Vitamin D and Cardiovascular Disease: An Updated Narrative Review.

During the last two decades, the potential impact of vitamin D on the risk of cardiovascular disease (CVD) has been rigorously studied. Data regarding the effect of vitamin D on CVD risk are puzzling: observational data indicate an inverse nonlinear association between vitamin D status and CVD events, with the highest CVD risk at severe vitamin D deficiency; however, preclinical data and randomized controlled trials (RCTs) show several beneficial effects of vitamin D on the surrogate parameters of vascular and cardiac function. By contrast, Mendelian randomization studies and large RCTs in the general population and in patients with chronic kidney disease, a high-risk group for CVD events, largely report no significant beneficial effect of vitamin D treatment on CVD events. In patients with rickets and osteomalacia, cardiovascular complications are infrequently reported, except for an increased risk of heart failure. In conclusion, there is no strong evidence for beneficial vitamin D effects on CVD risk, either in the general population or in high-risk groups. Whether some subgroups such as individuals with severe vitamin D deficiency or a combination of low vitamin D status with specific gene variants and/or certain nutrition/lifestyle factors would benefit from vitamin D (metabolite) administration, remains to be studied.

Effects of Vitamin D Supplementation on Surrogate Markers of Fertility in PCOS Women: A Randomized Controlled Trial.

Vitamin D (VD) might play an important role in polycystic ovary syndrome (PCOS) and female fertility. However, evidence from randomized controlled trials (RCT) is sparse. We examined VD effects on anti-Müllerian hormone (AMH) and other endocrine markers in PCOS and non-PCOS women. This is a post hoc analysis of a single-center, double-blind RCT conducted between December 2011 and October 2017 at the endocrine outpatient clinic at the Medical University of Graz, Austria. We included 180 PCOS women and 150 non-PCOS women with serum 25-hydroxyvitamin D (25(OH)D) concentrations <75 nmol/L in the trial. We randomized subjects to receive 20,000 IU of VD3/week (119 PCOS, 99 non-PCOS women) or placebo (61 PCOS, 51 non-PCOS women) for 24 weeks. Outcome measures were AMH, follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol, dehydroepiandrosterone sulfate, and androstenedione. In PCOS women, we observed a significant treatment effect on FSH (mean treatment effect 0.94, 95% confidence interval [CI] 0.087 to 1.799, p = 0.031) and LH/FSH ratio (mean treatment effect -0.335, 95% CI -0.621 to 0.050, p = 0.022), whereas no significant effect was observed in non-PCOS women. In PCOS women, VD treatment for 24 weeks had a significant effect on FSH and LH/FSH ratio but no effect on AMH levels.

Genetic Components of 25-Hydroxyvitamin D Increase in Three Randomized Controlled Trials.

The 25-Hydroxyvitamin D (25[OH)D) serum concentration depends on vitamin D intake, endogenous vitamin D production and genetic factors. The latter have been demonstrated in large genome-wide association studies indicating that single nucleotide polymorphisms (SNPs) in genes related to the vitamin D metabolism are as important for serum 25(OH)D levels as the influence of season. The mechanism on how these SNPs influence serum 25(OH)D levels are still unclear. The aim of the present study was to investigate the genetic effects of ten selected SNPs related to vitamin D metabolism on 25-hydroxyvitamin D increase (∆25(OH)D) after vitamin D supplementation in three randomized controlled trials. Genotypes of SNPs related to vitamin D metabolism were determined in 411 participants with 25(OH)D concentrations < 75 nmol/l receiving 20,000 IU cholecalciferol per week for 8 or 12 weeks after study inclusion. For the vitamin D receptor (VDR) rs10783219 polymorphism, the minor A-allele was associated with lower ∆25(OH)D values in the entire study population (p = 0.022), which was not consistent in all three cohorts when analysed separately. VDR rs10783219 might therefore be a genetic modulator of increasing 25-hydroxyvitamin D concentrations. Considering the wide-spread use of vitamin D supplementation, future large and well-designed randomized controlled trials (RCTs) should investigate the clinical impact of this polymorphism.

