Featured Research

from universities, journals, and other organizations

Some Obese Individuals Appear 'Metabolically Healthy,' Without Increased Cardiovascular Risk

Date:
August 12, 2008
Source:
JAMA and Archives Journals
Summary:
Some obese individuals do not appear to have an increased risk for heart disease, while some normal-weight individuals experience a cluster of heart risks, according to two reports in the August 11/25 issue of Archives of Internal Medicine, one of the JAMA/Archives journals.

Some obese individuals do not appear to have an increased risk for heart disease, while some normal-weight individuals experience a cluster of heart risks, according to two reports in the August 11/25 issue of Archives of Internal Medicine, one of the JAMA/Archives journals.

"The prevalence of obesity is increasing worldwide, and this epidemic is accompanied by a high incidence of type 2 diabetes mellitus and cardiovascular disease," the authors write as background information in one of the articles. Research indicates that in addition to overall obesity, the way body fat is distributed may influence risk for heart disease and diabetes. For instance, individuals with fat within the abdominal cavity—estimated by measuring waist size—appear to be at higher risk for insulin resistance (a pre-diabetic condition that occurs when the body fails to respond to the hormone insulin) and for having an unhealthy cardiovascular risk profile.

In one study, Norbert Stefan, M.D., and colleagues at the University of Tόbingen, Germany, studied 314 individuals age 18 to 69 (average age 45). The researchers measured participants' total body fat, visceral fat (abdominal fat around the internal organs) and subcutaneous fat (fat under the skin) using magnetic resonance tomography. Insulin resistance was measured using an oral glucose tolerance test. The individuals were then divided into four groups: normal weight, overweight, obese but still sensitive to insulin and obese with insulin resistance.

Those in the overweight and obese groups had more total body and visceral fat than those at a normal weight, and there was no difference between obese groups. However, obese individuals with insulin resistance had more fat within their skeletal muscles and their livers than obese individuals without insulin resistance. In addition, those who were insulin-resistant had thicker walls in their carotid arteries, an early sign of atherosclerosis (narrowing of the arteries, a heart disease risk factor).

Individuals in the obese–insulin sensitive group did not differ from the normal-weight group in insulin sensitivity or artery wall thickness, the authors note. "In conclusion, we provide evidence that a metabolically benign obesity can be identified and that it may protect from insulin resistance and atherosclerosis," they write. "Furthermore, our data suggest that ectopic [misplaced] fat accumulation in the liver may be more important than visceral fat in the determination of such a beneficial phenotype in obesity."

In a second study, Rachel P. Wildman, Ph.D., of the Albert Einstein College of Medicine, Bronx, N.Y., and colleagues assessed body weight and cardiometabolic abnormalities (including high blood pressure, elevated triglycerides and low high-density lipoprotein or "good" cholesterol) in 5,440 individuals participating in the National Health and Nutritional Examination Surveys between 1999 and 2004. Participants were considered metabolically healthy if they had none or one abnormality and metabolically abnormal if they had two or more abnormalities.

"Among U.S. adults 20 years and older, 23.5 percent (approximately 16.3 million adults) of normal-weight adults were metabolically abnormal, whereas 51.3 percent (approximately 35.9 million adults) of overweight adults and 31.7 percent (approximately 19.5 million adults) of obese adults were metabolically healthy," the authors write. Normal-weight individuals with metabolic abnormalities tended to be older, less physically active and have larger waists than healthy normal-weight individuals. Obese individuals with no metabolic abnormalities were more likely to be younger, black, more physically active and have smaller waists than those with metabolic risk factors.

"These data show that a considerable proportion of overweight and obese U.S. adults are metabolically healthy, whereas a considerable proportion of normal-weight adults express a clustering of cardiometabolic abnormalities," the authors write. "Further studies into the behavioral, hormonal or biochemical and genetic mechanisms underlying these differential metabolic responses to body size are needed and will likely further the identification of possible obesity intervention targets and improve cardiovascular disease screening tools."


Story Source:

The above story is based on materials provided by JAMA and Archives Journals. Note: Materials may be edited for content and length.


Journal References:

  1. Stefan et al. Identification and Characterization of Metabolically Benign Obesity in Humans. Archives of Internal Medicine, 2008; 168 (15): 1609 DOI: 10.1001/archinte.168.15.1609
  2. Wildman et al. The Obese Without Cardiometabolic Risk Factor Clustering and the Normal Weight With Cardiometabolic Risk Factor Clustering: Prevalence and Correlates of 2 Phenotypes Among the US Population (NHANES 1999-2004). Archives of Internal Medicine, 2008; 168 (15): 1617 DOI: 10.1001/archinte.168.15.1617

Cite This Page:

JAMA and Archives Journals. "Some Obese Individuals Appear 'Metabolically Healthy,' Without Increased Cardiovascular Risk." ScienceDaily. ScienceDaily, 12 August 2008. <www.sciencedaily.com/releases/2008/08/080811195635.htm>.
JAMA and Archives Journals. (2008, August 12). Some Obese Individuals Appear 'Metabolically Healthy,' Without Increased Cardiovascular Risk. ScienceDaily. Retrieved September 20, 2014 from www.sciencedaily.com/releases/2008/08/080811195635.htm
JAMA and Archives Journals. "Some Obese Individuals Appear 'Metabolically Healthy,' Without Increased Cardiovascular Risk." ScienceDaily. www.sciencedaily.com/releases/2008/08/080811195635.htm (accessed September 20, 2014).

Share This



More Health & Medicine News

Saturday, September 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Sierra Leone's Nationwide Ebola Curfew Underway

Sierra Leone's Nationwide Ebola Curfew Underway

Newsy (Sep. 20, 2014) — Sierra Leone is locked down as aid workers and volunteers look for new cases of Ebola. Video provided by Newsy
Powered by NewsLook.com
Changes Found In Brain After One Dose Of Antidepressants

Changes Found In Brain After One Dose Of Antidepressants

Newsy (Sep. 19, 2014) — A study suggest antidepressants can kick in much sooner than previously thought. Video provided by Newsy
Powered by NewsLook.com
Could Grief Affect The Immune Systems Of Senior Citizens?

Could Grief Affect The Immune Systems Of Senior Citizens?

Newsy (Sep. 19, 2014) — The study found elderly people are much more likely to become susceptible to infection than younger adults going though a similar situation. Video provided by Newsy
Powered by NewsLook.com
Jury Delivers Verdict in Salmonella Trial

Jury Delivers Verdict in Salmonella Trial

AP (Sep. 19, 2014) — A federal jury has convicted three people in connection with an outbreak of salmonella poisoning five years ago that sickened hundreds of people and was linked to a number of deaths. (Sept. 19) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins