Risk of Leukemia Associated with Protracted Low-Dose Radiation Exposure: Updated Results from the National Registry for Radiation Workers Study

Abstract

While the link between risk of leukemia and acute radiation exposure is well established for large doses received acutely, uncertainty remains around the translation of these risk estimates to occupational exposure scenarios where the doses are low and accumulated over time, possibly over many years. We present leukemia incidence and mortality radiation risk estimates derived from the National Registry for Radiation Workers, which is a large cohort of occupationally exposed workers from the United Kingdom (UK). The cohort comprised 173,081 workers from the UK who were monitored for occupational exposure to radiation. The cohort was followed for a total of 5.3 million person-years and the incidence and mortality due to leukemia was identified through to the end of follow-up in 2011. Poisson regression was used to investigate the relationship between cumulative radiation dose and leukemia mortality and incidence rates using excess relative risk (ERR) and excess additive risk (EAR) models. The results of this work showed a collective dose of 4,414 person-Sv accumulated by the cohort with an average cumulative dose of 25.5 mSv. Among male workers both the ERR and EAR models showed evidence of increased leukemia risk (excluding chronic lymphatic leukemia) associated with increasing cumulative dose. The ERR was 1.38 per Sv (90% CI: 0.04; 3.24) and EAR was 1.33 per 10,000 person-year-Sv (90% CI: 0.04; 2.89) when a linear model was used. These excess risks were driven by increased risks for chronic myeloid leukemia [ERR/Sv ¼ 6.77 (90% CI: 2.14; 15.44)]. In conclusion, this study provides further evidence that leukemia risks may be increased by low-dose and protracted external radiation exposure. The risks are generally consistent with those observed in the atomic bomb survivor studies, as well as with risk coefficients on which international radiation safety standards, including the dose limits and constraints used to control exposures, are based.

Influence of Individual Radiosensitivity on the Hormesis Phenomenon: Toward a Mechanistic Explanation Based on the Nucleoshuttling of ATM Protein

“…In the epidemiological data obtained from individuals exposed to lower dose rates (like for nuclear workers), the general slope of the relative risk decreases, which is consistent with a lower rate of DSB induction and a longer time allocated to repair DNA damage 63 (Figure 5E). However, in these cases, the peak reflecting HRS is found shifted to lower values (about 150 mGy in the example shown in Figure 4E).…”

“…The inset shows the same information for the fuller dose range. 62 E, Leukemia dose-response from UK national registry for nuclear workers study reproduced from figure 1 of reference 63 with permission. Nonlymphatic leukemia ERR estimates and 90% CI 2-year-lagged external cumulative dose category with linear ERR/Sv estimate and associated 90% CI reference lines.…”

“…Nonlymphatic leukemia ERR estimates and 90% CI 2-year-lagged external cumulative dose category with linear ERR/Sv estimate and associated 90% CI reference lines. 63 F, Schematic illustration of the double occurrence of hormesis and HRS and its theoretical evolution as far as the dose rate decreases (gray arrows). The dashed line shows theoretical data from lower dose rate than those shown with solid line.…”

Impact of Host, Lifestyle and Environmental Factors in the Pathogenesis of MPN

“…Acute exposure to high doses of atomic bomb radiation among Japanese residents is associated with AML and CML [86] while protracted low-dose radiation exposure also increases the risk for CML [87]. Although the incidence of MPN following low-dose radiation is not reported, the genomic characteristics of MPN patients with and without exposure to radiation from the Chernobyl nuclear accident have been evaluated.…”

Cancer Incidence and Mortality in the U.S. Astronaut Corps, 1959-2017

“…Hematologic cancers are of concern to space exploration because these malignancies are known to be among the most radio-sensitive both in childhood and in adulthood. [18][19][20] We observed 4 hematologic cancers in the astronaut cohort when fewer than 2 were expected, for an SIR of approximately 200. While the 2 observed deaths from this cancer type represented an insigni cant reduction in the mortality rate, the expected number of deaths from this cancer exceeded the expected number of cases, making interpretation of the SMR di cult.…”