Not to be the correlation/causation asshole, but I wonder if possibly low vitamin D is to some extent a proxy for being a low income sedentary shut-in, all thin

Not to be the correlation/causation asshole, but I wonder if possibly low vitamin D is to some extent a proxy for being a low income sedentary shut-in, all things that on their own are tied to disease. As the article points out Vitamin D supplementation is not very effective vice working up a tan a couple times a year. So in modern America we can surmise the individual with low vitamin D levels is someone who sits inside watching TV all year. And can't afford a winter vacation to somewhere sunny. Is the problem low vitamin D, or is it being sedentary inside all year? It's probably actually the vitamin D.