Effects of High-Dose Vitamin D Supplementation on Metabolic Status and Pregnancy Outcomes in Pregnant Women at Risk for Pre-Eclampsia

Effect of early vitamin D supplementation on the incidence of preeclampsia in primigravid women: a randomised clinical trial in Eastern Democratic Republic of the Congo

BACKGROUND

Previous studies have reported the association between maternal vitamin D deficiency and preeclampsia. However, the efficacy of vitamin D supplementation in reducing the occurrence of preeclampsia remains unclear. The objective of this study was to evaluate the effect of cholecalciferol supplementation on the incidence of preeclampsia in primigravid women and its related maternal and foetal outcomes.

METHODS

A single-blinded clinical trial was conducted in fourteen antenatal care health facilities in the North (Goma, Mwesso, Nyiragongo) and South Kivu (Bukavu-Panzi) provinces of the Democratic Republic of Congo from March 1, 2020, to June 30, 2021. A total of 1300 primigravid women not exceeding 16 weeks of gestation were randomised with a 1:1 ratio to either the supplemented (A) or control (B) group. Each pregnant woman (A) presenting for antenatal care received a single monthly dose of cholecalciferol (60,000 IU) orally for 6 months. The control group received no vitamin D supplementation or placebo. Serum 25(OH)D was measured at recruitment and at 34 weeks of gestation. Outcomes were assessed monthly until delivery.

RESULTS

The median maternal age was 21 years (14-40), while the median gestational age was 15 weeks (5.4-29.0). A significant reduction in the risk of preeclampsia [RR = 0.36 (0.19-0.69); p = 0.001] and preterm delivery [RR = 0.5 (0.32-0.78); p = 0.002] was observed in the intervention group. An RR of 0.43 [(0.27-0.67); p < 0.001] was found for low birth weight. The RR for caesarean section was 0.63 [(0.52-0.75); p < 0.001]. The APGAR score at the 5th minute (p = 0.021) and the size of the newborn were significantly higher in the supplemented group (p = 0.005).

CONCLUSION

A single monthly dose (60,000 IU) of vitamin D supplementation, started in earlypregnancy, significantly reduced the incidence of preeclampsia and its maternal and foetal complications.

TRIAL REGISTRATION

ISRCTN Register with ISRCTN46539495 on 17 November 2020.

[Preeclampsia: Guidelines for clinical practice from the French College of Obstetricians and Gynecologists]

OBJECTIVE

To identify strategies to reduce maternal and neonatal morbidity related to preeclampsia.

MATERIAL AND METHODS

The quality of evidence of the literature was assessed following the GRADE® method with questions formulated in the PICO format (Patients, Intervention, Comparison, Outcome) and outcomes defined a priori and classified according to their importance. An extensive bibliographic search was performed on PubMed, Cochrane, EMBASE and Google Scholar databases. The quality of the evidence was assessed (high, moderate, low, very low) and recommendations were formulated as a (i) strong, (ii) weak or (iii) no recommendation. The recommendations were reviewed in two rounds with external reviewers (Delphi survey) to select the consensus recommendations.

RESULTS

Preeclampsia is defined by the association of gestational hypertension (systolic blood pressure≥140mmHg and/or diastolic blood pressure≥90mmHg) and proteinuria≥0.3g/24h or a Proteinuria/Creatininuria ratio≥30mg/mmol occurring after 20 weeks of gestation. Data from the literature do not show any benefit in terms of maternal or perinatal health from implementing a broader definition of preeclampsia. Of the 31 questions, there was agreement between the working group and the external reviewers on 31 (100%). In general population, physical activity during pregnancy should be encouraged to reduce the risk of preeclampsia (Strong recommendation, Quality of the evidence low) but an early screening based on algorithms (Weak recommendation, Quality of the evidence low) or aspirin administration (Weak recommendation, Quality of the evidence very low) is not recommended to reduce maternal and neonatal morbidity related to preeclampsia. In women with preexisting diabetes or hypertension or renal disease, or multiple pregnancy, the level of evidence is insufficient to determine whether aspirin administration during pregnancy is useful to reduce maternal and perinatal morbidity (No recommendation, Quality of the evidence low). In women with a history of vasculo-placental disease, low dose of aspirin (Strong recommendation, Quality of the evidence moderate) at a dosage of 100-160mg per day (Weak recommendation, Quality of the evidence low), ideally before 16 weeks of gestation and not after 20 weeks of gestation (Strong recommendation, Quality of the evidence low) until 36 weeks of gestation (Weak recommendation, Quality of the evidence very low) is recommended. In a high-risk population, additional administration of low molecular weight heparin is not recommended (Weak recommendation, Quality of the evidence moderate). In case of preeclampsia (Weak recommendation, Quality of the evidence low) or suspicion of preeclampsia (Weak recommendation, Quality of the evidence moderate, the assessment of PlGF concentration or sFLT-1/PlGF ratio is not routinely recommended) in the only goal to reduce maternal or perinatal morbidity. In women with non-severe preeclampsia antihypertensive agent should be administered orally when the systolic blood pressure is measured between 140 and 159mmHg or diastolic blood pressure is measured between 90 and 109mmHg (Weak recommendation, Quality of the evidence low). In women with non-severe preeclampsia, delivery between 34 and 36+6 weeks of gestation reduces severe maternal hypertension but increases the incidence of moderate prematurity. Taking into account the benefit/risk balance for the mother and the child, it is recommended not to systematically induce birth in women with non-severe preeclampsia between 34 and 36+6 weeks of gestation (Strong recommendation, Quality of evidence high). In women with non-severe preeclampsia diagnosed between 37+0 and 41 weeks of gestation, it is recommended to induce birth to reduce maternal morbidity (Strong recommendation, Low quality of evidence), and to perform a trial of labor in the absence of contraindication (Strong recommendation, Very low quality of evidence). In women with a history of preeclampsia, screening maternal thrombophilia is not recommended (Strong recommendation, Quality of the evidence moderate). Because women with a history of a preeclampsia have an increased lifelong risk of chronic hypertension and cardiovascular complications, they should be informed of the need for medical follow-up to monitor blood pressure and to manage other possible cardiovascular risk factors (Strong recommendation, Quality of the evidence moderate).

