Health Nerd

I'm 22 which is only around 15 years off.

I'll let you guess whether they've under or overestimated 😉

But even if the underlying units were always divisible by 4, would this result in units that are divisible by 4 for means with different sample sizes?

Yeh I can't think of anything plausible

I should probably clarify - unless there's a reasonable biochemical explanation for this, it is...extremely odd.

I am not familiar enough with calcium scores to know if this is weird.

Is there any biochemical reason that all of these means/SDs would end in even numbers?

I don't think it's clickbait. It's a catchy headline that is both true, usefully informative, and references one of my favourite podcasts.

There's No Such Thing As A Vitamin D Deficiency - Part One The complex science about vitamin D levels and what they mean

My new piece looks at the science about low vitamin D levels and why the US Endocrine Society no longer uses the term "deficiency" at all.

gidmk.substack.com/p/theres-no-...

It's quite remarkable watching the very minimal respect I had for Vinay entirely disappear.

Influencers made millions pushing ‘wild’ births – now the Free Birth Society is linked to baby deaths around the world A year-long investigation reveals how mothers lost children after being radicalised by uplifting podcast tales of births without midwives or doctors

The Guardian investigation into freebirthing is one of the most horrifying things I've read in a long time.

Just awful. So many preventable deaths.

www.theguardian.com/world/ng-int...

One of the biggest reasons is also meta-analyses. One study can have an outsized impact on the literature if it has a low SE and therefore a big effect size, which ends up polluting all recommendations from that point on.

I found a partial explanation, but from my understanding you can't possibly randomize a 3:2 study with block sizes of 4

bsky.app/profile/gidm...

Ok, I have partially solved the problem! The authors ran an imbalanced 3:2 randomization.

But, uh, how? Can you randomize 3:2 with blocks of 4?

Nope the study specifies that this was the allocation before dropout.

They said permutated, which implies that they are balanced but I suppose they could've done something really odd whereby each block could be entirely made up of one group. But that seems deeply bizarre. They would've had to have 5 full blocks allocating to only 1 group!

I've come across a trial which randomized in blocks of 4 but had baseline allocations of 54 vs 35.

This does not seem possible to me. Am I missing something?

I would guess that most peer reviewers, particularly in 2009, never check pre-registrations and are so not aware that researchers have switched their outcomes.

There are also lots of other errors in the paper, but honestly who cares that much.

And this isn't some nothing of a study. Here it is being cited in the Endocrine Society guidelines which currently recommend vitamin D supplements for children to reduce the risk of respiratory disease.

There were 18/167 Influenza A infections in the intervention and 31/167 in the control. There were 39/167 influenza B infections in intervention and 28/167 in the control.

Overall lab-confirmed influenza was 57/167 vs 59/167. About as null an effect as you can imagine.

Problem is, the researchers didn't pre-register influenza A as their outcome. They registered doctor-diagnosed influenza, and didn't specify the type.

Is that important? Well...

Randomized trial of vitamin D supplementation to prevent seasonal influenza A in schoolchildren Background: To our knowledge, no rigorously designed clinical trials have evaluated the relation between vitamin D and physician-diagnosed seasonal in…

The paper is here: www.sciencedirect.com/science/arti...

It's in pretty much every SR/MA on the topic. Japanese researchers randomized 430 kids to either get vitamin D or a placebo in 2008. There was a massive reduction in influenza A infections in the intervention group.

The stuff you find when you actually read the RCTs in a systematic review...

This paper is one of the foundational studies on vitamin D to prevent respiratory infections in kids. Cited 1,400 times as per Google Scholar.

Ok, two main things I noticed:

1. Most of the p-values are wrong.
2. The all means of Ct values are not the weighted means of the two groups in many cases even with potential rounding.

The averages are actually correct as far as I can tell! They're just row averages for some bizarre reason.

The ct averages though...are they even simple averages?

This is the sort of critique that makes sense, but it's not an ~error~ as such. Think more mathematical mistakes and the like.

Scientific error-checking, difficulty: easy

Find some issues in this table of results from an RCT of vitamin D for COVID-19. There's a couple of obvious issues, and some that are less easy to spot.

No one got the main thing, which is that the menopause durations are both remarkably homogenous (pretty much everyone in this study hit menopause at age 49-51), impossible (they are all GRIM errors), and also impossible (SDs are too low given the range)

Yes, the menopause regularity is...remarkable. It's not quite proof of anything, but it is to my understanding very unusual!

The 2 d.p. is an average. I would say that these values are odd, because they do imply that the data was COLLECTED in non-integer form, but that's also not quite an issue.

Reporting to 2 d.p. for means is not suspicious - certainly the vitamin D values are possible.

But tell me more about menopause onset. Are these timelines believable?

Scientific error-checking, difficulty: easy

Find the problems in this table of results from an RCT. Two main things I've noticed so far.

Every time I think that the story of vitamin D supplementation can't get any more ridiculous, it somehow does.

The most used pill in the world and we know it's probably a waste of time for most people.