Il questionario anamnestico è uno strumento valido per determinare l'abitudine al fumo di sigaretta? : Valutazione di validità utilizzando la cotinina urinaria come standard

Cigarette smoke contains almost 4000 chemical compounds, among which several carcinogens for humans; for this reason it is the most common confounding factor in biological monitoring. Aim of this study was to evaluate the validity of the questionnaire in detecting smoking habit using urinary cotinine as standard. A group of 365 subjects was investigated through an interviewer-administered questionnaire and measurement of urinary cotinine (metabolite of nicotine) as a biomarker of smoking habit. 147 subjects (40.3%) reported themselves as smokers, with a mean number of 15 cigarettes per day, and median cotinine excretion of 1422 µg/L. Assuming that 100 µg/L of cotinine corresponds to 1 cigarette, 164 (44.9%) subjects with cotinine ≥100 µg/L were classified as true smokers. Validity tests show good sensibility (94%) and specificity (82%) of the questionnaire in predicting smoking habit; even if the percentage of misclassification was found to be as high as 17.8% in former smokers.