Evaluation of Antioxidant Capacity and Cotinine Levels of Saliva in Male Smokers and Non-smokers

Background: The cigarette compounds are associated with the increase in the incidence of oral cancer andprecancerous lesions. Salivary antioxidant system plays an important role in anti-carcinogenic capacity ofsaliva. Cotinine, a nicotine metabolite, has a longer half-life in comparison with nicotine and is a suitablemarker for exposure to cigarette smoke. This study aims to measure total antioxidant capacity (TAC) andcotinine level in saliva of smokers and non-smokers and compare salivary cotinine level and TAC in each grou.Methods: In this cross-sectional study, 32 smokers and 34 non-smokers were recruited by consecutivesampling from Department of Oral Medicine, School of Dentistry, Mashhad University of Medical Sciences,Mashhad, Iran. Salivary cotinine and TAC concentrations were determined using the enzyme-linkedimmunosorbent assay (ELISA) technique. For data analysis, correlation tests of Spearman, Mann-WhitneyU, and independent samples t-test were used.Findings: A significant difference was observed between the two groups in the mean cotinine level and in themean TAC (P = 0.015, P = 0.027, respectively). TAC showed a weak negative correlation with the cotininelevel, but the difference was not significant (P = 0.651).Conclusion: Antioxidants are of great importance to smokers because antioxidants are able to scavenge freeradicals found in cigarette smoke. According to the results of present study, the salivary TAC in smokers waslower than that of non-smokers, and the salivary cotinine level in smokers was higher than non-smokers.Therefore, smoking endangers the oral cavity health by reducing the salivary TAC. Further studies with ahigher sample size and other factors affecting the salivary TAC are needed for definitive comment.