Vitamin D and calcium dysregulation in the polycystic ovarian syndrome

Vitamin D and its role in gynecology: emerging importance of checking vitamin D status in certain gynecological entities

Among non-bone effects of vitamin D, the three main chronological stages in gynecology ‒ menarche, reproductive stage and menopause/postmenopause - are possibly impacted by vitamin D deficiency. A large amount of emerging data show that vitamin D is a confounding factor in these parameters. Gynecology stays at the crossroads with endocrinology and, in the light of the rising knowledge about the involvement of vitamin D in many gynecological disorders, it is worth to investigate the exact role of vitamin D in this area. Especially since vitamin D is easy to substitute in case of deficiency. Authors present some emerging data on the role of vitamin D in gynecology, suggesting when it is necessary to check vitamin D status to intervene with vitamin D supplementation and raising gynecologists' awareness of the need for further clinical studies.

Effect of Vitamin D3 on Chemerin and Adiponectin Levels in Uterus of Polycystic Ovary Syndrome Rats

BACKGROUND

Polycystic ovary syndrome (PCOS) is an endocrine disorder with disrupted uterus structure and function. A positive effect of vitamin D3 (VD3) in female reproduction was observed. Chemerin (RARRES2) and adiponectin (ADIPOQ) are the main adipokines whose levels are altered in PCOS patients. Therefore, the aim of this study was to investigate the impact of VD3 supplementation on RARRES2 and ADIPOQ levels in the uterus of PCOS rats.

METHODS

We analyzed the plasma levels and uterine transcript and protein expression of RARRES2 and ADIPOQ and their receptors (CCRL2, CMKLR1, GPR1, and ADIPOR1 and ADIPOR2, respectively) in rats with letrozole-induced PCOS.

RESULTS

In control animals, VD3 did not change plasma levels of both adipokines, while in PCOS rats supplemented with VD3, they returned to control levels. The expression of RARRES2 and all investigated receptors increased in the uterus of VD3-treated rats; however, the levels of Rarres2 and Gpr1 genes remained unchanged. VD3 supplementation decreased RARRES2, CMKLR1, and GPR1 but increased CCRL2 level to the control value. In the uterus of VD3-treated rats, the transcript and protein levels of ADIPOQ and both receptors ADIPOR1 increased. At the same time, VD3 supplementation induced an increase in Adipoq, Adipor1, and Adipor2 gene expression and restored protein levels to control level values.

CONCLUSIONS

our findings indicate a new mechanism of VD3 action in the uterine physiology of PCOS rats.

Heat Stress Altered the Vaginal Microbiome and Metabolome in Rabbits

Heat stress can have an impact on parental gamete maturation and reproduction functions. According to current research, the microbial composition of the vaginal cavity is species specific. Pregnancy, menstruation, and genital diseases have been linked to the dynamics of vaginal ecology. In this study, we characterized the vaginal microbiota and metabolites after heat stress. At the phylum level, the rabbit’s vaginal microbial composition of rabbit showed high similarity with that of humans. In the Heat group, the relative abundance of the dominant microbiota Actinobacteria, Bacteroidetes, and Proteobacteria increased, while the relative abundance of Firmicutes decreased. Furthermore, heat stress significantly increased the relative abundance of W5053, Helcococcus, Thiopseudomonas, ldiomaarina, atopostipes, and facklamia, whereas the relative abundance of 12 genera significantly decreased, including Streptococcus, UCG-005, Alistipes, [Eubacterium]_xylanophilum_group, Comamonas, RB41, Fastidiosipila, Intestinimonas, Arthrobacter, Lactobacillus, Leucobacter, and Family_xlll_AD3011_group. Besides, the relative concentrations of 158 metabolites differed significantly between the Heat and Control groups. Among them, the endocrine hormone estradiol (E₂) increased in the Heat group and was positively associated with a number of metabolites such as linolelaidic acid (C18:2N6T), N-acetylsphingosine, N-oleoyl glycine, trans-petroselinic acid, syringic acid, 2-(1-adamantyl)-1-morpholinoethan-1-one, 5-OxoETE, and 16-heptadecyne-1,2,4-triol. Further, the majority of the differential metabolites were enriched in steroid biosynthesis and endocrine and other factor-regulated calcium reabsorption pathways, reflecting that heat stress may affect calcium metabolism, hormone-induced signaling, and endocrine balance of vaginal ecology. These findings provide a comprehensive depiction of rabbit vaginal ecology and reveal the effects of heat stress on the vagina via the analysis of vaginal microbiome and metabolome, which may provide a new thought for low female fertility under heat stress.

Major Nutritional Metabolic Alterations Influencing the Reproductive System of Postpartum Dairy Cows

Early successful conception of postpartum dairy cows is crucial in determining the optimum reproductive efficiency and profitability in modern dairy farming. Due to the inherent high production potential of modern dairy cows, the extra stress burden of peri-parturient events, and associated endocrine and metabolic changes causes negative energy balance (NEBAL) in postpartum cows. The occurrence of NEBAL is associated with excessive fat mobilization in the form of non-esterified fatty acids (NEFAs). The phenomenon of NEFA mobilization furthers with occurrence of ketosis and fatty liver in postpartum dairy cows. High NEFAs and ketones are negatively associated with health and reproductive processes. An additional burden of hypocalcemia, ruminal acidosis, and high protein metabolism in postpartum cows presents further consequences for health and reproductive performance of postpartum dairy cows. This review intends to comprehend these major nutritional metabolic alterations, their mechanisms of influence on the reproduction process, and relevant mitigation strategies.

Oral Vitamin D supplementation impacts gene expression in granulosa cells in women undergoing IVF

STUDY QUESTION

Does oral Vitamin D supplementation alter the hormonal milieu of follicular fluid (FF) and the transcriptomic profile of luteinised granulosa cells (GCs) in women with Vitamin D deficiency undergoing IVF?

SUMMARY ANSWER

A transcriptomic signature relevant to oral Vitamin D supplementation in luteinised GCs was demonstrated, although Vitamin D supplementation did not alter hormone levels in FF.

WHAT IS KNOWN ALREADY

Vitamin D deficiency is linked to lower live birth rates among women undergoing IVF. It is unclear whether Vitamin D elicits a targeted action in reproductive physiology or is a surrogate marker of overall well-being. Several in-vitro studies, but none in vivo, have examined the impact of Vitamin D on the periovulatory follicle, focusing on GCs as a proxy marker of oocyte competence.

STUDY DESIGN, SIZE, DURATION

We present a report of secondary outcomes from the SUNDRO clinical trial, which was launched in 2016 to determine whether Vitamin D supplementation can improve the IVF outcomes of women who are deficient in Vitamin D (<30 ng/ml). FF samples of 145 women who were randomised to receive Vitamin D or placebo from March 2017 to January 2019 were collected. All follicles that were aspirated in our study measured ≥11 mm on the day of hCG trigger. The first cohort of samples was collected from the dominant follicle of each participant and utilised for hormone profiling (n = 50 Vitamin D, n = 45 Placebo). For the second cohort, the follicle aspirates of each participant were pooled to create a single FF sample, which was used for the isolation of GCs for gene expression studies (n = 20 Vitamin D, n = 30 placebo). Six of the samples from the second cohort were used for RNA-sequencing analysis (n = 3 Vitamin D, n = 3 placebo).

PARTICIPANTS/MATERIALS, SETTING, METHODS

Two academic infertility units were involved in the recruitment of the participants, who received a single dose of oral 25-hydroxyvitamin D (600 000 IU) or placebo, 2-12 weeks before oocyte retrieval. Women in both groups were deficient in Vitamin D, aged 18-39 years with a normal BMI (18-25 kg/m2) and <3 previous IVF cycles. The FF was aspirated at the time of oocyte retrieval and stored. Liquid chromatography tandem mass spectrometry was used to measure FF abundance of 25-hydroxyvitamin D, aldosterone, androstenedione, cortisol, cortisone, corticosterone, 11-deoxycorticosterone, 11-deoxycortisol, 21-deoxycortisol, dehydroepiandrosterone, dehydroepiandrosterone sulfate, dihydrotestosterone, oestradiol (E2), 17-OH-hydroxyprogesterone, progesterone (P4) and testosterone. GCs were isolated from pooled FFs and the transcriptome was evaluated by RNA-sequencing and RT-PCR. Ingenuity pathway analysis (IPA) was used to assess the top canonical pathways and upstream regulators mediating the action of Vitamin D.

MAIN RESULTS AND THE ROLE OF CHANCE

At oocyte retrieval, FF concentration of 25-hydroxyvitamin D was 2.8-fold higher (P < 0.001) in the Vitamin D group (39.5 ng/ml; n = 50) compared to placebo (13.8 ng/ml; n = 45) but no other hormonal differences were detected. In the placebo group, but not the Vitamin D group, weak correlations of 25-hydroxyvitamin D concentration with P4 (r = 0.31, P = 0.03) and E2 (r = 0.45, P = 0.002) were observed. RNA-sequencing identified 44 differentially expressed genes in the GCs of patients who received Vitamin D (n = 3) compared to placebo (n = 3). RT-PCR demonstrated upregulation of VDR (vitamin D receptor), GSTA3 (glutathione S-transferase A3) and IL21R (interleukin 21 receptor), and downregulation of P T GS2 (prostaglandin-endoperoxide synthase 2), KLF4 (kruppel-like factor 4), T RP C4 (transient receptor potential cation channel subfamily C member 4), VEGF (vascular endothelial growth factor), RXRB (retinoid X receptor beta) and AGER (advanced glycosylation end-product specific receptor) genes in the Vitamin D (n = 17) versus placebo (n = 27) group. IPA suggested roles of Vitamin D in antioxidant defence.

