For non-invasive heart disease risk prediction nothing beat ECG, period.
Somehow American Heart Association and its European counterpart are in denial, and still pushing dinasour screening mechanism with very low accuracy for heart disease risk prediction.
The standard risk model for CVD based on PREVENT (US) and SCORE-2 (Europe) like parameters are very poor as reported in the recently published paper on the their accuracy performance by the Swedish team [1]. As all CVD risk stratification with cardiologist review (expert-in-the-loop), the most important accuracy metric is sensivity/recall (avoiding false negative that will escape review) of PREVENT and SCORE-2, 26% and 48%, respectively.
The paper alternative proposal increased the sensitivity to 58% by performing clustering instead of conventional regression models as practiced in the PREVENT and SCORE-2.
These type of models including the latest proposal performed very poorly as indicated by their otherwise excellent and intuitive display of graphical abstract results [1].
[1] Risk stratification for cardiovascular disease: a comparative analysis of cluster analysis and traditional prediction models:
I thought this was pretty well known already. Being “overfat” is the problem, not being overweight (though they’re often correlated). BMI is really easy to measure, and is mostly accurate, that’s why it’s so pervasive. However it remains a pretty rudimentary metric (and really should use the third power or your height instead of the second).
> BMI is really easy to measure, and is mostly accurate, that’s why it’s so pervasive.
BMI is easily misunderstood by people who know just enough to see that it’s imperfect, but not enough to understand why it’s still a valuable screening tool.
I’ve been in the “overweight” BMI range with low body fat before. It’s not too hard to get there if you’re lifting weights and paying attention to your diet consistently for years, but it takes a lot of work to get there. It doesn’t happen accidentally except for people who win some genetic lottery to build a lot of muscle and keep body fat low without trying.
Getting all the way to the obese BMI range while having healthy body fat is only happening for people with an extreme dedication to body building and diet (and let’s be honest, a lot of the people in this category are manipulating hormones too).
Yet whenever BMI comes up some people try to dismiss it as too flawed based on these possible edge cases. The edge cases for BMI exist, but that doesn’t mean it’s not useful. It’s a good general purpose screening tool with numbers that are available. If someone has more precise measurements available, those should be used instead. BMI is a really good first pass screener to determine if a closer look should happen.
Yes, it is a pretty high level metric with good correlation a bunch of diseases, but really many of these is because it is ALSO correlated to percent of fat, which is often the more relevant metric. But as you said BMI is so much simpler to measure.
Many active gym people have pretty high BMIs but fairly low fat (because muscle is dense), and unsurprisingly have better outcomes than the average person (if you ignore the share that uses/overuses anabolic steroids and co)
> Many active gym people have pretty high BMIs but fairly low fat (because muscle is dense),
I’ve been in the overweight BMI category with low body fat by being active at the gym and focusing on diet. It takes some work to get there.
If I check the calculators for the obese BMI range, there was no way I could get there without either gaining a lot of fat on top of the muscle. The amount of muscle required to have an obese BMI with healthy amount of fat is absurd.
Not sure I follow the logic here, but happy to be proven wrong if I'm misunderstanding. It's not intuitive to me that a 300 lb. person at 20% body fat is generally at the same risk as a 200 lb. person at 30% body fat.
Fat is inherently unhealthy for you beyond some low baseline level.
Additional muscle is positive for health, but only up to some reasonable threshold. There is no health benefit to having very high levels of muscle, and in fact it may be negative for your health at extreme levels. E.g. many bodybuilders have trouble breathing, sleep apnea etc.
Both people in the example have 60lbs of fat. 1lb of muscle doesn't cancel out the negative health effect of 1lb of fat
How accurate is it, in practice, for a given individual? I'm not that out of the ordinary proportion wise. I have a slightly longer torso and arms versus my legs, a somewhat muscular-ish baseline and broad shoulders, but I accumulate fat almost exclusively abdominally. My teenage self, lifetime peak of my fitness, no visible body fat, hyperactive football player, qualified as solidly overweight. If I was to listen to it, I'd be called obese before I noticeably start to show body fat.
I often wonder far from the median I am in this regard. I was under the impression that it was pretty accurate for assessing populations, but fell apart very quickly at the individual level. How many "normal"/otherwise healthy people do fall outside BMI's numbers?
Yeah BMI is sort of a 'good enough' technique but also has some very obvious areas that it can miss. If you fall outside the typical fat to muscle ratio is a good example.
