BMI alone not sufficient, waist-to-height ratio more effective in diagnosing obesity: Researchers

New Delhi, July 6

Obesity can no longer be just defined by body mass index (BMI) and rather should be about how body fat is distributed throughout one’s body, researchers said while launching a new framework for diagnosing and managing obesity.

Published in the journal Nature Medicine, the framework looks specifically at fat accumulated in the abdomen, measured as ‘waist-to-height ratio’—an increased value of which is related to a higher risk of developing cardiometabolic complications, according to the researchers.

An “important novelty” of the framework is including a waist-to-height ratio higher than 0.5, along with a BMI of 25-30, for diagnosing obesity, the authors, representing the European Association for the Study of Obesity (EASO), said.

“The choice of introducing waist-to-height ratio, instead of waist circumference, in the diagnostic process is due to its superiority as a cardiometabolic disease risk marker,” they wrote.

Accumulation of abdominal fat is a more reliable predictor of health deterioration, compared to BMI, even for individuals not meeting the current standard cut-off value for obesity diagnosis, which is a BMI of 30, the authors said.

They said that the current guidelines are based on evidence from studies in which participants meeting cut-off values were included for analysis, rather than on a “complete clinical evaluation”.

“The basis for this change is the recognition that BMI alone is insufficient as a diagnostic criterion, and that body fat distribution has a substantial effect on health,” they wrote.

The researchers said that introducing the suggested changes in the diagnostic processes could reduce risk of undertreatment in this particular group of patients—low BMI and high abdominal fat—in comparison to the current BMI-based definition of obesity.