LIMITATIONS, REASONS FOR CAUTION

Interpretation of the data is influenced by our intervention strategy (2-12 weeks prior to retrieval). As folliculogenesis may last 5-6 months, our protocol can only examine with confidence the impact of Vitamin D on the final stages of follicular growth. Furthermore, we examined the hormonal profile of the dominant follicle only, while the GC data reflect the transcriptome of all (pooled) follicles large enough to be used for IVF. Luteinised GCs from controlled ovarian stimulation were used in this study, which may be functionally distinct from the GCs of developing follicles. Moreover, the sample size for RNA-sequencing analysis was low (n = 3 per group), regardless of validation by RT-PCR that was performed on a larger cohort, introducing complexity to the IPA analysis, which required an input of data with P-adjusted <0.08 instead of <0.05 to be informative.

WIDER IMPLICATIONS OF THE FINDINGS

This is the first in-vivo study to show that Vitamin D supplementation alters gene expression in luteinised GCs. In contrast to some in-vitro evidence, no effect of the intervention on expression of genes encoding steroidogenic enzymes was observed. Unlike other studies, our results suggest that supplementation with Vitamin D is unlikely to directly influence hormone availability in FF. Our findings instead reinforce the hypothesis that Vitamin D could be considered one of the gatekeepers in protecting against an exaggerated response to ovarian stimulation.

STUDY FUNDING/COMPETING INTEREST(S)

The study has been funded by the Italian Ministry of Health (RF-2013-02358757) following peer review in the competitive 'Bando di Ricerca Finalizzata e Giovani Ricercatori 2013' for the clinical trial SUNDRO (EudraCT registration number 2015-004233-27). There are no competing interests.

TRIAL REGISTRATION NUMBER

EudraCT registration number 2015-004233-27.

Vitamin D in follicular development and oocyte maturation

Vitamin D (VD) is a secosteroid hormone synthesized predominantly in the skin upon UV light exposure, which can also be obtained from dietary sources. In target cells, the bioactive VD binds to specific VD receptor to regulate downstream transcription of genes that are involved in a wide range of cellular processes. There is an increasing recognition that the proper physiological levels of VD are critical for optimizing reproductive potential in women. The direct VD action in the ovary was first suggested in the 1980s. Since then, research has attempted to determine the role of VD in follicular development and oocyte maturation in animal models and clinical settings. However, data published to date are inconclusive due to the complexity in VD metabolism and the fact that VD actions are pervasive in regulating physiological functions in various systems, including the reproductive, endocrine and nervous systems that control reproduction. This review summaries in vitro, in vivo, and clinical evidence regarding VD metabolism and signaling in the ovary, as well as VD-regulated or VD-associated ovarian follicular development, steroidogenic function, and oocyte maturation. It is suggested that adequate animal models are needed for well-controlled studies to unravel molecular mechanisms of VD action in the ovary. For clinical studies, follicular development and function may be evaluated more effectively in a relatively homogeneous patient population under a well-controlled experimental design. A comprehensive understanding of VD-regulated folliculogenesis and oogenesis will provide critical insight into the impact of VD in female reproductive health.

Vitamin D, Bone Metabolism, and Fracture Risk in Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder among premenopausal women. PCOS may have reproductive, metabolic, cardiovascular, and psychological implications. Vitamin D deficit is often encountered in PCOS women and may contribute to the pathophysiology of this disorder. As of the key role of vitamin D in bone and mineral metabolism, and because the vitamin D status appears to be closely linked with the PCOS manifestations including insulin resistance, obesity, ovulatory and menstrual irregularities, oxidative stress and PTH elevation, hypovitaminosis D may directly and indirectly via the different facets of PCOS impair bone health in these women. Although limited data are available on life-long fracture risk in women with PCOS, the importance of preserving bone health in youth and adults to prevent osteoporosis and related fractures is also recognized in PCOS women. Evidence of the association between vitamin D and the clinical hallmarks of PCOS are summarized and discussed. Vitamin D arises as a cornerstone in women with PCOS and contributes to the pathophysiological link between PCOS and bone metabolism.

Vitamin D supplementation prior to in vitro fertilisation in women with polycystic ovary syndrome: a protocol of a multicentre randomised, double-blind, placebo-controlled clinical trial

INTRODUCTION

Polycystic ovary syndrome (PCOS) is one of the leading causes of female infertility, affecting around 5% of women of childbearing age in China. Vitamin D insufficiency is common in women with PCOS and is associated with lower live birth rates. However, evidence regarding the effectiveness of vitamin D supplementation in women with PCOS is inconclusive. This multicentre randomised, double-blinded, placebo-controlled trial aims to evaluate the effectiveness of vitamin D supplementation prior to in vitro fertilisation (IVF) on the live birth rate in women with PCOS.

METHODS AND ANALYSIS

We plan to enrol women with PCOS scheduled for IVF. After informed consent, eligible participants will be randomised in a 1:1 ratio to receive oral capsules of 4000 IU vitamin D per day or placebo for around 12 weeks until the day of triggering. All IVF procedures will be carried out routinely in each centre. The primary outcome is live birth after the first embryo transfer. The primary analysis will be by intention-to-treat analysis. To demonstrate or refute that treatment with vitamin D results in a 10% higher live birth rate than treatment with placebo, we need to recruit 860 women (48% vs 38% difference, anticipating 10% loss to follow-up and non-compliance, significance level 0.05 and power 80%).

ETHICS AND DISSEMINATION

This study has been approved by the Ethics Committee in Women's Hospital of Zhejiang University on 2 March 2020 (reference number: IRB-20200035-R). All participants will provide written informed consent before randomisation. The results of the study will be submitted to scientific conferences and a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

NCT04082650.

Altered vitamin D metabolic system in follicular cysts of sows

This study aimed to examine 25OHD₃ concentration in the fluid of follicular and follicular lutein cysts of sows in comparison with preovulatory follicles as well as immunolocalize vitamin D metabolic enzymes (CYP27B1 and CYP24A1) and determine their protein abundances in the cyst wall. We have shown for the first time that 25OHD₃ level in the fluid of both cyst types was significantly lower than in preovulatory follicles. Furthermore, we have demonstrated CYP27B1 and CYP24A1 protein immunolocalization and abundance in follicular and follicular lutein cysts. The abundance of protein for both metabolic enzymes was decreased in ovarian cysts when compared to preovulatory follicles. We propose that altered VD metabolism in ovarian cyst might associate with their formation in sows.

The association between anti-Müllerian hormone and vitamin 25(OH)D serum levels and polycystic ovarian syndrome in adolescent females

BACKGROUND

High anti-Müllerian hormone (AMH) levels and 25-hydroxyvitamin D [25(OH)D] deficiency have been associated with polycystic ovarian syndrome (PCOS) in adult women, and implicated in its pathogenesis. Herein we determined if the level of both AMH and 25(OH)D are altered in adolescent females with clinical features of PCOS.

METHODS

This is a cross-sectional study utilizing a retrospective chart review of 128 patients aged 12-20 referred to an academic adolescent gynecology and endocrinology clinic for an evaluation of suspected PCOS. Unadjusted comparisons of AMH and 25(OH)D distributions between subjects with and without PCOS were performed using the Wilcoxon Rank Sum test. Quantile regression was used to compare the median AMH and 25(OH)D between subject groups; adjusting for race, ethnicity, BMI, insurance type, age, and season when bloodwork was performed.

RESULTS

Seventy-four subjects were classified as having PCOS by meeting ≥2 of the three Rotterdam diagnostic criteria, and 47 subjects met only one Rotterdam diagnostic criteria, and were used as the comparative non-PCOS group. There were statistically significant unadjusted differences in median levels of AMH and 25(OH)D. In the adjusted analyses, median AMH was significantly higher in the PCOS group compared to the non-PCOS group (+ 2.39 ng/mL, 95% CI 0.43, 4.35, p = 0.018); 25(OH)D was significantly lower in the PCOS group (- 9.01 ng/mL, 95% CI -14.49, - 3.53 p = 0.001). In our sample, adolescents in both groups had insufficient 25(OH)D level (22 ng/mL) and elevated BMI (32.2 kg/m2).

CONCLUSIONS

Adolescents with PCOS display high levels of AMH and low 25(OH)D levels. Since traditional clinical markers of PCOS may be physiologic in adolescents, AMH and 25(OH)D may be used as surrogate markers of PCOS risk in adolescents.

Vitamin D and Polycystic Ovary Syndrome: a Narrative Review

Polycystic ovary syndrome (PCOS) is one of the most common endocrine disorders of reproductive age women and contributes to metabolic dysfunctions including insulin resistance (IR) and dyslipidemia. Vitamin D is a steroid hormone, which is involved in calcium metabolism and bone structure and has a potential role in the prevention of many illnesses, including cancers, autoimmune disorders, hypertension, diabetes, and obesity. Recently, it has been reported that vitamin D deficiency was a common complication of PCOS and vitamin D status was associated with reproductive ability, metabolic alterations, and mental health of PCOS patients. This review summarizes the advances between vitamin D status and the pathophysiological process of PCOS. Vitamin D level was negatively associated with serum androgen level. Vitamin D treatment could reduce serum androgen and anti-MüllerianHormone (AMH) levels, and decrease endometrial thickness, which resulted in improvement of menstrual cycle and folliculogenesis of PCOS patients. Moreover, vitamin D concentrations were negatively correlated with parameters of IR and body fat mass. Vitamin D supplementation has beneficial effects on IR and lipid metabolism. In addition, a positive of vitamin D on mental health of PCOS patients was proposed. Understanding the relationship between vitamin D status and the symptoms of PCOS patients is of great clinical significance to treat and prevent the progression of PCOS.