A muscular person can be "overweight" by BMI standards but not overfat at all. This is the case for many types of athletes, specially in strength disciplines but not only. It is the case in the fitness world that people ignore BMI and are intesterested in body-fat-percentage instead. This is hard to measure accurately so not so useful metric for the general population.
It's also possible to be overfat without being overweight! These "skinny fat" people often look normal enough but they carry very little muscle. It is a concerning condition because a doctor might not recommend a normal-weight person to hit the weights.
I like to think of this as four quadrants around two axes. Low fat/low muscle is simply skinny. High fat/high muscle is the "big guy/gal" look that I associate with laborers. Low fat/high muscle is an athletic look; unhealthy in extremes (bodybuilding) but generally desirable. High fat/low muscle is skinny fat, which I associate with sedentary knowledge workers.
The dominant discrepancies are "expected" fat (boobs, etc), and "unexpected" muscle (cyclists, body builders, hard labour careers, etc). I'm currently around 10-15lb overfat and 40-50lb overweight [0]. Only the former statistic matters.
[0] And that, at least somewhat, tracks visual perceptions. Nobody looks at me with a shirt on and believes I need to lose weight, because 10-15lb isn't _that_ much extra on a tall frame. If I were 40-50lb overfat then that would be painfully obvious regardless.
Same for me, no one considers BMI to be a good indicator of anything, but it is better than nothing, and more importantly, it is super simple.
Any idiot with a bathroom scale and a measuring tape can do it. And by adulthood, height doesn't change significantly and you probably know it, so you may not even need that measuring tape. Other metrics need specialized equipment, error prone or complex procedures, etc... I don't even know how to make a waist measurement. Where exactly? How relaxed should the subject be? How long after eating?...
That's the value of BMI: simple repeatable. Not the best but enough to get and idea and make statistics.
> Studies have shown that visceral fat, which is fat that surrounds the internal organs in the abdominal area, is associated with chronic diseases like heart disease and diabetes, while subcutaneous fat, which is located directly under the skin, is not as strongly associated.
How does one determine if one has an excess of visceral fat?
whats wild is there are people who look very fat - who have lots of subcutaneous fat, who don't have visceral fat. The excessive subcutaneous fat can be hard on your joints but doesn't seem to correlate to other health issues.
For two people that are the same height, one could have X lbs of pure muscle, and one could have X lbs of pure fat, and they would have the same BMI. Color me shocked that it is not always a good predictor of disease.
Those who fart in short, loud bursts versus those who fart slowly versus those who don’t fart at all (they have mastered the sphincter to the point they can control a slow, steady, barely audible hiss that can be disguised by a concurrent stream of pee or nearby running faucet), are correlated with higher intelligence, believed to be related to how the gut flora FEASTS on bacteria.
The irony of BMI is that people with plenty of muscle mass are more likely to have a high BMI as well as lowered risk for heart disease.
BMI was never meant to be used as a diagnostic measure. BMI is just a rough filter for large data sets, and entirely dependent on the average height and habits of that population.
Anyone taller than about 6'3" could tell you the recommended weight according to their BMI has always been absurdly low. If it's a printed chart on the wall, they might not even be on it.
BMI is not a good metric for really short and really tall people.
The "ideal weight" of a person is proportional to height to an exponent somewhere between 2 and 3. Simple physics would say 3 but because tall people are not just scaled up copies of small people, it is closer to 2 in practice, maybe around 2.3, but we say 2 because it is easier to calculate.
The downside is that BMI overestimates the "ideal weight" for short people and underestimate it for tall people. But BMI is not great at capturing exceptions anyways, so there is little interest in "fixing" this.
This is a common misconception. BMI while an ok population metric, for individual's the biggest problem with is its poor sensitivity - it fails to classify people as obese who are obese.
Using your 6 3" male as an example, they are significantly more likely to be clinically obese (using waist circumference, body fat % etc) at a weight lower than BMI cut-off of 240 lbs.
Somehow American Heart Association and its European counterpart are in denial, and still pushing dinasour screening mechanism with very low accuracy for heart disease risk prediction.
The standard risk model for CVD based on PREVENT (US) and SCORE-2 (Europe) like parameters are very poor as reported in the recently published paper on the their accuracy performance by the Swedish team [1]. As all CVD risk stratification with cardiologist review (expert-in-the-loop), the most important accuracy metric is sensivity/recall (avoiding false negative that will escape review) of PREVENT and SCORE-2, 26% and 48%, respectively.
The paper alternative proposal increased the sensitivity to 58% by performing clustering instead of conventional regression models as practiced in the PREVENT and SCORE-2.
