[shakil]

Here we go again confusing correlation with causation. The medical field is mired with these: eat less to lose weight, reduce cholesterol to prevent heart attacks, reduce stress to prevent stomach ulcers ...

Have they considered people prone to dementia just aren't able to get quality sleep, and both of these are due to some other underlying cause where fixing one doesn't really fix the other?

[rzmmm]

This kind of prospective study is not perfect but it's what is possible for this type of risk factor and disease. Researchers can't create an RCT study with blinded deep sleep intervention group with placebo and then after 17 years see which got less dementia. The authors avoid the C-word on purpose but it's implied that this kind of study brings more evidence than just association.

[gopher2000]

The article is literally titled "Association Between Slow-Wave Sleep Loss and Incident Dementia". Association is not causation.