INS and type 2 diabetes mellitus: The earlier demonstration that supplementation with 4000 IU/d vitamin D3 for six months in vitamin D deficient but normoglycemic south Asian women to 25(OH)D values of 32 ng/mL or above reduced insulin resistance to normal supports this view [99], as do the reduced T2DM rates seen with high achieved 25(O)D levels in the D2d study [35].