Effect of Active Smoking on Salivary Periodontitis-related Biomarkers

Objectives: Smoking is generally accepted as a major environmental risk factor of periodontitis. We have previously reported that levels of salivary biomarkers such as IL-1b, albumin and AST were significantly elevated in passive smokers compared to non-smokers. The present study aimed to evaluate the effects of active smoking on periodontitis-related biomarkers and periodontal pathogens in saliva in comparison with passive smoking. Methods: In 2003, 273 Japanese employees were surveyed via an oral examination and collection of saliva. Levels of salivary cotinine and biomarkers were measured by competitive ELISA or enzymatic methods. Six periodontal pathogens were detected via real-time PCR method. Periodontal parameters included probing pocket depth (PPD) and clinical attachment level (CAL). We classified 53 non-, 118 passive and 102 active smokers as subjects exhibiting salivary cotinine levels of 0, 1-7 and 8+ ng/ml respectively. Results: Bivariate analysis showed that levels of salivary biomarkers including IL-1b, PGE₂, MMP-9, lactoferrin, albumin and AST decreased in active smokers in comparison with passive smokers (p<0.1); however, no meaningful differences in the levels of markers such as MMP-8, S-IgA and the periodontal pathogens were observed. Multiple linear regression analysis was conducted employing salivary cotinine levels as dependent variable, and age, sex, the number of teeth with PPD 3.5+ mm or CAL 3.5+ mm, and biomarkers as independent variables. Albumin and AST showed significant negative standardized regression coefficient, while IL-1b showed positive (p<0.05). These results suggest that high exposure of tobacco smoke may decrease levels of antioxidants such as albumin but may elevate levels of proinflammatory cytokines such as IL-1b. Conclusion: Changes in levels of these biomarkers in saliva by high exposure of tobacco smoke could contribute to the tissue destruction observed in active smokers. This work was supported by Health and Labour Science Research Grants, and Japan Foundation for Aging and Health.