Obesity and mortality association differs between individuals with and without diabetes

August 12, 2013

The relationship between body mass index (BMI) appears to be stronger in adults without diabetes than those with existing diabetes. These findings¹ are published in the Journal of General Internal Medicine in a study by Chandra Jackson of the Harvard School of Public Health and colleagues. The researchers suggest that studies on body weight and mortality should take into account the impact of diabetes status in the population.

In their analysis, Jackson's team used data from a nationally representative sample of 74,710 Black and White American adults between 35 and 75 years old who were part of the National Health Interview Survey. Of the participants, 5 percent reported physician-diagnosed diabetes. The participants were followed over a six-year period and death was confirmed by the National Death Index.

The so-called (or BMI) takes height and into account to measure a person's . Someone with a high body-mass index is generally considered to have a higher risk of death, and to experience a poorer health-related quality of life.

Obesity, which is defined as BMI?30, is a serious public health issue in the United States. Obesity is a well-established risk factor for various serious and costly health conditions, including heart disease, Type 2 diabetes and certain cancers. People with excess adiposity or body fat are generally considered to have a significantly higher risk of death than others in a normal weight population. However, the relationship between mortality and BMI in diseased populations is still unclear and remains a controversial topic.

The results of the study suggest that weight may have a different impact on mortality for diabetics than for the general population. Throughout, were substantially higher among diabetics than nondiabetics. However, compared to individuals with normal weight, at a higher body weight, death rates dipped considerably for diabetics, but rose sharply in people who do not suffer from the disease.

Because of these differences, Jackson and her colleagues believe that Type 2 diabetes status should be taken into account in future BMI-mortality studies, much as is done with heart disease, smoking and cancer to ensure valid population estimates because these conditions can influence body weight and may distort the relationship between BMI and mortality. She concludes: "This finding was surprising, but it may be due to a commonly observed phenomenon in chronic disease epidemiology called 'reverse causation' where a person's weight at the time of the survey can be affected by their disease if it leads to weight loss and muscle wasting during advanced stages. This apparent obesity paradox that has been observed in the past among individuals with diabetes may actually be due to methodological limitations that can bias these types of studies. From clinical and public health points of view, achieving and maintaining a healthy weight should continue to be recommended for both those with and without diabetes."

Explore further: Lifetime 'dose' of excess weight linked to risk of diabetes

More information: Jackson, C.L. et al (2013). Body-Mass Index and All-Cause Mortality in US Adults With and Without Diabetes, Journal of General Internal Medicine; DOI: 10.1007/s11606-013-2553-7

Related Stories

Rethinking body mass index for assessing cancer risk

November 8, 2012

A study by researchers at Albert Einstein College of Medicine of Yeshiva University suggests that body mass index (BMI)—the most commonly used weight-for-height formula for estimating fatness—may not be the best measure ...

U-shaped link for BMI at diagnosis with mortality in T2DM

November 16, 2012

(HealthDay)—For patients with type 2 diabetes mellitus (T2DM), classification as normal weight or obese within a year of initial diabetes diagnosis correlates with significantly higher mortality, forming a U-shaped association ...

Recommended for you

A metabolic master switch underlying human obesity

August 19, 2015

Obesity is one of the biggest public health challenges of the 21st century. Affecting more than 500 million people worldwide, obesity costs at least $200 billion each year in the United States alone, and contributes to potentially ...

Scientists probe obesity's ties to breast cancer risk

August 20, 2015

Obesity is a well-known risk factor for breast cancer, but researchers haven't figured out what connects the two. A new study suggests the link may be due to a change in breast tissue structure, which might promote breast ...

Can a new drug brown the fat and trim the obese person?

May 28, 2015

New research has found that a variant of a drug used to treat pulmonary arterial hypertension prompts weight loss in obese mice. Among mice fed a high-fat diet, those who did not get the medication became obese while medicated ...

Changing stem cell structure may help fight obesity

February 17, 2015

The research, conducted at Queen Mary University of London (QMUL), found that a slight regulation in the length of primary cilia, small hair-like projections found on most cells, prevented the production of fat cells from ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.