[Usefulness of biological markers in the evaluation of smoking at the first visit of a smoking cessation program].

Introduction: We have studied the relationship between urinary cotinine and other tobacco markers to assess the relevance of urinary cotinine in the dosage of nicotine substitutes.

Methods: One hundred and fifty-five patients, who were regular cigarette smokers not taking any nicotine substitutes took part in the study. The parameters examined were daily consumption, nicotine contents of the cigarettes, the Fagerström test score, levels of carbon monoxide (CO) in exhaled breath air and urinary cotinine.

Results: The most significant correlation was between urinary cotinine and exhaled CO (Spearman rs=0,59 p<0,001). The correlation between urinary cotinine, the Fagerström test (rs=0,32 p<0,001) and daily cigarette consumption (rs=0,32 p<0,001) was less significant. The nicotine content was not related to urinary cotinine (rs =-0,10NS).

Conclusions: For economic reasons measuring urinary cotinine is not necessary when the CO level is or=35 ppm. It becomes useful if the CO level is between 15 and 34 ppm, as CO level in itself is insufficient to determine the dosage of nicotine substitutes.