CONCLUSION

The purpose of these recommendations was to reassess the definition of preeclampsia, and to determine the strategies to reduce maternal and perinatal morbidity related to preeclampsia, during pregnancy but also after childbirth. They aim to help health professionals in their daily clinical practice to inform or care for patients who have had or have preeclampsia. Synthetic information documents are also offered for professionals and patients.

Vitamin D and preeclampsia: A systematic review and meta-analysis

Objectives

Preeclampsia is one of the most frequent pregnancy disorders, with a global incidence of 2%-8%. Serum 25-hydroxyvitamin D is an essential mineral for human health; some studies suggest link between 25-hydroxyvitamin D deficiency and preeclampsia, while others offer contradictory findings. Thus, the goal of this study is to evaluate the relationships between maternal 25- hydroxyvitamin D concentrations and the risk of preeclampsia. In addition to this, our study also evaluates the effects of 25- hydroxyvitamin D supplementation on the incidence of preeclampsia. Therefore, assessing 25- hydroxyvitamin D's potential as a possible intervention to lower the risk of preeclampsia.

Methods

The Medline database was queried from inception until July 2021 for randomized controlled trials and observational studies without any restrictions. The studies assessing the association between 25-hydroxyvitamin D deficiency and preeclampsia and the impact of 25-hydroxyvitamin D supplementation on the incidence of preeclampsia were incorporated. The results were reported using a random-effects meta-analysis and the Mantel-Haenszel odds ratio. A p-value of <0.05 was considered significant for the analysis.

Results

This analysis includes 34 papers, including 10 randomized controlled trials and 24 observational studies. According to our pooled analysis, 25-hydroxyvitamin D supplementation was significantly associated with a lower risk of preeclampsia in pregnant women (OR: 0.50; 95% CI: 0.40-0.63; p = 0.00001), while 25-hydroxyvitamin D deficiency was significantly associated with an increased risk of preeclampsia (OR: 4.30; 95 % CI: 2.57-7.18; p < 0.00001, OR: 1.71; 95 % Cl: 1.27-2.32; p = 0.0005, OR 1.61; 95 % Cl: 1.21-2.16; p = 0.001).

Conclusion

Results suggest that 25-hydroxyvitamin D has a significant relationship with preeclampsia as confirmed by the findings that low maternal 25-hydroxyvitamin D concentrations cause increased risk of preeclampsia while 25-hydroxyvitamin D supplementation reduces the incidence of preeclampsia. Our findings indicate that 25-hydroxyvitamin D supplementation can be used as a possible intervention strategy in preventing one of the most common causes of maternal mortality around the world, preeclampsia.

Micronutrient supplementation interventions in preconception and pregnant women at increased risk of developing pre-eclampsia: a systematic review and meta-analysis

BACKGROUND

Pre-eclampsia can lead to maternal and neonatal complications and is a common cause of maternal mortality worldwide. This review has examined the effect of micronutrient supplementation interventions in women identified as having a greater risk of developing pre-eclampsia.

METHODS

A systematic review was performed using the PRISMA guidelines. The electronic databases MEDLINE, EMBASE and the Cochrane Central Register of Controlled trials were searched for relevant literature and eligible studies identified according to a pre-specified criteria. A meta-analysis of randomised controlled trials (RCTs) was conducted to examine the effect of micronutrient supplementation on pre-eclampsia in high-risk women.

RESULTS

Twenty RCTs were identified and supplementation included vitamin C and E (n = 7), calcium (n = 5), vitamin D (n = 3), folic acid (n = 2), magnesium (n = 1) and multiple micronutrients (n = 2). Sample size and recruitment time point varied across studies and a variety of predictive factors were used to identify participants, with a previous history of pre-eclampsia being the most common. No studies utilised a validated prediction model. There was a reduction in pre-eclampsia with calcium (risk difference, -0.15 (-0.27, -0.03, I2 = 83.4%)), and vitamin D (risk difference, -0.09 (-0.17, -0.02, I2 = 0.0%)) supplementation.

CONCLUSION

Our findings show a lower rate of pre-eclampsia with calcium and vitamin D, however, conclusions were limited by small sample sizes, methodological variability and heterogeneity between studies. Further higher quality, large-scale RCTs of calcium and vitamin D are warranted. Exploration of interventions at different time points before and during pregnancy as well as those which utilise prediction modelling methodology, would provide greater insight into the efficacy of micronutrient supplementation intervention in the prevention of pre-eclampsia in high-risk women.

Effect of Vitamin D Supplementation on Serum 25-Hydroxyvitamin D and Homeostatic Model of Insulin Resistance Levels in Healthy Pregnancy: A Systematic Review and Meta-Analysis

Background

Progressive insulin resistance is a physiological condition during pregnancy that can lead to gestational diabetes. Given the association between low blood vitamin D levels and insulin resistance, the present meta-analysis evaluated the effect of vitamin D supplementation on serum 25-hydroxyvitamin D (25[OH]D) and the homeostatic model of insulin resistance (HOMA-IR) levels in non-diabetic pregnant women.

Methods

A comprehensive literature search was conducted using electronic databases and gateways such as Cochrane Library, Medline, Google Scholar, Science Direct, Web of Sciences, Embase, and Scopus. Articles up to 2020 in both English and Persian were included in the study. The effect of vitamin D supplementation on 25(OH)D and HOMA-IR was determined based on the differences in mean changes from baseline to post-intervention. Weighted mean and 95% confidence intervals (CI) were pooled using a random-effects model. Data were analyzed using STATA software.

