The investigators7 previously showed that mild hepatic dysfunction in patients with T2D was associated with a high prevalence (47.5%) of vitamin D deficiency as defined by 25(OH)D level of < 20 ng/mL, as well as poor glycemic control. The investigators further reported a significant inverse relationship between HbA1c and 25(OH)D, and also between 25(OH)D and alanine transaminase. These data suggest that mild hepatic dysfunction could impair vitamin D metabolism and negatively impact glycemic control in patients with T2D. The investigators have also accumulated data 8 to show that 25(OH)D supplementation was associated with a significant reduction in HbA1c in T2D without a significant change in insulin or metformin dose. Histologically, a recent animal study reported significant hepatic steatosis in vitamin D-deficient mice compared to vitamin D-sufficient mice 2.