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Kazunori Kodama - One of the best experts on this subject based on the ideXlab platform.
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japanese legacy cohorts the life span study Atomic Bomb survivor cohort and survivors offspring
Journal of Epidemiology, 2018Co-Authors: Kotaro Ozasa, Eric J. Grant, Kazunori KodamaAbstract:Cohorts of Atomic Bomb survivors-including those exposed in utero-and children conceived after parental exposure were established to investigate late health effects of Atomic Bomb radiation and its transgenerational effects by the Atomic Bomb Casualty Commission (ABCC) in the 1950s. ABCC was reorganized to the Radiation Effects Research Foundation (RERF) in 1975, and all work has been continued at RERF. The Life Span Study, the cohort of survivors, consists of about 120,000 subjects and has been followed since 1950. Cohorts of in utero survivors and the survivors' children include about 3,600 and 77,000 subjects, respectively, and have been followed since 1945. Atomic Bomb radiation dose was estimated for each subject based on location at the time of the Bombing and shielding conditions from exposure, which were obtained through enormous efforts of investigators and cooperation of subjects. Outcomes include vital status, cause of death, and cancer incidence. In addition, sub-cohorts of these three cohorts were constructed to examine clinical features of late health effects, and the subjects have been invited to periodic health examinations at clinics of ABCC and RERF. They were also asked to donate biosamples for biomedical investigations. Epidemiological studies have observed increased radiation risks for malignant diseases among survivors, including those exposed in utero, and possible risks for some non-cancer diseases. In children of survivors, no increased risks due to parental exposure to radiation have been observed for malignancies or other diseases, but investigations are continuing, as these cohorts are still relatively young.
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Cardiovascular disease among Atomic Bomb survivors
International Journal of Radiation Biology, 2017Co-Authors: Kotaro Ozasa, Ikuno Takahashi, Eric J. Grant, Kazunori KodamaAbstract:AbstractPurpose: 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 w...
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radiation exposure and circulatory disease risk hiroshima and nagasaki Atomic Bomb survivor data 1950 2003
BMJ, 2010Co-Authors: Yukiko Shimizu, Ritsu Sakata, Eric J. Grant, Kazunori Kodama, Midori Soda, Nobuo Nishi, Fumiyoshi Kasagi, Akihiko Suyama, Hiromi Sugiyama, Hiroko MoriwakiAbstract:Objective To investigate the degree to which ionising radiation confers risk of mortality from heart disease and stroke. Design Prospective cohort study with more than 50 years of follow-up. Setting Atomic Bomb survivors in Hiroshima and Nagasaki, Japan. Participants 86 611 Life Span Study cohort members with individually estimated radiation doses from 0 to >3 Gy (86% received Main outcome measures Mortality from stroke or heart disease as the underlying cause of death and dose-response relations with Atomic Bomb radiation. Results About 9600 participants died of stroke and 8400 died of heart disease between 1950 and 2003. For stroke, the estimated excess relative risk per gray was 9% (95% confidence interval 1% to 17%, P=0.02) on the basis of a linear dose-response model, but an indication of possible upward curvature suggested relatively little risk at low doses. For heart disease, the estimated excess relative risk per gray was 14% (6% to 23%, P Conclusion Doses above 0.5 Gy are associated with an elevated risk of both stroke and heart disease, but the degree of risk at lower doses is unclear. Stroke and heart disease together account for about one third as many radiation associated excess deaths as do cancers among Atomic Bomb survivors.
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solid cancer incidence in Atomic Bomb survivors 1958 1998
Radiation Research, 2007Co-Authors: Dale L. Preston, Midori Soda, Elaine Ron, Shoji Tokuoka, Kiyohiko Mabuchi, Sachiyo Funamoto, Nobuo Nishi, Kazunori KodamaAbstract:Abstract Preston, D. L., Ron, E., Tokuoka, S., Funamoto, S., Nishi, N., Soda, M., Mabuchi, K. and Kodama, K. Solid Cancer Incidence in Atomic Bomb Survivors: 1958–1998. Radiat. Res. 168, 1–64 (2007). This is the second general report on radiation effects on the incidence of solid cancers (cancers other than malignancies of the blood or blood-forming organs) among members of the Life Span Study (LSS) cohort of Hiroshima and Nagasaki Atomic Bomb survivors. The analyses were based on 17,448 first primary cancers (including non-melanoma skin cancer) diagnosed from 1958 through 1998 among 105,427 cohort members with individual dose estimates who were alive and not known to have had cancer prior to 1958. Radiation-associated relative risks and excess rates were considered for all solid cancers as a group, for 19 specific cancer sites or groups of sites, and for five histology groups. Poisson regression methods were used to investigate the magnitude of the radiation-associated risks, the shape of the dose respon...
