Remote life-style causes of cancer.

Most epidemiologists regard more or less proximal variables as life-style factors--smoking, diet, sex behavior, occupation. Within this framework, life-style factors making for high risk of cancer are defined and presented. Three estimates of the contribution to cancer incidence by the major proximal causes are presented, using the variables specified by each estimator. For purposes of completeness and possible prevention action, however, intermediate and distant precursors should be considered--local ecology, culture, industrialization, etc. The possibility that stress may affect cancer risk is addressed and evidence presented to suggest that any contribution to risk, if it exists at all, is probably small.