Background: Smoking is a leading cause of morbidity and mortality worldwide. Cotinine, the primary metabolite of nicotine, is a reliable biomarker of tobacco exposure, with a half-life of 15–40 hours detected in various body fluids, including saliva. No data exist on salivary cotinine levels assessed by high-performance liquid chromatography (HPLC) in the North Karnataka region. Objectives: To estimate and compare salivary cotinine levels and total protein content among smokers and nonsmokers using HPLC. Methods: A cross-sectional clinical study was conducted on 60 individuals (30 smokers, 30 nonsmokers) aged 15–45 years. Unstimulated whole saliva samples (1 mL) were collected, centrifuged, and stored for analysis. Total protein content was measured by the Bradford method. Salivary cotinine levels were analyzed using HPLC under standardized conditions. Data were analyzed using SPSS v22. Results: The mean salivary protein content was significantly lower in smokers (285.57 ± 222.61 µg/mL) compared to nonsmokers (816.37 ± 284.35 µg/mL, P < 0.001). Mann–Whitney and Chi-square tests were applied, with significance set at P < 0.05. The mean HPLC cotinine peak area percentage among smokers was 10.98 ± 6.83. Conclusions: Salivary cotinine detected using HPLC was elevated with reduced salivary protein concentration in smokers.
Byahatti et al. (Thu,) studied this question.