Results

Four studies, including six trials with 380 participants, reported that vitamin D supplementation increased 25(OH)D (mean change: 13.72, 95% CI: 7.28-20.17) and decreased HOMA-IR (mean change: 1.46, 95% CI: 0.56-2.37) levels compared with the placebo group. A high weekly dose of vitamin D further reduced HOMA-IR levels (adjusted R²=77.99, I² residuals=80.49%, P=0.047). There was no significant association between the dose of vitamin D and 25(OH)D (P=0.974). Intervention duration was not associated with an increase in 25(OH)D (P=0.102), nor with a decrease in HOMA-IR (P=0.623).

Conclusion

Vitamin D supplementation increased 25(OH)D and decreased HOMA-IR levels in non-diabetic pregnant women. Vitamin D in high doses further reduced HOMA-IR, but did not affect 25(OH)D concentrations.

Maternal vitamin D and growth of under-five children: a systematic review and meta-analysis of observational and interventional studies

Background

Even though previous systematic reviews have reported on the role of prenatal vitamin D on birth outcomes, its effect on child growth is poorly understood.

Objective

To synthesize a systematic summary of the literature on the effect of maternal vitamin D supplementation on the linear growth of under-five children.

Method

This study includes studies (both observational and interventional with a control group) that evaluated the effects of prenatal vitamin D status on child linear growth. The mean child length/length for age with 95% confidence interval (CI) was pooled as the weighted mean difference using a random-effects model. A funnel plot was used to assess potential publication bias.

Results

A total of 45 studies and 66 reports covering a total population of 44,992 (19,683 intervention or high vitamin D group, and 25,309 control or low vitamin D group) were analyzed. Studies spanned from 1977 to 2022. The pooled weighted mean difference was 0.4 cm (95% CI: 0.15–0.65). A subgroup analysis, based on vitamin D supplementation frequency, showed that mothers who supplemented monthly or less frequently had a 0.7 cm (95% CI: 0.2–1.16 cm) longer child. Supplementation with a dose of >2000 international units increased child length at birth. The weighted mean difference was 0.35 cm (95% CI: 0.11–0.58).

Conclusion

The evidence from this review shows that maternal supplementation of vitamin D is associated with increased birth length. This is apparent at higher doses, low frequency (monthly or less frequent), and during the second/third trimester. It appears that vitamin D supplementation during pregnancy is protective of future growth in under-five children. Clinical trials are needed to establish evidence of effectiveness for the frequency and dose of supplementation.

Review: Influence of 25(OH)D Blood Concentration and Supplementation during Pregnancy on Preeclampsia Development and Neonatal Outcomes

Briefly, 25-hydroxyvitamin D (25(OH)D) plays an essential role in embryogenesis and the course of intra- and postnatal periods and is crucially involved in the functioning of the mother–placenta–fetus system. The low quantity of 25(OH)D during pregnancy can lead to an elevated risk for preeclampsia occurrence. Despite the numerous studies on the association of 25(OH)D deficiency and preeclampsia development, the current research on this theme is contradictory. In this review, we summarize and analyze study data on the effects of 25(OH)D deficiency and supplementation on pregnancy, labor, and fetal and neonatal outcomes.

Effects of vitamin D supplementation during pregnancy on bone health and offspring growth: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Whether vitamin D supplementation during pregnancy is beneficial to bone health and offspring growth remains controversial. Moreover, there is no universal agreement regarding the appropriate dose and the time of commencement of vitamin D supplementation during pregnancy.

OBJECTIVE

We aimed to systematically review the effects of vitamin D supplementation during pregnancy on bone development and offspring growth.

METHODS

A literature search for randomized controlled trials (RCTs) was performed in 7 electronic databases to identify relevant studies about the effects of vitamin D supplementation during pregnancy on bone development and offspring growth from inception to May 22, 2022. A Cochrane Risk Assessment Tool was used for quality assessment. Vitamin D supplementation was compared with placebo or standard supplements. The effects are presented as the mean differences (MDs) with 95% CIs. The outcomes include bone mineral content (BMC), bone mineral density (BMD), bone area (BA), femur length (FL) and humeral length (HL); measurement indicators of growth, including length, weight and head circumference; and secondary outcome measures, including biochemical indicators of bone health, such as the serum 25(OH)D concentration. Additionally, subgroup analyses were carried out to evaluate the impact of different doses and different initiation times of supplementation with vitamin D.

RESULTS

Twenty-three studies with 5390 participants met our inclusion criteria. Vitamin D supplementation during pregnancy was associated with increased humeral length (HL) (MD 0.13, 95% CI 0.06, 0.21, I2 = 0, P = 0.0007) during the fetal period (third trimester). Vitamin D supplementation during pregnancy was associated with a significantly increased length at birth (MD 0.14, 95% CI 0.04, 0.24, I2 = 24%, P = 0.005) and was associated with a higher cord blood 25(OH)D concentration (MD 48.74, 95% CI 8.47, 89.01, I2 = 100%, P = 0.02). Additionally, subgroup analysis revealed that birth length was significantly higher in the vitamin D intervention groups of ≤1000 IU/day and ≥4001 IU/day compared with the control group. Prenatal (third trimester) vitamin D supplementation was associated with a significant increase in birth length, while prenatal (second trimester) vitamin D supplementation was associated with a significant increase in birth weight.

CONCLUSION

Vitamin D supplementation during pregnancy may be associated with increased humeral length (HL) in the uterus, increased body length at birth and higher cord blood 25(OH)D concentration. Evidence of its effect on long-term growth in children is lacking. Additional rigorous high-quality, long-term and larger randomized trials are required to more fully investigate the effects of vitamin D supplementation during pregnancy.

Calcium for pre-eclampsia prevention: A systematic review and network meta-analysis to guide personalised antenatal care

BACKGROUND

Calcium supplementation reduces the risk of pre-eclampsia, but questions remain about the dosage to prescribe and who would benefit most.

OBJECTIVES

To evaluate the effectiveness of high (≥1 g/day) and low (<1 g/day) calcium dosing for pre-eclampsia prevention, according to baseline dietary calcium, pre-eclampsia risk and co-interventions, and intervention timing.

