Mortality of employees of the Atomic Weapons Establishment, 1951-82.

Abstract

A total of 22 552 workers employed by the Atomic Weapons Establishment between 1951 and 1982 were followed up for an average of 18*6 years. Of the 3115 who died, 865 (28%) died of cancer. Mortality was 23% lower than the national average for all causes ofdeath and 18% lower for cancer. These low rates were consistent with the findings in other workforces in the nuclear industry and reflect, at least in part, the selection of healthy people to work in the industry and the disproportionate recruitment of people from the higher social classes.At some time during their employment 9389 (42%) of the workers were monitored for exposure to radiation, the average cumulative whole body exposure to external radiation being 7*8 mSv. Their mortality was generally similar to that of other employees, even when exposures were lagged by 10 years. The rate ratio after a 10 year lag in workers with a radiation record compared with other workers was 1*01 (95% confidence interval 0-92 to 1.10) for all causes of death and 1-06 (0.89 to 1-27) for all malignant neoplasms. The only significant differences were for prostatic cancer (rate ratio 2*23; 95% confidence interval 1*13 to 4.40) and for cancers of ill defined and secondary sites (rate ratio 2*37; 1-23 to 4.56). Cancers of lymphatic and haemopoietic tissues were notable for their low occurrence in the study population, with only four deaths from leukaemia and two from multiple myeloma in workers with a radiation record, 9 16 and 3*55 deaths respectively being expected on the basis of national rates.Among workers who had a radiation record 3742 (40%) were also monitored for possible internal exposure to plutonium, 3044 (32%) to uranium, 1562 (17%) to tritium, 638 (7%) to polonium, and 281 (3%) to actinium. In these workers mortality from malignant neoplasms as a whole was not increased, but after a 10 year lag death rates from prostatic and renal cancers were generally more than twice the national average, these excesses arising in a small group of workers monitored for exposure to multiple radionucfides. Though mortality from lung cancer in workers monitored for exposure to plutonium was below the national average, it was some two thirds higher than in other radiation workers, the excess being of borderline statistical significance.Mortality from malignant neoplasms as a whole showed a weak and non-significant increasing trend with increasing level of cumulative whole body exposure to external radiation. When the exposures were lagged by 10 years the trend became stronger and significant, the estimated increase in relative risk per 10 mSv being 7*6% (95% confidence interval 0*4% to 15.3%). This trend was confined almost entirely to workers who were also monitored for exposure to radionuclides (p<0001), the main contributions coming from lung cancer and prostatic cancer. Exposures of the lung and prostate from internal sources of radiation were not quantified, except for the contribution from tritium. It was therefore not possible to assess the extent to which the associati...

Cancer mortality and morbidity among workers at the Sellafield plant of British Nuclear Fuels

“…This finding is consistent with radiation being a cause of these cancers, but does not account for most of the excess being among those not monitored for radiation exposure. An excess of these cancers has not been found in other studies of nuclear workers and nor has an association with radiation dose (Beral et al, 1988;Fraser et al, 1993), and our findings are difficult to interpret. For 35 of the 53 deaths from this cause there was a cancer registration, but these did not help identify the site of the primary cancer in most cases, since for 28 the registration was also of an ill-defined or secondary cancer.…”

“…The findings of mortality are very similar to those reported in our earlier paper (Smith & Douglas, 1986). In other studies of workers in nuclear plants, overall mortality rates have been found to be substantially lower than those of the general population (Beral et al, 1988;Wing et al, 1991;Fraser et al, 1993;Gilbert et al, 1993) and this has usually been attributed to the 'healthy worker' effect, often found in studies of occupational mortality, resulting from higher death rates in the general population among individuals with chronic sicknesses who either do not seek employment or who are not selected for employment. We commented at some length on the apparent absence of this effect among the Sellafield workers (Smith & Douglas, 1986) and concluded that it seemed unlikely that such an effect was masked owing to a deleterious effect of radiation exposure, the two principal reasons being that overall mortality rates were lower among radiation workers than among other workers and that there was little evidence of an association between accumulated radiation dose and death rates from all causes combined.…”

“…The radiation doses that have been accumulated by workers at the Sellafield plant, since it opened in 1947, are higher, on average, than those experienced by workers at other nuclear facilities in the UK (Beral et al, 1988;Fraser et al, 1993) and in the USA Wing et al, 1991 (Table VII). The findings of mortality are very similar to those reported in our earlier paper (Smith & Douglas, 1986).…”

Nuclear industry family study: methods and description of a United Kingdom study linking occupational information held by employers to reproduction and child health

“…These databases are of a generally high quality, not only because radiation dose records have to be maintained for United Kingdom regulatory purposes, but also because the data have been used previously for several large epidemiological studies of the workers themselves. [15][16][17][18][19][20][21][22] Data were supplied for all those responding who had ever had, or who had ever attempted to have, children, and were linked by computer to the cleaned, coded, and validated questionnaire based data with the subjects' unique personal identifiers. Thus the researchers were blind to the occupational exposure status of the workers when collecting data on reproduction and child health outcomes.…”

“…1-4 6 8 10 14 Generally, when an occupational hazard is suspected the health of the workers in the industries concerned is studied directly: for example, within the nuclear industry, several cohort studies have investigated the relation between cancer and mortality in relation to exposure to ionising radiation at work. [15][16][17][18][19][20][21][22] The nuclear industry family study takes this one step further, linking the occupational exposure of workers to their pregnancies and the health of their children.…”