Comparative Analysis of Anthropometric Parameters and Their Association with Metabolic Health in Patients with Obesity

Background and aim: Body mass index (BMI) is the cornerstone of obesity classification. As the prevalence of obesity as a chronic disease increases, more precise stratification tools are being explored. The aim of this study is to compare established and alternative anthropometric parameters in terms of their association with metabolic health indices in adults with BMI > 25 kg/m².

Materials and methods: Cross-sectional analysis was performed on first-visit assessment data of 401 individuals from an outpatient endocrinology clinic. Weight, height, and waist circumference values were used to calculate the following anthropometrics: waist-to-height ratio (WHtR), Body Shape Index (ABSI), Body Roundness Index (BRI), Conicity Index (CI), Weight-adjusted Waist Index (WWI), and Relative Fat Mass (RFM). The outcomes of interest were metabolic laboratory indices of glycemia (FPG, HbA1c), lipid metabolism (LDL, TG), and hepatic enzymes (ALT, GGT). After log-transformation, they were standardized and combined into glycemic, lipid, hepatic, and overall metabolic burden composite scores. Hierarchical linear regression models adjusted for age and sex were used to measure the association between each anthropometric index and the composite scores. Incremental explained variance (ΔR2) and regression coefficients were compared.

Results: The strongest association with the overall metabolic composite was shown by RFM (β = 0.480, 95% Cl = 0.269-0.692; ΔR² = 0.085), followed by WHtR (ΔR² = 0.080), BMI (ΔR² = 0.076), and BRI (ΔR² = 0.076). ABSI, Cl, and WWI showed no significant incremental contributions. BMI showed the largest ΔR² for the glycemic composite, whereas RFM ranked highest for lipid and hepatic composites.

Conclusion: Waist-based indices – particularly RFM and WHtR – were most consistently associated with composite metabolic laboratory burden in routine outpatient practice.