SEARCH STRATEGY

CENTRAL, PubMed, Global Index Medicus and CINAHL, from inception to 2 February 2021, clinical trial registries, reference lists and expert input (CRD42018111239).

SELECTION CRITERIA

Randomised controlled trials of calcium supplementation for pre-eclampsia prevention, for women before or during pregnancy. Network meta-analysis (NMA) also included trials of different calcium doses.

DATA COLLECTION AND ANALYSIS

Two independent reviewers extracted published data. The meta-analysis employed random-effects models and the NMA, a Bayesian random-effects model, to obtain direct and indirect effect estimates.

MAIN RESULTS

The meta-analysis included 30 trials (N = 20 445 women), and the NMA to evaluate calcium dosage included 25 trials (N = 15 038). Calcium supplementation prevented pre-eclampsia similarly with a high dose (RR 0.49, 95% CI 0.36-0.66) or a low dose (RR 0.49, 95% CI 0.36-0.65). By NMA, high-dose (vs low-dose) calcium did not differ in effect (RR 0.79, 95% CI 0.43-1.40). Calcium was similarly effective regardless of baseline pre-eclampsia risk, vitamin D co-administration or timing of calcium initiation, but calcium was ineffective among women with adequate average baseline calcium intake.

CONCLUSIONS

Low- and high-dose calcium supplementation are effective for pre-eclampsia prevention in women with low calcium intake. This has implications for population-level implementation where dietary calcium is low, and targeted implementation where average intake is adequate.

TWEETABLE ABSTRACT

A network meta-analysis of 25 trials found that low-dose calcium supplementation (<1 g/day) is as effective as high-dose calcium supplementation (≥1 g/day) in halving the risk of pre-eclampsia when baseline calcium intake is low.

The Weak Relationship between Vitamin D Compounds and Glucose Homeostasis Measures in Pregnant Women with Obesity: An Exploratory Sub-Analysis of the DALI Study

Studies on the relationship between vitamin D (VitD) and glucose homeostasis usually consider either total VitD or 25OHD3 but not 25OHD2 and epimers. We aimed to evaluate the cross-sectional association of VitD compounds with glucose homeostasis measurements in pregnant women with overweight/obesity participating in the Vitamin D And Lifestyle Intervention for Gestational Diabetes Mellitus Prevention study. Methods: The analysis included 912 women. Inclusion criteria: <20 weeks gestation, body mass index ≥29 kg/m2 and information on exposure and outcome variables at baseline. Measurements: A 75 g OGTT at <20, 24−28 and 35−37 weeks gestation (except if previous diabetes diagnosis). Exposure variables: 25OHD2, 25OHD3 and C3-epimer. Outcome variables: fasting and post-challenge insulin sensitivity and secretion indices, corresponding disposition indices (DI), plasma glucose at fasting and 1 and 2 h, hyperglycemia in pregnancy (HiP). Statistics: Multivariate regression analyses with adjustment. Results: Baseline VitD sufficiency was 66.3%. Overall, VitD compounds did not show strong associations with any glucose homeostasis measures. 25OHD3 showed direct significant associations with: FPG at <20 and 24−28 weeks (standardized β coefficient (β) 0.124, p = 0.030 and 0.111, p = 0.026 respectively), 2 h plasma glucose at 24−28 weeks (β 0.120, p = 0.018), and insulin sensitivity (1/HOMA-IR, β 0.127, p = 0.027) at 35−37 weeks; it showed an inverse association with fasting DI (QUCKI*HOMA-β) at <20 and 24−28 weeks (β −0.124, p = 0.045 and β −0.148, p = 0.004 respectively). 25OHD2 showed direct associations with post-challenge insulin sensitivity (Matsuda, β 0.149, p = 0.048) at 24−28 weeks) and post-challenge DI (Matsuda*Stumvoll phase 1) at 24−28 and 35−37 weeks (β 0.168, p = 0.030, β 0.239, p = 0.006). No significant association with C3-epimer was observed at any time period. Conclusions: In these women with average baseline VitD in sufficiency range, VitD compounds did not show clear beneficial associations with glucose homeostasis measures.

Adherence to Oxidative Balance Scores is Associated with a Reduced Risk of Breast Cancer; A Case-Control Study

We aimed to examine whether anthropometric indices, dietary factors, and nutrient intakes of women with and without breast cancer (BrCa) are associated with the oxidative balance score (OBS). This case-control study was carried out among 253 patients with BrCa and 267 healthy subjects aged >18 years. The OBS was calculated by using the following 13 dietary and non-dietary anti- and prooxidant components: dietary antioxidants (selenium, fiber, β-carotene, vitamin D, vitamin C, vitamin E, and folate), dietary prooxidants (iron and saturated and polyunsaturated fatty acids), and nondietary anti- (physical activity) and prooxidants (smoking and obesity). The binary logistic regression was used to determine the association OBS with BrCa. After adjusting for potential confounders in the final model, there was evidence that the odds of BrCa decreased with increasing categories of the OBS (OR = 0.53, 95% CI 0.28 - 0.98; P-trend = 0.021). When we made stratified analysis by menopausal status, OBS was inversely associated with odds of BrCa in premenopausal women after adjusting for potential confounders. No significant association was found between OBS and odds of BrCa among post-menopausal women. Our data suggest that OBS scores were associated with decreased BrCa risk in the overall population.

Vitamin D supplementation higher than 2000 IU/day compared to lower dose on maternal–fetal outcome: Systematic review and meta-analysis

Introduction:

Although vitamin D is widely known as an essential micronutrient during pregnancy, the exact supplementation dose to prevent maternal–fetal outcomes remains a question. This study aims to provide a systematic review and a meta-analysis of data from randomized controlled trial on > 2000 IU/day vitamin D supplementation compared to ⩽ 2000 IU/day; and ⩽ 2000 IU/day compared to placebo, on their effects on the incidence of preeclampsia, gestational diabetes mellitus, preterm birth, and differences on birth weight.

