be involved partly in disease development so frequently observed in A-bomb survivors. CONCLUSIONS: Significant immunological alterations noted include: (i) attrition of T-cell functions, as reductions in mitogen-dependent proliferation and interleukin-2 (IL-2) production; (ii) decrease in helper T-cell populations; and (iii) increase in blood inflammatory cytokine levels. These findings suggest that A-bomb radiation exposure perturbed one or more of the primary processes responsible for T-cell homeostasis and the balance between cell renewal and survival and cell death among naive and memory T cells. Such perturbed T-cell homeostasis may result in acceleration of immunological aging. Persistent inflammation, linked in some way to the perturbation of T-cell homeostasis, is key in addressing whether such noted immunological changes observed in A-bomb survivors are in fact associated with disease development.     

A comparison of the degree of curvature in the cancer incidence dose-response in Japanese atomic bomb survivors with that in chromosome aberrations measured in vitro

PURPOSES: To compare the degree of curvature in the dose-response for chromosome aberrations and for radiation-induced cancer. MATERIALS AND METHODS: Comparison of the ratio of the quadratic and linear coefficients (in dose) in Japanese atomic bomb survivor cancer incidence data, based on follow-up to 1987 and taking account of random errors in DS86 dose estimates with the same ratio in four datasets of chromosome aberrations in peripheral blood lymphocytes measured in vitro and exposed to 60Co gamma radiation. RESULTS: There are no statistically significant differences between the four in vitro datasets in the ratio of the quadratic to the linear coefficients for dicentrics or chromosome translocations, nor are there indications of differences between this ratio for dicentrics and that for complete chromosome translocations (p > 0.1 in all cases). If the 0-4 Gy dose range is used in the Japanese atomic bomb survivor data, the ratio of the quadratic to the linear coefficients for all solid cancers is 0.06 -1 (95% CI -0.22, 0.67) and so is not significantly different from 0; this ratio is statistically highly inconsistent (p<0.0001) with the analogous ratio estimated for the in vitro chromosome aberration data (4.20 Sv-1; 95% CI 3.06, 6.51). By contrast, there are no statistically significant differences (p=0.42) between the ratio of the quadratic to the linear coefficients for leukaemia incidence in the Japanese cohort, 1.81 Sv-1 (95% CI 0.21, > 1,000), with that for chromosome aberrations in vitro. These results are not markedly changed if the 0-2 Gy dose range is used in the Japanese atomic bomb survivor data. CONCLUSIONS: It is unlikely that in vitro chromosome aberrations could be a correlate for the initiating radiogenic lesions leading to radiation-induced solid cancers. However, taken together with certain other biological information, it may not be unreasonable on this basis to use in vitro chromosome aberrations in peripheral blood lymphocytes as a correlate of the radiogenic lesions leading to radiation-induced leukaemia.     

A comparison of the degree of curvature in the cancer incidence dose-response in Japanese atomic bomb survivors with that in chromosome aberrations measured in vitro

Purposes : To compare the degree of curvature in the dose-response for chromosome aberrations and for radiation-induced cancer. Materials and methods : Comparison of the ratio of the quadratic and linear coeffcients (in dose) in Japanese atomic bomb survivor cancer incidence data, based on follow-up to 1987 and taking account of random errors in DS86 dose estimates with the same ratio in four datasets of chromosome aberrations in peripheral blood lymphocytes measured in vitro and exposed to 60 Co gamma radiation. Results : There are no statistically significant differences between the four in vitro datasets in the ratio of the quadratic to the linear coeffcients for dicentrics or chromosome translocations, nor are there indications of differences between this ratio for dicentrics and that for complete chromosome translocations (p >0.1 in all cases). If the 0-4 Gy dose range is used in the Japanese atomic bomb survivor data, the ratio of the quadratic to the linear coeffcients for all solid cancers is 0.06 Sv 1 (95% CI 0.22, 0.67) and so is not significantly different from 0; this ratio is statistically highly inconsistent (p <0.0001) with the analogous ratio estimated for the in vitro chromosome aberration data (4.20Sv 1; 95% CI 3.06, 6.51). By contrast, there are no statistically significant differences (p =0.42) between the ratio of the quadratic to the linear coeffcients for leukaemia incidence in the Japanese cohort, 1.81 Sv 1 (95% CI 0.21, > 1000), with that for chromosome aberrations in vitro. These results are not markedly changed if the 0-2 Gy dose range is used in the Japanese atomic bomb survivor data. Conclusions : It is unlikely that in vitro chromosome aberrations could be a correlate for the initiating radiogenic lesions leading to radiation-induced solid cancers. However, taken together with certain other biological information, it may not be unreasonable on this basis to use in vitro chromosome aberrations in peripheral blood lymphocytes as a correlate of the radiogenic lesions leading to radiation-induced leukaemia.     

日本广岛原爆幸存者NK细胞的变化

本文报道126名原爆幸存者NK细胞的变化及其对IL-2刺激的反应能力。结果表明；同一年龄组内各剂量照射组NK细胞活性和数量,皆无明显差异。但比较不同受照年龄组,则反映出辐射对小年龄组(<14岁)主要起抑制作用,中间年龄组(15～24岁)变化不明显；大年龄组(>25岁)NK细胞活性有上升趋势。尤其是0.01～1Gy和>1Gy两组内上述年龄组间差异有显着性(P<0.05).说明儿童期受照可能对NK细胞活性产生明显的远后效应。     

Prevalence of atherosclerosis in relation to atomic bomb radiation exposure: an RERF Adult Health Study

PURPOSE: To determine whether exposure to atomic bomb radiation altered the prevalence of asymptomatic atherosclerosis. MATERIAL AND METHODS: In a cross-sectional analysis, we examined aortic arch calcification by plain chest radiography and common carotid artery intima-media thickness (IMT) by ultrasonography among 1804 survivors of the atomic bombing in Hiroshima. We evaluated the association between atherosclerotic changes and radiation exposure, while adjusting for potentially confounding factors. RESULTS: Multivariate logistic regression analysis showed that aortic arch calcification was significantly associated with radiation exposure (p < 0.05). The odds ratio at 1 Gy was 1.30 (95% confidence interval [CI]: 1.05 - 1.53) for men and 1.31 (95% CI: 1.13 - 1.51) for women. Carotid artery IMT did not vary significantly with radiation dose (p = 0.18). CONCLUSION: Radiation dose contributed to the prevalence of aortic atherosclerosis but not carotid artery atherosclerosis in atomic bomb survivors.