Fat distribution in women and men provides clues to heart attack risk

November 28, 2017

CHICAGO - It's not the amount of fat in your body but where it's stored that may increase your risk for heart attack, stroke and diabetes, according to a new study presented today at the annual meeting of the Radiological Society of North America (RSNA). The study looked at the differences in fat distribution patterns among overweight and obese men and women and their associated cardiometabolic risk.

According to the National Center for Health Statistics, more than 70 percent of Americans are considered overweight or obese. Obesity puts individuals at risk for a variety of health problems, and is the second leading cause of preventable death in the U.S.

However, people of the same weight or body mass index (BMI) may have very different risk profiles, based on genetics, lifestyle and diet. In addition, body composition differs between men and women, with women having proportionately more fat and men having more muscle mass.

Fat distribution is an important determinant of cardiometabolic risk. Most people have heard the phrases "apple-shaped" and "pear-shaped." These are common descriptors of human body shapes, based on where fat tends to be stored in the body. In apple-shaped bodies, fat is distributed largely around the midsection, while in pear-shaped bodies, fat is distributed lower around the hips and thighs. The type of fat stored also plays a role in cardiometabolic risk. One type of fat--ectopic fat--is particularly dangerous. It may be found in places such as the abdominal region, muscles, liver and other organs.

"We hypothesized that there are gender-based differences in body composition and ectopic fat depots and that these could be associated with gender-specific risk profiles for diseases like diabetes, heart disease and stroke," said lead author Miriam A. Bredella, M.D., radiologist at Massachusetts General Hospital and associate professor of radiology at Harvard Medical School in Boston.

For the study, Dr. Bredella and colleagues recruited 200 young (mean age 37), overweight and obese individuals who were otherwise healthy. Of the 200, 109 were women and 91 were men. Women and men were of a similar age and BMI.

After fasting overnight, the study participants underwent dual-energy x-ray absorptiometry (DXA) and CT scans to determine body composition, as well as magnetic resonance spectroscopy (MRS) for fat quantification and analysis.

The results showed that the women had a higher percentage of fat and more subcutaneous (below-the-skin) fat but lower lean mass, compared to men. However, men had more visceral adipose tissue (VAT), or ectopic fat depots located in the abdomen around the internal organs (commonly known as a "beer belly"), and more ectopic fat in the muscles and liver.

"Obese men have relatively higher visceral fat, fat within muscle cells and liver fat, which are all risk factors for cardiometabolic disease, compared to women with the same BMI," Dr Bredella said. "However, men have higher muscle and lean mass, which are protective for cardiometabolic health. Women have a higher relative amount of total body fat and higher superficial thigh fat, which is protective for cardiometabolic health."

Compared to women, men had higher measures of cardiometabolic risk overall, but ectopic fat was not significantly associated with cardiometabolic risk in men. Ectopic fat in women, however, was strongly associated with cardiometabolic risk measures.

"The detrimental fat depots deep in the belly, muscles and liver are more damaging for cardiometabolic health in women compared to men," Dr. Bredella said.

In a related study presented by Dr. Bredella today at RSNA 2017, the researchers looked at the relationship between sarcopenic obesity--or the loss of skeletal lean muscle mass in the presence of obesity--and its relationship to cardiometabolic risk.

Many factors can lead to sarcopenic obesity in young adults, particularly obesity and lack of exercise.

"But there are also hormonal abnormalities," Dr. Bredella said, "such as low growth hormone secretion in individuals with abdominal obesity. Growth hormone helps to build muscle mass. Nutrition also plays an important role, and too little intake of protein can lead to muscle loss."

The researchers studied 188 young, overweight and obese adults who were otherwise healthy. Participants underwent DXA and CT scans and various metabolic tests. Results showed that having a lower lean muscle mass to BMI ratio was associated with cardiometabolic risk, and these effects were stronger in women than in men.

"Sarcopenic obesity may be an under-appreciated mechanism linking obesity to cardiometabolic disease," Dr. Bredella said. "That stresses the importance of building up muscle mass in the setting of obesity."
-end-
Co-authors on both studies are Melanie Schorr, M.D., Laura Dichtel, M.D., Martin Torriani, M.D., and Karen K. Miller, M.D.

Note: Copies of RSNA 2017 news releases and electronic images will be available online at RSNA.org/press17 beginning Monday, Nov. 27.

RSNA is an association of over 54,000 radiologists, radiation oncologists, medical physicists and related scientists, promoting excellence in patient care and health care delivery through education, research and technologic innovation. The Society is based in Oak Brook, Ill. (RSNA.org)

For patient-friendly information on DXA, CT and MRS, visit RadiologyInfo.org.

Radiological Society of North America

Related Obesity Articles from Brightsurf:

11 years of data add to the evidence for using testosterone therapy to treat obesity, including as an alternative to obesity surgery
New research covering 11 years of data presented at this year's European and International Congress on Obesity (ECOICO 2020) show that, in obese men suffering from hypogonadism (low testosterone), treatment with testosterone injections lowers their weight and improves a wide range of other metabolic parameters.

Overlap between immunology of COVID-19 and obesity could explain the increased risk of death in people living with obesity, and also older patients
Data presented in a special COVID-19 session at the European and International Congress on Obesity (ECOICO 2020) suggests that there are overlaps between the immunological disturbances found in both COVID-19 disease and patients with obesity, which could explain the increased disease severity and mortality risk faced by obese patients, and also elderly patients, who are infected by the SARS-CoV-2 virus that causes COVID-19 disease.

New obesity guideline: Address root causes as foundation of obesity management
besity management should focus on outcomes that patients consider to be important, not weight loss alone, and include a holistic approach that addresses the root causes of obesity, according to a new clinical practice guideline published in CMAJ (Canadian Medical Association Journal) http://www.cmaj.ca/lookup/doi/10.1503/cmaj.191707.

Changing the debate around obesity
The UK's National Health Service (NHS) needs to do more to address the ingrained stigma and discrimination faced by people with obesity, says a leading health psychologist.

Study links longer exposure to obesity and earlier development of obesity to increased risk of type 2 diabetes
Cumulative exposure to obesity could be at least as important as actually being obese in terms of risk of developing type 2 diabetes (T2D), concludes new research published in Diabetologia (the journal of the European Association for the Study of Diabetes [EASD]).

How much do obesity and addictions overlap?
A large analysis of personality studies has found that people with obesity behave somewhat like people with addictions to alcohol or drugs.

Should obesity be recognized as a disease?
With obesity now affecting almost a third (29%) of the population in England, and expected to rise to 35% by 2030, should we now recognize it as a disease?

Is obesity associated with risk of pediatric MS?
A single-center study of 453 children in Germany with multiple sclerosis (MS) investigated the association of obesity with pediatric MS risk and with the response of first-line therapy in children with MS.

Women with obesity prior to conception are more likely to have children with obesity
A systematic review and meta-analysis identified significantly increased odds of child obesity when mothers have obesity before conception, according to a study published June 11, 2019 in the open-access journal PLOS Medicine by Nicola Heslehurst of Newcastle University in the UK, and colleagues.

Obesity medicine association announces major updates to its adult obesity algorithm
The Obesity Medicine Association (OMA) announced the immediate availability of the 2019 OMA Adult Obesity Algorithm, with new information for clinicians including the relationship between Obesity and Cardiovascular Disease, Diabetes Mellitus, Dyslipidemia, and Cancer; information on investigational Anti-Obesity Pharmacotherapy; treatments for Lipodystrophy; and Pharmacokinetics and Obesity.

Read More: Obesity News and Obesity Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.