Interaction of tobacco with other risk factors

Tobacco exposure causes both malignant and non-malignant disease and has been estimated to be the aetiology of approximately 4% of the global burden of disease. Because of the frequency of smoking, it is predictable that smokers will be exposed to other factors that can have an independent deleterious effect on health. This chapter reviews the interaction of tobacco and four additional substances: alcohol, asbestos, radiation, and arsenic. Of these four exposures, alcohol is the commonest and has the strongest link to smoking. Alcohol is especially troublesome because a large proportion of the population has had recent exposure to both agents. For heavy smokers, dual exposure is extremely common. Synergistic effects of alcohol and tobacco exposure are seen for both malignant and non-malignant diseases.