BMI poor predictor of undesirable fat and disease risk

Kathleen Blanchard's picture

New research shows that even when body mass index (BMI) is normal, heart function worsens from fat collection around the organs. The findings come from researchers at Boston University School of Medicine (BUSM), suggesting that BMI measurement may be a poor predictor of undesired fat that can leads to heart disease and diabetes. Fat around the organs was present in non-obese individuals with normal BMI. Obesity is normally associated with increased risk for heart disease and diabetes.

According to background information in the study, published online in the journal Obesity, fat around the heart and liver increases risk of heart disease and diabetes and was found to decrease pumping action of the heart. Thirty percent of Americans are obese or overweight. The researchers found that BMI was not associated with fat accumulation around the heart and liver.

The BUSM scientists compared obese and lean healthy individuals. All of the study participants underwent fasting blood testing for lipoproteins, glucose, insulin, and free fatty acids. Magnetic resonance imaging (MRI) and proton MR spectroscopy were used to measure pericardial and peri-aortic lipid (fat) volumes, heart function, aortic compliance and accumulation of fat content in the liver, finding that being leaner did not correlate with the amount of fat around the heart and aorta. The researchers also found declines in heart function associated with fat around the organs even in lean individuals.


According to James Hamilton, PhD, senior author and project leader, and a professor of biophysics, physiology and biomedical engineering at BUSM, "Our study found that fat collection around the heart, the aorta and within the liver is clearly associated with decreased heart functions and that an MRI can quickly and noninvasively measure fat volume in these areas. Our study also found that looking at BMI of the individual does not reliably predict the amount of undesired fat in and around organs."

The research suggests that treatment for heart disease and diabetes could be individualized by using MRI and MR spectroscopy to measure fat accumulation in the heart and liver as a basis for treatment – the scientists say testing takes “about an hour”.

Fat deposits in the heart and liver were found in study participants with normal body mass index. Measuring fat accumulation around the organs could prove to be a better predictor of heart disease and diabetes risk than just looking at BMI. The new research found that fat accumulation around the heart and liver results in decreased pumping action of the heart, and was found among study participants who were not obese.