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lifestyle factors radiation and gastric cancer in Atomic Bomb survivors japan
Cancer Causes & Control, 2005Co-Authors: Catherine Sauvaget, Jun Nagano, Midori Soda, Frederic Lagarde, Kojiro Koyama, Kazunori KodamaAbstract:Objective To examine the association between the incidence of gastric cancer and lifestyle factors such as cigarette smoking, alcohol drinking, and diet as well as Atomic Bomb radiation exposure.
Midori Soda - One of the best experts on this subject based on the ideXlab platform.
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Effects of radiation on the incidence of prostate cancer among Nagasaki Atomic Bomb survivors
Cancer Science, 2013Co-Authors: Hisayoshi Kondo, Mariko Mine, Midori Soda, Kenichi YokotaAbstract:Atomic Bomb survivors have been reported to have an increased risk of some cancers, especially leukemia. However, the risk of prostate cancer in Atomic Bomb survivors is not known to have been examined previously. This study examined the association between Atomic Bomb radiation and the incidence of prostate cancer among male Nagasaki Atomic Bomb survivors. The subjects were classified by distance from the hypocenter into a proximal group (
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risk of myelodysplastic syndromes in people exposed to ionizing radiation a retrospective cohort study of nagasaki Atomic Bomb survivors
Journal of Clinical Oncology, 2011Co-Authors: Masako Iwanaga, Midori Soda, Wanling Hsu, Yumi Takasaki, Masayuki Tawara, Tatsuro Joh, Tatsuhiko Amenomori, Masaomi Yamamura, Yoshiharu Yoshida, T KobaAbstract:Purpose The risk of myelodysplastic syndromes (MDS) has not been fully investigated among people exposed to ionizing radiation. We investigate MDS risk and radiation dose-response in Japanese Atomic Bomb survivors. Patients and Methods We conducted a retrospective cohort study by using two databases of Nagasaki Atomic Bomb survivors: 64,026 people with known exposure distance in the database of Nagasaki University Atomic-Bomb Disease Institute (ABDI) and 22,245 people with estimated radiation dose in the Radiation Effects Research Foundation Life Span Study (LSS). Patients with MDS diagnosed from 1985 to 2004 were identified by record linkage between the cohorts and the Nagasaki Prefecture Cancer Registry. Cox and Poisson regression models were used to estimate relationships between exposure distance or dose and MDS risk. Results There were 151 patients with MDS in the ABDI cohort and 47 patients with MDS in the LSS cohort. MDS rate increased inversely with exposure distance, with an excess relative risk ...
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radiation exposure and circulatory disease risk hiroshima and nagasaki Atomic Bomb survivor data 1950 2003
BMJ, 2010Co-Authors: Yukiko Shimizu, Ritsu Sakata, Eric J. Grant, Kazunori Kodama, Midori Soda, Nobuo Nishi, Fumiyoshi Kasagi, Akihiko Suyama, Hiromi Sugiyama, Hiroko MoriwakiAbstract:Objective To investigate the degree to which ionising radiation confers risk of mortality from heart disease and stroke. Design Prospective cohort study with more than 50 years of follow-up. Setting Atomic Bomb survivors in Hiroshima and Nagasaki, Japan. Participants 86 611 Life Span Study cohort members with individually estimated radiation doses from 0 to >3 Gy (86% received Main outcome measures Mortality from stroke or heart disease as the underlying cause of death and dose-response relations with Atomic Bomb radiation. Results About 9600 participants died of stroke and 8400 died of heart disease between 1950 and 2003. For stroke, the estimated excess relative risk per gray was 9% (95% confidence interval 1% to 17%, P=0.02) on the basis of a linear dose-response model, but an indication of possible upward curvature suggested relatively little risk at low doses. For heart disease, the estimated excess relative risk per gray was 14% (6% to 23%, P Conclusion Doses above 0.5 Gy are associated with an elevated risk of both stroke and heart disease, but the degree of risk at lower doses is unclear. Stroke and heart disease together account for about one third as many radiation associated excess deaths as do cancers among Atomic Bomb survivors.
