Featured Research

from universities, journals, and other organizations

Best to be overweight, but not obese? Higher levels of obesity associated with increased risk of death

Date:
January 1, 2013
Source:
JAMA and Archives Journals
Summary:
In an analysis of nearly 100 studies that included approximately 3 million adults, relative to normal weight, overall obesity (combining all grades) and higher levels of obesity were both associated with a significantly higher all-cause risk of death, while overweight was associated with significantly lower all-cause mortality.

In an analysis of nearly 100 studies that included approximately 3 million adults, relative to normal weight, overall obesity (combining all grades) and higher levels of obesity were both associated with a significantly higher all-cause risk of death, while overweight was associated with significantly lower all-cause mortality, according to a study in the January 2 issue of JAMA.

"Estimates of the relative mortality risks associated with normal weight, overweight, and obesity may help to inform decision making in the clinical setting," according to background information in the article.

Katherine M. Flegal, Ph.D., of the National Center for Health Statistics, Centers for Disease Control and Prevention, Hyattsville, Md., and colleagues conducted a study to compile and summarize published analyses of body mass index (BMI) and all-cause mortality that provide hazard ratios (HRs) for standard BMI categories. For the review and meta-analysis, the researchers identified 97 studies that met inclusion criteria, which provided a combined sample size of more than 2.88 million individuals and more than 270,000 deaths. Regions of origin of participants included the United States or Canada (n = 41 studies), Europe (n = 37), Australia (n = 7), China or Taiwan (n = 4), Japan (n = 2), Brazil (n = 2), Israel (n = 2), India (n = l), and Mexico (n = l).

All-cause mortality HRs for overweight (BMI of 25-<30), obesity (BMI of ≥30), grade 1 obesity (BMI of 30-<35), and grades 2 and 3 obesity (BMI of ≥35) were calculated relative to normal weight (BMI of 18.5-<25).

The researchers found that the summary HRs indicated a 6 percent lower risk of death for overweight; a 18 percent higher risk of death for obesity (all grades); a 5 percent lower risk of death for grade 1 obesity; and a 29 percent increased risk of death for grades 2 and 3 obesity.

The authors note that the finding that grade 1 obesity was not associated with higher mortality suggests that that the excess mortality in obesity may predominantly be due to elevated mortality at higher BMI levels.

The researchers add that their findings are consistent with observations of lower mortality among overweight and moderately obese patients. "Possible explanations have included earlier presentation of heavier patients, greater likelihood of receiving optimal medical treatment, cardioprotective metabolic effects of increased body fat, and benefits of higher metabolic reserves."

The use of predefined standard BMI groupings can facilitate between-study comparisons, the authors conclude.

Editorial: Does Body Mass Index Adequately Convey a Patient's Mortality Risk?

"Can overweight as defined by BMI actually have a protective association with mortality?" write Steven B. Heymsfield, M.D., and William T. Cefalu, M.D., of the Pennington Biomedical Research Center, Baton Rouge, La., in an accompanying editorial.

"The presence of a wasting disease, heart disease, diabetes, renal dialysis, or older age are all associated with an inverse relationship between BMI and mortality rate, an observation termed the obesity paradox or reverse epidemiology. The optimal BMI linked with lowest mortality in patients with chronic disease may be within the overweight and obesity range. Even in the absence of chronic disease, small excess amounts of adipose tissue may provide needed energy reserves during acute catabolic illnesses, have beneficial mechanical effects with some types of traumatic injuries, and convey other salutary effects that need to be investigated in light of the studies by Flegal et al and others."

"Not all patients classified as being overweight or having grade 1 obesity, particularly those with chronic diseases, can be assumed to require weight loss treatment. Establishing BMI is only the first step toward a more comprehensive risk evaluation."


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 Reference:

  1. Katherine M. Flegal, Brian K. Kit, Heather Orpana, Barry I. Graubard. Association of All-Cause Mortality With Overweight and Obesity Using Standard Body Mass Index CategoriesA Systematic Review and Meta-analysis. JAMA, Jan 2013 DOI: 10.1001/jama.2012.113905

Cite This Page:

JAMA and Archives Journals. "Best to be overweight, but not obese? Higher levels of obesity associated with increased risk of death." ScienceDaily. ScienceDaily, 1 January 2013. <www.sciencedaily.com/releases/2013/01/130101182008.htm>.
JAMA and Archives Journals. (2013, January 1). Best to be overweight, but not obese? Higher levels of obesity associated with increased risk of death. ScienceDaily. Retrieved October 20, 2014 from www.sciencedaily.com/releases/2013/01/130101182008.htm
JAMA and Archives Journals. "Best to be overweight, but not obese? Higher levels of obesity associated with increased risk of death." ScienceDaily. www.sciencedaily.com/releases/2013/01/130101182008.htm (accessed October 20, 2014).

Share This



More Health & Medicine News

Monday, October 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

How Nigeria Beat Its Ebola Outbreak

How Nigeria Beat Its Ebola Outbreak

Newsy (Oct. 20, 2014) The World Health Organization has declared Nigeria free of Ebola. Health experts credit a bit of luck and the government's initial response. Video provided by Newsy
Powered by NewsLook.com
Another Study Suggests Viagra Is Good For The Heart

Another Study Suggests Viagra Is Good For The Heart

Newsy (Oct. 20, 2014) An ingredient in erectile-dysfunction medications such as Viagra could improve heart function. Perhaps not surprising, given Viagra's history. Video provided by Newsy
Powered by NewsLook.com
Ebola Worries End for Dozens on U.S. Watch Lists

Ebola Worries End for Dozens on U.S. Watch Lists

Reuters - US Online Video (Oct. 20, 2014) Forty-three people who had contact with Thomas Eric Duncan, the first person diagnosed with Ebola in the U.S., were cleared overnight of twice-daily monitoring after 21 days of showing no symptoms. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com
Fauci: Ebola Protocols to Focus on Training

Fauci: Ebola Protocols to Focus on Training

AP (Oct. 20, 2014) Dr. Anthony Fauci, head of the National Institute of Allergy and Infectious Diseases, says he expects revised CDC protocols on Ebola to focus on training, observation and ensuring health care workers are more protected. (Oct. 20) 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:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

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