In the 12-month supplementation trial by Davidson et al. in 117 Latino and African American subjects in California with hypovitaminosis D3 (i.e., serum 25(OH)D3 concentration <30 ng/mL (75 nmol/L)), the average weekly dose of 88,865 IU (2,222 μg, or about 317 μg/day) of vitamin D3 had no effect on insulin secretion, insulin sensitivity, or development of type 2 diabetes, as compared with placebo [9]. This evidence concerns the gene INS and type 2 diabetes mellitus.