Is BMI Hindering Innovative Treatments for Obesity?

A new study aims to replace BMI with BRI, giving care providers a better way to measure a patient’s fat content

Could a new measurement of obesity replace BMI and give healthcare providers a more accurate representation of their patients’ weight issues?

A new study published this month in JAMA, co-authored by researchers from China and Brown University in Providence, Rhode Island, makes the argument for what is called the body roundness index, or BRI. Whereas BMI, or body mass index, measures a person’s height and weight, BRI adds in waist circumference to gain a better understanding of where fat is distributed on the body.

The difference could affect how providers develop innovative programs to address obesity and other weight-related health concerns. With a better idea of how a body is proportioned and where fat is located, providers can develop better treatments and gain a better idea of those programs’ effectiveness.

It’s a key element to care management at a time when obesity and weight-related issues are a popular topic of conversation. From the effect that weight has on chronic diseases like diabetes, asthma, and heart disease to the popularity of Ozempic and Wegovy, both consumers and their care providers are keenly interested in how to address excess body fat.

BMI has been considered the standard for body fat measurement since the 1980s, but critics have long questioned whether it’s an accurate assessment, since it doesn’t take into account organs, bone, muscle and water. The JAMA study takes this one step further, arguing that providers need a better measurement “to decipher population-based characteristics and potential association with mortality risk.”

“Besides weight and height, BRI additionally considers waist circumference, and hence it can more comprehensively reflect visceral fat distribution,” the study’s authors note. “BRI was found to be superior over other anthropometric indicators in estimating the risk for various clinical end points, including cardiometabolic disease, kidney disease, and cancer. Furthermore, longitudinal studies have shown that high BRI was associated with the significantly increased risk of all-cause mortality and cardiovascular disease-specific mortality.”

The study, using data from almost 33,000 U.S. adults taken from the National Health and Nutrition Examination Survey (NHANES) and NHANES Linked Mortality File, compared a person’s all-cause mortality risk based on BMI and BRI, and found BRI to be more accurate. This was especially true for muscular people and the elderly, who tend to have inaccurate BMI measurements because of their body shape.

Those findings, the authors said, “provide compelling evidence for the application of BRI as a noninvasive and easy to obtain screening tool for estimation of mortality risk and identification of high-risk individuals, a novel concept that could be incorporated into public health practice pending consistent validation in other independent studies.”