Non-obese adults with prediabetes in Central Vietnam: Metabolic risk factors and associations with the triglyceride-glucose index

Abstract

Background: Insulin resistance can occur even in non-obese individuals, particularly among Asian populations, where visceral adiposity contributes to metabolic risk. The triglyceride-glucose (TyG) index has emerged as a simple and reliable surrogate marker of insulin resistance. In Vietnam, evidence linking the TyG index to metabolic abnormalities in this group is still scarce. Objective: To describe the metabolic characteristics of non-obese adults with prediabetes in Central Vietnam and to examine the associations between the TyG index and selected anthropometric and lipid-related risk factors. Methods: A cross-sectional study of 104 non-obese adults (BMI < 25 kg/m²), aged 20 - 65 years, with newly diagnosed prediabetes (ADA 2022 criteria) consecutively enrolled from community health centers in Quang Binh, Hue, and Da Nang City (October 2022  to October 2025). Anthropometric, glycaemic, and lipid parameters were assessed. An elevated TyG index (≥ 8.5) was used as a surrogate marker of insulin resistance. Pearson correlation and multiple linear regression were performed; triglycerides were excluded from the multivariable model as a direct mathematical component of the TyG formula. Results: Mean age 50.56 ± 9.68 years; mean BMI of 23.39 ± 1.88 kg/m². Central adiposity (WHtR ≥ 0.5) was present in 67.3%, and 76.0% exhibited elevated TyG index. Dyslipidaemia was prevalent: TC ≥ 5.2 mmol/L in 55.8%, hypertriglyceridaemia in 42.3%, elevated non-HDL-C in 73.1%. TyG correlated significantly with TC/HDL-C (r = 0.532), non-HDL-C (r = 0.479), TC (r = 0.395), and WC (r = 0.243). In multivariable regression, independent predictors of TyG were: TC (β = 0.463, p < 0.001), HDL-C (β = -0.303, p = 0.001), female sex (β = -0.287, p = 0.002), and fasting plasma glucose (β = 0.255, p = 0.002); adjusted R² = 0.371, F(8,95) = 8.589, p < 0.001. Conclusions: In non-obese Vietnamese adults with prediabetes, the TyG index was significantly associated with central adiposity and atherogenic dyslipidaemia, with total cholesterol emerging as its strongest independent predictor. TyG may serve as a practical surrogate marker for cardiometabolic risk assessment in resource-limited primary care settings. Further prospective studies are needed to confirm these findings and establish clinical utility.