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Low level radiation studies

Nuclear Monitor Issue: 
#322
01/12/1989
Article

(December 1, 1989) (Peter Diehl also sent the following abstracts of studies presented at the Birkenfeld Symposium on Low Level Radiation and Health held 1 to 3 November (see WISE News Communique 321.3219). The full papers are available in English from the address below.)

(322.3229) WISE Amsterdam -

Cancer in Swedish Iron Miners: A Nearly Complete Follow-up Study, by Edward P. Radford, M.D., England

We have obtained mortality data for 1,415 Swedish iron miners who worked underground and were exposed to relatively low concentrations of radon daughters. The cohorts studied were men born between 1880 and 1919 who were alive on January 1, 1930. Control populations have been the Swedish national population and men from the nearLy communities from the same birth years. Followup is now completed through 1986, at which time only 30% of the miners were still alive. Thus, this study population is epidemiologically the most complete one in the world of any group studied prospectively. Comparison of the two control popuulations shows that causes of death differed significantly for the local population compared to Swedish national rates. For example, a stomach cancer excess among miners is found to be present among controls as well. Seventy-three deaths from lung cancer have been observed among miners compared with the 17.6 expected; the absolute excess lung cancer risk for cigarette smokers is 1.66 times that for non-smokers, but the relative risk coefficient for non-smokers is four times that for smokers. The excess relative risk for lung cancer has continued unchanged even though all the men have been retired from underground work since 1978. A significant excess of multiple myeloma has been observed among the miners in recent follow-up years, and a more than three-fold excess of liver and gall bladder cancers has also been found. The evidence suggests that these last two observations may be related to occupational radon exposure.

Preliminary Results of a Pilot Study on Radon and Lung Cancer in Belglum, by A. Poffijn, Rijksuniversiteit Gent, Belgium

Indoor radon is the most important source of population exposure to ionizing radiation. Risk assessment for low doses is still a matter of controversy. Most estimates are extrapolations of the observation among uranium miners, where a clear relation between high radon exposure and the incidence of lung cancer has been established. As epidemiology provides a unique way of obtaining direct evidence about potential risk, a pilot study on indoor radon and lung cancer was set up at the end of 1987 in southern Belgium. This region was selected as a study area because the highest radon levels were found there and because the variation in exposure levels is much larger than in other parts of the country. Indoor levels are measured by tracketch detectors in a group of some hundred incident lung cancer cases and in a comparable group of some 200 people without the disease. The prevalence in both groups of other factors possibly associated with lung cancer is assessed by means of a standardized questionnaire. For the moment complete results for some 60 cases and 120 controls are available. From the analysis of these preliminary data a crude rate-ratio of 2.7 was obtained for all subjects. A clear significant increase in lung cancer risk was observed for the subgroup of male smokers, exposed to levels above 100 Bq/m1

Contact: Kreisverwaltung Birkenfeld, z.H. Herrn Stefan Schupp, Schlossallee 11, D-6588 Birkenfeld, Wesi Germany, tel: +49-6782-15-318.