Effects of vitamin D supplementation on metabolic and endocrine parameters in healthy premenopausal women: A randomized controlled trial.

BACKGROUND & AIMS: Vitamin D supplementation may affect glycemic as well as hormonal regulation. Thus, the aim of the current study was to investigate whether vitamin D supplementation has any significant effects on metabolic and endocrine parameters in healthy premenopausal women. Primary outcome measure was the plasma glucose area under the curve (AUCgluc). METHODS: The current study was a single-center, double-blind, randomized placebo-controlled trial that was conducted at the Medical University of Graz, Austria, between March 2013 and October 2017. One-hundred and fifty healthy premenopausal women with 25-hydroxyvitamin D [25(OH)D] concentrations <75 nmol/L once weekly received either 20,000 IU of cholecalciferol or placebo (2:1 ratio) over a total of 24 weeks. RESULTS: In total, 127 women [age 36.2 ± 8.7 years; BMI 25.3 ± 5.6 kg/m2; baseline 25(OH)D 55.8 ± 19.7 nmol/L] completed the study. Vitamin D supplementation had no significant effect on AUCgluc (mean treatment effect 11.70; p = 0.069), while it had a significant treatment effect on homeostatic model assessment-insulin resistance (HOMA-IR; mean treatment effect 0.31; p = 0.019) and quantitative insulin-sensitivity check index (QUICKI; mean treatment effect -0.019; p = 0.013). There was no significant effect on the remaining secondary outcome parameters. CONCLUSIONS: In this randomized-controlled trial in healthy premenopausal women, there was a significant treatment effect of vitamin D supplementation on HOMA-IR and QUICKI, while there was no significant treatment effect on AUCgluc.

Effects of Vitamin D Supplementation on Body Composition and Metabolic Risk Factors in Men: A Randomized Controlled Trial.

Vitamin D might play a role in metabolic processes and obesity. We therefore examined vitamin D effects on metabolic markers and obesity in a randomized controlled trial (RCT). This is a post-hoc analysis of the Graz Vitamin D&TT-RCT, a single-center, double-blind, randomized placebo-controlled trial. We included 200 healthy men with serum 25-hydroxyvitamin D (25(OH) D) levels <75 nmol/L. Subjects received 20,000 IU of vitamin D3/week (n = 100) or placebo (n = 100) for 12 weeks. Outcome measures were metabolic markers, anthropometric measures, and body composition assessed by Dual-energy X-ray absorptiometry. One-hundred and ninety-two men completed the study. We found a significant treatment effect on fasting glucose/fasting insulin ratio (-5.3 (-10.4 to -0.2), p = 0.040), whereas we observed no significant effect on the remaining outcome parameters. In subgroup analyses of men with baseline 25(OH)D levels <50 nmol/L (n = 80), we found a significant effect on waist circumference (1.6 (0.3 to 2.9) cm, p = 0.012), waist-to-hip ratio (0.019 (0.002 to 0.036), p = 0.031), total body fat (0.029 (0.004 to 0.055) %, p = 0.026), and android fat (1.18 (0.11 to 2.26) %, p = 0.010). In middle-aged healthy men, vitamin D treatment had a negative effect on insulin sensitivity. In vitamin D deficient men, vitamin D has an unfavorable effect on central obesity and body composition.

Effects of Vitamin D Supplementation on Bone Turnover and Bone Mineral Density in Healthy Men: A Post-Hoc Analysis of a Randomized Controlled Trial.

