Visceral adiposity index calculator

The formula

VAI uses different constants for men and women (Amato 2010):

Men: VAI = [waist ÷ (39.68 + 1.88 × BMI)] × (TG ÷ 1.03) × (1.31 ÷ HDL)

Women: VAI = [waist ÷ (36.58 + 1.89 × BMI)] × (TG ÷ 0.81) × (1.52 ÷ HDL)

Waist is in cm, BMI in kg/m², and fasting triglycerides (TG) and HDL cholesterol in mmol/L. If your lab reports mg/dL, we divide triglycerides by 88.57 and HDL by 38.67 to get mmol/L; a waist in inches is multiplied by 2.54.

Each part has a meaning (Amato 2010):

• Waist for your BMI. In the 315 healthy adults, waist rose in a straight line with BMI. The first bracket compares your waist with the waist that line predicts for your BMI. The study calls this the model of adipose distribution; it was 1.00 on average in the healthy group.
• Triglycerides. 1.03 mmol/L (men) and 0.81 mmol/L (women) were the median triglycerides of the healthy group.
• HDL. 1.31 mmol/L (men) and 1.52 mmol/L (women) were the median HDL of the healthy group. A lower HDL raises the index.

So a value of 1 means a waist typical for your BMI with triglycerides and HDL at the healthy group's medians. Higher waist for your BMI, higher triglycerides or lower HDL each push VAI up.

For example, a man with a 100 cm waist, a BMI of 28, triglycerides of 1.8 mmol/L (about 159 mg/dL) and HDL of 1.0 mmol/L (about 39 mg/dL) has a VAI of 100 ÷ 92.32 × 1.75 × 1.31 = about 2.48. A woman with an 88 cm waist, a BMI of 26, triglycerides of 1.2 mmol/L and HDL of 1.4 mmol/L has a VAI of about 1.65. The paper prints no worked example; these are worked from its formulas.

In the study, waist was measured midway between the lowest rib and the top of the hip bone (Amato 2010).

How values were spread in the study

The paper sets no cutoff for a high or normal VAI. It split its 1,498 primary care patients into five equal groups (fifths) by VAI, men and women together (Amato 2010):

From Supplemental Table 1 of the paper (Amato 2010). Metabolic syndrome was judged by the ATP III criteria. The calculator tells you which fifth your value falls in. That is a comparison with this Sicilian group, not a risk level, and the fifths were not split by sex.

What the study found

Age and the share of patients with metabolic syndrome, diabetes, high blood pressure, low HDL, high triglycerides, past heart disease or heart attack, and past mini-stroke (TIA) or stroke all rose across the VAI fifths (Amato 2010). The authors noted the trend was most clear from the third fifth on (Amato 2010).

After allowing for other factors, each 1-point higher VAI went with higher odds of past heart disease or heart attack (odds ratio 2.45) and of past TIA or stroke (odds ratio 1.63). Waist and BMI on their own were not linked to these events in the same models (Amato 2010). In 74 patients who had a detailed insulin test (a clamp study), higher VAI went with lower insulin sensitivity, while waist and BMI did not (Amato 2010).

These links were found by looking back at existing records. The authors wrote that VAI is not a diagnostic tool for heart disease or stroke, and suggested it might help in judging the heart and metabolic risk that comes with belly fat (Amato 2010).

A research index, with limits

The name says visceral, but VAI does not measure belly fat directly. Only the waist and BMI part was checked against MRI scans, in 26 healthy people, where it tracked fat around the organs and not fat under the skin (Amato 2010). The formula was built in one Italian population, it has no cutoff from its original study, and it does not diagnose metabolic syndrome, diabetes, fatty liver or heart disease. A high value is a reason to talk to your doctor about your waist size, blood fats and other heart risk factors, not a diagnosis.

Related checks

The metabolic syndrome criteria checker uses waist size, triglycerides and HDL with set cutoffs, plus blood pressure and blood sugar. The lipid accumulation product uses waist and triglycerides only, and the TyG index calculator pairs triglycerides with fasting glucose. The waist-to-height ratio and waist-to-hip ratio look at waist size on its own, and the body roundness index turns waist and height into a body shape score. For what triglyceride numbers mean, read triglycerides explained.