Though a single study doesn’t create a causal link anyways. When they write that, it contributes to the meme that a study can reveal causation rather than march the convergence of evidence towards causal inferences.

All studies investigate correlation and that’s okay. Though this discussion overshadows that study’s actual problems.

I wager it’s only on HN because its title is an excuse for everyone to hone their hobby horse opinion on sun exposure.

I mean, perhaps we don't need to say it because they say it explicitly.

Which makes me think that the title about "avoidance of sun exposure" is misleading, even if not deliberately so. "Avoidance" in the general lexicon usually means conscious choices to deliberately not expose yourself to something. Is someone who is, say, obese and bedridden "avoiding" sun exposure?

Sure. This is in every single study using surveys or statistics and yet everyone thinks the paper is making a casual argument. The paper itself actually does do that. So the whole limitations part is just ass covering for the fact that the authors are lying.

Why call it anything else. I mean it's like me writing a long paper proving that thermodynamics is flawed and then ending the paper with some acknowledgement that one of the key arguments has a logical flaw which renders the whole proof incorrect. So then the whole paper is worthless.

They do adjust the results for certain lifestyle factors, in particular exercise and smoking. They are just pointing out that they can't correct for all lifestyle factors.

Found a sun avoidance advocate.

You should look into Big Shade, quite shocking stuff.