• Soleos@lemmy.world
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    7 months ago

    I was talking about how widespread BMI is used in health sciences, I.e. everything from basic physiology to clinical trials to program evaluation to epidemiology. This is different from medical practice, e.g. family doctor taking your BMI. Whether it makes for good science or not, it’s use makes it part of science and replacing outdated tools is part of the broader scientific process–that doesn’t make the tools “not science”.

    You’re asking about “accuracy” which is a good question, as well as “precision”. However in health sciences we usually evaluate such measures more thoroughly with similar concepts of validity (construct and discriminant) and reliability; you’ll also see sensitivity in the literature but it’s a kind of discriminant validity.

    So if you do your own search using “BMI” and these terms on PubMed or even Google Scholar, you will find a range or scientific evidence. Most will say BMI is not good but not terrible, even good in some specific contexts. You will also find lots of evidence of how BMI is associated with other health indicators and health outcomes. I’m not going to spend an hour collating this for you. “Review” is also a useful search term. You seem smart enough to do it if you really want it. In any case, the argument is moot because we agree BMI should be replaced.

    Edit: okay I was curious comparing BMI to WtHR and actually found a couple cherry-picked examples that might be interesting for you

    https://www.mdpi.com/2072-6643/8/8/512

    https://www.sciencedirect.com/science/article/pii/S2405457723021642

    https://pubmed.ncbi.nlm.nih.gov/23775352/

    • TempermentalAnomaly@lemmy.world
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      7 months ago

      I appreciate the systematic review and meta-analysis. It’s a good starting statement and if I worked with children, I would look at the paper more closely. As a whole, these studies don’t address the most at risk groups with a high level of evidence. Perhaps that last paper will be part of a meta-analysis that gives clearer evidence of BMI indicating CVD in children. This would be great.

      I focus on medical practices because it’s my area of expertise and where I do my work. So I see the negative effects of people’s conceptions around weight, BMI, obesity, and how difficult it is to change even with the best applied efforts. I wrote my initial response when I saw an avalanche of self-righteous, care trolling with vague allusion to science and medicine with a level of certainty that isn’t warranted. At best, I was being confrontationally polemical, at worst, I lack nuance or sensitivity to work in the field.

      The ease at which people fat shame and delude themselves that they are helping is astounding. I was a little surprised to see it on Lemmy.

      Admittedly, my statistical training isn’t the best, but I appreciate the role it plays in making sense of large datasets. Still, I appreciate the reminder to dive deeper into how statistics are used in observational studies. For me, at least, I wish that much of this was done before the wide deployment of BMI in the populous. I’m not saying that fat-shaming wouldn’t continue, but there doesn’t need to be poorly applied scientific ammunition either.

      PS. You might like this study that examined some of the boundaries for BMI.