HbA1c mediates association between masticatory function and hypertension results from NHANES: An observational study

Hypertension constitutes a widespread public health concern. While epidemiological evidence has linked tooth loss with hypertension, the precise association between masticatory function operationally defined through functional tooth units (FTUs) and hypertension remains insufficiently elucidated. The aim to investigate the relationship between masticatory function and hypertension. This study analyzed data from the National Health and Nutrition Examination Survey (NHANES) spanning 2005-2018. Hypertension status was ascertained through standardized questionnaires and triplicate blood pressure measurements. Masticatory function, defined as FTUs, was characterized by the presence of antagonistic natural or prosthetic tooth pairs in premolar and molar regions. To investigate the FTUs-hypertension association, we employed logistic regression models coupled with restricted cubic spline analyses. Subgroup stratification and mediation analysis were subsequently conducted to elucidate potential effect modifiers and biological mechanisms. Individuals with optimal masticatory function (10 ≤ FTUs ≤ 12) exhibited an 18% reduction in hypertension risk compared to those with compromised function (FTUs < 3), demonstrating an adjusted odds ratio of 0.82 (95% confidence interval: 0.72-0.92, P < .0001). Mediation analysis identified metabolic markers: glycated hemoglobin as a significant intermediary, accounting for 18.0% (95% confidence interval: 14.8-21.1) of the total effect. Subgroup analyses revealed significant effect modification by gender and age (P-interaction < .05). Restricted cubic spline modeling demonstrated a nonlinear association, with hypertension risk following an inverted U-shaped curve across FTU quintiles (P-nonlinearity < .001). Our findings suggest that higher FTUs may lower the risk of hypertension via the metabolic markers: glycated hemoglobin pathway.