Future studies should elucidate whether age-related IGF-1 deficiency is further exacerbated by age-related changes in vascular expression of IGF-1–binding proteins (BPs), IGF-1 receptors or alterations in signaling pathways activated by IGF-1 receptors and whether it increases atherosclerosis risk in men and women. This evidence concerns the gene IGF1 and hyperinsulinemic hypoglycemia, familial, 4.