Entries in Body Mass Index (12)


Is Being Overweight Really Bad For You?

Creatas/Thinkstock(NEW YORK) -- If your New Year's resolution is to lose those last few pounds that are keeping you out of your skinny jeans, a new review suggests you may want to think twice.

The research reinforces a counterintuitive point that past studies have suggested -- being a bit on the heavy side may actually cut your risk of dying prematurely.

In the review, published in this week's Journal of the American Medical Association, researchers looked at nearly 100 studies involving 2.88 million people that compared body mass index, or BMI, to the risk of death from any cause.

BMI is derived from a formula that compares your height to your weight. It is currently the standard means of determining whether someone is underweight, of normal weight, overweight or obese.

Not surprisingly, the researchers found that the heaviest among us -- those who have a BMI above 30 -- have a higher risk of death than those who are considered to be at a "normal" weight, or a BMI between 18.5 and 25.

But the researchers also found a slight dip in death risk -- about 6 percent -- in those whose BMIs were between 25 and 30. In other words, people who would be classified as overweight appear to have a lower risk of death from any cause.

Moreover, for those who were considered to be on the lower end of the obesity spectrum, with a BMI of 30 to 35, the risk of death from any cause was not significantly different from that experienced by those who were at a normal weight.

As is apparent from the number of studies examined in this review, this is not the first time that a link has been suggested between being a tad on the heavy side and having a decreased risk of death. And several past studies have disputed this link. But this new review may lend support to the idea that our health may not be as closely tied to the numbers on our scales as we might have been led to believe.

Lead study researcher Katherine Flegal, Ph.D., of the CDC's National Center for Health Statistics, said the review was in many ways a follow-up to research she and her colleagues published in 2005 that suggested a slightly higher-than-normal BMI was necessarily attached to life-threatening conditions such as heart disease.

"We found that being overweight in that study was not associated with excess mortality from cardiovascular disease or cancer, but it reduced mortality from other things," Flegal said. "There's even some research that suggests body fat itself could be cardioprotective."

On one hand, said obesity experts not involved with the research, the findings suggest that the current widespread use of BMI as a way to determine if one is overweight or obese may need to be reconsidered. Flegal said that the problem may not be the BMI scale, but, rather, how the different rungs on the BMI ladder are interpreted by doctors. In this way, such research may have implications for physicians who currently advise patients in the overweight BMI category to lose a few pounds.

"These are not health categories, these are weight categories," Flegal said.

Dr. David Katz, director of Yale University's Prevention Research Center, agreed that this review supports the idea that doctors may need to reexamine the way they advise certain patients.

"In a society prone to both epidemic and increasingly severe obesity, it may be that those who manage to remain in the 'overweight' class are, in fact, those who are actually doing quite well," said Katz, who was not involved with the study. "This study suggests that if the basis for defining 'overweight' is adverse health effects, we may want to raise the threshold. The definition of 'overweight' should begin where health risks begin."

Katz pointed out that the study looked only at death rates -- not quality of life. And this is an area, he said, that may be affected by being overweight or slightly obese.

"We have recent evidence -- from the Lancet's 'Global Burden of Disease' study -- that we are living longer, but sicker," he said. "It may be that overweight does, indeed, contribute to type 2 diabetes and heart disease, but not to premature death.

"Living is not really the prize; living well is the prize. So we should be careful before jumping to conclusions about these findings."

Copyright 2013 ABC News Radio


New Obesity Measure ABSI Better Than BMI?

iStockphoto/Thinkstock(NEW YORK) -- Body mass index (BMI) is a widely used indicator of obesity, but a new study suggests it may not be the best predictor of whether your weight raises your risk of death.

Researchers at The City College of New York developed a new obesity measurement tool called A Body Shape Index (ABSI) that combines BMI and waist circumference.

Waist circumference is a measure used to determine the amount of belly fat a person has.  Abdominal fat has been linked to a number of health conditions, including high cholesterol, insulin resistance and high blood pressure.

The researchers measured ABSI in more than 14,100 American adults who participated in the National Health and Nutrition Examination Survey (NHANES) between 1999 and 2004.  They found that a high ABSI, indicative of a large amount of belly fat, significantly increased the risk of premature death.  A high BMI also predicted the risk of an early death, but to a lesser degree than ABSI.

“If BMI measures body size or ‘bigness’, ABSI can be thought of as measuring a component of body shape, or ’roundness,’” Nir Krakauer, an assistant professor of civil engineering and a study co-author, told ABC News via email.

Krakauer said his research suggests that ABSI is a reliable metric, but other studies need to confirm the findings before it can be used clinically.

