THE ROLE OF TOBACCO, ALCOHOL-USE, AND BODY-MASS INDEX IN ORAL AND PHARYNGEAL CANCER

Background. Although tobacco smoking and alcohol drinking are well-est ablished risk factors for oral cancer, relatively few studies have add ressed the comparative effect of filter versus non-filter cigarettes, the nature of the reduction in risk following cessation, and the joint effects of tobacco and alcohol. In addition, recent studies suggest a n inverse association of body mass index with oral cancer. We used dat a from a large, hospital-based case-control study to investigate these issues. Methods. The data set consisted of 1097 male and 463 female o ral cancer cases and 2075 male and 873 female controls. Unconditional logistic regression was used to estimate the effect of risk factors in the presence of covariates. Results. Among male current smokers, user s of filter cigarettes (whether lifetime users or those who switched t o filter cigarettes) had a significantly reduced risk of oral cancer w hich approached 50%. Among female current smokers, only those who swit ched to filter cigarettes 10+ years previously showed a significantly reduced risk. Those who quit smoking experienced a marked decrease in risk compared to current smokers. Smoking and alcohol consumption show ed a significant interaction on a multiplicative model. After adjustme nt for covariates, leanness was significantly associated with oral can cer among male current and ex-smokers. Conclusions. The results of thi s study: 1) indicate that smokers of filter cigarettes and those who q uit smoking are at substantially reduced risk of oral cancer, 2) demon strate interaction between smoking and drinking, and 3) suggest that l eanness preceding diagnosis may be associated with oral cancer.