Objective: The aim of this paper is to review the evidence from studies that evaluated the relationship between vitamin D and endometriosis.
Design: Comprehensive review.
Materials and methods: Systematic literature search in Medline for relevant publications from 1946 until June 2013.
Results: Endometriosis risk may be influenced by dietary vitamin D intake and plasma hydroxyvitamin D concentration. Vitamin D receptor and vitamin D metabolizing enzymes, 24-hydroxylase and 1-α hydroxylase, are found in the normal cycling endometrium and also in the eutopic and ectopic endometrium of women with endometriosis. The endometrium is a target of 1, 25 dihydroxyvitamin D actions through regulation of specific genes and via immunomodulation. The endometrium in endometriosis expresses dysregulation of some vitamin D enzymes and receptors. If vitamin D and its metabolites are implicated in endometriosis-associated infertility, it is likely through interference with HOXA10 gene expression. The Gc2 phenotype of vitamin D binding protein is prevalent in women with endometriosis and may be implicated in its pathogenesis. In a mouse model, Elocalcitol, a VDR-agonist was shown to reduce the development of endometriotic lesions and recurrence.
Conclusion: A biological plausibility for a role of vitamin D, as an immunomodulator and anti-inflammatory agent, in the pathogenesis and treatment of endometriosis is suggested in this article, but is difficult to illustrate due to sparse evidence from human studies limited primarily to case-control studies. A significant knowledge gap precludes the establishment of a clear cause-effect relationship. The intriguing leads presented herein need to be investigated further with placebo-controlled supplementation trials.
Keywords: 1, 25 dihydroxyvitamin D; 1,25(OH)2D; 25-OHD; 25-hydroxyvitamin-D3; DBP; Elocalcitol; Endometrium; Gc; Gc-protein derived macrophage-activating factor; GcMAF; HOXA 10 gene; HOXA10; IBD; MMP; OPN; Osteopontin; VD; VD binding protein; VD responsive element; VDRE; Vitamin D binding protein; group-specific component; homeobox A10; inflammatory bowel disease; matrix metalloproteinase; vitamin D.