A case-control study of tobacco-related cancers in Colombia

The work reported here examined the effects of smoking cigarettes made predominantly of dark tobacco, alcohol consumption, and coffee drinking upon the risk of developing cancers of the bladder, larynx, lung, and oral cavity/hypopharynx in Medellín, Colombia. For this purpose 439 subjects with newly diagnosed cancers at the indicated sites were selected. Each subject was then matched by age, sex, and socioeconomic status with at least one control. Data from interviews with the selected subjects, upon analysis, showed both the intensity and duration of cigarette smoking to be statistically significant predictors of cancer at all four sites. In addition, heavy alcohol consumption and coffee drinking in excess of seven cups daily were associated with some elevation of cancer risk at most of the sites studied. Multivariate analyses of cigarette smoking, alcohol consumption, and coffee drinking showed that adjustment for coffee and alcohol consumption did not change the observed associations between elevated cancer risks and cigarette smoking. However, adjustment of the coffee and alcohol consumption data for cigarette smoking reduced most of the observed relative risks of coffee and alcohol consumption and eliminated the statistical significance of certain associations.