“I expect that formulating recommendations based on ABSI instead of waist circumference as a health indicator will make them more useful, because ABSI adjusts the waist circumference for height and weight to quantify body shape,” he said.  “High ABSI may identify people who have unhealthy body shapes despite having weight and waist circumference within the normal range, and such
people may benefit from diet and lifestyle changes.”

Nutrition experts not involved in the ABSI research said this new tool has a lot of potential because of its inclusion of waist circumference.

“We always knew that BMI didn’t indicate body indicate body composition.  That was always its weakness,” said Keith Ayoob, an associate professor of pediatrics at the Albert Einstein College of Medicine in New York.  “Waist circumference, without BMI, ties in pretty well with mortality and predicts hazards.”

But regardless of how reliable ABSI may prove to be, BMI is still very useful as an overall measure of body fat.

“We’re not moving away from BMI,” Ayoob said.  “It’s a general tool that’s very easy to figure out.  It’s too simple to give up.”

Copyright 2012 ABC News Radio


Obesity Might Lower Cognitive Function in Older Adults, Study Finds

Jupiterimages/Thinkstock(NEW YORK) -- Older adults with a high body mass index (BMI) and big bellies are more likely to have lower cognitive function than those with a lower BMI, new research suggests.

The study, published in the journal Age and Aging, included 250 people older than 59 who underwent a variety of weight measurement, scans and cognitive performance tests.  People between 60 and 70 with the highest BMIs were linked to the lowest cognitive function.

The Korean study showed a particular association between visceral fat, or fat around the torso, and poor mental performance.

“Aging is characterized by lean body mass loss and adipose tissue increase without weight gain, which may not be captured by BMI, and traditional adiposity measures like BMI are less useful in elderly persons,” said Dr. Dae Hyun Yoon, associate professor of psychiatry at Seoul National University Hospital.

Study results changed in adults older than 70, and the high BMI and large weight circumferences were not associated with cognitive decline.

“A higher BMI is related to lower dementia risk in the oldest old.  It is possible that persons with low BMI lost their weight because of premorbid dementia,” Yoon said.  “It is also possible that a low BMI is the consequence of hyperinsulinemia (high insulin levels), which precedes weight loss and is related to higher dementia risk.”

Dr. Ken Fujioka, director of the Center for Weight Management at Scripps Clinic in San Diego, said the results make sense and are on par with what he sees clinically.

“As patients gain central obesity -- that is the key -- they increase their level of inflammatory agents and atherosclerotic agents that will wreck havoc on the brain,” Fujioka said.

While it is unclear whether the participants in the study went on to develop dementia or Alzheimer’s disease, past research has shown that excess fat might play a role in a person’s cognitive decline.

Copyright 2012 ABC News Radio


US Obesity Rates Level Off, Remain High

Jupiterimages/Thinkstock(WASHINGTON) -- The good news is that obesity rates overall among children and adults appear to be leveling off. But the bad news is that these rates have consistently remained high since 2003, a black eye for those who have worked for years to curb the obesity crisis.

“Many efforts both at the national level and at state and local levels focus on reducing childhood obesity,” researchers wrote in a study released Tuesday in JAMA. But these efforts may not have contributed to significant reductions in obesity in any age group, especially for males.

Nearly 36 percent of adults and 17 percent of children are obese – meaning they have a body mass index (BMI) above 30, according to the 2010 results from the U.S. Centers for Disease Control and Prevention National Health and Nutrition Examination Survey (NHANES). These numbers were similar to the data taken from 1999 to 2008.

The number doubles when the prevalence of people who are simply overweight instead of obese are also taken into account. Overweight indicates a body mass index between 25 and 25.9. Nearly 70 percent of men and women are either considered overweight or obese, according to the latest survey data. Nearly 32 percent of children ages 2 to 19 are considered overweight or obese.

Slight increases were found in males of both age groups. Nearly 36 percent of men are considered obese, which is a slight increase from previous years.

“The rapid increases we saw in the 1980s and 1990s have not occurred in the last decade. It’s leveling off,” said Cynthia Ogden, epidemiologist and lead author of the study, which looked at children and adolescent obesity rates.

But the studies did not address why obesity rates have leveled off compared to previous decades.

Ogden and her colleagues also found a slight increase in body mass index (BMI) among adolescent males ages 12 through 19 years, but not among any other age group or among females.

Copyright 2012 ABC News Radio


Study Finds Possible Link Between Low BMI, Alzheimer's Disease

Creatas/Thinkstock(KANSAS CITY, Kan.) -- Maintaining a low Body Mass Index (BMI) has long been considered a healthy practice for the general population, but a new study suggests there could be a link between one's BMI and cognitive impairment.