These type of models including the latest proposal performed very poorly as indicated by their otherwise excellent and intuitive display of graphical abstract results [1].
[1] Risk stratification for cardiovascular disease: a comparative analysis of cluster analysis and traditional prediction models:
https://academic.oup.com/eurjpc/advance-article/doi/10.1093/...
BMI is easily misunderstood by people who know just enough to see that it’s imperfect, but not enough to understand why it’s still a valuable screening tool.
I’ve been in the “overweight” BMI range with low body fat before. It’s not too hard to get there if you’re lifting weights and paying attention to your diet consistently for years, but it takes a lot of work to get there. It doesn’t happen accidentally except for people who win some genetic lottery to build a lot of muscle and keep body fat low without trying.
Getting all the way to the obese BMI range while having healthy body fat is only happening for people with an extreme dedication to body building and diet (and let’s be honest, a lot of the people in this category are manipulating hormones too).
Yet whenever BMI comes up some people try to dismiss it as too flawed based on these possible edge cases. The edge cases for BMI exist, but that doesn’t mean it’s not useful. It’s a good general purpose screening tool with numbers that are available. If someone has more precise measurements available, those should be used instead. BMI is a really good first pass screener to determine if a closer look should happen.
Many active gym people have pretty high BMIs but fairly low fat (because muscle is dense), and unsurprisingly have better outcomes than the average person (if you ignore the share that uses/overuses anabolic steroids and co)
I’ve been in the overweight BMI category with low body fat by being active at the gym and focusing on diet. It takes some work to get there.
If I check the calculators for the obese BMI range, there was no way I could get there without either gaining a lot of fat on top of the muscle. The amount of muscle required to have an obese BMI with healthy amount of fat is absurd.
E.g. 20% bodyfat at 250lbs is still a lot of fat.
Of course it's difficult to ever get very high on absolute fat if at 15% or below.
Additional muscle is positive for health, but only up to some reasonable threshold. There is no health benefit to having very high levels of muscle, and in fact it may be negative for your health at extreme levels. E.g. many bodybuilders have trouble breathing, sleep apnea etc.
Both people in the example have 60lbs of fat. 1lb of muscle doesn't cancel out the negative health effect of 1lb of fat
Taller people live shorter lives than short people on average.
Being 15% bodyfat at 300lbs is very unhealthy. The % does not say much about whether you have a healthy level of fat
I often wonder far from the median I am in this regard. I was under the impression that it was pretty accurate for assessing populations, but fell apart very quickly at the individual level. How many "normal"/otherwise healthy people do fall outside BMI's numbers?
The people most obsessed with "BMI isn't accurate" are overweight people making excuses for themselves.
I like to think of this as four quadrants around two axes. Low fat/low muscle is simply skinny. High fat/high muscle is the "big guy/gal" look that I associate with laborers. Low fat/high muscle is an athletic look; unhealthy in extremes (bodybuilding) but generally desirable. High fat/low muscle is skinny fat, which I associate with sedentary knowledge workers.
[0] And that, at least somewhat, tracks visual perceptions. Nobody looks at me with a shirt on and believes I need to lose weight, because 10-15lb isn't _that_ much extra on a tall frame. If I were 40-50lb overfat then that would be painfully obvious regardless.
Any idiot with a bathroom scale and a measuring tape can do it. And by adulthood, height doesn't change significantly and you probably know it, so you may not even need that measuring tape. Other metrics need specialized equipment, error prone or complex procedures, etc... I don't even know how to make a waist measurement. Where exactly? How relaxed should the subject be? How long after eating?...
That's the value of BMI: simple repeatable. Not the best but enough to get and idea and make statistics.
How does one determine if one has an excess of visceral fat?
BMI was never meant to be used as a diagnostic measure. BMI is just a rough filter for large data sets, and entirely dependent on the average height and habits of that population.
Anyone taller than about 6'3" could tell you the recommended weight according to their BMI has always been absurdly low. If it's a printed chart on the wall, they might not even be on it.
The "ideal weight" of a person is proportional to height to an exponent somewhere between 2 and 3. Simple physics would say 3 but because tall people are not just scaled up copies of small people, it is closer to 2 in practice, maybe around 2.3, but we say 2 because it is easier to calculate.
The downside is that BMI overestimates the "ideal weight" for short people and underestimate it for tall people. But BMI is not great at capturing exceptions anyways, so there is little interest in "fixing" this.
Using your 6 3" male as an example, they are significantly more likely to be clinically obese (using waist circumference, body fat % etc) at a weight lower than BMI cut-off of 240 lbs.