Postoperative PTH levels in patients with severe vitamin D deficiency (16.5 ± 2.9 pg/mL) were significantly lower than those in patients with vitamin D deficiency (31.2 ± 4.7 pg/mL), vitamin D insufficiency (36.7 ± 4.5 pg/mL) and vitamin D sufficiency (36.9 ± 4.1 pg/mL). This evidence concerns the gene PTH and vitamin D deficiency.