S100G and vitamin D deficiency: Additionally, Dennis et al. (2020) [26]showed that baseline vitamin D deficiency (25-OH-vitamin D < 20 ng/mL) significantly impaired intestinal calcium absorption and renal calcium reabsorption via downregulation of calbindin-D9k, increasing the risk of hypocalcemia during bone-modifying therapy (OR, 2.546; P = 0.023).