Insulin Resistance Indices and Masticatory Function in Postmenopausal Korean Women: A 15-Year Nationwide Survey

Postmenopausal women experience increased visceral adiposity and insulin resistance owing to oestrogen deficiency, which may affect oral structure and function. Their relation to oral health is unclear.

To examine the associations of five non-insulin-based insulin resistance indices with tooth loss and masticatory discomfort in postmenopausal Korean women.

This cross-sectional study analysed 14 265 naturally postmenopausal women aged ≥ 40 years from the Korea National Health and Nutrition Examination Survey 2010-2024. Triglycerides, HDL cholesterol, the triglyceride-to-HDL cholesterol ratio, the triglyceride-glucose index and the metabolic score for insulin resistance (METS-IR) were standardised, so estimates are expressed per 1 standard deviation. Missing teeth were analysed by survey-weighted negative binomial regression, and fewer than 20 remaining teeth and masticatory discomfort by survey-weighted logistic regression. Discrimination was characterised descriptively using receiver operating characteristic curves.

Masticatory discomfort was associated with triglycerides (odds ratio 1.065, 95% confidence interval 1.030-1.102), HDL cholesterol (0.919, 0.886-0.952), the triglyceride-to-HDL cholesterol ratio (1.072, 1.035-1.111) and the triglyceride-glucose index (1.069, 1.032-1.108), but not with METS-IR (1.036, 0.997-1.076). No index was associated with missing teeth or with fewer than 20 remaining teeth. Estimates were unchanged after adjustment for survey cycle. Discrimination was attributable almost entirely to age: adding any index to an age-only model raised the area under the curve by at most 0.0014 and 0.016, respectively.

Several indices showed small associations with self-reported masticatory discomfort but none with tooth loss. These findings describe patterns of association and do not establish any index as a tool for screening or for integrated medical-dental management.