Opinion : Smart people live longer

A study described in this article claims that people who are "medically illiterate" die faster (see study for more technical description). I tend to question whether "medically illiterate" couldn't just be replaced by the more genaralized "ignorant". I realize there is something to be said for following directions, and I realize that people who don't understand physicians may be good at understanding other things, but I think that in some of these academic studies, scientists miss the big picture.
A good example was a study at a brain aging conference last year where a researcher reported that people with higher mental abilities (which he measured by level of education attained) had less rapid brain deterioration over time. The scientist indulged some theory about "reserve" which he could neither measure of explain. Let me propose a more obvious theory (but alas, one that will not win any grant money): Smarter people do less stupid things. "Stupid things" in this case are actions which cause brain damage. Unfortunately, I cant find any study that shows that PhD's get into less bar fights or are less likely to be professional boxers, but the anecdotal evidence is there....
Back to the study on medical literacy, I can't think of how they could have separated the effect of not understanding medical directions vs the effect of not understanding other directions in life. If a patient doesn't understand "take twice a day", do they understand "use by 7/23"? Not taking antibiotics for a GI infection and eating spoiled food will have the same effect. The fact is that ignorant people frequently make choices that shorten their life compared to their peers. This is as clear today as it was to social darwinists in past centuries. We need to fix the problem through better education, and also by identifying who the susceptible people are and treating them differently. The different treatment must be in the benevolent sense however, otherwise the identification will lead to unfair discrimination.