Association of per- and polyfluoroalkyl substances (PFAS) with periodontitis: the mediating role of sex hormones

OBJECTIVES

To investigate the association between serum per- and polyfluoroalkyl substances (PFAS) and periodontitis, and further explore the possible mediating role of sex hormones in this association.

METHODS

We extracted data from National Health and Nutrition Examination Survey (NHANES) 2009-2014. Univariable and multivariable logistic regression models were performed to investigate the association between serum levels of seven PFASs and periodontitis. Bayesian kernel machine regression (BKMR) was conducted to assess the joint effect of PFASs in mixtures. Mediation analyses were used to explore the potential mediating role of sex hormones.

RESULTS

Participants with periodontitis had higher concentrations of serum perfluorooctane sulfonate (PFOS) and perfluorononanoic acid (PFNA) than those without periodontitis (both P < 0.05). In fully adjusted models, high serum concentrations of PFOS and PFNA were positively associated with periodontitis (tertile 3 vs. tertile 1: prevalence ratio (PR) = 1.19 for PFOS, 95% CI: 1.01-1.39; PR = 1.17 for PFNA, 95% CI: 1.02-1.34). The results from the BKMR models consistently showed a positive association between PFAS mixtures and periodontitis. Of note, testosterone and the ratio of testosterone to estradiol significantly mediated the relationship between high level of PFOS and periodontitis, accounting for 16.5% and 31.7% of the total effect, respectively. Sensitivity analyses yielded similar results when using periodontal clinical indices (mean loss of attachment, mean periodontal probing depth, and the number of teeth) as dependent variables.

CONCLUSIONS

These findings provide evidence to support a positive association between certain PFASs and periodontitis, which might be partially mediated by sex hormones.

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.

Selenoprotein genetic variants may modify the association between serum selenium and oral cancer risk

OBJECTIVE

The relationship between selenium (Se) and oral cancer is still controversial, and the selenoprotein genes play crucial roles in selenium metabolism. We aim to investigate the potential effect of selenoprotein genes (including GPx and TXNRD) in the association of serum Se with oral cancer risk.

METHODS

A case-control study including 235 oral cancer cases and 406 controls from September 2011 to December 2018 was conducted in Fujian, China. The peripheral blood samples were obtained from each participant. Genotyping was performed by MassARRAY system, and serum Se levels were measured by inductively coupled plasma mass spectrometry (ICP-MS).

RESULTS

Compared with the lowest tertile of Se concentration, those with Se levels in the third tertile were associated with the lower risk of oral cancer (OR = 0.228; 95% CI: 0.135, 0.384). After additional adjustment for genetic risk score (GRS, derived from selenoprotein genetic variants), the model demonstrated the superior goodness of fit. When stratified by GRS, the negative correlation of serum Se was more pronounced among those with low risk (i.e., lower GRS). Moreover, there is a multiplicative interaction between serum Se and GRS for the risk of oral cancer (p = .001).

CONCLUSIONS

The present study suggests that serum Se levels may be significantly associated with oral cancer risk, yet the association may be modified by the effects of selenoprotein genetic variants.