N-Nitroso compounds and human cancer. A molecular epidemiologic approach.

N-Nitroso compounds are known to be potent animal carcinogens. However, evidence of their effect on human cancers is inconclusive, and further investigations are needed. A mathematical model to create indices of nitrate, nitrite, and N-nitrosamine exposures, both exogenous and endogenous, is described in this paper. Estimation of the endogenous formation is based on the current knowledge of biochemistry and chemical kinetics of these compounds. The model can be applied to analyze data regarding the dietary history and use of tobacco products and alcoholic beverages obtained from epidemiologic questionnaires. Exposure levels of study and control subjects to these compounds can then be compared by conventional epidemiologic methods. This is an approach toward the combination of conventional epidemiologic methods and laboratory findings to study disease etiology.