These findings are consistent with evidence from observational studies that have demonstrated that low vitamin D levels influence risk of an increasing TPOAb level, and also in line with a very current case-control study which enrolled 200 euthyroid subjects: 100 newly diagnosed HT patients and 100 healthy individuals, matched for age, sex, and BMI, which aimed to investigate the association of HT with vitamin D status and SNPs of the vitamin D receptor (VDR). Here, VDR is linked to hematocrit.