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| Body roundness index | |
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 BRI vs height (vertical axis) vs waist circumference (horizontal axis) |
Body roundness index (BRI) is a calculated geometric index used to quantify an aspect of a person's individual body shape. Based on the principle of body eccentricity, it provides a rapid visual and anthropometric tool for health evaluation.[1]
Introduced in 2013, the BRI calculation can be used to estimate total and visceral body fat. Ranges of healthy body roundness have been established to accurately classify people with healthy fat mass (weight) compared to obese people who are at risk for morbidities.[1]
Compared to traditional metrics, such as the body mass index (BMI), (which uses weight and height), BRI may improve predictions of the amount of body fat and the volume of visceral adipose tissue. Despite its common use, BMI can misclassify individuals as obese because it does not distinguish between a person's lean body mass and fat mass. Instead, BRI quantifies body girth as well as height, potentially providing more accurate estimates of fat mass.
BRI scores range from 1 to 16, with most people between 1 and 10, although people with scores of 6.9 and up – indicating wider, rounder bodies – were found to have a risk of all-cause mortality that was increased by up to 49% compared to people having a medium BRI of 5.[2][3] In a 2020 review, high BRI was associated with increased risk of metabolic syndrome and several other diseases.[4]
Typical American adult BRI values range from 3 or less (midsection leanness) to 7 or more (midsection roundness), with a medium index of about 5.[1][3] As a relatively newer predictive metric, BRI has a smaller research record compared to long-established indices like the BMI and waist-to-hip ratio, so its accuracy and applications remain to be as fully established. Conversely, the simple waist-to-height ratio (which uses the same measurements and is simpler to calculate) has a better research base, leading to its adoption as the preferred guideline in some countries.
- ^ a b c Thomas DM, Bredlau C, Bosy-Westphal A, et al. (November 2013). "Relationships between body roundness with body fat and visceral adipose tissue emerging from a new geometrical model". Obesity. 21 (11): 2264–71. doi:10.1002/oby.20408. PMC 3692604. PMID 23519954.
- ^ Rabin RC (6 September 2024). "Time to Say Goodbye to the B.M.I.?". The New York Times. Retrieved 21 September 2024.
- ^ a b Zhang X, Ma N, Lin Q, et al. (June 2024). "Body roundness index and all-cause mortality among US adults". JAMA Network Open. 7 (6): e2415051. doi:10.1001/jamanetworkopen.2024.15051. PMC 11154161. PMID 38837158.
- ^ Rico-Martín S, Calderón-García JF, Sánchez-Rey P, et al. (July 2020). "Effectiveness of body roundness index in predicting metabolic syndrome: A systematic review and meta-analysis". Obesity Reviews. 21 (7): e13023. doi:10.1111/obr.13023. PMID 32267621.