Association between Mediterranean diet and periodontitis among US adults: The mediating roles of obesity indicators.

Objective: This study aimed to assess the association between the Mediterranean diet (MedDiet) and periodontitis in US adults and to further explore the mediating roles of obesity indicators in this association.

Background Data: The relationship between MedDiet and periodontitis is controversial. And it is unclear whether obesity indicators are potential mediators of this relationship.

Methods: Using data derived from the National Health and Nutrition Examination Survey (2009-2014). Weighted binary logistic regression and restricted cubic spline were used to assess the association between MedDiet and periodontitis. Weighted ordinal logistic regression was performed to evaluate the relationship between MedDiet and periodontitis severity. The mediating roles of body mass index (BMI) and waist circumference in the relationship between the MedDiet and periodontitis were explored. Association analyses were further performed using mean clinical attachment loss (CAL) or mean periodontal probing depth (PPD) as dependent variables. The false discovery rate method was used to correct the p-values in the regression analyses.

Results: A total of 8290 eligible participants (4159 participants with periodontitis and 4131 without periodontitis) were included. A negative association between the MedDiet adherence score and periodontitis was observed in the binary logistic regression model (adjusted odds ratio = 0.94, 95% confidence interval: 0.90-0.97, p = .001). Restricted cubic spline regression revealed a dose-response relationship between the MedDiet adherence score and periodontitis. BMI and waist circumference significantly mediate this association, with mediation proportions of 9.7% (p = .032) and 9.3% (p = .012), respectively. Multivariable ordinal logistic regression showed that the MedDiet adherence score was negatively associated with the severity of periodontitis (all p < .05). Additionally, the MedDiet adherence score was negatively associated with mean PPD or mean CAL (all p < .05).

Conclusions: This study suggests a significant negative association between adherence to the MedDiet and periodontitis and a possible mediating role of obesity indicators in this association. Furthermore, studies are still warranted to confirm our findings.