Altered vitamin D3 metabolism in the ovary and periovarian adipose tissue of rats with letrozole-induced PCOS

Vitamin D₃ (VD₃) plays an important role in the ovary and its deficiency is associated with ovarian pathologies, including polycystic ovary syndrome (PCOS). However, there is no data related to VD₃ metabolism in the ovary during PCOS. Herein, we investigated differences in the expression of VD₃ receptor (VDR) and key VD₃ metabolic enzymes, 1α-hydroxylase (CYP27B1) and 24-hydroxylase (CYP24A1), in the ovary and periovarian adipose tissue (POAT) of control (proestrus and diestrus) and PCOS induced by letrozole rats. Vdr, Cyp27b1 and Cyp24a1 mRNA expression was determined, their protein abundance was examined and immunolocalized. Furthermore, VD₃ metabolite concentrations in plasma (25OHD) and tissues (ovary and POAT; 1,25(OH)₂D₃), and plasma calcium level were determined. 25OHD concentration decreased markedly in letrozole-treated rats in comparison with controls, whereas calcium concentration did not vary among the examined groups. The amount of 1,25(OH)₂D₃ decreased in both ovary and POAT of PCOS rats. In the ovary, we found decreased Cyp27b1 and increased Vdr mRNA expression in letrozole-treated and diestrus control group. Corresponding protein abundances were down-regulated and up-regulated, respectively but only following letrozole treatment. In POAT, only Cyp27b1 transcript level and CYP27B1 protein abundance were decreased in letrozole-treated rats. VDR was immunolocalized in healthy and cystic follicles, while CYP27B1 and CYP24A1 were found exclusively in healthy ones. Concluding, our results provide the first evidence of disrupted VD₃ metabolism in the ovary and POAT of PCOS rats. The reduced 1,25(OH)₂D₃ concentration in those tissues suggests their contribution to VD₃ deficiency observed in PCOS and might implicate in PCOS pathogenesis.

Effects of 25-hydroxycholecalciferol supplementation in maternal diets on reproductive performance and the expression of genes that regulate lactation in sows

One hundred Yorkshire × Landrace sows were randomly assigned to one of two dietary treatments (diet ND: 6,000 IU vitamin D₃ /d feed; diet 25-D: 200 μg/day 25OHD₃ feed). The experiment began on d 90 of gestation and continued until weaning on day 21 of lactation. In sows that received 25OHD₃ , the growth rate of the piglets before weaning was significantly accelerated (0.266 kg/day, p < .05). Sow serum was collected after weaning, and those in the 25OHD₃ group were found to have significantly higher serum calcium (CA) and phosphorus (PI) levels (p < .05). Interestingly, the oestrus cycle of sows fed 25OHD₃ was significantly shortened (p < .05), the oestrus time was concentrated on the fifth day after weaning, and the piglets were born with a higher degree of uniformity (p < .05). Colostrum was collected on the day of delivery, and the colostrum of sows fed 25OHD₃ contained higher milk fat content than the control group (p < .05). 25OHD₃ supplementation increased the mRNA and protein expression of INSIG1 and SREBP1, which regulate milk fat synthesis, in the mammary gland of lactating sows (p < .05). In conclusion, 25OHD₃ supplementation in maternal diets improved reproductive performance, milk fat content and the mRNA and protein levels of genes regulating milk fat synthesis in lactating sows.

Androgens and hirsutism score of overweight women with polycystic ovary syndrome improved after vitamin D treatment: A randomized placebo controlled clinical trial

BACKGROUND & AIM

The objective of this study was to investigate the effect of vitamin D treatment on androgen levels and hirsutism scores in overweight women with PCOS.

METHODS

A prospective, randomized, double-blind, placebo-controlled clinical study was conducted at King Abdullah University Hospital in Irbid, Jordan. Overweight Jordanian females aged 18-49 years with vitamin D deficiency and PCOS (n = 60) were assigned to two groups: the treatment group (n = 30) who received 50,000 IU per week of vitamin D₃ and the control group (n = 30) who received a placebo.

RESULTS

After receiving the treatment for 12 consecutive weeks, the levels of total testosterone, parathyroid hormone, free androgen index, and hirsutism score were significantly decreased (P < 0.001), and the levels of 25-hydroxyvitamin D (25(OH)D), sex hormone binding globulin, and phosphorus were significantly increased (P < 0.05). Furthermore, significant changes were observed in ovarian volume and follicle numbers and size ultrasonography, and in the regularity of the menstrual cycle (P < 0.001). In the placebo group, no significant changes were observed in either androgen levels, hirsutism score, or menstrual regularity.

CONCLUSION

Vitamin D₃ at a treatment dose of 50,000 IU per week improved 25(OH)D levels and decreased the hirsutism scores and androgen levels of overweight women with PCOS. These results could mean increased fertility and better reproductive health for overweight women with PCOS; the use of vitamin D₃ as a treatment for these patients should be further investigated. CLINICALTRIALS.

GOV REGESTRATION NUMBER

NCT02328404.

Assessing the effect of MitoQ10 and Vitamin D3 on ovarian oxidative stress, steroidogenesis and histomorphology in DHEA induced PCOS mouse model

Polycystic ovary syndrome (PCOS) continues to be one of the most complex reproductive and endocrine disorder among women of reproductive age. Recent reports have identified close interaction of Vitamin D deficiency and oxidative stress (OS) in exacerbating the pathophysiology of PCOS. This current study aims at assessing the combine effect of MitoQ₁₀ and Vitamin D3 on dehydroepiandrosterone (DHEA) induced PCOS. Following successful induction of PCOS using DHEA, mice were organized into five groups (n = 8) namely: Negative Control (NC), Vitamin D3 Vehicle (VDV), Vitamin D3 (VD), MitoQ₁₀ (MQ), Vitamin D3 plus MitoQ₁₀ (V+M) and DHEA, ethanol and distilled water, Vitamin D3, MitoQ₁₀ and Vitamin D3 plus MitoQ₁₀ were respectively administered for 20 consecutive days. The study also included positive control (PC) group (n = 8) in which no treatment was applied. Treatment effects were assessed using hormonal assays, biochemical assays, Real-Time PCR, western blotting and histological analysis. Combination of Vitamin D3 and MitoQ₁₀ significantly reduced levels of estradiol, progesterone, FSH, LH, LH/FSH, SOD and MDA. The expression rate of mRNAs of 3β-HSD, Cyp19a1, Cyp11a1, StAR, Keap1, HO-1 and Nrf2 were also significantly low in V+M group. Moreover, the histomorphological inspection of ovaries from this group revealed many healthy follicles at various stages of development including few atretic follicles, pre-antral and antral follicles and many corpora lutea. The characteristics observed in this group were in many ways similar to that of the PC group. The combination of MitoQ₁₀ and Vitamin D3 may be potential candidate to ameliorate PCOS.

Vitamin D-Binding Protein in Pregnancy and Reproductive Health

Vitamin D-binding protein (VDBP), the main carrier of vitamin D, has recently been implicated in reproductive health and pregnancy outcomes including endometriosis, polycystic ovary syndrome (PCOS), pre-eclampsia, and gestational diabetes mellitus (GDM). Improved methods for measuring VDBP and an increased understanding of its role in biological processes have led to a number of newly published studies exploring VDBP in the context of pregnancy. Here, we synthesize the available evidence regarding the role of VDBP in reproductive health and pregnancy, and we highlight areas requiring further study. Overall, low levels of maternal serum VDBP concentrations have been associated with infertility, endometriosis, PCOS and spontaneous miscarriage, as well as adverse pregnancy outcomes including GDM, pre-eclampsia, preterm birth and fetal growth restriction. However, increased VDBP concentration in cervicovaginal fluid has been linked to unexplained recurrent pregnancy loss and premature rupture of membranes. Some genetic variants of VDBP have also been associated with these adverse outcomes. Further studies using more accurate VDBP assays and accounting for ethnic variation and potential confounders are needed to clarify whether VDBP is associated with reproductive health and pregnancy outcomes, and the mechanisms underlying these relationships.

Pre-conception 25-hydroxyvitamin D (25(OH)D) and fecundability

STUDY QUESTION

Is pre-conception 25(OH)D associated with the per cycle probability of conception, i.e fecundability, in a prospective cohort study?

SUMMARY ANSWER

There are suggestive associations of high 25(OH)D (at least 50 ng/ml) with increased fecundability and low 25(OH)D (<20 ng/ml) with reduced fecundability, but the estimates were imprecise.

WHAT IS KNOWN ALREADY

Vitamin D has been associated with reproductive function and fertility in animal studies, but few human studies exist.

STUDY DESIGN, SIZE, DURATION

This community-based prospective cohort study included 522 women attempting to become pregnant between 2010 and 2016. The women completed online daily and monthly diaries until a positive home pregnancy test was observed or 12 months had elapsed.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The study included women from central North Carolina who were aged 30-44 with no history of infertility, with no more than 3 months of attempt time at recruitment. Women recorded vaginal bleeding so that the ongoing number of attempt cycles could be counted and used to quantify a woman's pregnancy attempt time. Blood collected at the study entry was analysed for 25(OH)D using liquid chromatography tandem mass spectrometry. Associations with fecundability were estimated with a log-binomial discrete time-to-event model.

