IGF1 and glioblastoma: Genetically predicted circulating levels of carnitine/selenium/zinc/25-hydroxyvitamin-D/carotenoids/fetuin-A/plasma IGF-1/vitamins (A1, B12, and E), height, iron status, and circulating levels of monounsaturated/omega-3/omega-6 fatty acids showed no evidence for association with risk of all glioma, GBM or non-GBM (Fig. 2–4).