Background. Although tobacco smoking and alcohol drinking are well-established risk factors for oral cancer, relatively few studies have addressed 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 an inverse association of body mass index with oral cancer. We used data from a large, hospital-based case-control study to investigate these issues. Methods. The data set consisted of 1097 male and 463 female oral 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, users of filter cigarettes (whether lifetime users or those who switched to filter cigarettes) had a significantly reduced risk of oral cancer which approached 50%. Among female current smokers, only those who switched 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 showed a significant interaction on a multiplicative model. After adjustment for covariates, leanness was significantly associated with oral cancer among male current and ex-smokers. Conclusions. The results of this study: 1) indicate that smokers of filter cigarettes and those who quit smoking are at substantially reduced risk of oral cancer, 2) demonstrate interaction between smoking and drinking, and 3) suggest that leanness preceding diagnosis may be associated with oral cancer.
