An interesting study. They claim that self-reported chronotype has been taken into account - but I have to wonder as to how they did that. At a minimum, they could have broken out a multivariate of chronotype, sleep duration, and CVD events. I didn't see anything like that.

Also, this study shows multi-year CVD risk, but studies sleep patterns for a week. This assumes that a person's sleep pattern is ever-unchanging, which I'd question, particularly for owl-types who retire and so no longer need to wake up to satisfy our lark-centric society.