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Thyroid diseases in Atomic Bomb survivors exposed in utero.
The Journal of Clinical Endocrinology & Metabolism, 2008Co-Authors: Misa Imaizumi, Kiyoto Ashizawa, Kazuo Neriishi, Masazumi Akahoshi, Eiji Nakashima, Toshiro Usa, Tan Tominaga, Ayumi Hida, Nobuko Sera, Midori SodaAbstract:Objective: The objective of the study was to evaluate the association of thyroid disease with radiation dose in Atomic Bomb survivors exposed in utero. Design: This was a cross-sectional study. Setting: The study was conducted in Atomic Bomb survivors in Hiroshima and Nagasaki, Japan. Participants: Participants included 328 Atomic Bomb survivors exposed in utero (mean age 55.2 yr, 162 males) who participated in the thyroid study at the Radiation Effects Research Foundation. Examinations were conducted between March 2000 and February 2003. Main Outcome Measures: The relationships of various thyroid conditions to Atomic Bomb radiation dose were measured. Results: Among the 319 participants excluding nine participants whose exposure radiation dose was not estimated, the mean maternal uterine radiation dose was 0.256 Gy. We observed no significant dose-response relationship for the prevalence of solid thyroid nodules (odds ratio at 1 Gy, 2.78; 95% confidence interval 0.50–11.80, P = 0.22), but the risk estima...
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solid cancer incidence in Atomic Bomb survivors 1958 1998
Radiation Research, 2007Co-Authors: Dale L. Preston, Midori Soda, Elaine Ron, Shoji Tokuoka, Kiyohiko Mabuchi, Sachiyo Funamoto, Nobuo Nishi, Kazunori KodamaAbstract:Abstract Preston, D. L., Ron, E., Tokuoka, S., Funamoto, S., Nishi, N., Soda, M., Mabuchi, K. and Kodama, K. Solid Cancer Incidence in Atomic Bomb Survivors: 1958–1998. Radiat. Res. 168, 1–64 (2007). This is the second general report on radiation effects on the incidence of solid cancers (cancers other than malignancies of the blood or blood-forming organs) among members of the Life Span Study (LSS) cohort of Hiroshima and Nagasaki Atomic Bomb survivors. The analyses were based on 17,448 first primary cancers (including non-melanoma skin cancer) diagnosed from 1958 through 1998 among 105,427 cohort members with individual dose estimates who were alive and not known to have had cancer prior to 1958. Radiation-associated relative risks and excess rates were considered for all solid cancers as a group, for 19 specific cancer sites or groups of sites, and for five histology groups. Poisson regression methods were used to investigate the magnitude of the radiation-associated risks, the shape of the dose respon...
Dale L. Preston - One of the best experts on this subject based on the ideXlab platform.
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solid cancer incidence in Atomic Bomb survivors 1958 1998
Radiation Research, 2007Co-Authors: Dale L. Preston, Midori Soda, Elaine Ron, Shoji Tokuoka, Kiyohiko Mabuchi, Sachiyo Funamoto, Nobuo Nishi, Kazunori KodamaAbstract:Abstract Preston, D. L., Ron, E., Tokuoka, S., Funamoto, S., Nishi, N., Soda, M., Mabuchi, K. and Kodama, K. Solid Cancer Incidence in Atomic Bomb Survivors: 1958–1998. Radiat. Res. 168, 1–64 (2007). This is the second general report on radiation effects on the incidence of solid cancers (cancers other than malignancies of the blood or blood-forming organs) among members of the Life Span Study (LSS) cohort of Hiroshima and Nagasaki Atomic Bomb survivors. The analyses were based on 17,448 first primary cancers (including non-melanoma skin cancer) diagnosed from 1958 through 1998 among 105,427 cohort members with individual dose estimates who were alive and not known to have had cancer prior to 1958. Radiation-associated relative risks and excess rates were considered for all solid cancers as a group, for 19 specific cancer sites or groups of sites, and for five histology groups. Poisson regression methods were used to investigate the magnitude of the radiation-associated risks, the shape of the dose respon...
