Association between triglyceride-glucose index and vitamin D levels in Saudi postmenopausal women: a cross-sectional study.

Objectives: To investigate the relationship between the Triglyceride-Glucose Index (TGI), a surrogate marker of insulin resistance (IR), and serum vitamin D levels in postmenopausal Saudi women, a population at high risk of both metabolic dysfunction and vitamin D deficiency.

Methods: This cross-sectional study included 1,020 postmenopausal Saudi women who were categorized into two groups based on TGI values (< 8.7 and ≥ 8.7). Anthropometric, biochemical, and clinical parameters were assessed. Statistical analyses, including multivariate regression, were performed to evaluate the association between TGI and vitamin D levels, adjusting for confounding variables such as body mass index (BMI).

Results: Women with TGI ≥ 8.7 had significantly higher BMI, systolic and diastolic blood pressure, fasting glucose, and triglyceride levels, along with lower high-density lipoprotein cholesterol (HDL) cholesterol and serum vitamin D concentrations compared to those with TGI < 8.7. A significant inverse association between TGI and vitamin D levels was found, which remained robust after adjusting for BMI and other confounders. Multivariate regression revealed systolic blood pressure and HDL cholesterol as positive and negative predictors of TGI, respectively, while vitamin D levels showed an independent inverse association. Contributing factors to vitamin D deficiency included limited sun exposure, poor dietary intake, and cultural practices.

Conclusions: The study identifies a significant inverse association between TGI and vitamin D levels, underscoring the metabolic interrelationship between insulin resistance and vitamin D deficiency in postmenopausal Saudi women. Public health strategies targeting both conditions may mitigate metabolic and cardiovascular risks in this vulnerable population. Further longitudinal and interventional research is warranted to confirm causality and evaluate the benefits of vitamin D supplementation.