[en] The best estimate of risk to which everyone is exposed from natural radon in buildings is now obtained by extrapolation from observations on men exposed to radon in mines. The relationship between dose and effect derived by the US National Research Council implies that about 6% of the current life-time risk of developing the disease in the UK is attributable to radon, but for residents of some houses it will be much greater. This estimate is dependent on many assumptions, some of which are certainly wrong, and reliable estimates can be obtained only by direct observations on people living in different houses. It is possible that radon may also cause some risk of other cancers, notably leukaemia, but such risks, if real, are certainly small. Studies in progress should provide reliable estimates of all radon induced risks within a few years. (author)

[en] Possible explanations for the recently reported increased incidence of childhood leukaemia around Dounreay were examined in the light of changes in the national incidence of leukaemia that occurred during the period of exposure to fallout from international testing of nuclear weapons in the atmosphere. It was concluded that the increase could not be accounted for by underestimate of the risk of leukaemia per unit dose of radiation at low doses and low dose rates, nor by underestimate of the relative biological efficiency of high compared with low linear energy transfer radiation. One possible explanation was underestimation of doses to the red bone marrow due to the discharges at Dounreay relative to dose from fallout, though investigation of ways in which this might have occurred did not suggest anything definite. Other explanations included a misconception of the site of origin of childhood leukaemia, outbreaks of an infectious disease and exposure to other, unidentified environmental agents. These findings weigh against the hypothesis that the recent increase in childhood leukaemia near Dounreay might be accounted for by radioactive discharges from nuclear plants, unless the doses to the stem cells from which childhood leukaemia originates have been grossly underestimated. (author)

[en] Weak associations in epidemiology may offer major opportunities for the improvement of public health if they are observed between common diseases and agents that are prevalant in the community. This article discusses two weak associations which require to be clarified by collaboration reviews or very large studies. These are relating the risk of lung cancer to the concentration of radon in houses and between the risks of leukaemia and brain cancer to extremely low frequency electromagnetic fields. (UK)

[en] Recent reassessments of data from the survivors at Hiroshima and Nagasaki suggest that the risk of cancer from acute doses of radiation is higher than had previously been thought. For leukaemia the risk is about six time higher and for other cancers about eleven times higher than previous estimates. Epidemiological studies are an important means, in principle, of establishing the risks due to low doses received over a protracted period. The current status of epidemiological studies of workers in the nuclear industry, and of the general public exposed either to weapons fallout or to discharges from the industry, is summarized. (author)

[en] Short communication

[en] Need for precise estimation of small occupational hazards has required the development of new epidemiological techniques, including the combination of the results of many different studies. Data for 10 cohorts of nuclear energy workers support the belief that occupational hazards have been small, but are insufficient to provide precise estimates of their size. The few that can be used to relate risk quantitatively to dose are compatible with the risks predicted from the experience of persons exposed acutely to high doses. Several unsolved biological problems complicate accurate predictions. (author)

[en] Two types of evidence suggest that the prevention of cancer is a practical possibility: first, our increasing knowledge of the causes of cancer, many of which can be avoided without difficulty, and second, evidence that all common cancers whose causes are still unknown vary in incidence with place, time or social group. Many known causes still exist, however, and are responsible for hundreds of thousands of cases annually throughout the world. Practical possibilities for prevention now and in the near future include changes in personal habits (tobacco, alcohol, diet), control of exposure to known cancer-producing substances (carcinogens) in both industry and the general environment, and immunization against viruses causing cancer. (author)

[en] Small doses of radiation are usually understood to be doses less than about 0.25 Sv - nearly 100 times the dose received annually from natural sources. Such doses can, it is thought, have three effects. First, they can damage DNA in the germ cells, causing mutations and hereditary defects in subsequent offspring. Secondly, they can damage the fetal brain causing some intellectual impairment. Thirdly, they can damage DNA in somatic cells and consequently cause cancer. (author)

[en] The possible explanations of the recently reported increase in the incidence of childhood leukaemia around Dounreay are examined in the light of the changes in national leukaemia incidence that occurred during the period of exposure to fallout from international atmospheric testing of nuclear weapons. It is concluded that the increase cannot be due to underestimation of the risk of leukaemia per unit dose of radiation, nor to an underestimate of the relative biological efficiency of high as compared with low LET radiation. Possible explanations of the increase include an underestimate of the red bone marrow doses due to the Dounreay discharges relative to those from fallout, a misconception of the site of origin of childhood leukaemia, epidemics of infectious disease and exposure to some other unidentified environmental agent. (author)

[en] Mortality up to 1 January 1983 has been studied in 14,106 patients with ankylosing spondylitis given a single course of x-ray treatment. For leukaemia there was a threefold increase in mortality. The relative risk was at its highest between 2.5 and 4.9 years after the treatment and then declined, but the increase did not disappear completely, and the risk was still nearly twice that of the general population more than 25.0 years after treatment. For neoplasms other than leukaemia or colon cancer, mortality was 28% greater than that of the general population of England and Wales. The proportional increase reached a maximum of 71% between 10.0 and 12.4 years after irradiation and then declined. There was only a 7% increase in mortality from these tumours more than 25.0 years after irradiation and only for cancer of the oesophagus was the relative risk significantly raised in this period. (author)