Why would openness to experience be the least predictive of the Big Five personality dimensions when it comes to physical health?

A good answer would include the following key points:
-By its very nature, openness to experience is the least well defined and most amorphous of the Big Five personality dimensions.
-As such, its ability to predict a variety of attitudes and behaviors is tenuous at times.
-Strong predictions for health outcomes, therefore, would be unlikely.
-Some facets of openness to experience, such as creativity, are associated with longevity.
-Other facets, such as exploring new ideas, may lead a person toward dubious medical treatments or idiosyncratic lifestyle choices that either hold no health benefits or may actually be harmful.