Scientists are turning to a novel way to calculate obesity using a system known as the Body Roundness Index (BRI), which they claim is a more accurate measurement than Body Mass Index (BMI). The new international study, headed by scientists at Montclair University and other research institutions in the United States and Germany, found that a higher BRI was associated with an increased risk of death from any cause.
The large retrospective study, involving nearly 33,000 US adults, is not only another research that confirms the growing obesity epidemic in the United States, but also an indicator of a potential new tool in the fight against obesity. The researchers behind the study conclude that the BRI is a tool that is almost as easy to perform as BMI, but offers a more accurate assessment of body composition and health risks.
The new findings 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. The innovative concept could be incorporated into public health practices provided it receives consistent validation from other independent studies on BRI.
Data from the large cohort of nearly 33,000 American adults was taken from the . National Health and Nutrition Examination Survey (NHANES) database — a self-reported survey that assesses the health and nutrition of Americans. Researchers looked at a 20-year period of NHANES data between 1999-2018. The average age of cohort members was 46 years old. Half of the group was women.
Then, using BRI which is a slightly more complex body measurement than BMI, they assessed one major outcome: all-cause mortality. The major finding was that the mortality risk associated with BRI score was ‘U-shaped’. A U-shaped curve, as its name suggests, shows high risk at either end of a given spectrum, and lower risk in the middle.
In this case, individuals with a BRI below and above the normal range were at greater risk of death from any cause. Meanwhile those in the middle, in the normal range, had the lowest risk. Individuals with a BRI less than 3.4 had a 25 percent increased mortality risk compared to the normal range, while those with a BRI of 6.9 had 49 percent increased risk. Researchers also documented a steady increase in average BRI over the 20 year period from 4.8 to 5.62. The trend was more obvious within certain groups, including women, and the elderly.
The Body Roundness Index is similar to the Body Mass Index, but relies on more anthropometric variables. The index uses height, weight, waist circumference, and sometimes hip circumference for its calculation. The BRI, which was first proposed in 2013, is a more direct measure of central adiposity, which strongly correlates with metabolic diseases like type 2 diabetes.
The researchers explained their findings by noting that similar to BMI, the Body Roundness Index has to do with geometry. Using the necessary variables, you create an image of a circle, but the circle could be more egg-shaped, cylindrical, or maybe totally round. It uses the concept of ‘eccentricity’, which describes how round (like a circle) or narrow (like an ellipse) something is. It represents a number between zero, for a perfect circle, and one, which is closest to straight.
However, with BMI you are actually using just two measurements — weight and height. In the Body Roundness Index, you are also using other measurements to capture the geometric shape. That BRI number can then be used to make a more accurate calculation of body composition. The closer to zero, the rounder your body, and the greater the risk of all-cause mortality.
BMI is a simple measurement of body size based on your height and weight that has been used for decades as a general health assessment. Your BMI is a crude measurement of whether or not you fall into a healthy weight range. However, the measurement is far from perfect: for example, it does not distinguish between muscle and fat; so an individual with obesity could very likely have the same BMI as, say, a bodybuilder.
On the other hand, BRI could offer a new method of assessing body composition and health risk in a manner that is still simple to perform but offers a more accurate assessment. To perform a BRI test, you just need a few measurements. In fact, if you are curious about your own BRI, you can even plug them into an online calculator such as the one found at https://webfce.com/bri-calculator/. However, you need to keep in mind that BRI is still a novel technique that needs further validation, so it is far from commonplace today.