Vitamin D is well known for its effects on calcium and mineral metabolism. However, vitamin D effects on bone turnover markers (BTMs), which are used together with bone mineral density (BMD) to evaluate bone health, are less clear. We therefore examined vitamin D effects on BTMs (beta-cross laps (CTX) and osteocalcin (OC)) and BMD in a post-hoc analysis of a randomized controlled trial (RCT). This is a post-hoc analysis of the Graz Vitamin D&TT-RCT, a single-center, double-blind, randomized placebo-controlled trial conducted between December 2012 and November 2017 at the endocrine outpatient clinic at the Medical University of Graz, Austria. A total of 200 healthy men with serum 25-hydroxyvitamin D (25(OH)D) levels <75 nmol/L participated in the trial. Subjects were randomized to receive 20,000 IU of vitamin D3/week (n = 100) or placebo (n = 100) for 12 weeks. Outcome measures were BTMs, BMD, and trabecular bone score (TBS). A total of 192 men (mean age and 25(OH)D: 43 (±13) years and 54.9 (±18.3) nmol/L, respectively) completed the study. We found no significant treatment effect on BTMs, BMD, or TBS (p > 0.05 for all). In middle-aged healthy men, vitamin D treatment for 12 weeks had no significant effect on BTMs or BMD.

Vitamin D testing and treatment: a narrative review of current evidence.

Vitamin D testing and treatment is a subject of controversial scientific discussions, and it is challenging to navigate through the expanding vitamin D literature with heterogeneous and partially opposed opinions and recommendations. In this narrative review, we aim to provide an update on vitamin D guidelines and the current evidence on the role of vitamin D for human health with its subsequent implications for patient care and public health issues. Vitamin D is critical for bone and mineral metabolism, and it is established that vitamin D deficiency can cause rickets and osteomalacia. While many guidelines recommend target serum 25-hydroxyvitamin D (25[OH]D) concentrations of ≥50 nmol/L (20 ng/mL), the minimum consensus in the scientific community is that serum 25(OH)D concentrations below 25-30 nmol/L (10-12 ng/mL) must be prevented and treated. Using this latter threshold of serum 25(OH)D concentrations, it has been documented that there is a high worldwide prevalence of vitamin D deficiency that may require public health actions such as vitamin D food fortification. On the other hand, there is also reason for concern that an exploding rate of vitamin D testing and supplementation increases costs and might potentially be harmful. In the scientific debate on vitamin D, we should consider that nutrient trials differ from drug trials and that apart from the opposed positions regarding indications for vitamin D treatment we still have to better characterize the precise role of vitamin D for human health.

Effects of vitamin D supplementation on metabolic and endocrine parameters in PCOS: a randomized-controlled trial.

PURPOSE: Vitamin D status may be associated with insulin resistance and other key features of polycystic ovary syndrome (PCOS), but data from preliminary randomized controlled trials (RCTs) are conflicting. Therefore, we aimed to investigate the effects of vitamin D supplementation on plasma glucose area under the curve (AUCgluc, primary outcome measure) and on other metabolic and endocrine parameters (secondary outcome measures). METHODS: This study was a single-center, double-blind, randomized placebo-controlled trial conducted between December 2011 and July 2017 at the Medical University of Graz, Austria. One-hundred and eighty women with PCOS and 25-hydroxyvitamin D [25(OH)D] concentrations < 75 nmol/L were randomized in a 2:1 ratio to either receive 20,000 IU of cholecalciferol weekly or placebo over 24 weeks. Primary outcome was the between-group difference in AUCgluc at study end while adjusting for baseline values. RESULTS: In total, 123 participants completed the study [age 25.9 ± 4.7 years; BMI 27.5 ± 7.3 kg/m2; baseline 25(OH)D 48.8 ± 16.9 nmol/L, baseline fasting glucose 84 ± 8 mg/dL]. Vitamin D supplementation lead to a significant increase in 25(OH)D [mean treatment effect 33.4 nmol/L; 95% confidence interval (CI) 24.5 to 42.2; p < 0.001] but had no significant effect on AUCgluc (mean treatment effect - 9.19; 95% CI - 21.40 to 3.02; p = 0.139). Regarding secondary outcome measures, we observed a significant decrease in plasma glucose at 60 min during oral glucose tolerance test (mean treatment effect - 10.2 mg/dL; 95% CI - 20.2 to - 0.3; p = 0.045). CONCLUSIONS: Vitamin D supplementation had no significant effect on metabolic and endocrine parameters in PCOS with the exception of a reduced plasma glucose during OGTT.

