Nicotine depedence and salivary cotinine concentration in daily smokers

There is scant information on nicotine dependence in smokers not seeking cessation treatment. This study analyses the relationship between nicotine dependence, measured by the Fagerström Test for Nicotine Dependence (FTND), and salivary cotinine concentration in a sample of smokers from the general population. We conducted a cross-sectional study (2004-2005) of a representative sample of the general population of Barcelona, Spain (n=1245). The analysis included 196 daily smokers aged more than 16 years. Information on smoking was obtained by questionnaire and cotinine concentration was determined in saliva. Geometric means of cotinine concentration by every single FTND item were computed, and multivariate linear regression was used to explore the relationship among these variables. Participants smoked a mean of 17.0 cigarettes per day, and the mean FTND score was 3.27 (95% confidence interval: 2.92-3.61). Around 17% of subjects (95% confidence interval: 12.0-22.5%) had high nicotine dependence. Cotinine concentration differed significantly by nicotine dependence levels. In a multiple linear regression model including the sum of the FTND items 2, 3, and 6, and the single FTND items 1, 4, and 5, adjusted for sex, the time to first cigarette after waking up (item 1), the number of cigarettes smoked daily (item 4), and smoking more in the first hours of the day (item 5) were significantly related to salivary cotinine concentration (R(2)=0.414). Salivary cotinine levels were associated with nicotine dependence as measured by the FTND, especially with the items on daily tobacco consumption, time to first cigarette after waking up, and smoking more in the first hours of the day.