Methods:

A systematic literature search on PubMed, EBSCO-MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials databases was carried out to evaluate randomized controlled trial studies on the effects of oral vitamin D > 2000 IU/day versus ⩽ 2000 IU/day; and ⩽ 2000 IU/day versus placebo, on preeclampsia, gestational diabetes mellitus, preterm birth and birth weight. Risk ratio, mean difference, and 95% confidence interval were calculated.

Results:

There were a total of 27 randomized controlled trials selected. Maternal vitamin D supplementation > 2000 IU/day had a positive effect only on gestational diabetes mellitus (seven randomized controlled trials; risk ratio = 0.70, 95% confidence interval: 0.51–0.95, I2 = 0). Vitamin D supplementation ⩽ 2000 IU/day has reduced the risk of preeclampsia (three randomized controlled trials; risk ratio = 0.29, 95% confidence interval: 0.09–0.95, I2 = 0), with no significant difference when compared to > 2000 IU/day (eight randomized controlled trials; risk ratio = 0.80, 95% confidence interval: 0.51–1.24, I2 = 31). No difference in preterm birth risk and birth weight after vitamin D supplementation. The quality of evidence varies from moderate to very low certainty. The risk of preeclampsia and gestational diabetes mellitus after high-dose versus low-dose vitamin D supplementation was the ones with moderate certainty.

Conclusion:

Vitamin D supplementation > 2000 IU/day might be important to reduce the risk of gestational diabetes mellitus. Lower dose vitamin D supplementation (⩽ 2000 IU/day) seemed adequate to reduce the risk of preeclampsia, with no significant difference compared to the higher dose.

Could Vitamin D Be Effective in Prevention of Preeclampsia?

Prevention of preeclampsia (PE) remains one of the most significant problems in perinatal medicine. Due to the possible unpredictable course of hypertension in pregnancy, primarily PE and the high complication rate for the mother and fetus/newborn, it is urgent to offer pregnant women in high-risk groups effective methods of preventing the PE development or delaying its appearance. In addition, due to the association of PE with an increased risk of developing cardiovascular diseases (CVD) in later life, effective preeclampsia prevention could also be important in reducing their incidence. Ideal PE prophylaxis should target the pathogenetic changes leading to the development of PE and be safe for the mother and fetus, inexpensive and freely available. Currently, the only recognized method of PE prevention recommended by many institutions around the world is the use of a small dose of acetylsalicylic acid in pregnant women with risk factors. Unfortunately, some cases of PE are diagnosed in women without recognized risk factors and in those in whom prophylaxis with acetylsalicylic acid is not adequate. Hence, new drugs which would target pathogenetic elements in the development of preeclampsia are studied. Vitamin D (Vit D) seems to be a promising agent due to its beneficial effect on placental implantation, the immune system, and angiogenic factors. Studies published so far emphasize the relationship of its deficiency with the development of PE, but the data on the benefits of its supplementation to reduce the risk of PE are inconclusive. In the light of current research, the key issue is determining the protective concentration of Vit D in a pregnant woman. The study aims to present the possibility of using Vit D to prevent PE, emphasizing its impact on the pathogenetic elements of preeclampsia development.

Effects of Maternal Nutritional Supplements and Dietary Interventions on Placental Complications: An Umbrella Review, Meta-Analysis and Evidence Map

The placenta is a vital, multi-functional organ that acts as an interface between maternal and fetal circulation during pregnancy. Nutritional deficiencies during pregnancy alter placental development and function, leading to adverse pregnancy outcomes, such as pre-eclampsia, infants with small for gestational age and low birthweight, preterm birth, stillbirths and maternal mortality. Maternal nutritional supplementation may help to mitigate the risks, but the evidence base is difficult to navigate. The primary purpose of this umbrella review is to map the evidence on the effects of maternal nutritional supplements and dietary interventions on pregnancy outcomes related to placental disorders and maternal mortality. A systematic search was performed on seven electronic databases, the PROSPERO register and references lists of identified papers. The results were screened in a three-stage process based on title, abstract and full-text by two independent reviewers. Randomized controlled trial meta-analyses on the efficacy of maternal nutritional supplements or dietary interventions were included. There were 91 meta-analyses included, covering 23 types of supplements and three types of dietary interventions. We found evidence that supports supplementary vitamin D and/or calcium, omega-3, multiple micronutrients, lipid-based nutrients, and balanced protein energy in reducing the risks of adverse maternal and fetal health outcomes. However, these findings are limited by poor quality of evidence. Nutrient combinations show promise and support a paradigm shift to maternal dietary balance, rather than single micronutrient deficiencies, to improve maternal and fetal health. The review is registered at PROSPERO (CRD42020160887).

Prevention and Management of Gestational Diabetes Using Vitamin D Supplementation: An Overview and Appraisal of Clinical Trials

A number of studies have examined the role of vitamin D in reproductive processes and disorders of pregnancy such as gestational diabetes mellitus (GDM). Although observational studies have linked maternal vitamin D deficiency with a plethora of adverse pregnancy outcomes including GDM, intervention trials generally do not support the use of vitamin D supplementation for GDM prevention or management. This narrative review provides an up-to-date overview and critical appraisal of randomised controlled trials (RCTs) to describe the current state of knowledge regarding the efficacy of vitamin D supplementation for preventing and/or managing GDM. Overall, although RCT data indicates a potential benefit of vitamin D in maternal glycaemic control, results are highly disparate and the data published to date have not conclusively established the efficacy of vitamin D in GDM prevention. There are, however, several limitations within the existing literature, including some considerable challenges that are unique to vitamin D trials, which should be carefully considered in the interpretation of the evidence and design of future studies. For now, many unanswered questions remain, and there is still a need for adequately powered and well-designed trials before routine supplementation can be recommended in the context of GDM.