Effects of vitamin D supplementation on androgens in men with low testosterone levels: a randomized controlled trial.

PURPOSE: It has been hypothesized that vitamin D is associated with androgen levels in men. We, therefore, aimed to evaluate whether vitamin D supplementation increases serum total testosterone (TT) levels in men with low TT levels at baseline. METHODS: The Graz Vitamin D&TT-RCT is a single-center, double-blind, randomized placebo-controlled trial conducted between March 2013 and November 2017 at the endocrine outpatient clinic at the Medical University of Graz, Austria. One-hundred healthy men with serum TT levels < 10.4 nmol/l and 25-hydroxyvitamin D [25(OH)D] levels < 75 nmol/l participated in the trial. Subjects were randomized to receive 20,000 IU of vitamin D3/week (n = 50) or placebo (n = 50) for 12 weeks. Primary outcome was TT measured using mass spectrometry. Secondary outcomes were free testosterone, free androgen index, sex hormone-binding globulin, estradiol, follicle-stimulating hormone, luteinizing hormone, metabolic characteristics, and body composition. RESULTS: Ninety-four men [mean age and 25(OH)D: 47 (± 12) years and 56.3 (± 18.3) nmol/l, respectively] completed the study. We found no significant treatment effect on serum TT or on the remaining secondary outcome variables. CONCLUSION: Vitamin D treatment had no effect on serum TT levels in middle-aged healthy men with low TT levels.

The Role of Vitamin D in Fertility and during Pregnancy and Lactation: A Review of Clinical Data.

Vitamin D deficiency is common and there exists a huge gap between recommended dietary vitamin D intakes and the poor vitamin D supply in the general population. While vitamin D is important for musculoskeletal health, there are accumulating data suggesting that vitamin D may also be important for fertility, pregnancy outcomes and lactation. Significant changes in vitamin D metabolism during pregnancy such as increased production of the "active vitamin D hormone" calcitriol support the important role of vitamin D in this setting. Observational studies show that vitamin D deficiency is a risk marker for reduced fertility and various adverse pregnancy outcomes and is associated with a low vitamin D content of breast milk. Meta-analyses of randomized controlled trials (RCTs) document that physiological vitamin D supplementation during pregnancy is safe and improves vitamin D and calcium status, thereby protecting skeletal health. Although certain RCTs and/or meta-analyses reported some other beneficial effects, it is still not clear whether vitamin D supplementation improves fertility or decreases the risk of adverse pregnancy outcomes such as low birth weight, pre-eclampsia and neonatal mortality, or reduces wheeze/asthma in the infants. Nevertheless, vitamin D supplementation in pregnant women is frequently required to achieve a sufficient vitamin D status as recommended by nutritional vitamin D guidelines. In this review, we provide an overview of systematic reviews, meta-analyses and large trials reporting clinical data on the role of vitamin D for fertility, pregnancy and lactation.

Rationale and Plan for Vitamin D Food Fortification: A Review and Guidance Paper.

