Factors Compound the Risks

If you smoke and drink, you are worse off than if you only smoke or only drink. Alcohol seems to multiply the cancer-causing effects of smoking--a phenomenon called synergism. A person who has one drink a day but does not smoke has a 60% higher risk of oral cancer than a nonsmoking teetotaler. A person who smokes up to a pack of cigarettes a day and does not drink has a 52% higher risk than a nonsmoking teetotaler.

But the risk for a moderate smoker and drinker (a pack or less a day and one drink a day) is four times greater than that for an abstainer. For a heavy smoker (two packs) and drinker (more than a drink a day), the risk is 15 times greater.

No one knows exactly why these risks compound in this instance. However, if you both smoke and drink and decide that you will give up only one of these habits, quit smoking. Overall, it is the more harmful of the two.