Integrated evaluation of visceral adiposity indices and markers in adults with type 2 diabetes mellitus: A cross-sectional analytical study

Introduction: Visceral adiposity plays a pivotal role in the metabolic disturbances characteristic of type 2 diabetes mellitus (T2DM). Although body mass index (BMI) is widely used to estimate overall adiposity, it fails to differentiate between subcutaneous fat and metabolically active visceral fat. In contrast, the visceral adiposity index (VAI) integrates anthropometric and lipid parameters to estimate visceral fat mass, while adipokines such as leptin and adiponectin provide biochemical insights into visceral adipose tissue (VAT) activity. This study aimed to perform an integrated evaluation of BMI, VAI, and biochemical markers of VAT activity in patients with T2DM, and to determine their associations with glycaemic and lipid profiles. Methods: This cross-sectional study included 90 adults (aged 30–60 years) diagnosed with T2DM. Participants were stratified into three groups based on BMI: normal weight (18.5–24.9 kg/m²), overweight (25.0–29.9 kg/m²), and obese (≥ 30.0 kg/m²). Clinical measurements included anthropometric data, blood pressure, fasting plasma glucose (FPG), postprandial blood glucose (PPBG), glycated haemoglobin (HbA1c), and comprehensive lipid profiles. Serum leptin and adiponectin levels were quantified via enzyme-linked immunosorbent assay (ELISA), and the VAI was calculated using a sex-specific formula. Statistical analyses were performed using analysis of variance (ANOVA), Pearson's correlation, and multivariate regression, with statistical significance defined as p < 0.05. Results: BMI, waist circumference (WC), and VAI increased significantly across the groups (p < 0.001). The mean VAI values were 1.4 ± 0.5, 3.3 ± 1.2, and 4.7 ± 1.9 in the normal-weight, overweight, and obese cohorts, respectively. Serum leptin levels demonstrated a progressive increase (from 11.0 ± 3.1 to 36.8 ± 6.0 ng/mL), whereas adiponectin levels exhibited a concurrent decrease (from 14.3 ± 2.5 to 6.2 ± 1.9 µg/mL). The VAI demonstrated a strong positive correlation with leptin (r = 0.72) and a negative correlation with adiponectin (r = -0.66). Furthermore, an elevated VAI was significantly associated with increased levels of FPG, HbA1c, triglycerides (TG), and low-density lipoprotein cholesterol (LDL-C), as well as decreased levels of high-density lipoprotein cholesterol (HDL-C) (p < 0.001). Multivariate regression analysis identified the VAI as the strongest independent predictor of both HbA1c levels (β = 0.52) and the leptin-to-adiponectin ratio (β = 0.71). Conclusion: The integration of anthropometric indices (BMI and VAI) with biochemical markers (leptin and adiponectin) facilitates a comprehensive evaluation of visceral adiposity and metabolic risk in patients with T2DM. Notably, the VAI exhibited stronger associations with glycaemic and lipid abnormalities than BMI alone, underscoring its clinical utility in assessing visceral fat dysfunction.