Analysis of the Mortality Experience amongst U.S. Nuclear Power Industry Workers after Chronic Low-Dose Exposure to Ionizing Radiation

Abstract

Workers employed in 15 utilities that generate nuclear power in the United States have been followed for up to 18 years between 1979 and 1997. Their cumulative dose from whole body ionizing radiation has been determined from the dose records maintained by the facilities themselves and the REIRS and REMS systems maintained by the Nuclear Regulatory Commission and the Department of Energy, respectively. Mortality in the cohort from a number of causes has been analyzed with respect to individual radiation doses. The cohort displays a very substantial healthy worker effect, i.e. considerably lower cancer and noncancer mortality than the general population. Based on 26 and 368 deaths, respectively, positive though statistically nonsignificant associations were seen for mortality from leukemia (excluding chronic lymphocytic leukemia) and all solid cancers combined, with excess relative risks per sievert of 5.67 [95% confidence interval (CI) -2.56, 30.4] and 0.506 (95% CI -2.01, 4.64), respectively. These estimates are very similar to those from the atomic bomb survivors study, though the wide confidence intervals are also consistent with lower or higher risk estimates. A strong positive and statistically significant association between radiation dose and deaths from arteriosclerotic heart disease including coronary heart disease was also observed in the cohort, with an ERR of 8.78 (95% CI 2.10, 20.0). While associations with heart disease have been reported in some other occupational studies, the magnitude of the present association is not consistent with them and therefore needs cautious interpretation and merits further attention. At present, the relatively small number of deaths and the young age of the cohort (mean age at end of follow-up is 45 years) limit the power of the study, but further follow-up and the inclusion of the present data in an ongoing IARC combined analysis of nuclear workers from 15 countries will have greater power for testing the main hypotheses of interest.

Cancer risk among chernobyl cleanup workers in Estonia and Latvia, 1986–1998

“…36 However, a similar increase in brain cancer risk was not demonstrated in the combined analysis of mortality among nuclear workers of the 3 countries 37 nor in recent studies of the nuclear workforce in Canada 38 and the nuclear industry in the United States. 39 The excess of brain cancer cases in our study was of borderline significance, and it might be a chance finding due to multiple comparisons or close surveillance. 40 It also is possible that some of the brain cancers of ill-defined histology were metastatic from other primary sites.…”

Radiation dose-rate effects, endogenous DNA damage, and signaling resonance

“…Data are available from cohort studies of Japanese atomic bomb survivors (reviewed in ref. 21), nuclear plant (and other nuclear industries) workers (22)(23)(24), and Chernobyl's accident operation (''clean-up'') workers (21). These data provide estimates for the leukemia risk (per unit of dose) induced in three very different DR regions, calculated here as percent increase of background risk per 10 cSv (Fig.…”

Evaluating shielding effectiveness for reducing space radiation cancer risks

“…Career radiation limits and shielding requirements could also be impacted by new knowledge of fatal non-cancer risks from radiation exposure such as heart disease (Preston et al, 2003;Howe et al, 2004;Yang et al, 1982) or damage to the central nervous system (CNS).…”

“…The risk of heart disease for ions is largely unknown because only one report (considered a pilot study by the authors of the report) has been made on the effects of HZE ions on heart disease (Yang et al, 1982), and human data for low LET radiation at low dose-rates is inconclusive on the level of risk to be expected (Howe et al, 2004;Cardis et al, 1995). CNS risks have the potential to impact both short-term and career radiation limits and mitigation approaches (NRC, 1996).…”

“…Radiation risks include carcinogenesis, degenerative tissue effects such as cataracts (Cucinotta et al, 2001a) or heart diseases (Preston et al, 2003, Howe et al, 2004, Yang et al, 1982, and acute radiation syndromes (NCRP, 2000). Other risks such as damage to the central nervous system (CNS) are a potential concern for the GCR heavy ions (NAS, 1996).…”