Demir etal.[30] found out that thelevel of vitamin D in patients with non-valvular AF was significantly lower than inpatients without AF and with valvular AF, and that parathyroid hormone (PTH) levelswere significantly higher in patients with non-valvular AF than in those without AF.This result suggested that hyperparathyroidism secondary to vitamin D deficiency mayplay a role in AF. Here, PTH is linked to vitamin D deficiency.