The study, published in the journal Neurology, found that older people in the earliest stages of Alzheimer's disease are more likely to have lower BMI.

"The earliest stages of Alzheimer's are associated with some metabolic dysfunction, as evidence with the differences in BMI," said Dr. Jeffrey Burns, lead author of the study and director of the Alzheimer and Memory Program at University of Kansas Medical Center.  "We saw the relationship between Alzheimer's markers with body composition with low BMI in people in the earliest stages of the disease, both in people with mild cognitive impairment and in people without functional problems."

While Burns said he does not have the evidence to support whether low BMI puts people at risk of cognitive impairment or cognitive impairment may contribute to lower BMI, he said it goes beyond simple changes in one's ability to remember to eat.

"It reflects there is a systemic response to an underlying problem," said Burns.  "We think of Alzheimer's as classically a brain disease, but now there's evidence that there are measurable changes going on in the body."

BMI is a number calculated from a person's height and weight that is meant to indicate body fatness in most people.  According to the Centers for Disease Control and Prevention, 18.5 and below is considered underweight; normal weight ranges from 18.5 to 24.9; overweight spans from 25 to 29.9; and obese is considered 30 and above.

Researchers analyzed more than 500 patients with Alzheimer's biomarkers through advanced brain imaging techniques and cerebrospinal fluid.  The biomarkers are often present years before symptoms set in.  Study participants included people without any memory problems and those with mild cognitive impairment.

While the link between later-life low body mass and Alzheimer's disease has been fairly established by previous research publications, William Thies, chief medical and scientific officer of the Alzheimer's Association, said this study appears to extend this relationship to the earliest stages of Alzheimer's pathology through the biomarker findings.

Interestingly, prior research has shown that middle-aged people who are overweight or obese (higher BMIs) are at greater risk of developing Alzheimer's disease.

Copyright 2011 ABC News radio


Thin People At Greater Risk of Dying After Surgery, Study Finds

Keith Brofsky/Thinkstock(CHARLOTTESVILLE, Va.) -- Being thin isn't an advantage when it comes to surviving surgery, a new study finds.

University of Virginia researchers say that heavier people have a lower chance of dying within 30 days after an operation as opposed to their thinner counterparts.  George Stukenborg and his team aren't really sure why that is after setting out to learn how obesity affects the risk of surviving surgery.

Typically, people with higher body mass index rates are prone to contract more life-threatening diseases, but these new findings of post-surgery complications among thin patients have left scientists puzzled.

Dr. Nestor de la Cruz-Munoz, chief of bariatric surgery at the University of Miami Miller School of Medicine, believes the answer is that, "a lot of these patients are malnourished -- maybe cancer patients, patients undergoing treatment for other medical problems.  A lot of time these patients don't have the defenses to do well with a major surgery."

Copyright 2011 ABC News Radio


Having More Muscle Mass Reduces Your Diabetes Risk: Study

Jeffrey Hamilton/Thinkstock(LOS ANGELES) -- Reducing one's body mass is known to improve insulin sensitivity, a major factor contributing to the development of diabetes.  But muscle mass also plays a role.

The lower it is, the greater the risk for insulin resistance, which begs the question: Could increasing muscle mass help with insulin sensitivity?

According to a new study published in the Journal of Clinical Endocrinology & Metabolism on Thursday, the answer is yes.

Researchers at the David Geffen School of Medicine at UCLA found that among over 13,500 individuals, increased levels of muscle mass were associated with better insulin sensitivity and a lower risk of pre-diabetes or overt diabetes.

The authors of the study conclude that their "research shows that beyond monitoring changes in waist circumference or BMI, we should also be monitoring muscle mass."

Copyright 2011 ABC News Radio


Could Wrist Size Predict Future Diabetes?

Jupiterimages/Thinkstock(WASHINGTON) -- Predicting an overweight child's risk of diabetes and heart disease may be as simple as measuring the size of his or her wrist, according to new research published by the American Heart Association. In the study, published in the latest addition of the journal Circulation, wrist size was linked to insulin resistance, a precursor for type 2 diabetes, in overweight kids and teens.

"This is the first evidence that wrist circumference is highly correlated to evidence of insulin resistance," Dr. Raffaella Buzzetti, senior study author and professor in the Department of Clinical Sciences at Sapienza University of Rome, Italy, said in a statement. "Wrist circumference is easily measured and if our work is confirmed by future studies, wrist circumference could someday be used to predict insulin resistance and cardiovascular disease risk."

Though measuring body fat is usually a reliable predictor of insulin resistance and heart disease risk in adults, this is not always the case for kids because their bodies grow and change so rapidly during puberty. Typically, doctors will measure a teen's BMI (body mass index) by comparing height and weight. This may be a misleading gauge, however, especially for athletes who may have a high percentage of muscle, which weighs more than fat.

