4 ms·

Sorry, but that's not what the results show: http://www.ncbi.nlm.nih.gov/pubmed/21121834 http://www.ncbi.nlm.nih.gov/pubmed/21121834 Body-mass index and mortal

Sorry, but that's not what the results show: http://www.ncbi.nlm.nih.gov/pubmed/21121834 http://www.ncbi.nlm.nih.gov/pubmed/21121834 Body-mass index and mortality among 1.46 million white adults. With a BMI of 22.5 to 24.9 as the reference category, hazard ratios among women were 1.47 (95 percent confidence interval [CI], 1.33 to 1.62) for a BMI of 15.0 to 18.4; 1.14 (95% CI, 1.07 to 1.22) for a BMI of 18.5 to 19.9; 1.00 (95% CI, 0.96 to 1.04) for a BMI of 20.0 to 22.4; 1.13 (95% CI, 1.09 to 1.17) for a BMI of 25.0 to 29.9; 1.44 (95% CI, 1.38 to 1.50) for a BMI of 30.0 to 34.9; 1.88 (95% CI, 1.77 to 2.00) for a BMI of 35.0 to 39.9; and 2.51 (95% CI, 2.30 to 2.73) for a BMI of 40.0 to 49.9. In general, the hazard ratios for the men were similar. And the conclusion: In white adults, overweight and obesity (and possibly underweight) are associated with increased all-cause mortality. All-cause mortality is generally lowest with a BMI of 20.0 to 24.9.

nkozyra 11y ago
This is going to shock you, but there are a great many studies on this, not all of which come to the same conclusion. From a meta-analysis: Relative to normal weight, both obesity (all grades) and grades 2 and 3 obesity were associated with significantly higher all-cause mortality. Grade 1 obesity overall was not associated with higher mortality, and overweight was associated with significantly lower all-cause mortality. The use of predefined standard BMI groupings can facilitate between-study comparisons. http://www.ncbi.nlm.nih.gov/pubmed/23280227 http://www.ncbi.nlm.nih.gov/pubmed/23280227
- ucaetano 11y ago
  This is going to shock you, but I guess you didn't read the Harvard link addressing that specific study that I posted on my first post. But here it goes: http://www.hsph.harvard.edu/nutritionsource/questions/ask-the-expert-does-being-overweight-really-decrease-mortality-no/ http://www.hsph.harvard.edu/nutritionsource/questions/ask-th... Shocking, right?
  - nkozyra 11y ago
    I've read this in the past, yes. The initial study you posted suffers from the same complaint. Which is not shocking given that the JAMA results are a meta-analysis (which include your study).
  - dang 11y ago
    Please don't use "I guess you didn't read" as a rhetorical device. That sort of point-scoring only makes comments more abrasive and doesn't add information. https://news.ycombinator.com/newsguidelines.html https://news.ycombinator.com/newsguidelines.html
    - ucaetano 11y ago
      My apologies, I got carried away by the "this is going to shock you" :)
    - Yakimoto 11y ago
      Good job PC Principle. Keep posting trigger warnings.
CuriouslyC 11y ago
BMI is such a stupid, useless metric. I can basically guarantee that the low BMI cohort in this study had significantly reduced lean body mass (skinny-fat), which greatly predisposes you to injury by things like falls and what not as you age. Being lean is healthy, being frail is not.
- omginternets 11y ago
  >BMI is such a stupid, useless metric. Yes, but it makes it trivial to get a good p-value, so people use it. The state of nutritional epidemiology is abysmal, and has been for much longer than that of social psych. The thing is, we have better measures than BMI, many of which are dead simple (e.g. % body fat as measured by calipers, or waist measurement). I also wish nutritional epidemiologists would stop using linear models all the time -- it's well known that mortality curves are U-shaped, as excessively thin people have high rates of all-cause mortality. Returning to your original point, I'm 6'3" and 220 lbs. I have 12% body fat. Somehow this makes me fat, according to BMI.
  - vonmoltke 11y ago
    BMI also seems to have the problem that it correlations are ethnically-dependent. The big outlier are East Asians, who tend to start having obesity-related issues in the upper end of "normal" and have less issues in the upper end of "underweight". Those categorizations were based on statistical studies of Europeans.
  - deleted 11y ago
    [deleted]

nkozyra 11y ago

This is going to shock you, but there are a great many studies on this, not all of which come to the same conclusion. From a meta-analysis: Relative to normal weight, both obesity (all grades) and grades 2 and 3 obesity were associated with significantly higher all-cause mortality. Grade 1 obesity overall was not associated with higher mortality, and overweight was associated with significantly lower all-cause mortality. The use of predefined standard BMI groupings can facilitate between-study comparisons. http://www.ncbi.nlm.nih.gov/pubmed/23280227 http://www.ncbi.nlm.nih.gov/pubmed/23280227

ucaetano 11y ago
This is going to shock you, but I guess you didn't read the Harvard link addressing that specific study that I posted on my first post. But here it goes: http://www.hsph.harvard.edu/nutritionsource/questions/ask-the-expert-does-being-overweight-really-decrease-mortality-no/ http://www.hsph.harvard.edu/nutritionsource/questions/ask-th... Shocking, right?
- nkozyra 11y ago
  I've read this in the past, yes. The initial study you posted suffers from the same complaint. Which is not shocking given that the JAMA results are a meta-analysis (which include your study).
- dang 11y ago
  Please don't use "I guess you didn't read" as a rhetorical device. That sort of point-scoring only makes comments more abrasive and doesn't add information. https://news.ycombinator.com/newsguidelines.html https://news.ycombinator.com/newsguidelines.html
  - ucaetano 11y ago
    My apologies, I got carried away by the "this is going to shock you" :)
  - Yakimoto 11y ago
    Good job PC Principle. Keep posting trigger warnings.

CuriouslyC 11y ago

BMI is such a stupid, useless metric. I can basically guarantee that the low BMI cohort in this study had significantly reduced lean body mass (skinny-fat), which greatly predisposes you to injury by things like falls and what not as you age. Being lean is healthy, being frail is not.

omginternets 11y ago
>BMI is such a stupid, useless metric. Yes, but it makes it trivial to get a good p-value, so people use it. The state of nutritional epidemiology is abysmal, and has been for much longer than that of social psych. The thing is, we have better measures than BMI, many of which are dead simple (e.g. % body fat as measured by calipers, or waist measurement). I also wish nutritional epidemiologists would stop using linear models all the time -- it's well known that mortality curves are U-shaped, as excessively thin people have high rates of all-cause mortality. Returning to your original point, I'm 6'3" and 220 lbs. I have 12% body fat. Somehow this makes me fat, according to BMI.
- vonmoltke 11y ago
  BMI also seems to have the problem that it correlations are ethnically-dependent. The big outlier are East Asians, who tend to start having obesity-related issues in the upper end of "normal" and have less issues in the upper end of "underweight". Those categorizations were based on statistical studies of Europeans.
- deleted 11y ago
  [deleted]