I wasn't going to respond to this until I noticed it is tagged under livelonger.

The study discussed doesn't show causation at all, simply correlation. In fact, it doesn't really tell us anything we didn't already know about education.

The only real thing to note from the study was the lowering of rates of all diseases as people got a ninth year of education in Sweden. However, considering the sample size of only one country, and a lack of other comparable international studies, we can't make much of that 8-9 year education barrier. Even the reasoning proposed by the head researcher of the study seemed pretty sketchy; he "speculates that the ninth year helped students develop a different attitude about themselves." A Stanford professor claims "the additional year contributed to the students' long-term ability to understand health messages, think effectively and manage their lives", which sounds better, but is very vague and without much evidence.

What I'm trying to get at, is that studying more doesn't necessarily help you to live any longer. The study only concluded that people who are more well educated tend to have lifestyles that are healthier because they have better jobs, thus leading to them being more healthy. Something that is fairly intuitive.