Food Variety Score and Geriatric Nutritional Risk Index Mediate the Relationship Between Masticatory Function and Osteoporosis

BACKGROUND: The association between masticatory function and osteoporosis is suggestive but inadequately defined. This study examines the association between Functional Tooth Units (FTUs) and osteoporosis. METHODS: Utilizing data from 9425 U.S. adults aged 50 and older (representing a weighted population of 76 809 922) from the National Health and Nutrition Examination Survey (NHANES; cycles 2005-2010, 2013-2014, 2017-2018), this study employed weighted multivariable logistic regression and restricted cubic splines analyses to examine the association between FTUs and osteoporosis. Subgroup analyses and tests for interaction were employed to investigate potential effect modification and assess the robustness of the observed associations. Sensitivity analysis was conducted to compute E-values for quantifying unmeasured confounding effects and assessing association robustness. Additionally, mediation analysis was conducted to assess the indirect pathways. RESULTS: After adjustment for all covariates, higher FTUs were inversely associated with osteoporosis prevalence (OR = 0.93, 95% CI: 0.89-0.98, p = 0.004). Furthermore, a significant dose-response relationship was observed: participants in the highest FTU tertile (6-8) had a 46% lower risk of osteoporosis compared to those in the lowest tertile (0-1) (OR = 0.54, 95% CI: 0.39-0.76, p < 0.001). Both subgroup and sensitivity analyses confirmed the robustness of these findings. Mediation analysis further revealed that Food Variety Score (FVS) and Geriatric Nutritional Risk Index (GNRI) mediated 7.96% and 6.27% of the association between FTUs and osteoporosis, respectively. CONCLUSION: This study confirms that better masticatory function, measured by FTUs, is significantly associated with a lower risk of osteoporosis, a link partially explained by improved food variety (FVS) and nutritional status (GNRI). Maintaining adequate masticatory function may therefore be related to a reduced incidence of osteoporosis, possibly through its supportive role in nutritional health. This study highlights the potential of oral health preservation in preventing osteoporosis. Further prospective studies are needed to confirm the causal relationship and optimize clinical intervention.