As someone when a poor sleep schedule, the inability it stick to a routine in this area tends to show up in every area… exercise, diet, etc.

I would imagine that someone with a very regimented life tends to stick to a lot of healthy habits. They aren’t going out to the bar every night, then waking up at 6am for their morning routine.

The article never says anything about causation. It says sleep regularity is a predictor of mortality. That means if you find someone who already has poor sleep regularity they're more likely to die sooner, not that if you force someone into a bad sleep schedule they will become more likely to die sooner.

>Couldn’t this effect be classic cause vs correlation?

Sometimes changing the correlated item, also affects the cause, through a link of causual changes.

E.g.: "Night visits to the fridge linked to high cholesterol".

Now, that's just correlation: it's not the visiting of the fridge, it's the snacking.

But if you read that and stop visiting the fridge, you likely reduce your snacking too as a side effect, and thus lower your cholesterol, without consciously trying to address the primary cause.

tfa: "Results were adjusted for age, sex, ethnicity, and sociodemographic, lifestyle, and health factors"

Or maybe if you are sick you don't sleep as well.

> Perhaps someone who has a consistent schedule is hypothetically more likely to make healthier choices on average

At least they aren’t shift workers