On: Sleep regularity is a stronger predictor of mortal...

[nojs]

I think a “correlation is not causation” cautionary note is important here - there are a lot of things that cause fragmented sleep, and also cause death. Stress and underlying disease are two obvious ones.

[sahmeepee → nojs]

"Finally, we acknowledge the correlational nature of our findings. Sleep regularity may be both a cause and marker of premature mortality risk."