VDR and colorectal cancer: While latitude and consequent UVB intensity influences vitamin D production in the skin [17], a major determinant of vitamin D status is believed to be skin melanin concentration [18]; with individuals with the darker skin type, VI, having notably less vitamin D than those with white skin type I. Similar to VDR variants being associated with disease, vitamin D deficiency have been associated with a higher incidence of TB [19], [20], colorectal cancer [21], [22], [23], cardiovascular disease and SLE [24].