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Studies of miners provide the basis for public health efforts to reduce residential radon progeny exposure. Because the preponderance of households do not have members who smoke indoors, studies of non-smoking miners contribute essential data for risk assessments for residential radon progeny exposure. We studied a cohort of 2,209 never-smokers who were underground uranium miners employed in the western U.S. from 1956 to the early 1990's and who participated in a screening program for lung cancer conducted by Saccomanno and colleagues. After determining the vital status and cause of death in the cohort, we conducted a nested case-control study of 55 lung cancer deaths in males and 3 age-matched controls for each case. The relative risk of lung cancer was 29.2 (95% CI 5.1, 167.2) for miners with greater than 1,450 WLM compared with those exposed to less than 80 WLM. Temporal factors affected risk, including average dose rate, which was inversely associated with lung cancer risk, and the length of time since last exposure, which was directly associated with decreased risk. As in studies of non-smokers and smokers combined, the exposure response relationship in never-smokers was consistent with a decreased slope at higher WLM, which resulted, in part, from an inverse dose rate effect.

Latitude influences the availability of fresh fruits and vegetables (which are associated with cancer protection) and the use of food preservation methods (which are associated with increased cancer). Such dietary differences might be reflected in the frequency of death from cancer of the digestive tract. Female mortality rates for states and provinces of the US and China, both of which cover a wide latitude range, were chosen to investigate latitude- and time-related changes. Mortality for cancer of the stomach, liver, and rectum did increase with latitude in both nations, which is consistent with the hypothesis. Exceptions were cancer of the colon and esophagus; these cancers had a variable association with latitude and did not decline markedly in the US by 1970-1979 as did mortality rates from cancer of the other digestive tract sites. Increased refrigeration and improved transportation, both of which result in increased consumption of fresh fruits and vegetables, and decreased use of older food preservation methods may be responsible for the US decline in mortality rates from stomach, liver, and rectal cancers.

Mortality of uranium miners from both lung cancer and other respiratory diseases is strongly dependent on exposure to radon daughters, cigarette smoking and height. Lung cancer among 15 different mining groups (uranium, iron, lead, zinc) was analyzed to determine what factors influence incidence and the induction-latent period. At low exposure or exposure rates, alpha radiation is more efficient in inducing lung cancer, producing an upward convex exposure-response curve. The induction-latent period is shortened by increased age at start of mining, by cigarette smoking and by high exposure rates. For a follow-up period of 20 to 25 years, the incidence increases with age at start of mining, with magnitude of exposure and with amount of cigarette smoking. Instead of extrapolating downward from high exposures to estimate risk at low levels, it is suggested that it might be more appropriate to use cancer rates associated with background radiation as the lowest point on the exposure-response curve. Although health risks are much greater in uranium mines than mills, there is some health risk in the mills from long-lived radioactive materials.

A mortality analysis of a group of white and Indian uranium miners was done by a life-table method. A significant excess of respiratory cancer among both whites and Indians was found. Nonmalignant respiratory disease deaths among the whites are approaching cancer in importance as a cause of death, probably as a result of diffuse parenchymal radiation damage. Exposure-response curves for nonsmokers are linear for both respiratory cancer and "other respiratory disease." Cigaret smoking elevates and distorts that curve. Light cigaret smokers appear to be most vulnerable to lung parenchymal damage. The predominant histologic cancer among nonsmokers is small-cell undifferntiated, just as it is among cigaret smokers.

The world population has been exposed to low levels of fission products from nuclear testing. Has this had any health effects? Six different epidemiological associations are demonstrated between leukemia and nuclear fallout in the general population. The strongest association is with acute and myeloid types of leukemia among children. They peaked at approximately 5.5 yr (among 5-9 yr olds) after the peaks in fallout. The entire United States population exhibited an increasing leukemia rate during and for several years after the open air nuclear testing and fell sharply thereafter. Regional differences in leukemia rates correspond to a composite exposure index that used 90Sr concentrations in food, cow's milk, and human bone. The calculated leukemia risk per rad for children was similar to that calculated for Japanese A-bomb children survivors.