Abstract |
Case-control, interview-based study of the risk of developing cancer from asbestos in drinking water was conducted in an area including Beverett, Washington, selected because of the unusually high concentration of chrysotile asbestos in drinking water from the Sultan River. Through a population-based tumor registry, 382 individuals with cancer of the buccal cavity, pharynx, respiratory system, digestive system, bladder, or kidney, diagnosed between 1977 and 1980, were identified, and they--or their next-of-kin--were interviewed. Data on asbestos exposure were collected based on residence and workplace history and on individual water consumption. Logistic regression was used to estimate cancer risk. No convincing evidence for increased cancer risks from imbibed asbestos was found. Confidence intervals for relative risks for almost all sites included unity. There were significantly elevated risks only for male stomach and male pharyngeal cancer, but there sex-inconsistent results, based on small numbers of cases, are probably due to the factors. |