网红黑料

GAINESVILLE, Fla. 鈥� A new University of Florida 网红黑料 study shows that body mass index, or BMI 鈥� commonly used to measure obesity and health risk 鈥� fails in predicting the risk of future death, suggesting the calculation is deeply flawed.

The study, published today (June 24) in the , concludes that a direct measure of body fat using a relatively inexpensive device that notes the resistance of body tissue to a small electrical current is far more accurate.

This method, bioelectrical impedance analysis, is increasingly found in medical practices.

Individuals who have high body fat as measured directly by bioelectric impedance are 78% more likely to die of any cause than those with healthy body fat levels during the 15 years they were tracked, the study found. They are also about three-and-a-half times more likely to die of heart disease.

By contrast, BMI proved entirely unreliable. The study showed no statistically significant association with 15-year mortality risk from any cause, including heart disease, when BMI is used.

BMI and bioelectrical impedance data were analyzed in a way that removes the effects of age, race and income.

Researchers in the 鈥檚 Department of Community 网红黑料 and Family Medicine who conducted the study urged physicians to move away from BMI as the standard body composition measure.

The study鈥檚 authors likened their research to a test between two competing means of measuring body fat, much like a product comparison.

鈥淭his study is a game-changer,鈥� said , lead author of the study and a professor and vice chair of research in the department. 鈥淭his is the ultimate Coke versus Pepsi test. And BMI failed.鈥�

The study pulled data from the National 网红黑料 and Nutrition Examination Survey, which is linked to the national death index. The analysis involved 4,252 people, a representative sample of the U.S. population.

The study鈥檚 senior author, Frank Orlando, M.D., medical director of 网红黑料 Family Medicine 鈥� Springhill, said BMI鈥檚 use as a 鈥渧ital sign鈥� of health isn鈥檛 supported by good evidence.

鈥淚鈥檓 a family physician, and on a regular basis, we鈥檙e faced with patients who have diabetes, heart disease, obesity and other conditions that are related to obesity,鈥� said Orlando, an associate professor in the department.

鈥淥ne of the routine measures we take alongside traditional vital signs is BMI. We use BMI to sort of screen for a person having an issue with their body composition, but it鈥檚 not accurate for everyone like vital signs are,鈥� he added.

BMI is calculated using an individual鈥檚 height and weight 鈥� the formula is weight divided by height, squared. But the measure cannot distinguish between muscle and fat mass, only providing an indirect indication.

鈥淔or example, people who are bodybuilders can really elevate their body mass index,鈥� Orlando said. 鈥淏ut they鈥檙e healthy even with a BMI indicating they鈥檙e obese.鈥�

Mainous said BMI gained popularity because of its simplicity. It requires no equipment, just a patient鈥檚 weight and height.

鈥淚t鈥檚 very easy to get,鈥� he said. 鈥淭he problem was, we didn鈥檛 have a practical alternative.鈥�

Devices that measure bioelectrical impedance, however, are increasingly affordable, with many models under $300. They are now found in some primary care practices. In fact, Orlando noted, one is available at the 网红黑料 Springhill family practice.

Mainous and Orlando said some researchers have criticized the devices for not being as accurate as a DEXA scan, or a dual-energy X-ray absorptiometry. That scan uses low-dose X-rays to measure bone, fat and lean muscle mass. DEXA, of course, requires expensive equipment, although it is considered the gold standard to measure body fat.

鈥淚f you talk to obesity researchers, they鈥檙e going to say you have to use the DEXA scan because it鈥檚 the most accurate,鈥� Mainous said. 鈥淎nd that鈥檚 probably true. But it鈥檚 never going to be viable in a doctor鈥檚 office or family practice.鈥�

Bioelectrical impedance, Mainous said, doesn鈥檛 need to be superior to DEXA. It just needs to be better than BMI, which the study shows that it clearly is.

Problems with BMI have been well-documented by researchers. For example, the method can classify some people with a 鈥渘ormal鈥� BMI even when they have a high percentage of body fat, which is known as normal-weight obesity. Body fat percentage can also vary by age.

BMI dates to the 19th century. Adolphe Quetelet, a Belgian statistician, astronomer and mathematician, created 鈥淨uetelet鈥檚 index鈥� in 1832. He would no doubt fail to recognize the uses being put to his index in the modern world.

Quetelet鈥檚 interest instead focused on a quixotic statistical quest to describe the characteristics of the 鈥渘ormal man.鈥� Later generations, starting with insurance actuaries, began using his index to assess health risk.

Today, BMI categorizes an individual as either underweight (BMI under 18.5), normal weight (18.5 to 24.9), overweight (25 to 29.9) or obese (30 and above). The formula does not change based on gender, another flaw cited by critics.

鈥淏MI is just so ingrained in how we think about body fat,鈥� Mainous said. 鈥淚 think the study shows it鈥檚 time to go to an alternative that is now proven to be far better at the job.鈥