Vitamin D deficiency can lead to musculoskeletal diseases such as rickets and osteomalacia, but vitamin D supplementation may also prevent extraskeletal diseases such as respiratory tract infections, asthma exacerbations, pregnancy complications and premature deaths. Vitamin D has a unique metabolism as it is mainly obtained through synthesis in the skin under the influence of sunlight (i.e., ultraviolet-B radiation) whereas intake by nutrition traditionally plays a relatively minor role. Dietary guidelines for vitamin D are based on a consensus that serum 25-hydroxyvitamin D (25[OH]D) concentrations are used to assess vitamin D status, with the recommended target concentrations ranging from ≥25 to ≥50 nmol/L (≥10-≥20 ng/mL), corresponding to a daily vitamin D intake of 10 to 20 µg (400-800 international units). Most populations fail to meet these recommended dietary vitamin D requirements. In Europe, 25(OH)D concentrations <30 nmol/L (12 ng/mL) and <50 nmol/L (20 ng/mL) are present in 13.0 and 40.4% of the general population, respectively. This substantial gap between officially recommended dietary reference intakes for vitamin D and the high prevalence of vitamin D deficiency in the general population requires action from health authorities. Promotion of a healthier lifestyle with more outdoor activities and optimal nutrition are definitely warranted but will not erase vitamin D deficiency and must, in the case of sunlight exposure, be well balanced with regard to potential adverse effects such as skin cancer. Intake of vitamin D supplements is limited by relatively poor adherence (in particular in individuals with low-socioeconomic status) and potential for overdosing. Systematic vitamin D food fortification is, however, an effective approach to improve vitamin D status in the general population, and this has already been introduced by countries such as the US, Canada, India, and Finland. Recent advances in our knowledge on the safety of vitamin D treatment, the dose-response relationship of vitamin D intake and 25(OH)D levels, as well as data on the effectiveness of vitamin D fortification in countries such as Finland provide a solid basis to introduce and modify vitamin D food fortification in order to improve public health with this likewise cost-effective approach.

Vitamin D supplementation and lipoprotein metabolism: A randomized controlled trial.

BACKGROUND: Vitamin D deficiency is associated with an unfavorable lipid profile, but whether and how vitamin D supplementation affects lipid metabolism is unclear. OBJECTIVE: To examine the effects of vitamin D supplementation on lipid and lipoprotein parameters. METHODS: This is a post hoc analysis of the single-center, double-blind, randomized, placebo-controlled Styrian Vitamin D Hypertension Trial (2011-2014). Two hundred individuals with arterial hypertension and 25-hydroxyvitamin D concentrations of <75 nmol/L were randomized to 2800 IU of vitamin D daily or placebo for 8 weeks. RESULTS: One hundred sixty-three participants (62.2 [53.1-68.4] years of age; 46% women) had available lipid data and were included in this analysis. Vitamin D supplementation significantly increased total cholesterol, triglycerides, very-low-density lipoprotein (VLDL) triglycerides, low-density lipoprotein (LDL) triglycerides, high-density lipoprotein (HDL) triglycerides, apolipoprotein B (ApoB), LDL-ApoB, ApoCII, ApoCIII, phospholipids, and ApoE (P < .05 for all). Except for ApoCII and ApoCIII and HDL-triglycerides, all other treatment effects remained statistically significant after adjustment for multiple testing with the Benjamini and Hochberg false discovery rate method. There was a nonsignificant increase in LDL cholesterol. Furthermore, no significant effects were seen on free fatty acids, lipoprotein (a), ApoAI, ApoAII, VLDL cholesterol, VLDL-ApoB, HDL cholesterol, LDL diameter, and VLDL diameter. CONCLUSIONS: The effects of vitamin D on lipid metabolism are potentially unfavorable. They require further investigation in view of the wide use of vitamin D testing and treatment.

Hormonal Contraceptive Use Is Associated With Higher Total but Unaltered Free 25-Hydroxyvitamin D Serum Concentrations.

