[Urinary cotinine as a biomarker of exposure to tobacco smoke]

Several markers are used to monitor active or passive exposure to tobacco smoke. They include measurements of carboxyhaemoglobin in the blood, carbon dioxide in the expired air, thiocyanates and nicotine in the saliva, plasma (serum) or urine. The determination of cotinine, the main nicotine metabolite, in biological fluids is a biomarker which finds still wider application. This metabolite can be determined in the urine and saliva and plasma. Cotinine, as a biomarker of exposure to tobacco smoke, is used in epidemiological studies aimed to find out to what extent the exposure to occupational harmful factors affects the workers' health. The application of this biomarker helped to classify workers more effectively into smokers and non-smokers, and to provide better conditions for finding out whether other non-occupational factors such as smoking do not confound the evaluation of health threats induced by work-related hazards.