News | Cardiac Diagnostics | September 28, 2016

Study Shows More Reasons Why Belly Fat is Dangerous for the Heart

Fat density may be just as important as volume

September 28, 2016 — Increasing stomach fat – especially the “hidden fat” in your abdomen – is associated with newly identified and worsening heart disease risk factors, according to a study published recently in the Journal of the American College of Cardiology. These adverse changes in cardiovascular risk were evident over a relatively short period of time and persisted even after accounting for changes in body mass index (BMI) and waist circumference, two commonly used methods to estimate whether someone is a healthy weight or not.

Previous studies have shown that people who carry excess abdominal fat around their midsection — a so-called “spare tire” — tend to face higher risks of heart disease compared to people who have fat elsewhere. This study adds to the growing body of evidence that regional fat deposits are harmful and further suggests that the density of the stomach fat — measured by computed tomography (CT) scan — is just as important as how much fat you have. In general, the higher the fat content, the lower the attenuation, or fat density, that is shown on the CT image.

“What’s really interesting is that we show that an increase in the amount of stomach fat and a lower density fat is associated with worse heart disease risk factors — even after accounting for how much weight was gained,” said Caroline Fox, M.D., M.P.H., former senior investigator for the National Heart Lung and Blood Institute and the study’s senior researcher. “This hasn’t been shown before.”

Fox said the fat density results were particularly strong.

“Measuring fat density is a new measure that we are still working to understand and warrants further investigation,” she said. “We used it as an indirect measure of fat quality and found that lower numbers were linked to greater heart disease risk.”

Fox and her team sought to determine whether there was a link between anatomical changes in belly fat — both its volume (quantity) and density — and changes in a broad array of cardiovascular disease risk factors during the average six-year study period. They reviewed CT scans to assess how much abdominal fat had accumulated, its location and its density in 1,106 participants from the Framingham Heart Study who received this imaging as part of a larger study to measure coronary and abdominal aortic calcification.

Participants’ average age was 45 years and 44 percent were women. Both subcutaneous adipose fat, the fat just under the skin, which is often visible “flab” or love handles, and visceral adipose fat, the fat inside the abdominal cavity, were measured. Over the six-year follow-up period, participants had a 22 percent increase in fat just under the skin and a 45 percent increase in fat inside the abdominal cavity on average.

In general, increases in the amount of fat and decreases in fat density were correlated with adverse changes in heart disease risk. Each additional pound of fat from baseline to follow up was associated with new onset high blood pressure, high triglycerides and metabolic syndrome. Even though increases in both types of fat were linked to new and worsening cardiovascular disease risk factors, the relationship was even more pronounced for fat inside the abdominal cavity compared to fat just under the skin.

In particular, individuals with greater increases in fat inside the abdominal cavity showed substantial increases in metabolic risk factors including high blood sugar, high triglycerides and low HDL, or good cholesterol. Fox said that higher levels of fat just under the skin may actually be protective because it serves as a “metabolic sink for storing excess fat particles.” Abdominal cavity fat, on the other hand, is thought to be more dangerous.

Overall, associations remained significant even after adjusting for changes in BMI or waist circumference. Researchers also grouped participants into three groups according to abdominal adipose tissue volume and density change; they found that those with greater increases in fat volume and more decreases in fat density had relatively higher incidence of heart disease risk factors.

An accompanying editorial, by James A de Lemos, M.D., said the findings support a growing body of literature that suggests identifying the location and type of fat deposits can provide important information about the risk of heart disease not found in the simple BMI measurement.

In terms of next steps, Fox said more work needs to be done to understand fat density, and why and how it is associated with metabolic consequences of obesity (e.g., hypertension, abnormal cholesterol, diabetes, inflammation and insulin resistance). As well, it will be important to tease apart how less dense fat, along with simultaneous increases in the amount of fat may spur the development of harmful cardiometabolic changes.

Because this is an observational study, researchers cannot draw any causal links. Still, previous studies have associated abdomen fat to higher risks of cancer, cardiovascular events and death.

This study was funded by the National Heart, Lung and Blood Institute’s Framingham Heart Study. Alison Pedley, Ph.D., one of the study authors, and Fox are employees of Merck & Company, Inc. None of the other study authors reported relevant financial relationships. Ian J. Neeland, M.D., an author of the editorial comment is supported by a grant from the National Institute of Diabetes and Digestive and Kidney Diseases of the National Institute of Health and by the Dedman Family Scholarship in Clinical Care from UT Southwestern. De Lemos reports no disclosures related to this paper.

For more information: www.onlinejacc.org

Related Content

Study Shows Multiple Benefits of Patient-to-Patient Connectivity in Familial Chylomicronemia Syndrome
News | Cardiac Diagnostics | August 07, 2018
Akcea Therapeutics Inc., an affiliate of Ionis Pharmaceuticals Inc., announced the publication of results from the...
Being Overweight May Change Young Adults' Heart Structure, Function
News | Cardiac Diagnostics | August 03, 2018
Even as a young adult, being overweight may cause higher blood pressure and thicken heart muscle, setting the stage for...
High Intensity Exercise in Teenagers Could Ward Off Heart Disease

Ultrasound image of the carotid artery. Lines in yellow were used to determine arterial diameter and stretching before and following exercise.

News | Cardiac Diagnostics | July 16, 2018
New research published in Experimental Physiology has indicated potential differences in heart health benefits of...
News | Cardiac Diagnostics | June 14, 2018
A team of researchers says it has linked sensitivity to an allergen in red meat to the buildup of plaque in the...
The blood of patients with familial chylomicronemia syndrome (FCS) can appear milky in color (lipemic) due to the buildup of fat in their body. Image courtesy of Akcea Therapeutics.

The blood of patients with familial chylomicronemia syndrome (FCS) can appear milky in color (lipemic) due to the buildup of fat in their body. Image courtesy of Akcea Therapeutics.

 

Feature | Cardiac Diagnostics | May 07, 2018 | Steven D. Freedman, M.D., Ph.D.
 
Male Triathletes May Be Putting Their Heart Health at Risk
News | Cardiac Diagnostics | January 09, 2018
Competitive male triathletes face a higher risk of a potentially harmful heart condition called myocardial fibrosis,...
ERT Acquires iCardiac Technologies
News | Cardiac Diagnostics | December 19, 2017
ERT recently announced it has acquired iCardiac Technologies, a provider of centralized cardiac safety and respiratory...
Overlay Init