In this review we summarize recent opinions on the possible role of vitamin D in the risk of thyroid diseases development. It may be concluded from the available data that vitamin D deficiency, particularly levels below 12.5 ng/ml should be considered as an additional, but important risk factor for development of thyroid autoimmunity, both chronic autoimmune thyroiditis and Graves´ disease. A higher risk of Graves´ disease development is also associated with several polymorphisms in the gene encoding for vitamin D binding protein and for the specific receptor of active form of vitamin D - 1,25-(OH)2D3 in the respective target cells. Important for development of thyroid cancer appeared polymorphisms of genes encoding for vitamin D receptors and of genes encoding for the participating hydroxylating enzymes in thyroid tissue, leading to a diminished local 1,25-(OH)2D3 formation capacity with following alteration of antiproliferatory, antiapoptotic and prodifferentiating efficacy of the latter. Whether supplementation with high doses of vitamin D or its analogues possesses preventive or therapeutic effect is an object of intensive studies., K. Vondra, L. Stárka, R. Hampl., and Obsahuje bibliografii
In women with chronic autoimmune thyroiditis and vitamin D deficiency we have found reference levels of relevant metabolichormonal 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., K. Vondra, R. Bílek, P. Matucha, M. Salátová, M. Vosátková, L. Stárka, R. Hampl., and Obsahuje bibliografii