And then - as one of the possible explanations behind the correlation - they speculate that "optimistic people might be more motivated to try to maintain good h

And then - as one of the possible explanations behind the correlation - they speculate that "optimistic people might be more motivated to try to maintain good health — such as maintaining a decent diet, engaging in regular exercise and not smoking". Surely this would have been controlled for already, as maintaining diet and exercising falls under the category of "health behaviors"? This is self-contradictory