The ABSI formula measures your waist circumference in relation to your BMI and height. The resulting z-score shows you your health risks (from belly fat) that BMI alone misses.
ABSI Formula
ABSI = WC / (BMI2/3 × Height1/2)
Z-Score
The ABSI value is then converted to a z-score which shows how you compare to others of your age and sex. The mean and standard deviation values come from population studies.
z = (ABSI - ABSImean) / ABSIstd
Example
A 40-year old man, 175 cm tall, weighing 80 kg and with a waist circumference of 90 cm calculates his BMI and ABSI as follows:
BMI = 80 / 1.75² = 26.1ABSI = 0.90 / (26.12/3 × 1.751/2) = 0.90 / (8.79 × 1.32) = 0.0776
The ABSI value is then compared against population averages to determine the z-score and risk category.
Understanding Your Z-Score
| Z-Score Range | Risk Category | Mortality Risk |
|---|---|---|
| z < -0.868 | Very Low Risk | Below average mortality risk |
| -0.868 to -0.272 | Low Risk | Lower than average mortality risk |
| -0.272 to +0.229 | Average Risk | Average mortality risk |
| +0.229 to +0.798 | High Risk | Elevated mortality risk |
| z ≥ +0.798 | Very High Risk | Significantly elevated mortality risk |
History
The ABSI formula was developed in 2012 from a study of more than 14,000 adults whose health was tracked for up to 24 years.