Salivary cotinine levels as a biomarker of tobacco use - A biochemical study

Background: Routine exposure to cigarette smoke has conventionally been assessed by questionnaire. The correctness of this method has been limited by incorrect reporting. Rejection and underrating the extent of smoking are common practices especially among youth and proclaimed quitters. Biochemical validation is the recommended choice in interventional studies where cessation results have to be evaluated. Cotinine measurement is the most common used method in population studies. It validates the use of tobacco consumption when compared to other markers available. Aim and Objectives: This study was designed to estimate the levels of salivary cotinine in tobacco smokers and chewers and compare them with the levels in subjects who do not report of any tobacco related habits. The study was also conducted to validate the self-report of tobacco use with a biological marker for tobacco exposure. Material and Methods: The study was performed in 200 study subjects divided into 4 groups (C, G1, G2 and G3) of 50 each. The saliva samples were collected from subjects who had no previous history of tobacco consumption, subjects with smoking, pan chewing habit, subjects who had both smoking and pan chewing habits were included in the study. The results were then compared and co-related between the groups. Results: The mean salivary cotinine levels in groups C, G1, G2 and G3 was found to be 10.74 ng/ml, 92.29 ng/ml, 108.80 ng/ml and 117.01 ng/ml respectively. When the mean values were compared between the groups the values were found to be statistically highly significant. Conclusion: The results of this study recommend that biochemical authentication of self-reported tobacco use must be done in any prevention and tobacco cessation programs. It is thus, highly recommended to use biological markers such as salivary cotinine to approve the information provided by the patients in terms of tobacco use.