Biomarkers of tobacco smoke exposure

Tobacco smoking is a major risk factor for cancer, cardiovascular diseases and respiratory illnesses. Smoking is increasing among children and adolescents with subsequent consequences on the health. Furthermore, maternal tobacco smoking during pregnancy adversely affects prenatal growth. Nicotine, the most important tobacco alkaloid, is responsible for maintaining tobacco addiction. According to a recent Circulaire de la direction generale de la sante, nicotine dependence should be determined through questionnaires and quantitative estimate of nicotine metabolites. Nicotine blood level fluctuates and urinary nicotine excretion is of short duration. Nicotine is intensively metabolized in the liver and oxidized into cotinine. Urinary measurement of cotinine appears to be highly related with degree of intoxication and to allow the differentiation between non exposed and exposed non smokers. In order to check the present application of nicotine metabolites measurement, a survey was conducted in 340 smoking cessation units. Forty percent physicians (n = 137) answered the survey. For 17% of them, the quantification of nicotine metabolites is included in their daily practise and for 79% guidelines about cotinine measurement should be given in France. Sixty-seven biologists answered the survey. Recommendations for immunoassay and HPLC determination of cotinine should be given as reported by 66 and 41% of them respectively. Indeed, urinary cotinine measurement with high performance liquid chromotography is highly sensitive and specific. However, immunoassays are more convenient. These two approaches are presently under investigation in order to provide guidelines for optimal use in various clinical situations. Traditional measures for nicotine dependence are the number of cigarrettes smoked per day, nicotine intake expressed as mg per day. Fagerstrom questionnaire, expired air carbon monoxide, thiocyanates and cotinine levels in biological fluids. Urinary cotinine measurements the most useful for the follow-up of smoking cessation including adjustment of nicotine replacement therapy, especially after a clinical event or for the follow up of smoking pregnant women. It allows the detection of passive smoke experience in children who are hospitalized for recurrent respiratory illnesses.