Evaluation of the efficacy of two doses of vitamin D supplementation on glycemic, lipidemic and oxidative stress biomarkers during pregnancy: a randomized clinical trial

BACKGROUND

Vitamin D deficiency during pregnancy is common and is likely to be associated with metabolic complications in the mother. The aim of this study was to assess the efficacy of two doses of vitamin D supplementation during pregnancy on maternal and cord blood vitamin D status and metabolic and oxidative stress biomarkers.

METHODS

The eligible pregnant women (n = 84) invited to participate in the study and randomly allocated to one of the two supplementation groups (1000 IU/d vitamin D and 2000 IU/d). Biochemical assessments of mothers including serum concentrations of 25(OH)D, calcium, phosphate, iPTH, fasting serum sugar (FBS), insulin, triglyceride, total cholesterol, LDL-C, HDL-C, malondialdehyde (MDA) and total antioxidant capacity (TAC) were done at the beginning and 34 weeks of gestation. Cord blood serum concentrations of 25(OH)D, iPTH, MDA and TAC were assessed at delivery as well. To determine the effects of vitamin D supplementation on metabolic markers 1-factor repeated-measures analysis of variance (ANOVA) was used. Between groups comparisons was done by using Independent-samples Student's t-test or Mann-Whitney test. P < 0.05 was considered as significant.

RESULTS

Supplementation with 1000 IU/d and 2000 IU/d vitamin D resulted in significant changes in vitamin D status over pregnancy (24.01 ± 21.7, P < 0.001 in 1000 IU/d group and 46.7 ± 30.6 nmol/L, P < 0.001 in 2000 IU/d group). Daily intake of 2000 compared with 1000 IU/d tended to increase the serum concentration of HDL-C (10 ± 8.37, P < 0.001 in 1000 IU/d group and 9.52 ± 11.39 mg/dL, P < 0.001 in 2000 IU/d group). A significant decrement in serum concentration of iPTH observed in both groups (- 4.18 ± 7.5, P = 0.002 in 1000 IU/d group and - 8.36 ± 14.17, P = 0.002 in 2000 IU/d group).

CONCLUSIONS

Supplementation with 2000 IU/d vitamin D as compared with 1000 IU/d, is more effective in promoting vitamin D status and HDL-C serum concentration and in decreasing iPTH over pregnancy.

TRIAL REGISTRATION

This trial is registered at clinicaltrials.gov ( NCT03308487 ). Registered 12 October 2017 'retrospectively registered'.

Vitamin D Supplementation during Pregnancy: An Evidence Analysis Center Systematic Review and Meta-Analysis

BACKGROUND

Given the high rates of vitamin D deficiency among pregnant women and possible effects on offspring health, a systematic review on this topic was conducted to help inform future practice guidelines.

OBJECTIVE

To evaluate associations between maternal vitamin D supplementation, maternal 25-hydroxyvitamin D (25(OH)D) concentrations, and health outcomes.

METHODS

A PubMed literature search was conducted to identify studies that examined the health effects of vitamin D supplementation during pregnancy on maternal and infant health outcomes published from 2000 to 2016. Among 976 identified publications, 20 randomized clinical trials met the inclusion criteria. The initial search was extended to include five studies published between July 2016 and September 2018.

MAIN OUTCOME MEASURES

Maternal and infant 25(OH)D concentrations, gestational diabetes, preeclampsia or gestational hypertension, cesarean section, maternal parathyroid hormone and calcium concentrations, and infant gestational age, birth weight, and birth length.

STATISTICAL ANALYSES

Mean differences, odds ratios, and 95% CIs were calculated, only for the initial search, using separate random-effects meta-analyses for each outcome.

RESULTS

Evidence was good or strong that maternal vitamin D supplementation significantly increased maternal (13 studies, n=18, mean difference, 14.1 ng/mL [35.2 nmol/L]; 95% CI=9.6-18.6 ng/mL [24.0-46.4 nmol/L]) and infant (nine studies, n=12; 9.7, 5.2, 14.2 ng/mL [24.2, 12.9, 35.5 nmol/L]) 25(OH)D concentrations, although heterogeneity was significant (I²=95.9% and I²=97.4, respectively, P<0.001). Evidence was fair that vitamin D supplementation significantly decreases maternal homeostatic model assessment-insulin resistance (five studies, n=7; -1.1, -1.5, -0.7) and increases infant birth weight (nine studies, n=11, 114.2, 63.4, 165.1 g), both had insignificant heterogeneity. A null effect of maternal supplementation on other maternal (preeclampsia, cesarean section) and infant (gestational age, birth length) outcomes was found.

CONCLUSIONS

Results show vitamin D supplementation during pregnancy improves maternal and infant 25(OH)D concentrations and may play a role in maternal insulin resistance and fetal growth. To further inform practice and policies on the amount of vitamin D, which supports a healthy pregnancy, high quality dose-response randomized clinical trials, which assess pregnancy-specific 25(OH)D thresholds, and appropriately powered clinical outcomes are needed.

Regimens of vitamin D supplementation for women during pregnancy

BACKGROUND

Vitamin D deficiency during pregnancy increases the risk of pre-eclampsia, gestational diabetes, preterm birth, and low birthweight. In a previous Cochrane Review we found that supplementing pregnant women with vitamin D alone compared to no vitamin D supplementation may reduce the risk of pre-eclampsia, gestational diabetes, and low birthweight and may increase the risk of preterm births if it is combined with calcium. However the effects of different vitamin D regimens are not yet clear.

OBJECTIVES

To assess the effects and safety of different regimens of vitamin D supplementation alone or in combination with calcium or other vitamins, minerals or nutrients during pregnancy, specifically doses of 601 international units per day (IU/d) or more versus 600 IU/d or less; and 4000 IU/d or more versus 3999 IU/d or less.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (12 July 2018), and the reference lists of retrieved studies.

SELECTION CRITERIA

Randomised trials evaluating the effect of different vitamin D regimens (dose, frequency, duration, and time of commencement of supplementation during pregnancy), alone or in combination with other nutrients on pregnancy and neonatal health outcomes. We only included trials that compared 601 IU/d or more versus 600 IU/d or less and 4000 IU/d or more versus 3999 IU/d or less. We did not include in the analysis groups that received no vitamin D, as that comparison is assessed in another Cochrane Review.