MAIN RESULTS AND THE ROLE OF CHANCE

Among 522 women, 257 conceived during the study. The mean age was 33 years and the mean 25(OH)D was 36 ng/ml. There was an estimated 10% higher fecundability with each 10 ng/ml increase in 25(OH)D (fecundability ratio (FR) 1.10, 95% CI: 0.96, 1.25). The suggestive dose-response association with the continuous measure of 25(OH)D was driven by women in the lowest and the highest categories of 25(OH)D. Compared to women with 25(OH)D of 30-40 ng/ml, women below 20 ng/ml had an estimated 45% reduction in fecundability (FR (CI): 0.55 (0.23, 1.32)), and women with at least 50 ng/ml had an estimated 35% increase in fecundability (FR (CI): 1.35 (0.95, 1.91)). Across these three categories (25(OH)D of <20 ng/ml, 30-40 ng/ml and > 50 ng/ml), the probability of taking longer than 6 months to conceive was, respectively, 51% (17%, 74%), 28% (17%, 39%) and 15% (10%, 37%).

LIMITATIONS, REASONS FOR CAUTION

While the distribution of 25(OH)D was wide, the number of observed cycles with high 25(OH)D (N = 107) or low 25(OH)D (N = 56) was small.

WIDER IMPLICATIONS OF THE FINDINGS

Our findings are consistent with prior reports of reduced fertility in women with 25(OH)D concentrations below the clinically defined deficiency level (20 ng/ml). Further studies are needed to evaluate the possible reproductive benefits of considerably higher 25(OH)D concentration (>50 ng/ml).

STUDY FUNDING/COMPETING INTEREST(S)

This research was supported by the Eunice Kennedy Shriver National Institute of Child Health and Human Development of the National Institutes of Health (NIH) under award numbers R00HD079659 and R01HD067683 and supported in part by the Intramural Research Program of the National Institute of Environmental Health Sciences, under projects ES103086, ES049003 and ES044003. ClearBlue ovulation predictor kits were generously donated to AMZJ and AJW by Swiss Precision Diagnostics. Drs Wilcox and Jukic report non-financial support from Swiss Precision Diagnostics during the conduct of the study; Dr Jukic reports non-financial support from Theralogix, LLC, outside the submitted work. Otherwise there are no competing interests.

TRIAL REGISTRATION NUMBER

N/A.

Effects of vitamin D supplementation on follicular development, gonadotropins and sex hormone concentrations, and insulin resistance in induced polycystic ovary syndrome

Objective:

Polycystic ovary syndrome (PCOS) as a reproductive disorder disturbs ovarian follicular development, vitamin D stimulated insulin activity, and sex hormone concentrations. This study aimed to examine the effects of vitamin D on ovarian follicular development, insulin resistance, and sex hormone changes in rats with induced PCOS.

Materials and Methods:

Forty female Wistar rats were randomly divided into four groups: (1) control, (2) induced PCOS, (3) vitamin D-treated non-PCOS (sham group), (4) vitamin D treated PCOS groups. All rats were then sacrificed under anesthesia and ovarian tissue samples were evaluated histomorphometrically. Blood samples were collected for analyzing the serum concentrations of sex hormones and insulin resistance.

Results:

The number of atretic follicles at different stages of development increased in the PCOS ovaries (p<0.001). Vitamin D treatment significantly increased the normality of follicles in rats with PCOS (p<0.001). The serum concentration of follicle stimulating hormone and the estradiol significantly increased in rats with PCOS, whereas the testosterone and luteinizing hormone concentrations, glucose, insulin, and insulin resistance concentrations significantly decreased during vitamin D treatment (p<0.001).

Conclusion:

This study indicated that vitamin D treatment may protect ovarian tissue from the negative effect of PCOS by improving insulin activity and gonadotropin concentrations.

Type 2 Diabetes Mellitus, Insulin Resistance, and Vitamin D

PURPOSE OF REVIEW

There is a growing, largely inconsistent, literature on the role of vitamin D in association with type 2 diabetes, insulin resistance/insulin secretion, glycemic indices, and complications of type 2 diabetes. Pathophysiologic, bystander, preventive, and treatment roles of vitamin D have all been proposed. In this focused review, we attempt to organize and clarify our current information in this area.

RECENT FINDINGS

Clinical study interpretation is difficult because of variability in dosage, dosage form, study duration, and populations studied, as well as recently reported normal human polymorphisms in vitamin D synthesis and catabolism, vitamin D-binding protein, and vitamin D receptors in addition to a host of potential epigenetic confounders. Low vitamin D status appears to be associated with type 2 diabetes and most other insulin resistance disorders reported to date. The extraskeletal benefits of supplementation/repletion in these disorders in our species, with a few highlighted exceptions, remain to be established. This focused review attempts to summarize our current knowledge in this burgeoning area through a review of key meta-analyses, observational studies, randomized control trials, and Mendelian randomization studies and will hopefully serve as a guide to indicate future research directions and current best practice.

Effect of Calcium and Vitamin D Supplements as an Adjuvant Therapy to Metformin on Menstrual Cycle Abnormalities, Hormonal Profile, and IGF-1 System in Polycystic Ovary Syndrome Patients: A Randomized, Placebo-Controlled Clinical Trial

Objective

This study aims to investigate the effect of combining calcium and vitamin D supplements with metformin on menstrual cycle abnormalities, gonadotropins, and IGF-1 system in vitamin D-deficient/insufficient PCOS women.

Study Design

This is a randomized, placebo-controlled clinical trial.

Setting

This study was performed in Damascus University of Obstetrics and Gynecology Hospital and Orient Hospital, in Damascus, Syria.

Materials and Methods

Forty PCOS women with 25-OH-vitamin D < 30 ng/ml were randomly assigned to take either metformin (1500 mg/daily) plus placebo or metformin (1500 mg/daily) plus calcium (1000 mg/daily) and vitamin D₃ (6000 IU/daily) orally for 8 weeks. Serum levels of gonadotropins (luteinizing hormone (LH) and follicle-stimulating hormone (FSH)), insulin-like growth factor-1 (IGF-1), and insulin-like growth factor binding protein-1 (IGFBP-1) were detected at the baseline during the early follicular phase of a spontaneous or induced menstrual cycle and after 8 weeks of intervention (except for the final gonadotropins levels which were assayed from samples obtained during the early follicular phase of a spontaneous menstrual cycle).

Results

Thirty-four patients (85%) completed the study. After 8 weeks of intervention, calcium and vitamin D co-supplementation led to a significant increase in 25-OH-vitamin D levels and calcium levels in the supplementation group compared to the other group (change in 25-OH-vitamin D levels: +19.38 ± 7.78 vs +0.11 ± 4.79 ng/ml, respectively; p value=0.0001) (change in calcium levels: +0.83 ± 0.82 vs +0.01 ± 0.86 mg/dl, respectively; p value=0.014). An improvement in menstrual cycle irregularity was detected in 38.5% and 58.8% of patients in metformin-placebo group and metformin-calcium-vitamin D group, respectively; but the change was statistically significant only in the supplementation group (p value=0.002). Nevertheless, the means of changes from baseline in gonadotropins levels (serum levels of LH, FSH, and LH to FSH ratio) and the studied parameters of IGF-1 system (serum levels of IGF-1, IGFBP-1, and IGF-1 to IGFBP-I ratio) did not differ significantly between the two groups.

Conclusions

Calcium and vitamin D supplements can support metformin effect on regulation of menstrual cycle irregularity in vitamin D-deficient/insufficient PCOS patients, but this effect is not associated with any significant changes in gonadotropins or IGF-1 system. These results suggest a possible role of calcium and vitamin D supplements in managing PCOS. However, further studies are needed to identify the underlying mechanisms. The Clinical Trial Registration Number is NCT03792984.

Association of vitamin D receptor gene variants with polycystic ovary syndrome: a meta-analysis

BACKGROUND

Polycystic ovary syndrome (PCOS) is a common endocrine disorder in reproductive-age women. Multiple susceptible gene as well as environmental factors and their interaction each other are contributed to the PCOS risk. Several case-control studies have researched the associations of the vitamin D receptor gene (VDR) polymorphisms with PCOS susceptibility, but the jury is still out. Here, we carried out a meta-analysis to clarify polymorphisms between ApaI (C/A) (rs7975232), BsmI (G/A) (rs1544410), FokI (C/T) (rs10735810), TaqI (T/C) (rs731236) and Tru9I (G/A) (rs757343) in the VDR gene and PCOS susceptibility based on relative lager sample size.

METHODS

English database of PubMed and Embase, and Chinese database of Wanfang and China National Knowledge Infrastructure (CNKI) databases were retrivaled for the relationship between VDR gene variates and PCOS susceptibility published before 31th, May 2018. Crude odds ratios (ORs) and its 95% confidence intervals (95% CIs) in different comparisons were used to detected the strength of the association. All the statistical analyses of the present meta-analysis were performed by STATA version 12.0 software.

RESULTS

Totally, 3587 (PCOS group 1922; control group 1665) participants from 13 studies were included which met our inclusion criteria. A statistically significant association between VDR ApaI (rs7975232) polymorphism and PCOS susceptibility (C vs. A: OR = 1.19, 95%CI = 1.06~1.34, P = 0.004) was found in the overall population. After stratified by ethnicity, we showed that there is a significant association between VDR ApaI (rs7975232) polymorphism and susceptibility to PCOS in the Asian (C vs. A: OR = 1.21, 95%CI = 1.04~1.42, P = 0.016) population, but this association was not found in the Caucasian population. Additionally, a significant relationship between VDR BsmI (rs1544410) variates with PCOS susceptibility in the Asian (G vs. A: OR = 1.27, 95%CI = 1.06~1.53, P = 0.011) population, but this association was not found in the Caucasian population. We didn't find any association between VDR FokI (rs2228570), VDR TaqI (rs731236), VDR Tru9I (rs757343) and PCOS susceptibility in the overall and the subgroup populations.