In the study, researchers analyzed how wrist size and BMI correlated with levels of insulin resistance. While BMI only accounted for 1 percent of variation in insulin resistance, the wrist measurement accounted for between 12 and 17 percent.

Insulin resistance occurs when the body has difficulty using the insulin it makes to break down blood sugar. Excess body fat is linked to developing insulin resistance, and insulin resistance has been identified as a major risk factor for developing cardiovascular disease and type 2 diabetes later in life.

Surprisingly, researchers found that it wasn't necessarily a fatter wrist that correlated with higher heart disease risk, just a larger one. Because higher insulin levels in kids can contribute to increased bone production, larger wrist bones may be a marker of insulin resistance, which in turn is a predictor of future heart disease.

"It's surprising that bone size correlated better [to insulin resistance] than body mass index," says Dr. Robert Gensure, endocrine specialist and pediatric bone density specialist at Montefiore Medical Center. "Insulin is a growth factor and it promotes growth in many tissues, including bone."

This means that some kids and teens who are overweight are actually becoming bigger-boned in response to the extra insulin their bodies are producing. Buzzetti's research is picking up on this change and using those bigger bones as an indicator of the higher levels of insulin that put kids at risk for future heart disease and diabetes.

Copyright 2011 ABC News Radio


Will New Fat Test Replace Body Mass Index?

Brand X Pictures/Thinkstock(LOS ANGELES) -- A new way to tell how fat a person is without having to step on a scale may replace Body Mass Index, a measure that hasn't been updated for nearly 200 years.

BMI uses height and weight to estimate body fat. The new index, known as Body Adiposity Index (BAI), uses hip-width and height measurements. Scientists hope it will be a simpler and more accurate assessment.

BMI long has been considered useful but flawed. A high BMI is one of several risk factors used to evaluate obesity-related diseases, but for many people, including athletes, BMI is unreliable.

BAI offers a potential advantage over BMI because it gives a clearer snapshot of how much unhealthy flab a person carries on their body and eliminates much of the guesswork of whether or not a person is truly carrying too much excess weight. It seems to be able to differentiate how much of a person's weight is fat and how much is muscle and fat-free mass -- although like BMI, it still doesn't reveal anything about where an individual's fat is deposited.

Richard Bergman and a team of researchers at the University of Southern California in Los Angeles derived their BAI calculations from a database of about 1,700 Mexican-Americans. When they analyzed an extensive series of physical characteristics they found that hip circumference and height correlated strongly with body fat percentage as measured by a highly reliable but expensive scanning method known as DEXA, or dual-energy X-ray absorptiometry. They reported their findings in the March issue of the journal Obesity.

Bergman said that as with any other new scientific measure, BAI still needs fine tuning such additional testing on other ethnicities and with children. But so far, results have been promising. Recent studies with groups of African Americans also have produced good results.

Determining your body fat percentage with BAI involves measuring your height in meters and the widest part of your hips (while your feet are placed together) in centimeters, then plugging those numbers into a complex formula.

Body fat percentage is just one number medical experts use to evaluate a person's overall health and level of "fatness." There are no universally accepted guidelines for the ideal percentage of body fat.

The American Council on Exercise recommends that women strive for between 16 percent and 26 percent body fat and men between 12 percent and 22 percent. Athletic men and women often have lower body fat percentages than that. Those above 38 percent body fat generally are considered to be obese.

Copyright 2011 ABC News Radio


Study: BMI In Adolescence Tied to Later Heart Disease  

Comstock/Thinkstock(BOSTON) -- Obesity in adulthood is known to be associated with diabetes and heart disease.  But does a longer history of being somewhat overweight pose an added risk of coronary disease?  That's what a new study sought to find out.

Teenagers with a body mass index (BMI) of 30 or above -- which is considered obese -- are at a greater risk for diabetes and heart disease later in life. 

But a study in the New England Journal of Medicine suggests that an elevated BMI in what would be a normal range during adolescence also increases the risk for coronary heart disease.

Researchers in Israel followed more than 37,000 healthy men in the Israeli army for an average of 17 and a half years.  The participants were 17 years old when the study began.

They found that an elevated BMI in the adolescent men who were not overweight posed a substantial risk for coronary heart disease in midlife.  The adolescents were four times more likely to develop heart problems compared to the teens with the lowest BMI.

The study concluded that the BMI at 17 is a predictor of heart disease later in life. 

Because the participants were limited to men in the Israeli army, the results may not fully apply to others elsewhere.

Copyright 2011 ABC News Radio

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