Better than BMI? Obesity disease predictions improved with metabolic information, study finds

Oct. 11, 2018 1:20 PM PT

Body Mass Index, or BMI is commonly used to determine obesity, and the risk of obesity-related diseases such as heart disease and diabetes. However, people of normal weight may get these diseases, while some technically obese people may not.

That disease risk is more accurately predicted by adding metabolic and genetic information to BMI, according to a study led by Scripps Research and Human Longevity scientists.

It found a strong risk correlation with the “metabolome,” the set of metabolic products found in individuals. There’s a genetic component as well, but it’s not as strong.

The research supports the existence of the so-called “healthy obese,” said Dr. Ken Fujioka, a weight-loss specialist at Scripps Health who was not involved in the study. This has been a matter of great debate in the medical community.

The study was published Thursday in the journal Cell Metabolism, and is available at j.mp/bmimeta. It was led by Amalio Telenti of Scripps Research, along with Elizabeth T. Cirulli of Human Longevity.

Body Mass Index has long been the standard to identify obesity. But evidence has mounted in recent decades that the diseases associated with obesity are more fundamental than just excess weight.

The study examined more than a thousand metabolic products, such as proteins, uric acid, and different kinds of fat, and used them to generate signatures correlated with health and disease.

“A metabolome signature identifies the healthy obese and lean individuals with abnormal metabolomes — these groups differ in health outcomes and underlying genetic risk,” the study stated. “Because metabolome profiling identifies clinically meaningful heterogeneity in obesity, this approach could help select patients for clinical trials.”

This ability to distinguish between these healthy obese and those most at risk is the most useful finding for clinical practice, Fujioka said.

“At this time in medicine, it is not a game changer, but clearly points towards a way of finding out which patients are at highest risk for running into medical problems related to their higher weight,” Fujioka said by email.

“Put another way, many patients are overweight but will do fine with their health and not have many medical problems related to their weight. We call these patient obese but healthy patients.”

Because excess weight is so common, doctors need to identify the highest-risk patients and get them on a weight-loss program before a serious disease develops, Fujioka said.

“This test would also tell us which patients are overweight but are healthy and so we may not need to use an aggressive treatment plan to get their weight down.”

Researchers analyzed body and metabolic information from nearly 2,000 people in TwinsUK, a study of environmental and genetic influences on health and aging. They also tracked how the correlation changed over time.

About one-third of the various metabolic products were found to be correlated with changes in BMI.

One of the most striking findings is that people with an abnormal metabolome had a much higher rate of cardiovascular problems, compared to those who had the same BMI, but opposing metabolic signatures.

“This is important as we can use this information to help guide more aggressive treatment for weight loss in the patients that are at high risk for these cardiovascular events,” Fujioka said.

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