In one of these studies performed in healthy adults at increased risk for T2D with low vitamin D status (≤55 nmol/l), only the subgroup of subjects with prediabetes had an advantage from daily cholecalciferol, administered at a dosage sufficient to target serum levels of 25(OH)D of >75 nmol/L in terms of increase in insulin sensitivity [82]. The gene discussed is INS; the disease is type 2 diabetes mellitus.