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dose estimation for Atomic Bomb survivor studies its evolution and present status
Radiation Research, 2006Co-Authors: Harry M Cullings, Eric J. Grant, Shoichiro Fujita, Sachiyo Funamoto, George D Kerr, Dale L. PrestonAbstract:Abstract Cullings, H. M., Fujita, S., Funamoto, S., Grant, E. J., Kerr, G. D. and Preston, D. L. Dose Estimation for Atomic Bomb Survivor Studies: Its Evolution and Present Status. Radiat. Res. 166, 219–254 (2006). In the decade after the Bombings of Hiroshima and Nagasaki, several large cohorts of survivors were organized for studies of radiation health effects. The U.S. Atomic Bomb Casualty Commission (ABCC) and its U.S./Japan successor, the Radiation Effects Research Foundation (RERF), have performed continuous studies since then, with extensive efforts to collect data on survivor locations and shielding and to create systems to estimate individual doses from the Bombs' neutrons and γ rays. Several successive systems have been developed by extramural working groups and collaboratively implemented by ABCC and RERF investigators. We describe the cohorts and the history and evolution of dose estimation from early efforts through the newest system, DS02, emphasizing the technical development and use of DS0...
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stable chromosome aberrations in Atomic Bomb survivors results from 25 years of investigation
Radiation Research, 2001Co-Authors: Yoshiaki Kodama, Takeo Honda, Dale L. Preston, David J Pawel, Nori Nakamura, Masahiro Itoh, Mimako Nakano, Kazuo Ohtaki, Sachiyo FunamotoAbstract:Abstract Kodama, Y., Pawel, D., Nakamura, N., Preston, D., Honda, T., Itoh, M., Nakano, M., Ohtaki, K., Funamoto, S. and Awa, A. A. Stable Chromosome Aberrations in Atomic Bomb Survivors: Results from 25 Years of Investigation. Radiat. Res. 156, 337–346 (2001). Frequencies of stable chromosome aberrations from more than 3,000 Atomic Bomb survivors were used to examine the nature of the radiation dose response. The end point was the proportion of cells with at least one translocation or inversion detected in Giemsa-stained cultures of approximately 100 lymphocytes per person. The statistical methods allow for both imprecision of individual dose estimates and extra-binomial variation. A highly significant and nonlinear dose response was seen. The shape of the dose response was concave upward for doses below 1.5 Sv but exhibited some leveling off at higher doses. This curvature was similar for the two cities, with a crossover dose (i.e. the ratio of the linear coefficient to the quadratic coefficient) of 1.7...
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Longevity of Atomic-Bomb survivors.
The Lancet, 2000Co-Authors: John B. Cologne, Dale L. PrestonAbstract:Summary Background Conflicting claims have been made regarding biological and health consequences of exposure to low doses of radiation. Studies have suggested that certain low-dose exposed Atomic-Bomb survivors live longer than their peers. Earlier studies in other radiation-exposed populations demonstrated life shortening from mortality from cancer but lacked dosimetry and relied on comparison groups which may introduce bias because of lack of comparability. We have re-examined the effect of radiation on life expectancy in one cohort of survivors of the Atomic Bombings of Hiroshima and Nagasaki, Japan. Methods We did a prospective cohort study of 120 321 survivors. The study encompasses 45 years of mortality follow-up with radiation-dose estimates available for most cohort members. We calculated relative mortality rates and survival distribution using internal comparison (cohortbased estimation of background mortality). Findings Median life expectancy decreased with increasing radiation dose at a rate of about 1·3 years per Gy, but declined more rapidly at high doses. Median loss of life among cohort members with estimated doses below 1 Gy was about 2 months, but among the small number of cohort members with estimated doses of 1 Gy or more it was 2·6 years. Median loss of life among all individuals with greater-than-zero dose estimates was about 4 months. Interpretation These results are important in light of the recent finding that radiation significantly increases mortality rates for causes other than cancer. The results do not support claims that survivors exposed to certain doses of radiation live longer than comparable unexposed individuals. Because the cohort was intentionally constructed to contain a higher proportion of high-dose Atomic-Bomb survivors, average loss of life among all exposed Atomic-Bomb survivors would be less than the 4 months found for the study cohort.
