While our present study was in progress, a study using the Mendelian randomization approach showed that a combined gene score of 25(OH)D genes involved in synthesis (DHCR7 rs12785878) and metabolism (CYP2R1 rs10741657) was associated with an increased risk for T2D in European and Chinese adults [31]. This evidence concerns the gene CYP2R1 and type 2 diabetes mellitus.