Punto de corte óptimo de la concentración de cotinina en saliva para discriminar entre fumadores y no fumadores en la población adulta de Barcelona

objective: to assess the optimal cut-point for salivary cotinine concentration to identify smoking status in the adult population of barcelona. methods: we performed a cross-sectional study of a representative sample (n=1,117) of the adult population (>16 years) in barcelona (2004-2005). this study gathered information on active and passive smoking by means of a questionnaire and a saliva sample for cotinine determination. we analyzed sensitivity and specificity according to sex, age, smoking status (daily and occasional), and exposure to second-hand smoke at home. roc curves and the area under the curve were calculated. results: the prevalence of smokers (daily and occasional) was 27.8% (95% ci: 25.2-30.4%). the optimal cut-point to discriminate smoking status was 9.2ng/ml (sensitivity=88.7% and specificity=89.0%). the area under the roc curve was 0.952. the optimal cut-point was 12.2ng/ml in men and 7.6ng/ml in women. the optimal cut-point was higher at ages with a greater prevalence of smoking. daily smokers had a higher cut-point than occasional smokers. conclusions: the optimal cut-point to discriminate smoking status in the adult population is 9.2ng/ml, with sensitivities and specificities around 90%. the cut-point was higher in men and in younger people. the cut-point increases with higher prevalence of daily smokers.