Correlation ≠ causation. I would assume that people with underlying health conditions sleep less/worse on average. Some of those health conditions could in some cases cause cancer and in others some could be cancer. Now let me actually read the article and see if they took account of this.

Edit: It has a bunch of caveats at the end quoting someone saying things like i did but with some actually expertise, e.g.

“So if your immune system takes a bit of a hit, then I suppose it would make sense that your risk of some cancers may increase. But it also might be the other way around. It could be that if you have cancer, and it’s not yet clinically obvious, it could be causing some change in how you sleep.”

So don’t stay up at night more worring that doing so is causing cancer. There’s every chance it isn’t and there are just a few unlucky people that are creating the association, because they have some form already.

This is 14 days old. Why post it now? I think most people interested will already know.