[asdfasgasdgasdg]

People will be tempted to infer causation here, but it's important to note that no evidence of causation is presented. It is most likely that some third condition causes both poor sleep and amyloid-b accumulation (since correlation usually doesn't indicate causation).

[rendall]

"It is most likely that ..."

I agree with your main point and was going to write something like this. But "most likely" is likely unjustified. It could be a 3rd factor that causes both, but its likelihood is unknown.

[asdfasgasdgasdg]

https://www.gwern.net/Causality

Correlation usually does not indicate causation. I.e. more than 50% of the time, correlative relationships in studies do not indicate causal ones. Taking that as a prior, and lacking any evidence to the contrary, it is indeed correct to say "it is most likely that ...".

[rendall]

... fair point! I stand corrected!

[andrewjl]

Causation is often treated as a binary outcome in the popular press, more recent attempts at adding nuance to that via statistics aren't much better. Hard to come up with solutions or alternatives but speaking personally I felt humbled at my own paltry understanding when reading this[1] reference.

[1] https://global.oup.com/academic/product/the-oxford-handbook-...

[lostcolony]

Yeah, but that's true with all long term nutrition and lifestyle studies, since it's impossible to test for causation with any degree of rigor (I don't even know what a long term double blind study would look like).

So, yes, correlation does not imply causation; it does still imply correlation. Even if a third variable, if you're getting poor sleep, you're more likely to have higher Amyloid-β build up

[gameswithgo]

establishing causation is not impossible, just hard.

[lostcolony]

We take a preponderance of correlation as evidence, but we can't really provide rigorous proof. I mean, imagine what a double blind study to, say, 'prove' that smoking causes lung cancer would entail. The ethics of causing something we have reason to suspect is harmful to a population sample is ethically extremely problematic; hence, all we frequently have is correlative.

Even when it's something there isn't as big an ethical issue for it's usually not single blinded, let alone double. Diet, for instance; the groups know what they're eating. Did the differences happen because of the different diet, or because of something else (such as increased energy leading to more exercise, or the perception that they were eating 'healthy' lead to them actually becoming so, or picking up other healthy habits? Etc).

As I said, establishing causation -with any degree of rigor-, is basically impossible. Otherwise we're just left with "hey, a whole buncha correlative studies indicate this, so, maybe take it as true?"