Context: Intake of hormonal contraceptives (HC) is associated with higher total 25-hydroxyvitamin D [25(OH)D] concentrations, but the effect of HC on free 25(OH)D is unclear. Objective: We investigated whether free 25(OH)D concentrations differ according to use of HC. Design: This is a post hoc analysis of a randomized open trial. Setting: This study was conducted from 13 January to 9 May, 2016, at a clinical research organization in Esslingen, Germany. Participants: We included 201 apparently healthy women of childbearing age. Intervention: Participants were randomly assigned to receive a daily multimicronutrient supplement for 8 weeks; the supplement contained 200 IU (n =100) or 800 IU (n = 101) of vitamin D3. Main Outcome Measures: Primary outcome was the difference in free 25(OH)D between users and nonusers of HC. Results: Overall, 176 participants [median (25th to 75th percentiles) age: 25 (22 to 29) years] with available free 25(OH)D were included in the present analysis. At baseline, total 25(OH)D was significantly higher in users (n = 110) than in nonusers (n = 66) of HC [49.2 (33.4 to 63.4) vs 39.1 (23.8 to 52.5) nmol/L; P < 0.001], whereas there was no difference in free 25(OH)D [7.87 (6.50 to 10.11) vs 7.88 (6.35 to 10.12) pmol/L; P = 0.923]. These results were confirmed after multimicronutrient supplementation and in subgroups according to treatment allocation. Conclusions: Use of HC was associated with, on average, 26% higher total 25(OH)D, whereas free 25(OH)D values did not differ according to use of HC. These findings are relevant for epidemiological studies, but the physiological implications remain to be clarified.

Vitamin D, PCOS and androgens in men: a systematic review.

BACKGROUND: Accumulating evidence from animal and human studies suggests that vitamin D is involved in many functions of the reproductive system in both genders. AIM: The aim of this review was to provide an overview on the effects of vitamin D on polycystic ovary syndrome (PCOS) in women and androgen metabolism in men. METHODS: We performed a systematic literature search in PubMed for relevant English language publications published from January 2012 until September 2017. RESULTS AND DISCUSSION: The vitamin D receptor and vitamin D-metabolizing enzymes are found in reproductive tissues of women and men. In women, vitamin D status has been associated with several features of PCOS. In detail, cross-sectional data suggest a regulatory role of vitamin D in PCOS-related aspects such as ovulatory dysfunction, insulin resistance as well as hyperandrogenism. Moreover, results from randomized controlled trials (RCTs) suggest that vitamin D supplementation may be beneficial for metabolic, endocrine and fertility aspects in PCOS. In men, vitamin D status has been associated with androgen levels and hypogonadism. Further, there is some evidence for a favorable effect of vitamin D supplementation on testosterone concentrations, although others failed to show a significant effect on testosterone levels. CONCLUSION: In summary, vitamin D deficiency is associated with adverse fertility outcomes including PCOS and hypogonadism, but the evidence is insufficient to establish causality. High-quality RCTs are needed to further evaluate the effects of vitamin D supplementation in PCOS women as well as on androgen levels in men.

Vitamin D and Testosterone in Healthy Men: A Randomized Controlled Trial.

Context: Available evidence shows an association of vitamin D with androgen levels in men. However, results from preliminary randomized controlled trials (RCTs) are conflicting. Objective: To evaluate whether vitamin D supplementation increases total testosterone (TT) levels in healthy men. Design: The Graz Vitamin D&TT-RCT is a single-center, double-blind, randomized, placebo-controlled trial conducted between December 2012 and January 2017. Setting: Endocrine outpatient clinic at the Medical University of Graz, Austria. Participants: Ninety-eight healthy men with TT levels ≥10.4 nmol/L and 25-hydroxyvitamin D [25(OH)D] levels <75 nmol/L completed the study. Intervention: Subjects were randomly assigned to receive 20,000 IU/wk of vitamin D3 (n = 50) or placebo (n = 50) for 12 weeks. Main Outcome Measures: Primary outcome was TT measured using mass spectrometry. Secondary outcomes were free testosterone, sex hormone-binding globulin, estradiol, follicle-stimulating hormone, and luteinizing hormone levels; free androgen index; metabolic characteristics; and body composition. Results: In healthy men [mean values ± standard deviation: age, 39 years (±13 years); 25(OH)D level, 53.3 nmol/L (±18.3 nmol/L); TT, 19.1 nmol/L (±5.6 nmol/l)], no significant treatment effect on TT was found; however, there were significant effects on quantitative insulin sensitivity check index (QUICKI) and a trend toward decreased Matsuda index. In the treatment group, median (interquartile range) changes for TT, QUICKI, and Matsuda index were 0.5 nmol/L (-0.63 to 0.63 nmol/L; P = 0.497), -0.02 (-0.04 to 0.01; P = 0.034), and -0.9 (-3.2 to 0.8; P = 0.051), respectively. Conclusion: Vitamin D treatment had no effect on TT levels in middle-aged healthy men with normal baseline TT, but it significantly decreased QUICKI. Additional studies investigating vitamin D effects on TT and insulin sensitivity in healthy men are required.

