Comments on: The no supplementation group was associated with 14.3 times the risk of death compared to those who regularly supplemented with vitamin D https://www.isegoria.net/2021/01/the-no-supplementation-group-was-associated-with-14-3-times-the-risk-of-death-compared-to-those-who-regularly-supplemented-with-vitamin-d/ From the ancient Greek for equality in freedom of speech; an eclectic mix of thoughts, large and small Mon, 20 Jul 2026 21:23:17 +0000 hourly 1 http://wordpress.org/?v=3.6.1 By: Gwern https://www.isegoria.net/2021/01/the-no-supplementation-group-was-associated-with-14-3-times-the-risk-of-death-compared-to-those-who-regularly-supplemented-with-vitamin-d/comment-page-1/#comment-3353093 Gwern Mon, 01 Feb 2021 01:28:50 +0000 https://www.isegoria.net/?p=47554#comment-3353093 An HR of >14 or >33 is all you need to know that it’s massively confounded. Has anything at all been established to work on coronavirus that well? That magnitude of silver bullets almost never actually exists in the real world. (For comparison, smoking and lung cancer has a HR <30. I'm not sure you would get a HR of 33 for vitamin D and even rickets!) Sometimes people argue that "these correlates are *so* large that they must reflect at least *some* causation", but they are a huge red flag: if the hidden and unmeasurable biases and confounding are so bad that, despite your best efforts, they can inflate the HR by 10+ from what is plausible, why can't they happen to inflate it by another 4 or so? (Similar to Feynman's observation about the Space Shuttle o-rings.)

Incidentally, Attia does not mention the later larger vitamin D RCT https://www.medrxiv.org/content/10.1101/2020.11.16.20232397v1 which turns in HRs closer to 1.

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