Background and objective: The objective of this study was to assess the exposure to environmental tobacco smoke (ETS) by means of the concentration of salivary cotinine in a sample of adolescent students, and its relationship with active and passive tobacco consumption.
Methods: A cross-sectional survey was conducted in 92 secondary education and high school pupils (16-20 years). Salivary samples were collected and salivary cotinine was measured by gas chromatography/mass spectrometry. Salivary cotinine medians and interquartile ranges were calculated. Significant statistical differences were detected with the non parametric test for medians.
Results: The median of salivary cotinine concentration in current smokers was 91.5 ng/ml (RI: 62.4-125); in former smokers 7.9 ng/ml (RI: 5.1-15.5) and in never smokers 1.9 ng/ml (RI: 0-3.6). In smokers of more than 10 cigarettes per day, the result was 98.3 ng/ml (RI:63.4-142.9). Among non-smokers (never-smoker and ex-smokers), the median of salivary cotinine in non-smokers living with smokers was 3.3 ng/ml (RI: 0-8.6) versus 2.9 ng/ml (RI: 1.1-6.9) in those living with non-smokers.
Conclusions: The salivary cotinine concentration increases with the intensity of tobacco consumption and the perception of passive exposure to tobacco smoke.