Exploring the Nonlinear Relationship Between Dietary Flavonoid Intake and Periodontitis

Introduction and aims: Flavonoids are non-nutrient bioactive substances widely found in plants, possessing antioxidant and anti-inflammatory properties. Periodontitis is a long-term inflammatory disease that impacts the tissues supporting the teeth, poses a substantial burden on public health and individuals alike. This study aims to explore the association between dietary flavonoid intake and periodontitis.

Methods: This study included 3005 participants from the 2009 to 2010 National Health and Nutrition Examination Survey. We compared the weighted prevalence of periodontitis across different participant groups. Binary logistic regression analysis was conducted to evaluate the relationship between dietary flavonoid intake and periodontitis. The restricted cubic spline plot was used to explore nonlinear relationships.

Results: The prevalence of periodontitis among participants with total flavonoid intake in quartiles Q1 to Q4 was 54.95%, 44.11%, 40.62%, and 48.28%, respectively. When compared to the Q1 group of total flavonoid intake, the OR values for Q2 to Q4 groups were 0.58 (95% CI: 0.39-0.86, P = .01), 0.50 (95% CI: 0.35-0.73, P = .001), and 0.68 (95% CI: 0.50-0.91, P = .01), respectively. A significant nonlinear association was observed between ln-transformed total flavonoid intake and the likelihood of developing periodontitis (nonlinearity P < .001). The inflection point was identified at an ln-transformed total flavonoid intake of 4.05, corresponding to a total flavonoid intake of 57.54 mg. Beyond this inflection point, as the total flavonoid intake value continues to rise, there was a diminishing protective effect against periodontitis.

Conclusions: Higher dietary flavonoid intake is associated with a reduced risk of periodontitis, with the greatest protective effect observed at moderate intake levels.

Clinical relevance: Understanding the association between flavonoid intake and periodontitis can guide dietary recommendations and interventions aimed at preventing periodontitis. This study supports the potential role of a flavonoid-rich diet in promoting periodontal health, suggesting that dietary modifications could be a viable strategy in periodontal disease prevention and management.