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Skin tumor risk among Atomic-Bomb survivors in Japan
Cancer Causes and Control, 1998Co-Authors: Elaine Ron, Dale L. Preston, Masao Kishikawa, Toshihiro Kobuke, Masachika Iseki, Shoji Tokuoka, Masayoshi Tokunaga, Kiyohiko MabuchiAbstract:Objectives: Elevated risks of skin cancer following high doses of ionizing radiation have long been known. Recent reports on Atomic-Bomb survivors indicate that nonmelanoma skin cancer can be induced at low to medium doses. We studied Atomic-Bomb survivors to determine the effects of radiation on specific histologic types of skin cancer and to describe the dose-response relationship.
Sachiyo Funamoto - One of the best experts on this subject based on the ideXlab platform.
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dosimetric impact of a new computational voxel phantom series for the japanese Atomic Bomb survivors pregnant females
Radiation Research, 2019Co-Authors: Colin Paulbeck, Sachiyo Funamoto, Harry M Cullings, Keith Griffin, Choonsik Lee, Stephen D Egbert, Tatsuhiko Sato, Akira Endo, Nolan E Hertel, Wesley E BolchAbstract:An important cohort of the Atomic Bomb survivors are women who were pregnant when exposed to the photon and neutron fields at both Hiroshima and Nagasaki, as well as their children who were exposed...
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promoting action of radiation in the Atomic Bomb survivor carcinogenesis data
Radiation Research, 2007Co-Authors: W F Heidenreich, Sachiyo Funamoto, Harry M Cullings, H G ParetzkeAbstract:Abstract Heidenreich, W. F., Cullings, H. M., Funamoto, S. and Paretzke, H. G. Promoting Action of Radiation in the Atomic Bomb Survivor Carcinogenesis Data? Radiat. Res. 168, 750– 756 (2007). The age–time patterns of risk in the Atomic Bomb survivor data on incidence of solid cancers suggest an action of low-LET radiation not only on the initiating event but also on promotion in a biologically motivated model that allows for both actions. The favored model indicates a decrease of radiation risks with age at exposure due to the initiating effect and with time since exposure due to the promoting effect. These result in a relative risk that depends mostly on attained age for ages at exposure above 20 years. According to the model, a dose of 100 mGy is inducing about the same number of initiating events that occur spontaneously in 1 year. Assuming that several mutations are needed to obtain intermediate cells with growth advantage does not improve the quality of fit. The estimated promoting effect could be e...
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solid cancer incidence in Atomic Bomb survivors 1958 1998
Radiation Research, 2007Co-Authors: Dale L. Preston, Midori Soda, Elaine Ron, Shoji Tokuoka, Kiyohiko Mabuchi, Sachiyo Funamoto, Nobuo Nishi, Kazunori KodamaAbstract:Abstract Preston, D. L., Ron, E., Tokuoka, S., Funamoto, S., Nishi, N., Soda, M., Mabuchi, K. and Kodama, K. Solid Cancer Incidence in Atomic Bomb Survivors: 1958–1998. Radiat. Res. 168, 1–64 (2007). This is the second general report on radiation effects on the incidence of solid cancers (cancers other than malignancies of the blood or blood-forming organs) among members of the Life Span Study (LSS) cohort of Hiroshima and Nagasaki Atomic Bomb survivors. The analyses were based on 17,448 first primary cancers (including non-melanoma skin cancer) diagnosed from 1958 through 1998 among 105,427 cohort members with individual dose estimates who were alive and not known to have had cancer prior to 1958. Radiation-associated relative risks and excess rates were considered for all solid cancers as a group, for 19 specific cancer sites or groups of sites, and for five histology groups. Poisson regression methods were used to investigate the magnitude of the radiation-associated risks, the shape of the dose respon...
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dose estimation for Atomic Bomb survivor studies its evolution and present status
Radiation Research, 2006Co-Authors: Harry M Cullings, Eric J. Grant, Shoichiro Fujita, Sachiyo Funamoto, George D Kerr, Dale L. PrestonAbstract:Abstract Cullings, H. M., Fujita, S., Funamoto, S., Grant, E. J., Kerr, G. D. and Preston, D. L. Dose Estimation for Atomic Bomb Survivor Studies: Its Evolution and Present Status. Radiat. Res. 166, 219–254 (2006). In the decade after the Bombings of Hiroshima and Nagasaki, several large cohorts of survivors were organized for studies of radiation health effects. The U.S. Atomic Bomb Casualty Commission (ABCC) and its U.S./Japan successor, the Radiation Effects Research Foundation (RERF), have performed continuous studies since then, with extensive efforts to collect data on survivor locations and shielding and to create systems to estimate individual doses from the Bombs' neutrons and γ rays. Several successive systems have been developed by extramural working groups and collaboratively implemented by ABCC and RERF investigators. We describe the cohorts and the history and evolution of dose estimation from early efforts through the newest system, DS02, emphasizing the technical development and use of DS0...