CONCLUSIONS

Our findings demonstrated that VDR ApaI (rs7975232) and VDR BsmI (rs1544410) polymorphisms are correlated with susceptibility to PCOS in the Asian population and VDR TaqI (rs731236), VDR FokI (rs2228570), VDR Tru9I (rs757343) did not reveal a relationship with the PCOS susceptibility.

Vitamin D and cardiometabolic disorders: a review of current evidence, genetic determinants and pathomechanisms

Vitamin D deficiency has been implicated in the pathophysiology of cardiometabolic disorders including obesity, type 2 diabetes mellitus, cardiovascular diseases and polycystic ovary syndrome. Despite a large number of experimental and observational studies supporting a role for vitamin D in these pathologies, randomized controlled trials have reported little to no effect of vitamin D supplementation in the prevention or treatment of these disorders, although some results remain ambiguous. Polymorphisms in genes related to vitamin D metabolism, particularly in the vitamin D receptor and binding protein and the metabolizing enzyme 1-α-hydroxylase, have emerged as potential contributors to these divergent results. It is now becoming increasingly recognized that the effects and potential benefits of vitamin D supplementation may vary by several factors including vitamin D deficiency status, ethnicity and/or the presence of genetic variants, which affect individual responses to supplementation. However, these factors have seldom been explored in the available literature. Future trials should consider inter-individual differences and, in particular, should aim to clarify whether certain subgroups of individuals may benefit from vitamin D supplementation in the context of cardiometabolic health.

Vitamin D Deficiency Is Associated With Poor Ovarian Stimulation Outcome in PCOS but Not Unexplained Infertility

CONTEXT

The impact of vitamin D deficiency on the success of ovarian stimulation according to underlying infertility diagnosis has not been investigated.

OBJECTIVE

To evaluate the relationship between vitamin D deficiency and reproductive outcomes after ovarian stimulation in women with either polycystic ovary syndrome (PCOS) or unexplained infertility.

DESIGN

Retrospective cohort study.

SETTING

Analysis of randomized controlled trial (RCT) data.

PARTICIPANTS

Participants from the Pregnancy in Polycystic Ovary Syndrome II (PPCOS II) RCT (n = 607); participants from the Assessment of Multiple Intrauterine Gestations from Ovarian Stimulation (AMIGOS) RCT of unexplained infertility (n = 647).

INTERVENTIONS

Serum 25(OH)D levels measured in banked sera.

MAIN OUTCOME MEASURES

Primary: live birth; secondary: ovulation (PPCOS II), pregnancy, and early pregnancy loss.

RESULTS

In PPCOS II, subjects with vitamin D deficiency [25(OH)D < 20 ng/mL or 50 nmol/L] were less likely to ovulate (adjusted OR, 0.82; 95% CI, 0.68 to 0.99; P = 0.04) and experienced a 40% lower chance of live birth (adjusted OR, 0.63; 95% CI, 0.41 to 0.98; P = 0.04) than those not deficient. In AMIGOS, no significant association between vitamin D deficiency and live birth was noted. In pregnant subjects from both studies, vitamin D deficiency was associated with elevated risk of early pregnancy loss (OR, 1.6; 95% CI, 1.0 to 2.6; P = 0.05).

CONCLUSIONS

In this investigation of women pursuing ovarian stimulation, the association between vitamin D deficiency and diminished live birth relied on carrying the diagnosis of PCOS and was not observed in unexplained infertility. Given the generally modest success of ovarian stimulation, addressing vitamin D deficiency may prove an important treatment adjunct for many infertile women.

Crosstalk between advanced glycation end products and vitamin D: A compelling paradigm for the treatment of ovarian dysfunction in PCOS

Women with PCOS have elevated levels of the harmful advanced glycation end products (AGEs) and low serum levels of vitamin D. AGEs and their receptors may contribute to the pathogenesis of PCOS and its metabolic and reproductive consequences. On the other hand, vitamin D might improve PCOS phenotype and could alleviate the detrimental effects of AGEs. A literature review using PubMed was performed. Critical analysis was carried out for articles pertaining to: 1) the role of AGEs and their receptors in the pathophysiology of PCOS, in particular ovarian dysfunction, and 2) the action of vitamin D in attenuating the adverse effects of AGEs in women with PCOS at both the serum and the cellular levels. Data from in vitro experiments, animal models, and human studies provide compelling evidence that AGEs and their receptors may contribute to the pathogenesis of ovarian dysfunction in PCOS. The actions of AGEs in PCOS might be attenuated and/or reversed by the presence or supplementation of vitamin D. Once a mechanistic understanding of the relationship between AGEs and vitamin D is established, this knowledge might contribute to the subsequent development of new-targeted pharmacological therapies for improving ovarian health in women with PCOS.

Vitamin D3 Regulates Follicular Development and Intrafollicular Vitamin D Biosynthesis and Signaling in the Primate Ovary

There is an increasing recognition that vitamin D plays important roles in female reproduction. Recent studies demonstrated that 1α,25-dihydroxyvitamin D3 (VD3), the biologically active form of vitamin D, improved ovarian follicle survival and growth in vitro. Therefore, we investigated the direct effects of VD3 at the specific preantral and antral stages of follicular development, and tested the hypothesis that vitamin D receptor (VDR) and enzymes critical for vitamin D biosynthesis are expressed in the primate ovary. Fourteen adult rhesus macaques provided ovarian tissue. Secondary and antral follicles were isolated for PCR analysis on VDR, vitamin D3 25-hydroxylase, and 25-hydroxyvitamin D3-1α-hydroxylase. VDR protein localization was determined by immunohistochemistry on ovarian sections. Isolated secondary follicles were cultured under conditions of control and VD3 supplementation during the preantral or antral stage. Follicle survival, growth, steroid and anti-Müllerian hormone (AMH) production, as well as oocyte maturation were evaluated. In vivo- and in vitro-developed follicles were also assessed for genes that are critical for vitamin D biosynthesis and signaling, gonadotropin signaling, steroid and paracrine factor production, and oocyte quality. The mRNA encoding VDR, 25-hydroxylase, and 1α-hydroxylase was detectable in in vivo- and in vitro-developed preantral and antral follicles. The 25-hydroxylase was elevated in cultured follicles relative to in vivo-developed follicles, which further increased following VD3 exposure. VD3 treatment increased 1α-hydroxylase in in vitro-developed antral follicles. The absence of VD3 during culture decreased VDR expression in in vitro-developed antral follicles, which was restored to levels comparable to those of in vivo-developed antral follicles by VD3 supplementation. Positive immunostaining for VDR was detected in the nucleus and cytoplasm of granulosa cells and oocytes. While only survival was improved in preantral follicles treated with VD3, VD3 supplementation promoted both survival and growth of antral follicles with increased estradiol and AMH production, as well as oocyte maturation. Thus, Vitamin D biosynthesis and signaling systems are expressed in primate ovarian follicles. Our findings support a role for VD3 in regulating follicular development in a stage-dependent manner, as well as the intrafollicular vitamin D biosynthesis and signaling, directly in the ovary.

25-Hydroxyvitamin D and Long Menstrual Cycles in a Prospective Cohort Study

BACKGROUND

Vitamin D insufficiency is associated with subfertility and prolonged estrus cycles in animals, but humans have not been well studied.

METHODS

A prospective time-to-pregnancy study, Time to Conceive (2010-2015), collected up to 4 months of daily diary data. Participants were healthy, late reproductive-aged women in North Carolina who were attempting pregnancy. We examined menstrual cycle length as a continuous variable and in categories: long (35+ days) and short (≤25 days). Follicular phase length and luteal phase length were categorized as long (18+ days) or short (≤10 days). We estimated associations between those lengths and serum 25-hydroxyvitamin D (25[OH]D) using linear mixed models and marginal models.

RESULTS

There were 1,278 menstrual cycles from 446 women of whom 5% were vitamin D deficient (25[OH]D, <20 ng/ml), 69% were between 20 and 39 ng/ml, and 26% were 40 ng/ml or higher. There was a dose-response association between vitamin D levels and cycle length. Compared with the highest 25(OH)D level (≥40 ng/ml), 25(OH)D deficiency was associated with almost three times the odds of long cycles (adjusted odds ratio [aOR] = 2.8 [95% confidence interval (CI) = 1.0, 7.5]). The aOR was 1.9 (1.1, 3.5) for 20 to <30 ng/ml. The probability of a long follicular phase and the probability of a short luteal phase both increased with decreasing 25(OH)D.

CONCLUSIONS

Lower levels of 25(OH)D are associated with longer follicular phase and an overall longer menstrual cycle. Our results are consistent with other evidence supporting vitamin D's role in the reproductive axis, which may have broader implications for reproductive success.

The effect of vitamin D supplementation in combination with low-calorie diet on anthropometric indices and androgen hormones in women with polycystic ovary syndrome: a double-blind, randomized, placebo-controlled trial

PURPOSE

Polycystic ovary syndrome (PCOS) is known as the most common endocrine disorder in reproductive age women. The aim of this studywas to evaluate the effects of vitamin D supplementation in combination with low-calorie diet on anthropometric indices, reproductive hormones and menstrual regularity in overweight and obese PCOS women.

