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Comment by eightfourteen | Hacker News Reader

BMI is a tool for doctors to use, along with clinical judgement. No doctor is going to look at a lean, well muscled individual and tell them they're at risk for heart disease because their BMI is high.

BMI is something that fails in theory and works in practice.

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I thought it was a tool for measuring large populations where the lean, well muscled outlier is heavily outnumbered/balanced out by their opposites. Either way though I agree that it's silly for individuals to try to apply it to themselves and then shit on the concept because it doesn't work like that.

That's correct. On a population basis BMI is useful, on an individual basis there's too much variation for it to be useful as more then a very loose guideline.

when you record someone's BMI and it gets thrown in a spreadsheet as patient 123456 has BMI 23.5 the doctor is no longer looking at the patient. perhaps it's good enough, i don't claim to be able to evaluate the methodology of the study (and perhaps using BMI simply results in more skeptical results, by leaving healthy people out of the low risk group, which I'm fine with - not sure this is true though). it really was an incidental note on my part, but i stand by it. i am a little surprised at how much we're talking about it, i guess it is bikeshedding, which is understandable, im not qualified to comment with authority on much of the material myself :)

They also record your blood-pressure measurements on the chart. If you've got a mildly high BMI and fine blood-pressure, they know you're actually ok.

See this reply downthread: https://news.ycombinator.com/item?id=12041053

The parent was saying BMI is not a good diagnostic tool for individuals, and it was good for populations.

You're not addressing that point. You're saying that populations don't consider people individually. Which is true.

But you haven't made an argument against the use of population wide BMI, which is the only case it's generally accepted as being valid for.

(I agree it's over recommended as a individual measure, or overrecommended without caveats. E.g. BMI + waistline, or BMI + strength test.)

https://news.ycombinator.com/item?id=12040933

"No person" is a rather extreme position.

Turns out some doctors are idiots, or frauds, or incompetent.

Turns out some just follow the protocol they're told to follow, even if they laugh at it (as in the link above, from this thread).

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