Visceral Adiposity Index Formula
The Visceral Adiposity Index (VAI) is calculated using a gender-specific formula that incorporates waist circumference (WC in cm), body mass index (BMI in kg/m²), triglycerides (TG in mmol/L), and HDL-cholesterol (HDL in mmol/L). 1, 2
Formula by Sex
For Men:
VAI = [WC / (39.68 + (1.88 × BMI))] × (TG / 1.03) × (1.31 / HDL)
For Women:
VAI = [WC / (36.58 + (1.89 × BMI))] × (TG / 0.81) × (1.52 / HDL)
Required Measurements
- Waist circumference (WC): Measured at the midpoint between the superior iliac crest and the lower margin of the last rib, in a horizontal plane 4
- BMI: Weight in kilograms divided by height in meters squared 4
- Triglycerides (TG): Fasting serum triglycerides in mmol/L 1, 2
- HDL-cholesterol: Fasting serum HDL in mmol/L 1, 2
Clinical Interpretation
VAI serves as a surrogate marker for visceral adiposity dysfunction and insulin resistance, with higher values indicating greater cardiometabolic risk. 2, 3, 5
Key Cut-off Values:
- VAI ≥ 2.37: Identifies metabolic syndrome with 86% sensitivity and 78% specificity 2
- VAI ≥ 1.89: Identifies insulin resistance (HOMA-IR ≥ 2.0) with 74% sensitivity and 68% specificity 2
- VAI ≥ 1.675: Useful for identifying metabolically unhealthy women with polycystic ovary syndrome 6
Clinical Utility
VAI demonstrates superior predictive capacity for unhealthy metabolic phenotype compared to traditional anthropometric measures (BMI, waist circumference, waist-to-hip ratio) in both normal-weight and overweight individuals. 5
- VAI shows the strongest correlation with HOMA-IR (r = 0.51) and insulin levels (r = 0.49) among simple clinical indices 2
- VAI is the sole independent predictor of adiponectin levels in multivariate analysis 3
- VAI predicts impaired fasting glucose and diabetes independent of age 3
- The index is particularly valuable for identifying metabolically unhealthy individuals who appear normal by BMI alone 5, 6
Important Caveats
While VAI provides valuable information about visceral adiposity dysfunction, it remains an indirect estimate. Direct imaging with CT or MRI provides the most accurate assessment of visceral adipose tissue, though VAI's simplicity makes it practical for routine clinical use 4, 7. The American Heart Association recognizes that visceral adipose tissue measured by imaging demonstrates stronger associations with cardiovascular outcomes than anthropometric surrogates alone 7.
VAI should be interpreted in the context of other cardiometabolic risk factors, as it reflects both anatomical (visceral fat distribution) and functional (lipid metabolism) components of metabolic dysfunction 2, 3, 5.