METHODS

In this randomized controlled clinical trial, 60 PCOS women with vitamin D insufficiency were randomly assigned to 12 weeks of either (1) weight-loss intervention + 50,000 IU/week oral vitamin D3 or (2) weight-loss intervention + placebo. At the beginning and end of the study, the anthropometric indices, body composition, 25-hydroxyvitamin D, total testosterone, dehydroepiandrosterone sulfate (DHEAS), sex hormone-binding globulin (SHBG) and free androgen index (FAI) were measured and regularity of menses was compared among the two groups.

RESULT

After 12-week intervention, median of serum 25-hydroxyvitamin D3 significantly increased from 18.5 (10.75-20) ng/ml to 42.69 (34-53.25) ng/ml in vitamin D group compared to placebo group (p < 001). Moreover, there was a significant improvement in frequency regular menstrual cycle (p = 0.01). Mean of weight, body mass index, fat mass, waist and hip circumference and waist-to-hip ratio significantly decreased in both groups, but was not different between two groups. Mean of total testosterone insignificantly decreased from 0.7 to 0.5 ng/ml in vitamin D group (p = 0.18). In addition, we did not observe significant differences regarding DHEAS, FAI and SHBG between two groups.

CONCLUSIONS

In women with PCOS, androgen profile did not change with vitamin D supplementation when combined with low-calorie diet, but menstrual frequency significantly improved.

CLINICAL TRIAL REGISTRATION NUMBER

IRCT2016062710826N19.

Vitamin D3 regulates steroidogenesis in granulosa cells through AMP-activated protein kinase (AMPK) activation in a mouse model of polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is an endocrine and metabolic disorder in reproductive-aged women. Hormonal abnormality caused by steroidogenesis disturbances appears to be the main culprit of the clinical picture in PCOS. Vitamin D3 could regulate steroidogenesis in granulosa cells, but the mechanism of action of vitamin D3 on steroidogenesis remains unknown. AMP-activated protein kinase (AMPK) has a modulating role in steroid hormone production. We investigated the effect of vitamin D3 on steroidogenesis in cultured granulosa cells of dehydroepiandrosterone-induced PCOS mice and studied the involvement of AMPK signalling pathway in the current process. Immunoblotting assay showed that vitamin D3 could increase phosphorylation of AMPK alpha and acetyl-CoA carboxylase, main substrate of AMPK. Vitamin D3 and 5-aminoimidazole-4-carboxamide-1-β-D-riboside or Aicar (AMPK activator) not only reduced gene expression of steroidogenic enzymes (P450scc or Cyp11a1, StAR, Cyp19a1 and 3B-HSD), but also reduced production of progesterone and 17B-estradiol assessed by radioimmunoassay. Pretreatment with compound C (AMPK inhibitor) decreased APMK phosphorylation and eliminated the effects of vitamin D3 and Aicar on steroidogenic enzymes expression and estradiol and progesterone production. This study showed that vitamin D3 has the main role in regulating of steroidogenesis in granulosa cells of mouse polycystic ovary through activation of the AMPK signalling pathway.

SIGNIFICANCE OF THE STUDY

Polycystic ovarian syndrome (PCOS) is an endocrine disorder of women in reproductive age. This disorder is partly related to disruption in steroidogenesis pathway and dysregulation of estradiol and progesterone production in granulosa cells of polycystic ovaries. Previously, we have shown that vitamin D3 could modulate steroidogenesis pathway in PCOS granulosa cells. In this study, we investigate the molecular mechanism of vitamin D3 in regulation of steroidogenesis pathway. We have shown that vitamin D3 has a modulating role in steroidogenesis pathway of granulosa cells by regulation of AMP-activated protein kinase (AMPK) as an underlying molecular mechanism in mouse polycystic ovary.

Vitamin D predictors in polycystic ovary syndrome: a meta-analysis

BACKGROUND

The aim of this meta-analysis was to examine differences and predictors of serum 25-hydroxyvitamin D concentrations in women with polycystic ovary syndrome (PCOS) compared with non-PCOS controls matched for body mass index.

MATERIALS AND METHODS

Three databases were searched (2003-2015) to retrieve studies that evaluated serum 25-hydroxyvitamin D in PCOS women and controls. Meta-regression analysis was performed with anthropometric and metabolic/endocrine parameters as covariates.

RESULTS

Fourteen studies that included 2262 women (1150 PCOS patients/1162 controls) were eligible. Serum 25-hydroxyvitamin D, follicle-stimulating hormone and sex hormone-binding globulin were significantly lower in patients with PCOS than controls. Homoeostatic model assessment-insulin resistance index, serum insulin, total cholesterol, triglycerides, low-density lipoprotein cholesterol, luteinising hormone and testosterone were significantly higher in patients with PCOS compared to controls. Meta-regression analysis demonstrated significant effects of waist-to-hip ratio and glucose in PCOS women (β = -1·60, 95% CI: -2·30 to -0·90, P = 0·003; β = 0·20, 95% CI: 0·80-0·32, P = 0·004, respectively) and controls (β = -2·36, 95% CI: -3·38 to -1·33, P = 0·003; β = 0·11, 95% CI: 0·00-0·21, P = 0·05, respectively) and of total calcium and luteinising hormone in PCOS cases (β = 2·43, 95% CI: 1·67-3·19, P = 0·005; β = -0·37, 95% CI: -0·68 to -0·06, P = 0·03, respectively).

CONCLUSIONS

Serum 25-hydroxyvitamin D may be predicted positively by serum calcium and negatively by luteinising hormone in women with PCOS, and negatively by waist-to-hip ratio and positively by fasting glucose in both PCOS and non-PCOS women, independently of the presence of obesity.

The effect of alfacalcidiol and metformin on metabolic disturbances in women with polycystic ovary syndrome

BACKGROUND

The aim of this randomized clinical trial (RCT) was to evaluate the effect of vitamin D supplementation in obese, insulin-resistant (IR) and vitamin D-deficient polycystic ovary syndrome (PCOS) women on metabolic abnormalities in comparison to the effect of metformin or combined metformin plus vitamin D therapy.

MATERIAL AND METHODS

Thirty-nine PCOS women who fulfilled the inclusion criteria were randomized into three groups and treated with alfacalcidiol, combined alfacalcidiol and metformin therapy and metformin for 6 months. Body weight, body mass index (BMI), waist circumference, total body fat and fat distribution were measured before and after 6 months of treatment. Plasma fasting glucose, insulin, homeostasis model assessment-insulin resistance (HOMA-IR) and lipid profiles were measured at the same time.

RESULTS

There was a significant decrease in body weight, BMI, waist circumference, total body fat and serum glucose levels in the metformin group (p<0.05), whereas PCOS women treated with alfacalcidiol did not significantly change their anthropometric and metabolic parameters. A significant decrease in waist circumference (p<0.05) in the group treated with metformin and alfacalcidiol was detected without other significant metabolic changes (all p>0.05). There were no significant changes in metabolic parameters (p>0.05) after vitamin D therapy except for a slight but non-significant trend towards higher high-density lipoprotein (HDL) cholesterol levels (p=0.087).

CONCLUSION

We conclude that vitamin D supplementation has no significant effect on anthropometric and metabolic parameters in PCOS women. Metformin has been still the most effective modality for the treatment of metabolic changes in PCOS.

Vitamin D receptor polymorphisms and the polycystic ovary syndrome: A systematic review

Polycystic ovary syndrome (PCOS) is the most frequent endocrinological disorder that affects women of reproductive age, leading to metabolic alterations, such as hyperandrogenism, obesity, menstrual irregularities, insulin resistance, and polycystic ovaries. The etiology remains unclear, but several genetic and environmental factors have been correlated with manifestations of this syndrome. Vitamin D plays important roles in metabolic pathways affected by PCOS, including calcium homeostasis, the insulin pathway, and sex hormone synthesis. Vitamin D concentration has been related with the severity of this disorder, and vitamin D receptor polymorphisms have been shown in some studies to have an association with some of the patterns presented by PCOS. The objective of this study is to provide an up-to-date review about vitamin D receptor polymorphisms and their association with PCOS.

Effects of Dietary Approach to Stop Hypertension diet on androgens, antioxidant status and body composition in overweight and obese women with polycystic ovary syndrome: a randomised controlled trial

BACKGROUND

Polycystic ovary syndrome (PCOS) is the most common endocrine disease in reproductive age women. The present study aimed to determine the effects of Dietary Approaches to Stop Hypertension (DASH) diet on reproductive hormones, plasma total antioxidant status and anthropometric indices in overweight and obese PCOS women.

METHODS

In this randomised controlled clinical trial, 60 women with PCOS were randomly assigned to one of two diets with energy restriction: the DASH diet and a control diet. The DASH and control diets consisted of 50-55% carbohydrate, 15-20% protein and 25-30% total fat. The DASH diet was designed to be rich in vegetables, fruits, whole grains and low-fat dairy products, as well as low in saturated fats, cholesterol, refined grains and sweets. In the present study, the anthropometric indices, body composition, total testosterone, androstenedione, sex hormone binding globulin (SHBG), free androgen index and 2,2'-diphenyl-1-picryylhydrazyl (DPPH) scavenging activity were measured before and after 3 months.