DATA COLLECTION AND ANALYSIS

Two review authors independently: i) assessed the eligibility of studies against the inclusion criteria; ii) extracted data from included studies, and iii) assessed the risk of bias of the included studies. Our primary maternal outcomes were: pre-eclampsia, gestational diabetes, and any adverse effects; our primary infant outcomes were preterm birth and low birthweight. Data were checked for accuracy. The certainty of the evidence was assessed using the GRADE approach.

MAIN RESULTS

In this review, we included data from 30 trials involving 7289 women. We excluded 11 trials, identified 16 ongoing/unpublished trials and two trials are awaiting classification. Overall risk of bias for the trials was mixed.Comparison 1. 601 IU/d or more versus 600 IU/d or less of vitamin D alone or with any other nutrient (19 trials; 5214 participants)Supplementation with 601 IU/d or more of vitamin D during pregnancy may make little or no difference to the risk of pre-eclampsia (risk ratio (RR) 0.96, 95% confidence interval (CI) 0.65 to 1.42); 5 trials; 1553 participants,low-certainty evidence), may reduce the risk of gestational diabetes (RR 0.54, 95% CI 0.34 to 0.86; 5 trials; 1846 participants; moderate-certainty evidence), may make little or no difference to the risk of preterm birth (RR 1.25, 95% CI 0.92 to 1.69; 4 trials; 2294 participants; low-certainty evidence); and may make little or no difference to the risk of low birthweight (RR 0.90, 95% CI 0.66 to 1.24; 4 trials; 1550 participants; very low-certainty evidence) compared to women receiving 600 IU/d or less.Comparison 2. 4000 IU or more versus 3999 IU or less of vitamin D alone (15 trials; 4763 participants)Supplementation with 4000 IU/d or more of vitamin D during pregnancy may make little or no difference to the risk of: pre-eclampsia (RR 0.87, 95% CI 0.62 to 1.22; 4 trials, 1903 participants, low-certainty evidence); gestational diabetes (RR 0.89, 95% CI 0.56 to 1.42; 5 trials, 2276 participants; low-certainty evidence); preterm birth (RR 0.85, 95% CI 0.64 to 1.12; 6 trials, 2948 participants, low-certainty evidence); and low birthweight (RR 0.92, 95% CI 0.49 to 1.70; 2 trials; 1099 participants; low-certainty evidence) compared to women receiving 3999 IU/d or less.Adverse events (such as hypercalcaemia, hypocalcaemia, hypercalciuria, and hypovitaminosis D) were reported differently in most trials; however, in general, there was little to no side effects reported or similar cases between groups.

AUTHORS' CONCLUSIONS

Supplementing pregnant women with more than the current vitamin D recommendation may reduce the risk of gestational diabetes; however, it may make little or no difference to the risk of pre-eclampsia, preterm birth and low birthweight. Supplementing pregnant women with more than the current upper limit for vitamin D seems not to increase the risk of the outcomes evaluated. In general, the GRADE was considered low certainty for most of the primary outcomes due to serious risk of bias and imprecision of results. With respect to safety, it appears that vitamin D supplementation is a safe intervention during pregnancy, although the parameters used to determine this were either not reported or not consistent between trials. Future trials should be consistent in their reports of adverse events. There are 16 ongoing trials that when published, will increase the body of knowledge.

Vitamin D supplementation and incident preeclampsia: A systematic review and meta-analysis of randomized clinical trials

BACKGROUND

Maternal vitamin D deficiency has been associated with an increased risk for preeclampsia. Despite this, the current evidence regarding the efficacy of vitamin D supplementation in preventing preeclampsia is controversial. To assess the impact of vitamin D supplementation on the risk of preeclampsia, we performed a systematic review of the literature and a meta-analysis of the available randomized clinical trials (RCTs).

METHODS

The primary outcome was preeclampsia. Subgroup analyses were carried out considering the timing of the supplementation, type of intervention and the study design. Meta-regression analysis, including the amount of vitamin D and maternal age, were planned to explore heterogeneity (PROSPERO database registration number: CRD42019119207).

RESULTS

Data were pooled from 27 RCTs comprising 59 arms, which included overall 4777 participants, of whom 2487 were in the vitamin D-treated arm and 2290 in the control arm. Vitamin D administration in pregnancy was associated with a reduced risk of preeclampsia (odd ratio [OR] 0.37, 95% confidence interval [CI]: 0.26, 0.52; I² = 0%). If the vitamin D supplementation was started up to 20 weeks' gestation, the odds was a little lower (OR 0.35, 95% CI: 0.24, 0.50, p < 0.001). The effect was largely independent of the supplementation cessation (until delivery or not), type of intervention (vitamin D alone or in association with calcium), and study design. Increasing dose of vitamin D was associated with reduced incidence of preeclampsia (slope of log OR: -1.1, 95% CI: -1.73, -0.46; p < 0.001).

CONCLUSIONS

Results suggest that vitamin D supplementation may be useful in preventing preeclampsia. These data are especially useful for health-care providers who engage in the management of pregnant women at risk for preeclampsia. Our findings are a call for action to definitively address vitamin D supplementation as a possible intervention strategy in preventing preeclampsia in pregnancy.

Calcium Metabolic Disorders in Pregnancy: Primary Hyperparathyroidism, Pregnancy-Induced Osteoporosis, and Vitamin D Deficiency in Pregnancy

Physiologic changes during pregnancy include calcium, phosphate, and calciotropic hormone status. Calcium metabolic disorders are rare in pregnancy and management with close calcium and vitamin D control and supplementation. Primary hyperparathyroidism is mostly asymptomatic and does not affect conception or pregnancy. It requires control of plasma calcium levels. Surgical intervention may be indicated. Data on severe cases are missing. Osteoporosis in or before pregnancy is rare but usually diagnosed from fractures. Medical treatment other than supplementation is contraindicated. Vitamin D deficiency is common and may affect conception and increase complications. Current evidence does not prove vitamin D supplements effective in improving outcomes.

