Vitamin D Supplementation Changed Relationships, Not Levels of Metabolic-Hormonal Parameters in Autoimmune Thyroiditis

Abstract

In women with chronic autoimmune thyroiditis and vitamin D deficiency we have found reference levels of relevant metabolic-hormonal parameters except for parathormone and total calcium. Three months supplementation with vitamin D (4300 IU/day, cholekalciferol) did not lead to significant changes of investigated hormonal parameters, while the levels of parathormone and calcium reached normal levels. However, a correlation analysis revealed marked changes in mutual relations. First, an inverse correlation of vitamin D with parathormone, insulin secretion (C peptide, insulin) and its efficiency (HOMA IR) disappeared. Relationships of vitamin D to hepatic insulin resistance (insulin/C peptide), to DHEA (both negative), and to DHEAS/DHEA ratio (positive) were newly found. Second, a positive correlation of CRP with insulin secretion remained, while its relation to insulin efficiency (HOMA IR, insulin/ C peptide) was newly observed. Analogical positive correlations appeared also among anti TPO and insulinemia, insulin/C peptide, HOMA IR, and anti Tg to C peptide. A relationship of the CRP with anti TPO became significant (+). Third, out of glucose metabolism parameters only insulin/C peptide and glycemia did not correlate with vitamin D during its deficiency, while after supplementation insulin/ C peptide alone correlated positively with both DHEAS and DHEA, and negatively with vitamin D.

Vitamin D and Autoimmune Thyroid Disease—Cause, Consequence, or a Vicious Cycle?

“…This is a counterintuitive hypothesis, with some theoretical background but with little data to support or contradict it directly, as 1,25(OH) 2 D is rarely quantified. However, some of the above-mentioned studies on VitD supplementation reported elevated PTH and normal/slightly low calcium values, associated with a deficiency of 25(OH)D at baseline with a tendency towards normalization after VitD supplementation [41,91,95]. This does not support the possibility that there is an increase in 1,25(OH) 2 D in AITD concealed by the quantification of 25(OH)D. Although it may be argued that PTH level elevation and lowering of calcium levels may be explained by VDR dysfunction, it is unlikely that such alterations were susceptible to correction by VitD supplementation, as it would not correct the primary mechanism.…”

“…In patients with AITD, Vondra et al found a positive relationship between 25(OH)D levels and the fT4/fT3 ratio, which disappeared after supplementation with cholecalciferol. The authors speculated that the decreased ratio may be a compensatory adaptation to VitD deficiency [41].…”

“…Vondra K. et al 2017 [41] Non-randomized Thirty-seven women with AITD were supplemented with 4300 IU/day of cholecalciferol for 3 months.…”

“…Most recent results ( Table 2 ) support the benefit of supplementation in individuals with AITD, which is generally higher in the presence of a deficiency, both in HT [ 90 , 91 , 92 , 93 , 94 ] and in TPP [ 84 , 95 ]. Three of the studies mentioned below also analyzed PTH and calcium levels at baseline and after supplementation, showing some degree of tendency towards the normalization of high PTH and low calcium levels [ 41 , 91 , 95 ].…”

The Relationship Between Serum Vitamin D Levels and Thyroid Function Tests in Euthyroid and Hypothyroid Patients with Elevated Anti-TPO

“…Similarly, Krysiak et al 3,4 have determined that there is a favourable effect of vitamin D on thyroid autoimmunity. However, there are many studies that have reported that vitamin D treatment cannot improve thyroid function and autoimmunity associated with thyroid [21][22][23] . In a recently-reported study, it has been found that vitamin D levels are similar in patients with HT and the healthy control group 8 .…”