Posted on 06/19/2023 1:12:56 PM PDT by nickcarraway
The traditional body mass index (BMI) measure may have misclassified millions of Americans as not having obesity, according to National Health and Nutrition Examination Survey (NHANES) data.
Among over 9,700 adults identified as having obesity according to total body fat percentage estimates using dual-energy x-ray absorptiometry (DEXA) scans, the BMI measure only accurately classified 47%, reported Aayush Visaria, MD, MPH, of Rutgers Robert Wood Johnson Medical School in New Brunswick, New Jersey, at ENDO 2023opens in a new tab or window, the annual meeting of the Endocrine Society.
When ruling out obesity, BMI and DEXA measures were congruent 95% of the time, he explained.
Only 36% of participants had a BMI of 30 or more -- the traditional cutoff for obesity -- while 74% had obesity according to total body fat percentage, defined as a body fat percentage of 25% or higher in males and 32% or higher for females.
However, adding waist circumference on top of the traditional BMI measure reduced misclassifications by 23%, said Visaria. When both measures were used, only 31% of people with DEXA-confirmed obesity were misclassified as not having obesity according to a combined BMI and waist-based obesity cutoff. This combo measure and DEXA were congruent 69% of the time for classifying obesity.
"I think the biggest thing here is that BMI is used throughout population health, throughout clinical care, but what we realize here is that BMI vastly underestimates true obesity," Visaria said, "suggesting its use alone without an additional measure like waist circumference may not be sufficient."
Certain races and ethnicities had a greater chance of obesity misclassification with BMI than others. Specifically, Asian and Hispanic adults were more likely to have a normal BMI but have DEXA-confirmed obesity according to their body fat percentage compared with white adults. Asian and Hispanic adults were also more likely to have a greater proportion of abdominal fat. On the other hand, Black adults with a normal BMI were far less likely to have high body fat percentages and tended to have less abdominal fat.
Visaria pointed out that the traditional cutoffs in BMI used to separate underweight (<18.5), normal weight (18.5 to <25), overweight (25 to <30), and obesity (30+; ≥27.5 for Asians) were established decades prior in predominantly white, European men.
"Showing the racial/ethnic differences here, the gender differences, adds to the case that BMI is really maybe even exacerbating the disparities that we see," he suggested.
But it's not yet time to completely ditch BMI, Visaria noted. "I think BMI still has a lot of use -- it's one of the most accessible measures. It's simply calculated, it's trackable, it's scalable. From a population health standpoint, I do think there are some uses for it."
"But from a clinical, individual patient level, I think it's the start of the end. I think BMI should be supplemented with other measures," he added, pointing to the American Medical Association's (AMA) policy statement advising against using BMI by itselfopens in a new tab or window, which was released earlier this week.
"There are numerous concerns with the way BMI has been used to measure body fat and diagnose obesity, yet some physicians find it to be a helpful measure in certain scenarios," said Jack Resneck Jr., MD, AMA's immediate past president, in a statement. "It is important for physicians to understand the benefits and limitations of using BMI in clinical settings to determine the best care for their patients."
Looking beyond the confines of the flawed BMI measure, Visaria said clinicians should also measure waist circumference, waist-to-height ratio, and waist-to-hip ratio. "I know [BMI] is entrenched in our clinical decision making," he noted, "but as we learn more about different measures and their validity ... we will slowly move away from BMI."
Data for the analysis came from the 2011-2018 NHANES on 9,784 U.S. adults ages 20 to 59 with whole-body DEXA scan data. Mean age was 39, 49% were women, and 61% were white.
Visaria said the next steps involve looking more closely at the long-term cardiometabolic health outcomes in individuals who have obesity per DEXA scans, but not BMI cutoffs. Kristen Monaco is a senior staff writer, focusing on endocrinology, psychiatry, and nephrology news. Based out of the New York City office, she’s worked at the company since 2015.
BMI is racist!.................
