URINARY MUTAGENICITY AND THIOETHERS IN NONSMOKERS - ROLE OF ENVIRONMENTAL TOBACCO-SMOKE (ETS) AND DIET

The urinary excretion of mutagens and thioethers was investigated in a controlled diet study and in two field studies. A diet containing cha rcoal-broiled meat and other items rich in mutagenic compounds increas ed the urinary mutagenicity as assessed in Salmonella typhimurium stra in TA98 with metabolic activation similar to 46-fold compared to a die t low in mutagens. The excretion of thioethers after ingestion of the diet rich in mutagens also increased significantly when compared to th e diet low in mutagens. The increase was associated with the content o f preformed thioethers in the diet, In the first field study with 21 n onsmokers, urinary mutagenicity as assessed in Salmonella typhimurium strain TA98 and excretion of thioethers showed no relation to either t he self-reported exposure to environmental tobacco smoke (ETS) or to s erum cotinine concentrations used as an objective marker for ETS expos ure. In the second field study, urinary mutagenicity was determined wi th a tobacco-smoke sensitive Salmonella typhimurium strain YG1024 with metabolic activation. No correlation was found between the mutagenic activity in urine and ETS exposure duration, nicotine on the personal sampler, cotinine in saliva and cotinine in urine. Our results suggest that real-life ETS exposure does not measurably increase either urina ry mutagen or urinary thioether excretion. Furthermore, diet seems to be the most important source for both urinary mutagen and thioether ex cretion in nonsmokers.