[Cotinine--a useful biomarker for tobacco use?]

Nicotine consumption is one of the most important avoidable risk factors for atherosclerosis and cardiovascular, pulmonary as well as many other diseases. In daily practice one cannot always clearly detect whether a patient remains really abstinent. 68 patients following consultations for risk factors were included in this study. Smoking habits were evaluated by means of a questionnaire and by measurement of carbon monoxide concentration in the breath; also the cotinine concentrations in saliva and urine were investigated during consultation. Cotinine is one of the most important metabolic product of nicotine. Smokers showed significantly increased carbon monoxide concentrations in the breath as well as increased cotinine concentrations in urine and saliva. Anamnestic information from patients about their nicotine consumption correlated well with the cotinine concentration in urine and saliva (r = 0.54). The best correlation was found between creatine-corrected cotinine concentration and cigarette consumption on the day preceding in measurement (p < 0.001, r = 0.66). It is not clear if and to what extent cotinine determination may qualify for the evaluation of passive smoking; however, measurement of cotinine concentrations in saliva (or urine) represents a good biochemical parameter for the control of nicotine abstinence.