because i wrote a short internet comment, not a science article. I just linked to the article most prominently stating the 3rd correlation in the triangle of correlations between those 3 vertices - autism, vitamin D deficiency and brain size. For people who interested it is just a simple google to get more related articles, in particular stating all 3 together though in more diffuse way and/or bridged by the pruning. And simple google also would bring you the Sweden study.