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stable chromosome aberrations in Atomic Bomb survivors results from 25 years of investigation
Radiation Research, 2001Co-Authors: Yoshiaki Kodama, Takeo Honda, Dale L. Preston, David J Pawel, Nori Nakamura, Masahiro Itoh, Mimako Nakano, Kazuo Ohtaki, Sachiyo FunamotoAbstract:Abstract Kodama, Y., Pawel, D., Nakamura, N., Preston, D., Honda, T., Itoh, M., Nakano, M., Ohtaki, K., Funamoto, S. and Awa, A. A. Stable Chromosome Aberrations in Atomic Bomb Survivors: Results from 25 Years of Investigation. Radiat. Res. 156, 337–346 (2001). Frequencies of stable chromosome aberrations from more than 3,000 Atomic Bomb survivors were used to examine the nature of the radiation dose response. The end point was the proportion of cells with at least one translocation or inversion detected in Giemsa-stained cultures of approximately 100 lymphocytes per person. The statistical methods allow for both imprecision of individual dose estimates and extra-binomial variation. A highly significant and nonlinear dose response was seen. The shape of the dose response was concave upward for doses below 1.5 Sv but exhibited some leveling off at higher doses. This curvature was similar for the two cities, with a crossover dose (i.e. the ratio of the linear coefficient to the quadratic coefficient) of 1.7...
Kotaro Ozasa - One of the best experts on this subject based on the ideXlab platform.
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medical radiation exposure among Atomic Bomb survivors understanding its impact on risk estimates of Atomic Bomb radiation
Radiation Research, 2019Co-Authors: Atsuko Sadakane, Reid D Landes, Ritsu Sakata, Jun Nagano, Roy E Shore, Kotaro OzasaAbstract:There have been some concerns about the influence of medical X rays in dose-response analysis of Atomic Bomb radiation on health outcomes. Among Atomic Bomb survivors in the Life Span Study, the association between Atomic Bomb radiation dose and exposures to medical X rays was investigated using questionnaire data collected by a mail survey conducted between 2007–2011, soliciting information on the history of computed tomography (CT) scans, gastrointestinal fluoroscopy, angiography and radiotherapy. Among 12,670 participants, 76% received at least one CT scan; 77%, a fluoroscopic examination; 23%, an angiographic examination; and 8%, radiotherapy. Descriptive and multivariable-adjusted analyses showed that medical X rays were administered in greater frequencies among those who were exposed to an Atomic Bomb radiation dose of 1.0 Gy or higher, compared to those exposed to lower doses. This is possibly explained by a greater frequency in major chronic diseases such as cancer in the ≥1.0 Gy group. The frequency of medical X rays in the groups exposed to 0.005–0.1 Gy or 0.1–1.0 Gy did not differ significantly from those exposed to <0.005 Gy. An analysis of finer dose groups under 1 Gy likewise showed no differences in frequencies of medical X rays. Thus, no evidence of material confounding of Atomic Bomb effects was found. Among those exposed to Atomic Bomb doses <1 Gy, doses were not associated with medical radiation exposures. The significant association of doses ≥1 Gy with medical radiation exposures likely produces no substantive bias in radiation effect estimates because diagnostic medical X-ray doses are much lower than the Atomic Bomb doses. Further information on actual medical X-ray doses and on the validity of self-reports of X-ray procedures would strengthen this conclusion.