RESULTS

The consumption of DASH diet compared to the control diet was associated with a significant reduction in weight [-5.78 (1.91) kg versus -4.34 (2.87) kg, P = 0.032], body mass index (BMI) [-2.29 (0.15) kg m^-2 versus -1.69 (0.20) kg m^-2 , P = 0.02], fat mass [-3.23(1.66) kg versus -2.13 (1.26) kg, P = 0.008] and serum androstenedione [-1.75 (1.39) ng mL^-1 versus -1.02 (0.72) ng mL^-1 , P-value = 0.019]. Increased concentrations of SHBG [28.80 (21.71) versus 11.66(18.82) nmol L^-1 , P = 0.003) and DPPH scavenging activity [30.23% (19.09) versus 12.97% (25.12) were also found in the DASH group.

CONCLUSIONS

The DASH diet could improve weight loss, BMI and fat mass. Furthermore, it could result in a significant reduction in serum androstenedione and a significant increase in antioxidant status and SHBG.

Evidence of sexual dimorphism in placental vitamin D metabolism: Testosterone inhibits calcitriol-dependent cathelicidin expression

Male fetus and neonates show increased immune vulnerability compared to females, which results in a higher risk of perinatal infections. These differences could partially be due to sex steroids differential modulation of vitamin D metabolism; since calcitriol, the most active vitamin D metabolite, regulates immune responses and transcriptionally induces the antimicrobial peptide cathelicidin in the human placenta. Calcitriol availability depends on CYP27B1 and CYP24A1 expression, the cytochromes involved in its synthesis and degradation, respectively. However, the effects of testosterone upon these enzymes and the final biological outcome upon the calcitriol-dependent immune-target cathelicidin in the placenta have not been studied. In this study we show that testosterone significantly inhibited CYP27B1 while stimulated CYP24A1 gene expression in cultured trophoblasts. These effects were accompanied by CREB activation through cAMP-independent and androgen receptor-dependent mechanisms. Male placental cotyledons showed reduced basal CYP27B1 and cathelicidin gene expression compared to females (P<0.05). Testosterone concentration was higher in the cord blood of male neonates (P=0.007), whereas cathelicidin levels were lesser compared to females (P=0.002). Altogether our results suggest that male placentas produce less cathelicidin due to decreased calcitriol bioavailability. We propose that the observed sex-dependent differences in placental vitamin D metabolism contribute in fetal responses to infections and could partially explain why the increased male fetuses immune vulnerability. Moreover, gestational hyperandrogenemia could adversely affect placental vitamin D metabolism independently of fetal sex.

Direct vitamin D3 actions on rhesus macaque follicles in three-dimensional culture: assessment of follicle survival, growth, steroid, and antimüllerian hormone production

OBJECTIVE

To investigate the direct actions of active 1,25-dihydroxy vitamin D3 (VD3) upon primate follicular development at specific stages of folliculogenesis.

DESIGN

Secondary preantral follicles were isolated from rhesus monkeys ovaries, encapsulated in alginate, and cultured for 40 days. Follicles were randomly assigned to experimental groups of control, low-dose VD3 (LVD3; 25 pg/mL), and high-dose VD3 (HVD3; 100 pg/mL).

SETTING

National primate research center.

ANIMAL(S)

Adult, female rhesus macaques (Macaca mulatta).

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Follicle survival and growth, as well as oocyte size, were assessed. Progesterone (P₄), androstenedione (A₄), E₂, and antimüllerian hormone (AMH) concentrations in culture media were measured.

RESULT(S)

Compared with the control group, LVD3 increased preantral follicle survival at week 2 by >66%, while HVD3 increased antral follicle diameters at week 5. Follicles with diameters ≥500 μm at week 5 were categorized as fast-growing follicles. Higher percentages of fast-growing follicles were obtained after HVD3 treatment. Although P₄, A₄, and E₂ production by antral follicles was not altered by VD3, AMH concentrations were 36% higher in the LVD3 group relative to controls at week 5. Oocytes with larger diameters were retrieved from antral follicles developed in both LVD3 and HVD3 groups compared with controls.

CONCLUSION(S)

The addition of LVD3 increased preantral follicle survival and maintained AMH production by antral follicles, while HVD3 improved antral follicle growth. VD3 supplement promoted oocyte growth in in vitro-developed follicles. Direct actions of VD3 on the primate follicle appear to be both dose and stage dependent.

Nutrients as novel therapeutic approaches for metabolic disturbances in polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is one of the most common endocrine disorders among women. This disease is characterized by infertility, menstrual dysfunction, and hyperandrogenism. Also, PCOS is often associated with hyperlipidemia and impaired glucose tolerance, conditions that are associated with cardiovascular disorder, type 2 diabetes, cancer and hypertension. Evidence supports that some nutrients may affect the hormonal and metabolic disturbances of PCOS. Here in this study, we aimed to review the available literature that assessed the nutrients such as inostol, isoflavonids, resveratrol, vitamin D, and PUFA (polyunsaturated fatty acids), known to influence the hormonal and metabolic disturbances of PCOS, along with the strategies and future directions of nutrient supplementations in such patients.

The effect of alfacalcidiol and metformin on phenotype manifestations in women with polycystic ovary syndrome - a preliminary study

Aim of this study was to evaluate the effect of vitamin D supplementation in obese, insulin resistant and vitamin D deficient PCOS women on biochemical and clinical hyperandrogenism and menstrual irregularity in comparison to effect of metformin or combined metformin plus vitamin D therapy. Thirty nine PCOS women were randomized into three groups and treated with alfacalcidiol (Group 1), combined alfacalcidiol and metformin therapy (Group 2) and metformin (Group 3) for 6 months. Serum TST, fTST, DHEAS, LH and LH/FSH were measured before and after six months of treatment. Menstrual cycle regularity, hirsutism, acne and pregnancy rate were assessed at the same time. There was a significant decrease in TST levels in the Group 2 and slight but not significant decrease in the Group 3. No significant changes in other parameters (fTST, DHEAS, LH, LH/FSH) have been found after 6 months therapy in all three groups. An improvement of menstrual cycle was detected in 78 % of patients in Group 1 (p<0.04), 80 % in the Group 2 (p<0.03) and in 90 % in the Group 3 (p<0.002), respectively. There was no significant improvement of acne and hirsutism in all three groups (all p not significant). Pregnancy rate was higher in the Group 3 as compared with Groups 1 and 2 (67 % vs. 0 % and 25 %, respectively), however without statistical significance. Vitamin D administration has no significant effect on androgen levels and clinical features of hyperandrogenism in obese vitamin D deficient PCOS women. However, it can potentiate effect of metformin on testosterone levels and LH/FSH ratio but not on clinical hyperandrogenism and pregnancy rate.

Increasing serum 25-hydroxyvitamin D is associated with reduced odds of long menstrual cycles in a cross-sectional study of African American women

OBJECTIVE

To examine the association between serum 25-hydroxyvitamin D [25(OH)D] and menstrual cycle length and regularity.

DESIGN

Community-based, cross-sectional study of serum 25(OH)D (adjusted for seasonal differences in timing of blood draw) and menstrual cycle length. Women aged 23-34 years reported their gynecologic history. Menstrual cycles were described with four independent categories (normal, short, long, irregular). We used polytomous logistic regression to estimate the association between a doubling of seasonally adjusted 25(OH)D and the odds of each cycle category.

SETTING

Not applicable.

PATIENT(S)

A total of 1,102 African American women.

INTERVENTION(S)

Not applicable.

MAIN OUTCOME MEASURE(S)

Self-reported menstrual cycle length over the previous 12 months, excluding women who were using cycle-regulating medications over the entire year. Women who reported that their cycles were "too irregular to estimate" were classified as having irregular cycles. A typical cycle length of <27 days was considered "short," >34 days was "long," and 27-34 days was "normal."

RESULT(S)

The median 25(OH)D level was 14.7 ng/mL (interquartile range, 10.9-19.6 ng/mL). A doubling of 25(OH)D was associated with half the odds of having long menstrual cycles: adjusted odds ratio (aOR) 0.54, 95% confidence interval (CI) 0.32-0.89. 25-Hydroxyvitamin D was not associated with the occurrence of short (aOR 1.03, 95% CI 0.82-1.29) or irregular (aOR 1.46, 95% CI 0.88-2.41) menstrual cycles. Results were robust to several sensitivity analyses.

CONCLUSION(S)

These findings suggest that vitamin D status may influence the menstrual cycle and play a role in ovarian function. Further investigation of 25(OH)D and ovarian hormones, and prospective studies of 25(OH)D and cycle length, are needed.

Expression and function of transient receptor potential channels in the female bovine reproductive tract

The epithelium lining the oviduct is critical for early reproductive events, many of which are mediated via intracellular calcium ions. Despite this, little is known about the regulation of calcium homeostasis in the oviductal epithelium. Epithelial transient receptor potential channels (TRPCs) modulate calcium flux in other tissues, and their expression and functional regulation have therefore been examined using the bovine oviduct as a model for the human. The effects of FSH, LH, 17β-estradiol, and progesterone on TRPCs expression and intracellular calcium flux were determined. Transient receptor potential channels 1, 2, 3, 4, and 6 were expressed in the bovine reproductive tract, and their gene expression varied throughout the estrous cycle. In more detailed studies undertaken on TRPC1 and 6, we show that protein expression varied through the estrus cycle; specifically, 17β-estradiol, FSH, and LH individually and in combination upregulated TRPC1 and 6 expression in cultured bovine oviduct epithelial cells although progesterone antagonized these effects. Functional studies showed changes in calcium mobilization in bovine oviduct epithelial cells were dependent on TRPCs. In conclusion, TRPC1, 2, 3, 4, and 6 are present in the epithelium lining the bovine oviduct, and TRPC1 and 6 vary through the estrous cycle suggesting an important role in early reproductive function.