Effects of vitamin D on blood pressure and cardiovascular risk factors: a randomized controlled trial.

UNLABELLED: Vitamin D deficiency is a risk factor for arterial hypertension, but randomized controlled trials showed mixed effects of vitamin D supplementation on blood pressure (BP). We aimed to evaluate whether vitamin D supplementation affects 24-hour systolic ambulatory BP monitoring values and cardiovascular risk factors. The Styrian Vitamin D Hypertension Trial is a single-center, double-blind, placebo-controlled study conducted from June 2011 to August 2014 at the endocrine outpatient clinic of the Medical University of Graz, Austria. We enrolled 200 study participants with arterial hypertension and 25-hydroxyvitamin D levels below 30 ng/mL. Study participants were randomized to receive either 2800 IU of vitamin D3 per day as oily drops (n=100) or placebo (n=100) for 8 weeks. Primary outcome measure was 24-hour systolic BP. Secondary outcome measures were 24-hour diastolic BP, N-terminal-pro-B-type natriuretic peptide, QTc interval, renin, aldosterone, 24-hour urinary albumin excretion, homeostasis model assessment-insulin resistance, triglycerides, high-density lipoprotein cholesterol, and pulse wave velocity. A total of 188 participants (mean [SD] age, 60.1 [11.3] years; 47% women; 25-hydroxyvitamin D, 21.2 [5.6] ng/mL) completed the trial. The mean treatment effect (95% confidence interval) for 24-hour systolic BP was -0.4 (-2.8 to 1.9) mm Hg (P=0.712). Triglycerides increased significantly (mean change [95% confidence interval], 17 [1-33] mg/dL; P=0.013), but no further significant effects were observed for secondary outcomes. Vitamin D supplementation in hypertensive patients with low 25-hydroxyvitamin D has no significant effect on BP and several cardiovascular risk factors, but it was associated with a significant increase in triglycerides. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT02136771.

Vitamin D and female fertility.

PURPOSE OF REVIEW: Apart from the well known effects of vitamin D on maintaining calcium homeostasis and promoting bone mineralization, there is some evidence suggesting that vitamin D also modulates human reproductive processes. We will review the most interesting and relevant studies on vitamin D and female fertility published over the past year. RECENT FINDINGS: In the past year, several observational studies reported a better in-vitro fertilization outcome in women with sufficient vitamin D levels (≥30 ng/ml), which was mainly attributed to vitamin D effects on the endometrium. One randomized controlled trial found an increased endometrial thickness in women with polycystic ovary syndrome (PCOS) receiving vitamin D during intrauterine insemination cycles. Further, vitamin D supplementation had a beneficial effect on serum lipids in PCOS women. Vitamin D treatment improved endometriosis in a rat model and increased vitamin D intake was related to a decreased risk of incident endometriosis. Vitamin D was also favorably associated with primary dysmenorrhea, uterine leiomyoma, and ovarian reserve in late reproductive aged women. SUMMARY: In women undergoing in-vitro fertilization, a sufficient vitamin D level (≥30 ng/ml) should be obtained. Vitamin D supplementation might improve metabolic parameters in women with PCOS. A high vitamin D intake might be protective against endometriosis.

