## What is A Body Shape Index (ABSI)

**ABSI **is a metric for assessing the health implications of a given body height, mass and waist circumference. It was developed by Nir and Jesse Krakauer from a sample of Americans in the National Health and Nutrition Examination Survey. It includes five variables:

- sex;
- age;
- weight;
- height;
- and waist circumference

A criticism of **BMI **is that it does not distinguish between muscle and fat mass and may be elevated in people with increased BMI due to muscle development rather than fat accumulation from overeating. A higher muscle mass may actually reduce the risk of **premature death**. A high ABSI appears to correspond to a higher proportion of central obesity or abdominal fat.

## A Body Shape Index (ABSI) Formula

The equation for ABSI is based on statistical analysis and is derived from an allometric regression.

ABSI = \frac{WC}{BMI^\frac{2}{3} * height^\frac {1}{2}}Studies have associated ABSI with total mortality and cardiovascular risk, indicating that it is useful in assessing cardio-metabolic risks.

where:

- WC – the waist circumference, expressed in m;
- height – expressed in m; and
- BMI – expressed in kg / m2 and is calculated using the following formula:
- BMI = weight / height².

To estimate the risk of premature mortality, we can calculate the ABSI z score as follows:

ABSI_z score = (ABSI – ABSI_{mean}) / ABSI_SDBased on this score, the results are classified into 5 risk levels of mortality:

ABSI z score | Mortality risk |

< -0.868 | Very low |

-0.868 and -0.272 | Low |

-0.272 and +0.229 | Average |

0.229 and 0.798 | High |

>0.798 | Very high |

## Why ABSI is perhaps better than BMI

In the research, Team Krakauer calculated ABSI and BMI on more than 14,000 Americans of various shapes and sizes and found that a high ABSI score was more accurate than a high BMI score in predicting **mortality**. Those with a high ABS score had more than double the chance of dying from some disease someone with a low score. And at the same time, their **BMI **score was within normal limits, but they were in the high limits of the **ABSI **score and the risk group.

## How to use A Body Shape Index (ABSI) calculator?

Using this calculator is very easy – **just follow these steps**:

- Choose your sex.
- Enter your age (the values must range from 2 to 85 years).
- Enter your height. Don’t bother about the units
- Enter your weight. Again, don’t bother about the units.
- Input your waist circumference. It should be measured horizontally around the waist, around your belly button.

Be sure to check out our BMI Calculator!