A case-control study on GDM mothers (n = 36) and controls (n = 37), found that maternal serum concentration of 25(OH)D was associated with IL-8 (r = 0.52, p = 0.020) and TNF-α (r = 0.48, p = 0.030) in a significant positive manner among GDM cases [31]. This evidence concerns the gene TNF and gestational diabetes.