Vitamin D effects on musculoskeletal health, immunity, autoimmunity, cardiovascular disease, cancer, fertility, pregnancy, dementia and mortality-a review of recent evidence.

BACKGROUND: Optimal vitamin D intake and its status are important not only for bone and calcium-phosphate metabolism, but also for overall health and well-being. Vitamin D deficiency and insufficiency as a global health problem are likely to be a risk for wide spectrum of acute and chronic illnesses. METHODS: A review of randomized controlled trials, meta-analyses, and other evidence of vitamin D action on various health outcomes. RESULTS: Adequate vitamin D status seems to be protective against musculoskeletal disorders (muscle weakness, falls, fractures), infectious diseases, autoimmune diseases, cardiovascular disease, type 1 and type 2 diabetes mellitus, several types of cancer, neurocognitive dysfunction and mental illness, and other diseases, as well as infertility and adverse pregnancy and birth outcomes. Vitamin D deficiency/insufficiency is associated with all-cause mortality. CONCLUSIONS: Adequate vitamin D supplementation and sensible sunlight exposure to reach optimal vitamin D status are among the front line factors of prophylaxis for the spectrum of disorders. Supplementation guidance and population strategies for the eradication of vitamin D deficiency must be included in the priorities of physicians, medical professionals and healthcare policy-makers.

Vitamin D and cancer mortality: systematic review of prospective epidemiological studies.

Accumulating evidence from experimental and epidemiological studies suggests that vitamin D deficiency might be a causal risk factor for cancer and therewith associated mortality. We performed a systematic review in Medline up to February 2012 to identify prospective studies on 25-hydroxyvitamin D (25[OH]D) and cancer mortality as well as on 25(OH)D and survival in cancer patients. Our search retrieved 13 studies on cancer-specific mortality and 20 studies on overall mortality in cancer patients. Data on 25(OH)D and cancer mortality were mainly derived from general populations. The results were inconsistent and yielded either no, inverse or positive associations. By contrast, the majority of studies in cancer patients showed that patients with higher 25(OH)D levels had a decreased risk of mortality. This relationship was particularly evident in cohorts of colorectal cancer patients. In contrast, there was no indication for increased mortality risk with higher vitamin D levels in any cancer cohort. In conclusion, the relationship of vitamin D status and cancerspecific mortality is still unclear and warrants further studies. Our results provide a strong rationale to perform prospective randomized controlled studies to document a potential effect of vitamin D supplementation on survival in cancer patients.

Vitamin D and cardiovascular disease: update and outlook.

Accumulating evidence suggests that vitamin D may play a role for cardiovascular health. Expression of the vitamin D receptor (VDR) and enzymes for vitamin D metabolism have been identified in the vasculature as well as in the heart. VDR knock-out mice suffer from cardiovascular disease (CVD) and even selective VDR deletion in cardiomyocytes causes myocardial hypertrophy. Many, but not all observational studies showed that vitamin D deficiency is associated with CVD and its risk factors. Low concentrations of 25-hydroxyvitamin D (25(OH)D) are an independent risk factor for cardiovascular events, in particular for strokes and sudden cardiac deaths. Only few randomized controlled trials (RCTs) are available on this topic. These RCTs are frequently limited by the additional supplementation of calcium which may increase the risk of CVD events. RCTs with pure vitamin D supplementation have partially but not consistently shown beneficial effects on cardiovascular risk factors such as arterial hypertension. A number of large RCTs on the impact of vitamin D supplementation on cardiovascular events and mortality have already started but limitations of the study designs such as inclusion of individuals with relatively high 25(OH)D concentrations have to be considered. At present, the evidence is not sufficient for general recommendations to supplement vitamin D in order to prevent and treat CVD. It should, however, be noted that justification for the prevention and treatment of vitamin D deficiency comes from evidence based benefits of vitamin D supplementation on musculoskeletal health.