Role of alcohol in cancers of the upper alimentary tract: use of models in risk assessment.

A case-control study of cancers of the upper alimentary tract was conducted in a hospital to assess the role of several risk factors, including alcohol consumption, which is reported here. Male patients from one community with cancers of the oral cavity (n = 278), pharynx (n = 225), and oesophagus (n = 236) formed the case group. Patients diagnosed as not having cancer (n = 215) formed one control group, and a comparable sample of individuals from the general population (n = 177) formed another control group. The risk of regular alcohol consumption along with the two well established risk factors of tobacco smoking and chewing were assessed from the linear logistic model fitted. The process of model fitting has been elaborated. Adjusted odds ratios of alcohol consumption in those under 60 years of age varied from 1.3 to 3.6-fold for developing oral cavity cancer, from 1.9 to 5.4-fold for pharyngeal cancer, and from 1.5 to 2.7-fold for oesophageal cancer, in different age groups. No association was observed between alcohol consumption and cancer in those over 60 years of age. A synergistic effect was observed for the combined habit of alcohol drinking with tobacco smoking and/or chewing. The fact that age is a risk factor independent of habit is also demonstrated.