This line of evidence prompted us to investigate if the vitamin D metabolism milieu modifies inherent risk of type 1 diabetes via effects on growth and related hormones, namely C-peptide, used as a proxy for insulin; IGF-1, found predominantly conjugated with IGF binding protein-3 (IGFBP-3) from which it is liberated to bind to the IGF-1 receptor and promote linear growth (19); and leptin, which is a cytokine-like hormone produced in adipose tissue. This evidence concerns the gene INS and type 1 diabetes mellitus.