Abstract |
The relationship between ingested asbestos (through drinking water) and cancer of various body sites was examined. This study was a follow-up to another article that investigated this relationship. Age-adjusted, sex and race specific 1969-1974 cancer incidence ratios for 410 census tract groupings ('super tracts') of the San Francisco-Oakland Standard Metropolitan Statistical Area were compared with measured chrysotile asbestos counts in drinking waters of super tracts. The earlier article analyzed cancer data for the 3 yr. period, 1969-1971. The present study used that data and an added set of cancer cases for 1972-1974. The water supplies serving the area have varying contact with naturally occurring serpentine. The t-test for multiple regression coefficients and the t-test for correlation coefficients showed significant (p<0.01) relationships between chrysotile asbestos content of super tract drinking water and white male digestive tract, esophageal, stomach and pancreatic cancers. For white females, significant (p<0.01) relationships on these tests were found for esophageal, stomach, digestive related organs, and pancreatic cancers. These associations appeared to be independent of income, education, asbestos occupation, marital status and mobility. |