IGF1 and type 1 diabetes mellitus: This is the first study, to the best of our knowledge, to investigate differential associations between polymorphisms mapped to vitamin D metabolism genes that have been known to associate with risk of type 1 diabetes (CYP2R1, DHCR7, and CYP27B1) (4) on early anthropometry (weight, length, and skinfold thickness) or blood levels of growth-related hormones (C-peptide, IGF-1, and leptin) in a general population-based cohort of infants.