The Cardiovascular
ToolsCalculators

Body Roundness Index (BRI)

Ellipse-based estimate of body shape and central adiposity from waist circumference and height.

Body Roundness Index (BRI)
Waist circumference
Height
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When to use

  • Estimating central adiposity/body shape as an alternative or adjunct to BMI and waist-to-height ratio.

Formula

Eccentricity = sqrt(1 - ((waist / 2pi) / (0.5 x height))^2); BRI = 364.2 - 365.5 x eccentricity (waist and height in the same units).

Pearls and pitfalls

  • Models the body as an ellipse rather than the cylinder implicit in BMI.
  • Derived from population data and best used as a continuous marker or for population-level risk stratification, not a diagnostic cutoff in an individual.

References

  1. Thomas DM, Bredlau C, Bosy-Westphal A, et al. Relationships between body roundness with body fat and visceral adipose tissue emerging from a new geometrical model. Obesity (Silver Spring). 2013;21(11):2264-2271.