When I lost 55 lbs about 25 years ago, I was, at 6’ 1”, 190 lbs. I looked like a bean stalk. My friends commented on the possibility that I was too skinny. Yet, the official government stats said I should have been at 160. That’s what I weighed in high school.
Emmitt Smith was around 5’7” and 220 lbs. when he played. BMI is BS.
the obese simply trying to redefine what obese is, the same way the fags took over the APA and declared themselves sane.
It’s pretty clear visually. What’s the kerfuffle?
How is it possible that so many have atrophied to such a great extent?
“Only 36% of participants had a BMI of 30 or more — the traditional cutoff for obesity — while 74% had obesity according to total body fat percentage, defined as a body fat percentage of 25% or higher in males and 32% or higher for females. “
No muscle mass.
muscle is much denser than fat, so for athletes the BMI is not accurate at all. But lets be honest here, the people that are pushing this are not athletes, they are morbidly obese with no muscle mass, but simply want to not be told they are what they are.
Yup. They want to get their own ‘participation trophies’ without doing any work.
Oddly enough, that same Texas guy I told you about on the other thread got caught up in the BMI ‘problem’ when the Marines started using it in the late 70’s to determine who was ‘fat’.
He was short, but very muscular and fit as a person could be. He worked out and jogged and the like, but his BMI showed him to be ‘fat’ because muscle is denser and heavier than fat tissue.
He had to report to what was called ‘Fat Body Platoon’ every afternoon for Physical Exercises. He didn’t mind it, because it got him out of work early and he was a physical fitness buff anyways.
So for that reason alone I have always considered BMI as not really accurate for everybody...................
as not having obesity,
Vice versa, more likely...
Mostly its genetic: people are just too short for their weight.
For example, a trained, non-heavyweight boxer, partially or fully dehydrated, can barely make 160 pounds at 5' 9", let alone make that weight at 6' 1".
Fat people looking loopholes to squeeze through.
Its a pofential indicator. By itself it doesn’t provide enough context. Its just a heith to weight ratio so it really can be a useless number for certain body types or people with chronic conditions.
Ie it would say a sick person who’s underweight is healthier than an athlete that says hes obese.
It would say a person who not overweight but doesn’t exercise is healthier than a person who exercises but muscle pushes them to a “overweight” bmi number.
It would say a fat person who doesnt exercise could be equal in hezlth to a fat person who does exercise.
It could say a person with a chronic illness could be healthier that a person who is called fat by their bmi number but who exercises.
That number alone doesn’t provide a full picture and often provides an inaccurate picture. More context is required.
Just another stupid idea that got packaged up nicely as “scientific.”
https://www.nhlbi.nih.gov/health/educational/lose_wt/risk.htm
Causality matters.
Yes, there is a correlation between BMI and all sorts of medical conditions, but not everyone is heavy because they are fat.
BMI is an over simplification.
When you create general rules like that, but where you have a lack of causality and many exceptions, you should not apply that rule rigidly, rather only as as an indicator to look further.
BMI has never been an accurate indicator of obesity. If you work out hard and have a muscle mass above average it skews the BMI upward. Evander Holyfield in his prime was categorized as obese according to his BMI.
Now if your ass is 3ft wide and you have a BMI that says you’re obese then you are most likely obese.
It looks to me like they need to specify the kinds of fat that are dangerous. Specifically, visceral fat around and in the inner organs is visceral fat. It has very bad effects on the body.
Subcutaneous fat or the love handles around the belly is relatively benign.
Brown fat is good for you.
Break the gauge before admitting what it tells.
I will never forget one of the times they 'updated' the BMI index. Michael Jordan was still winning NBA championships. According to the 'new & improved' BMI index, MJ is obese.
'Experts' 'Scientists' For most of these creeps PhD really does mean Piled Hire & Deeper Xxxxxxx
Makes sense. My wife sees me as a “big guy”. She said I have huge bones. It was confirmed when I had open heart surgery last march. I have a 12” scar in my chest. There was a LOT of bone there.
Some people just have delicate frames - even men. And some are ore substantial. The female version of the latter we call “amazon”.
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