Association Between Periodontitis and Salivary Nitric Oxide Metabolites Among Community Elderly Koreans

Background: Nitric oxide (NO) is known to play an important role in many biologic systems, although the relationship between NO metabolites and periodontitis remains controversial. Moreover, little evidence of an association between salivary NO (S-NO) and periodontitis in the general population has been reported. This study aims to investigate the relationship between S-NO and periodontitis in an elderly Korean population. Methods: A cross-sectional study was conducted using participants and salivary samples from Sunchang Elderly Cohort Study. The total number of final participants was 242 (91 males and 151 females; 48 to 93 years old). Periodontitis was determined by a clinical attachment loss of >6 mm at six probe points on 12 index teeth. NO was measured in unstimulated saliva via the Griess reaction. Sociodemographic status, general/oral health, and health-related behaviors were investigated as confounders. Bivariate analysis and multivariable linear regression analyses including confounders were applied. Results: After controlling for age, sex, education, salivary flow rate, number of teeth, smoking status, physical activity, hypertension, and diabetes, three metabolites of S-NO (total NO, nitrite, and nitrate) were independently associated with the percentage of probe points exhibiting periodontitis. Of these linear associations, total NO was found to have the strongest correlation with periodontitis (partial r = 0.181, P = 0.009). These associations were most pronounced in females (except for nitrate), non-smokers, those without hypertension, and those without diabetes. Conclusions: Our data suggest that high concentrations of S-NO are associated with severe periodontitis. Thus, S-NO may serve as a potential biologic marker for detecting and monitoring periodontitis.