Mortality among individuals exposed to atomic bomb radiation in utero: 1950–2012

Abstract

We examined the mortality risks among 2463 individuals who were exposed in utero to atomic bomb radiation in Hiroshima or Nagasaki in August 1945 and were followed from October 1950 through 2012. Individual estimates of mother’s weighted absorbed uterine dose (DS02R1) were used. Poisson regression method was used to estimate the radiation-associated excess relative risk per Gy (ERR/Gy) and 95% confidence intervals (CI) for cause-specific mortality. Head size, birth weight, and parents’ survival status were evaluated as potential mediators of radiation effect. There were 339 deaths (216 males and 123 females) including deaths from solid cancer (n = 137), lymphohematopoietic cancer (n = 8), noncancer disease (n = 134), external cause (n = 56), and unknown cause (n = 4). Among males, the unadjusted ERR/Gy (95% CI) was increased for noncancer disease mortality (1.22, 0.10–3.14), but not for solid cancer mortality (− 0.18, < − 0.77–0.95); the unadjusted ERR/Gy for external cause mortality was not statistically significant (0.28, < − 0.60–2.36). Among females, the unadjusted ERRs/Gy were increased for solid cancer (2.24, 0.44–5.58), noncancer (2.86, 0.56–7.64), and external cause mortality (2.57, 0.20–9.19). The ERRs/Gy adjusted for potential mediators did not change appreciably for solid cancer mortality, but decreased notably for noncancer mortality (0.39, < − 0.43–1.91 for males; 1.48, − 0.046–4.55 for females) and external cause mortality (0.10, < − 0.57–1.96 for males; 1.38, < − 0.46–5.95 for females). In conclusion, antenatal radiation exposure is a consistent risk factor for increased solid cancer mortality among females, but not among males. The effect of exposure to atomic bomb radiation on noncancer disease and external cause mortality among individuals exposed in utero was mediated through small head size, low birth weight, and parental loss.

Review of the risk of cancer following low and moderate doses of sparsely ionising radiation received in early life in groups with individually estimated doses

“…There are strong estimates of excess risk of cancer in childhood in the OSCC study of Bithell and Stiller ( Bithell and Stiller 1988 ) and of Bithell ( Bithell 1993 ) ( Table 2 , Supplementary Table S7 ), at doses that likely do not exceed 0.03 Gy, and borderline significant indications of excess risk for lympho-haematopoietic malignancies in the range of attained ages up to 61 years in the Southern Urals study of Schüz et al ( Schüz et al 2017 ) and for all thyroid nodules (mainly benign) at an attained age of 25–30 years in the Ukraine 131 I-exposed cohort of Hatch et al ( Hatch et al 2019 ) ( Table 3 , Supplementary Table S7 ). There are weaker indications of excess brain tumour risk in a case-control study of medical diagnostic exposures ( Pasqual et al 2020 ) ( Table 2 , Supplementary Table S7 ), for solid cancer in the in utero exposed Japanese atomic bomb survivors in the incidence study of Preston et al ( Preston et al 2008 ) at attained age of 12–55 years and in the mortality study of Sugiyama et al ( Sugiyama et al 2021 ) at attained age of 5–67 years ( Table 4 , Supplementary Table S7 ), and for lymphoma, leukaemia and solid cancer in the offspring of US radiologic technologists ( Johnson et al 2008 ) at attained age up to 20 years ( Table 3 , Supplementary Table S7 ).…”

A review of the types of childhood cancer associated with a medical X-ray examination of the pregnant mother

“…The cohort of 1878 Japanese people who were present in utero in Hiroshima and Nagasaki during the atomic bombings in 1945 and who survived until October 1950 are a particularly important group for study; 908 of these survivors received RBE-weighted absorbed doses (approximated by maternal DS02R1 uterine doses) of !5 mGy during the bombings, with a mean dose of 254 mGy (Sugiyama et al 2021). Two incident cases of childhood cancer were found among these exposed survivors on follow up: a kidney tumor and a liver tumor (Yoshimoto et al 1991).…”

“…There is accumulating evidence from the Japanese atomic bomb survivors irradiated in utero of a dose-related increased risk of solid cancer incidence and mortality in adult life (Preston et al 2008;Sugiyama et al 2021); no variation of risk with trimester of exposure was discernible. In the most recent follow-up (Sugiyama et al 2021), an excess risk of solid cancer mortality was apparent in women (ERR/ Gy ¼ 2.10 (95% CI: 0.26, 5.61)) but not men (ERR/Gy ¼ À0.08 (95% CI: < À0.82, 1.36)); survivors had attained an age of 67 years and only 15% of those exposed had died, so more data gathered at older ages will provide firmer inferences. In the interim, a plausible conclusion is that radiation exposure in utero during the atomic bombings has led to an increased risk of solid cancer in adulthood (at least, in women), although the magnitude of this increased risk is, at present, uncertain.…”

Chromosome aberrations among atomic-bomb survivors exposed in utero: updated analysis accounting for revised radiation doses and smoking

“…A cohort of atomic-bomb survivors who were exposed in utero is being followed by the Radiation Effects Research Foundation (Sugiyama et al 2021 ). The Adult Health Study (AHS) is a clinical program established in 1958, comprising atomic-bomb survivors who were exposed to the atomic bombings in Hiroshima or Nagasaki.…”