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To determine late health effects of radiation in atomic bomb survivors, the Radiation Effects Research Foundation has been conducting studies on the Life Span Study (LSS) population, which consists of 93 000 atomic bomb survivors and 27 000 controls. A recent report on the incidence of solid cancers estimates that at the age of 70 y, after exposure at the age of 30 y, solid-cancer rates increase by about 35 % per Gy for men and 58 % per Gy for women. The age-at-exposure is an important risk modifier. Furthermore, it seems that radiation-associated increases in cancer rates persist throughout life. In addition, radiation has similar effects upon first-primary and second-primary cancer risks. A recent report on leukemia mortality suggested that the effect of radiation on leukemia mortality persisted for more than five decades. In addition, a significant dose–response for myelodysplastic syndrome is found in Nagasaki LSS members 40–60 y after radiation exposure. In view of the nature of the continuing increase in solid cancers, the LSS should continue to provide important new information on cancer risks, as most survivors still alive today were exposed to the atomic bomb radiation under the age of 20 y and are now entering their cancer-prone years. [ABSTRACT FROM PUBLISHER]

The Radiation Effects Research Foundation succeeded 28 years' worth of activities of the Atomic Bomb Casualty Commission on long-term epidemiological studies in Hiroshima and Nagasaki. It has three major cohorts of atomic bomb survivors, i.e. the Life Span Study (LSS) of 120 000 people, the In Utero Cohort of 3600 and the Second Generation Study (F1) of 77 000. The LSS and F1 studies include a periodic health examination for each sub-cohort, i.e. the Adult Health Study and the F1 Clinical Study, respectively. An extensive individual dose estimation was conducted and the system was published as the Dosimetry System established in 2002 (DS02). As results of these studies, increases of cancers in relation to dose were clearly shown. Increases of other mortality causes were also observed, including heart and respiratory diseases. There has been no evidence of genetic effects in the survivors' children, including cancer and other multi-factorial diseases. The increase in the expected mortality number in the next 10 y would allow the analyses of further details of the observed effects related to atomic bomb exposures. [ABSTRACT FROM PUBLISHER]