Vitamin D Deficiency among Adolescent Females with Polycystic Ovary Syndrome

STUDY OBJECTIVE

Studies have suggested that low vitamin D levels may play a role in the pathogenesis of polycystic ovary syndrome (PCOS). The aim of our study was to compare 25-hydroxyvitamin D [25(OH)D] levels in adolescent females with and without PCOS.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective chart review at a tertiary care medical center for female adolescents aged 12-21 years with serum 25(OH)D measurements within a 5-year period. Participants were categorized as having PCOS or as controls based on National Institutes of Health PCOS diagnostic criteria.

MAIN OUTCOME MEASURE

Exact logistic regression analysis was done to compare normal (≥30 ng/mL) vs low (<30 ng/mL) serum 25(OH)D levels in the PCOS and control groups.

RESULTS

Two hundred ninety-nine charts were reviewed and 107 participants were included in the study. Of the included participants, 37 were in the PCOS group and 70 were in the control group, with a mean age of 15.2 years. In the PCOS group, 97.2% were obese and vitamin D deficiency was noted among 62.2% females. The mean serum 25(OH)D level was 18.4 and 21.6 ng/mL in PCOS and control groups, respectively. The difference in mean 25(OH)D levels between the 2 groups was not statistically significant (P > .05) when controlled for ethnicity, body mass index percentile, and season.

CONCLUSION

In our study, there was no statistically significant difference in mean 25(OH)D levels between PCOS and control groups. The majority of participants in PCOS group were obese. Further studies in adolescent females with PCOS and normal body mass index could be helpful in delineating the role of vitamin D in the pathogenesis of PCOS.

Lower plasma 25-hydroxyvitamin D is associated with irregular menstrual cycles in a cross-sectional study

BACKGROUND

In animals, low levels of vitamin D are associated with estrus cycle disturbances, but there are virtually no human data. We examined the association of 25-hydroxyvitamin D (25(OH)D) (a biomarker for vitamin D status) with menstrual cycle characteristics.

METHODS

Women aged 35-44 were randomly selected from a Washington D.C. health plan and invited to participate in the Uterine Fibroid Study (1996-1999). Our analysis includes 636 women (57% were African-American) who provided a blood sample and completed a telephone interview that included gynecologic history. Women were asked their usual cycle length in the preceding year. Women who reported it was "too irregular to estimate" were classified as having irregular cycles (N=48). Women were excluded if they currently or recently used hormonal contraception or any other medication that influences menstrual cycles. 25(OH)D was measured by radioimmunoassay in stored plasma samples.

RESULTS

The median 25(OH)D level was 12.0 ng/mL (interquartile range: 7.6, 19.7 ng/mL). After controlling for age, race, BMI, education, age of menarche, current smoking, alcohol use, and physical activity, a decrease in 25(OH)D of 10 ng/mL was associated with 1.9 times the odds of irregular cycles (Odds ratio (OR) (95% confidence interval (CI)): 1.9 (1.0, 3.4), p=0.04). 25(OH)D was not associated with the occurrence of short cycles (OR(CI): 1.08 (0.79, 1.48, p=0.6) or long cycles (OR(CI): 1.31 (0.66, 2.60), p=0.4).

CONCLUSIONS

Lower levels of 25(OH)D were associated with irregular cycles, but not with short or long cycles. Vitamin D may play a role in regulating ovulatory function. Further investigation of potential mechanisms is warranted.

Mechanisms in endocrinology: vitamin D as a potential contributor in endocrine health and disease

OBJECTIVE

It has been suggested that vitamin D may play a role in the pathogenesis of several endocrine diseases, such as hyperparathyroidism, type 1 diabetes (T1DM), type 2 diabetes (T2DM), autoimmune thyroid diseases, Addison's disease and polycystic ovary syndrome (PCOS). In this review, we debate the role of vitamin D in the pathogenesis of endocrine diseases.

METHODS

Narrative overview of the literature synthesizing the current evidence retrieved from searches of computerized databases, hand searches and authoritative texts.

RESULTS

Evidence from basic science supports a role for vitamin D in many endocrine conditions. In humans, inverse relationships have been reported not only between blood 25-hydroxyvitamin D and parathyroid hormone concentrations but also with risk of T1DM, T2DM, and PCOS. There is less evidence for an association with Addison's disease or autoimmune thyroid disease. Vitamin D supplementation may have a role for prevention of T2DM, but the available evidence is not consistent.

CONCLUSIONS

Although observational studies support a potential role of vitamin D in endocrine disease, high quality evidence from clinical trials does not exist to establish a place for vitamin D supplementation in optimizing endocrine health. Ongoing randomized controlled trials are expected to provide insights into the efficacy and safety of vitamin D in the management of endocrine disease.

Lower-limb veins are thicker and vascular reactivity is decreased in a rat PCOS model: concomitant vitamin D3 treatment partially prevents these changes

Polycystic ovary syndrome (PCOS) causes vascular damage to arteries; however, there are no data for its effect on veins. Our aim was to clarify the effects of dihydrotestosterone (DHT)-induced PCOS both on venous biomechanics and on pharmacological reactivity in a rat model and to test the possible modulatory role of vitamin D3 (vitD). PCOS was induced in female Wistar rats by DHT treatment (83 μg/day, subcutaneous pellet). After 10 wk, the venous biomechanics, norepinephrine (NE)-induced contractility, and acetylcholine-induced relaxation were tested in saphenous veins from control animals and from animals treated with DHT or DHT with vitD using pressure angiography. Additionally, the expression levels of endothelial nitric oxide synthase (eNOS) and cyclooxygenase (COX-2) were measured using immunohistochemistry. Increased diameter, wall thickness, and distensibility as well as decreased vasoconstriction were detected after the DHT treatment. Concomitant vitD treatment lowered the mechanical load on the veins, reduced distensibility, and resulted in vessels that were more relaxed. Although there was no difference in the endothelial dilation tested using acetylcholine (ACh), the blocking effect of N(G)-nitro-l-arginine methyl ester (l-NAME) was lower and was accompanied by lower COX-2 expression in the endothelium after the DHT treatment. Supplementation with vitD prevented these alterations. eNOS expression did not differ among the three groups. We conclude that the hyperandrogenic state resulted in thicker vein walls. These veins showed early remodeling and altered vasorelaxant mechanisms similar to those of varicose veins. Alterations caused by the chronic DHT treatment were prevented partially by concomitant vitD administration.

Vitamin D deficiency in women with polycystic ovary syndrome

Objective

To investigate: the prevalence of vitamin D deficiency in Korean women with polycystic ovary syndrome (PCOS), and the relationship between vitamin D status and clinical or metabolic features in this group.

Methods

We recruited 38 women with PCOS using the Rotterdam criteria. A total of 109 premenopausal control women were matched with patients based on age and body mass index. Serum 25-hydroxy vitamin D concentrations less than 20 ng/mL were classified as frank vitamin D deficiency. Since vitamin D may play a significant role in metabolic disturbances in women with PCOS, correlations between clinical or metabolic parameters and vitamin D status were analyzed separately in patients and controls.

Results

Women with PCOS showed no differences in the level of 25-hydroxy vitamin D (19.6±6.6 ng/mL in patients vs. 20.1±7.4 ng/mL in controls, respectively, p=0.696) or prevalence of vitamin D deficiency (57.9% in patients vs. 56.5% in controls, respectively, p=0.880). In addition, we did not find any correlations between serum vitamin D level and clinical or metabolic profiles in either PCOS patients or controls.

Conclusion

Our study found no differences in the absolute level of serum vitamin D between PCOS patients and matched controls. Prevalence of vitamin D deficiency was equally common among both patients and controls. Additionally, we did not find any correlations between serum vitamin D level and clinical or metabolic profiles, suggesting that the role of vitamin D in the pathogenesis of PCOS is not yet clear.

Genetic variation in the vitamin D receptor gene and vitamin D serum levels in Egyptian women with polycystic ovary syndrome

Obesity, insulin resistance, and hyperandrogenism are considered crucial parameters of polycystic ovary syndrome (PCOS) which might be related to vitamin D metabolism. The aim of this study was to investigate the associations between polymorphisms (TaqI and ApaI) in the vitamin D receptor gene (VDR) and PCOS among Egyptian women. We aimed also to elucidate the impact of these polymorphisms on vitamin D level, hormonal and metabolic parameters of PCOS. One hundred and fifty Egyptian women with PCOS and 150 unrelated controls were enrolled in this study. Polymorphisms of VDR Taq-I T/C (rs731236) and Apa-I A/C (rs7975232) gene were genotyped using polymerase chain reaction restriction fragment length polymorphism (PCR–RFLP). Serum 25 hydroxy vitamin D [25(OH) D] levels were measured by high-performance liquid chromatography. PCOS women had significantly lower levels of 25(OH) D compared to healthy women. Our results revealed that Taq-I CC genotype and C allele were associated with increased risk of PCOS, while the Apa-I polymorphism was not. Haplotype Taq-I C/ Apa-I C was associated with a higher PCOS risk more than controls. Moreover, there was a significant decrease of 25(OH) D levels in carriers of haplotype Taq-I C/ Apa-I C (with variant alleles) compared to the non-carriers. Results showed also that there was an obesity- VDR Taq-I genotypes interactions. These results suggested that, VDR Taq-I gene polymorphism is associated with increased risk of PCOS in Egyptian women.