Radiation and mortality of workers at Oak Ridge National Laboratory: positive associations for doses received at older ages.

Abstract

We examined associations between low-level exposure to ionizing radiation and mortality among 14,095 workers hired at the Oak Ridge Nationl Laboratory between 1943 and 1972. Workers at the facility were individually monitored for external exosure to ionizing radiation and have been followed through 1990 to ascertain cause of death information. Positive associations were observed between low-level exposure to external ionizing radiation and mortality. These associations were larger for doses received after 45 years of age, larger under longer lag assumptions, and primarily due to cancer causes of death. All cancer mortality was estimated to increase 4.98%[standard error (SE) = 1.5] per 10-mSv cumulative dose received after age 45 under a 10-year lag, and 7.31% (SE = 2.2) per 10-mSv cumulative dose received after age 45 under a 20-year lag.Associations between radiation dose and lung cancer were of similar magntude to associations between radiation dose and all cancers except lung cancer. Nonmalignant respiratory disease exhibited a positive association with cumulative radiation dose received after age 45, whereas ischemic heart disease exhibited no association with radiation dose. These findings suggest increases in cancer mortality associated with low-level external exposure to ionizing radiation and potentially greater sensitivity to the carcinogenic efcs of ionizing radiation with older ages at exposure.

Protracted Radiation Exposure and Cancer Mortality in the Techa River Cohort

“…There are suggestions in these data that the solid cancer ERR increases with increasing age at first exposure or attained age (age at death) and that the leukemia ERR increases with increasing age at first exposure. These patterns appear to contradict what one would expect on the basis of the atomic bomb survivors (20,24) and mechanistic considerations (25)(26)(27)(28), but some analyses of U.S. nuclear workers have suggested similar general patterns (29,30). To try to better understand these unexpected temporal patterns, we performed some more detailed descriptive analyses.…”

Mortality associated with chronic external radiation exposure in the French combined cohort of nuclear workers

“…Although some studies of nuclear workers have not reported results for this category of cancer mortality, results can be compared with those for all cancers except leukaemia, which are similar 4. Significant associations between dose and risk for all cancers except leukaemia were observed in several nuclear worker cohorts,4 8 13 27 28 noticeably in the 15-country study4 and the last UK National Registry of Radiation Workers (NRRW) analysis 8. The magnitude of the ERR/Sv estimated in our study appears similar to that estimated in the 15-country study after exclusion of the Canadian cohort 4.…”

Review and meta-analysis of epidemiological associations between low/moderate doses of ionizing radiation and circulatory disease risks, and their possible mechanisms

“…In other workforces (Richardson and Wing 1999; Vrijheid et al 2007), there were generally no statistically significant trends of circulatory disease with dose (Table 1). It should be noted that these studies overlap, and in particular there is substantial inclusion of the study populations of the studies of Richardson and Wing (1999) and Muirhead et al (2009) within that of the IARC study (Vrijheid et al 2007).…”