CORRELATING EXPOSURE TO ENVIRONMENTAL TOBACCO-SMOKE EXPOSURE WITH INCREASED INCIDENCE OF LUNG-CANCER IN NON SMOKERS - IS COTININE A VALID MARKER

Environmental Tobacco Smoke (ETS) is a complex mixture of Exhaled Main stream (EMS) and Sidestream Smoke (SS) composed of gases and Respirabl e Suspended Particles (RSP). It is both a highly diluted and an aged m ixture the composition of which is difficult to assess. Based mainly o n syllogisms it has been hypothesized that exposure to low levels of E TS increases the risk of lung cancer In nonsmokers. There is no questi on that nonsmokers living in the presence of smokers are exposed to to bacco smoke constituents. But, to conclude on the significance of such an exposure, in term of increased incidence of lung cancer in non smo kers, can only rely on a quantitative biomonitoring of exposure to age nts proven to play a causative role in lung carcinogenesis. Nether nic otine nor its metabolites are likely to be precise markers of exposure to such chemicals. Molecular epidemiology offers a promising, but sti ll to be validated, tool to meet such a challenge by measuring protein s and/or DNA adducts in serum or urine samples.