Tobacco smoking, alcohol drinking, and cancer of the oral cavity and oropharynx among U.S. veterans.

Independent carcinogenic effects of alcohol drinking and tobacco smoking as well as their interaction can be usefully studied in a population of heavy drinkers and smokers. A hospital-based case-control study was conducted during 1972 to 1983 in a large Veterans hospital in East Orange, New Jersey. A total of 359 oral cavity-oropharynx cancer cases and 2280 controls were interviewed according to tobacco smoking, use of smokeless tobacco, alcoholic beverage, coffee and tea drinking, race, family origin, religion, and occupation as bartender. Odds ratio of oral cancer increased up to the level of 35 cigarettes per day and 21 whiskey equivalents per day: no further increase was found for higher level of exposure to either factor. A protective effect of quitting smoking was found, but the number of former smokers was small. No difference occurred in oral cancer risk according to type of alcoholic beverage drunk. An interaction effect compatible with a multiplicative model was found between the two exposures. Blacks were at lower risk than whites, and, in the latter group, individuals of Italian origin were at lower risk than individuals from northern or central European countries. Alcohol drinking and tobacco smoking were responsible for the majority of oral cancer cases in this population of US Veterans.