Attributable risk for diet, alcohol, and family history in the Melbourne Colorectal Cancer Study.

From the data obtained in a large comprehensive population-based case-control study of colorectal cancer (The Melbourne Colorectal Cancer Study), attributable risk was calculated for a family history of colorectal cancer in near relatives for diet (when > or = 5 of the 11 previously determined dietary risk factors were present) and for beer consumption (for rectal cancer only). The attributable risk was 11% in the presence of a family history of colorectal cancer and 46% in the presence of five or more dietary risk factors. The attributable risk for rectal cancer in the presence of beer consumption was 31% in males and 11% in females. These data are relevant in the consideration of primary prevention of colorectal cancer in Australia, but their general application needs to be approached with caution in view of major differences in the genetic background and the dietary practices in various regions of the world and in view of the uncertainty of what is achievable change, especially for dietary practices.