Combined Effect of Nitrate Levels and Diabetes on the Risk of Severe Periodontitis: A Cross-sectional Study

Nitrate levels and diabetes are important factors influencing the risk of periodontitis. This study intended to assess the combined impact of urinary nitrate levels and diabetes on periodontitis risk in the general population.

This cross-sectional study employed the data on individuals aged 30 and above from the 2009-2014 National Health and Nutrition Examination Survey (NHANES) database. The urinary nitrate levels were divided into three groups based on the tertiles (low, median, and high). A multivariate logistic regression model was used to investigate the relationship between urinary nitrate levels and the risk of stage III/IV periodontitis, with stratified analysis conducted according to diabetes. The multiplicative interaction between nitrate levels and diabetes on periodontitis risk was analysed using the likelihood ratio test. A restricted cubic splines curve was utilised to assess the non-linear association.

Among the 3,292 included participants, 841 (19.28%) individuals had stage III/IV periodontitis, while 2,451 (80.72%) did not. Compared with median nitrate levels, high nitrate levels (odds ratio [OR] = 1.58, 95% confidence interval [CI]: 1.12 to 2.22]) were associated with higher odds of stage III/IV periodontitis, but no statistically significant association was observed between low nitrate levels and periodontitis risk (P > 0.05). Urinary nitrate levels and diabetes showed a multiplicative interaction on the risk of stage III/IV periodontitis (P = 0.020). Specifically, high urinary nitrate levels (OR = 1.68, 95% CI: 1.16 to 2.43) were correlated with a higher risk of periodontitis in non-diabetic individuals, whereas in diabetic individuals, low urinary nitrate levels (OR = 1.66, 95% CI: 1.07 to 2.58) were associated with a higher risk of periodontitis. Moreover, urinary nitrate levels exhibited a statistically significant nonlinear relationship with stage III/IV periodontitis risk in the general population.

High nitrate levels and diabetes exhibit a multiplicative interaction on periodontitis risk. Clinicians may need to monitor both blood glucose and urinary nitrate levels to screen individuals at high risk of periodontitis.