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Medical Radiation Exposure among Atomic Bomb Survivors: Understanding its Impact on Risk Estimates of Atomic Bomb Radiation
Radiation Research, 2019Co-Authors: Atsuko Sadakane, Reid D Landes, Ritsu Sakata, Jun Nagano, Roy E Shore, Kotaro OzasaAbstract:There have been some concerns about the influence of medical X rays in dose-response analysis of Atomic Bomb radiation on health outcomes. Among Atomic Bomb survivors in the Life Span Study, the association between Atomic Bomb radiation dose and exposures to medical X rays was investigated using questionnaire data collected by a mail survey conducted between 2007–2011, soliciting information on the history of computed tomography (CT) scans, gastrointestinal fluoroscopy, angiography and radiotherapy. Among 12,670 participants, 76% received at least one CT scan; 77%, a fluoroscopic examination; 23%, an angiographic examination; and 8%, radiotherapy. Descriptive and multivariable-adjusted analyses showed that medical X rays were administered in greater frequencies among those who were exposed to an Atomic Bomb radiation dose of 1.0 Gy or higher, compared to those exposed to lower doses. This is possibly explained by a greater frequency in major chronic diseases such as cancer in the ≥1.0 Gy group. The frequency of medical X rays in the groups exposed to 0.005–0.1 Gy or 0.1–1.0 Gy did not differ significantly from those exposed to
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japanese legacy cohorts the life span study Atomic Bomb survivor cohort and survivors offspring
Journal of Epidemiology, 2018Co-Authors: Kotaro Ozasa, Eric J. Grant, Kazunori KodamaAbstract:Cohorts of Atomic Bomb survivors-including those exposed in utero-and children conceived after parental exposure were established to investigate late health effects of Atomic Bomb radiation and its transgenerational effects by the Atomic Bomb Casualty Commission (ABCC) in the 1950s. ABCC was reorganized to the Radiation Effects Research Foundation (RERF) in 1975, and all work has been continued at RERF. The Life Span Study, the cohort of survivors, consists of about 120,000 subjects and has been followed since 1950. Cohorts of in utero survivors and the survivors' children include about 3,600 and 77,000 subjects, respectively, and have been followed since 1945. Atomic Bomb radiation dose was estimated for each subject based on location at the time of the Bombing and shielding conditions from exposure, which were obtained through enormous efforts of investigators and cooperation of subjects. Outcomes include vital status, cause of death, and cancer incidence. In addition, sub-cohorts of these three cohorts were constructed to examine clinical features of late health effects, and the subjects have been invited to periodic health examinations at clinics of ABCC and RERF. They were also asked to donate biosamples for biomedical investigations. Epidemiological studies have observed increased radiation risks for malignant diseases among survivors, including those exposed in utero, and possible risks for some non-cancer diseases. In children of survivors, no increased risks due to parental exposure to radiation have been observed for malignancies or other diseases, but investigations are continuing, as these cohorts are still relatively young.
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Cardiovascular disease among Atomic Bomb survivors
International Journal of Radiation Biology, 2017Co-Authors: Kotaro Ozasa, Ikuno Takahashi, Eric J. Grant, Kazunori KodamaAbstract:AbstractPurpose: 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 w...
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epidemiological research on radiation induced cancer in Atomic Bomb survivors
Journal of Radiation Research, 2016Co-Authors: Kotaro OzasaAbstract:The late effects of exposure to Atomic Bomb radiation on cancer occurrence have been evaluated by epidemiological studies on three cohorts: a cohort of Atomic Bomb survivors (Life Span Study; LSS), survivors exposed IN UTERO : , and children of Atomic Bomb survivors (F1). The risk of leukemia among the survivors increased remarkably in the early period after the Bombings, especially among children. Increased risks of solid cancers have been evident since around 10 years after the Bombings and are still present today. The LSS has clarified the dose-response relationships of radiation exposure and risk of various cancers, taking into account important risk modifiers such as sex, age at exposure, and attained age. Confounding by conventional risk factors including lifestyle differences is not considered substantial because people were non-selectively exposed to the Atomic Bomb radiation. Uncertainty in risk estimates at low-dose levels is thought to be derived from various sources, including different estimates of risk at background levels, uncertainty in dose estimates, residual confounding and interaction, strong risk factors, and exposure to residual radiation and/or medical radiation. The risk of cancer in subjects exposed IN UTERO : is similar to that in LSS subjects who were exposed in childhood. Regarding hereditary effects of radiation exposure, no increased risk of cancers associated with parental exposure to radiation have been observed in the F1 cohort to date. In addition to biological and pathogenetic interpretations of the present results, epidemiological investigations using advanced technology should be used to further analyze these cohorts.