Vitamin D supplementation for women during pregnancy

BACKGROUND

Vitamin D supplementation during pregnancy may be needed to protect against adverse pregnancy outcomes. This is an update of a review that was first published in 2012 and then in 2016.

OBJECTIVES

To examine whether vitamin D supplementation alone or in combination with calcium or other vitamins and minerals given to women during pregnancy can safely improve maternal and neonatal outcomes.

SEARCH METHODS

For this update, we searched Cochrane Pregnancy and Childbirth's Trials Register (12 July 2018), contacted relevant organisations (15 May 2018), reference lists of retrieved trials and registries at clinicaltrials.gov and WHO International Clinical Trials Registry Platform (12 July 2018). Abstracts were included if they had enough information to extract the data.

SELECTION CRITERIA

Randomised and quasi-randomised trials evaluating the effect of supplementation with vitamin D alone or in combination with other micronutrients for women during pregnancy in comparison to placebo or no intervention.

DATA COLLECTION AND ANALYSIS

Two review authors independently i) assessed the eligibility of trials against the inclusion criteria, ii) extracted data from included trials, and iii) assessed the risk of bias of the included trials. The certainty of the evidence was assessed using the GRADE approach.

MAIN RESULTS

We included 30 trials (7033 women), excluded 60 trials, identified six as ongoing/unpublished trials and two trials are awaiting assessments.Supplementation with vitamin D alone versus placebo/no interventionA total of 22 trials involving 3725 pregnant women were included in this comparison; 19 trials were assessed as having low-to-moderate risk of bias for most domains and three trials were assessed as having high risk of bias for most domains. Supplementation with vitamin D alone during pregnancy probably reduces the risk of pre-eclampsia (risk ratio (RR) 0.48, 95% confidence interval (CI) 0.30 to 0.79; 4 trials, 499 women, moderate-certainty evidence) and gestational diabetes (RR 0.51, 95% CI 0.27 to 0.97; 4 trials, 446 women, moderate-certainty evidence); and probably reduces the risk of having a baby with low birthweight (less than 2500 g) (RR 0.55, 95% CI 0.35 to 0.87; 5 trials, 697 women, moderate-certainty evidence) compared to women who received placebo or no intervention. Vitamin D supplementation may make little or no difference in the risk of having a preterm birth < 37 weeks compared to no intervention or placebo (RR 0.66, 95% CI 0.34 to 1.30; 7 trials, 1640 women, low-certainty evidence). In terms of maternal adverse events, vitamin D supplementation may reduce the risk of severe postpartum haemorrhage (RR 0.68, 95% CI 0.51 to 0.91; 1 trial, 1134 women, low-certainty evidence). There were no cases of hypercalcaemia (1 trial, 1134 women, low-certainty evidence), and we are very uncertain as to whether vitamin D increases or decreases the risk of nephritic syndrome (RR 0.17, 95% CI 0.01 to 4.06; 1 trial, 135 women, very low-certainty evidence). However, given the scarcity of data in general for maternal adverse events, no firm conclusions can be drawn.Supplementation with vitamin D and calcium versus placebo/no interventionNine trials involving 1916 pregnant women were included in this comparison; three trials were assessed as having low risk of bias for allocation and blinding, four trials were assessed as having high risk of bias and two had some components having a low risk, high risk, or unclear risk. Supplementation with vitamin D and calcium during pregnancy probably reduces the risk of pre-eclampsia (RR 0.50, 95% CI 0.32 to 0.78; 4 trials, 1174 women, moderate-certainty evidence). The effect of the intervention is uncertain on gestational diabetes (RR 0.33,% CI 0.01 to 7.84; 1 trial, 54 women, very low-certainty evidence); and low birthweight (less than 2500 g) (RR 0.68, 95% CI 0.10 to 4.55; 2 trials, 110 women, very low-certainty evidence) compared to women who received placebo or no intervention. Supplementation with vitamin D and calcium during pregnancy may increase the risk of preterm birth < 37 weeks in comparison to women who received placebo or no intervention (RR 1.52, 95% CI 1.01 to 2.28; 5 trials, 942 women, low-certainty evidence). No trial in this comparison reported on maternal adverse events.Supplementation with vitamin D + calcium + other vitamins and minerals versus calcium + other vitamins and minerals (but no vitamin D)One trial in 1300 participants was included in this comparison; it was assessed as having low risk of bias. Pre-eclampsia was not assessed. Supplementation with vitamin D + other nutrients may make little or no difference in the risk of preterm birth < 37 weeks (RR 1.04, 95% CI 0.68 to 1.59; 1 trial, 1298 women, low-certainty evidence); or low birthweight (less than 2500 g) (RR 1.12, 95% CI 0.82 to 1.51; 1 trial, 1298 women, low-certainty evidence). It is unclear whether it makes any difference to the risk of gestational diabetes (RR 0.42, 95% CI 0.10 to 1.73) or maternal adverse events (hypercalcaemia no events; hypercalciuria RR 0.25, 95% CI 0.02 to 3.97; 1 trial, 1298 women,) because the certainty of the evidence for both outcomes was found to be very low.

AUTHORS' CONCLUSIONS

We included 30 trials (7033 women) across three separate comparisons. Our GRADE assessments ranged from moderate to very low, with downgrading decisions based on limitations in study design, imprecision and indirectness.Supplementing pregnant women with vitamin D alone probably reduces the risk of pre-eclampsia, gestational diabetes, low birthweight and may reduce the risk of severe postpartum haemorrhage. It may make little or no difference in the risk of having a preterm birth < 37 weeks' gestation. Supplementing pregnant women with vitamin D and calcium probably reduces the risk of pre-eclampsia but may increase the risk of preterm births < 37 weeks (these findings warrant further research). Supplementing pregnant women with vitamin D and other nutrients may make little or no difference in the risk of preterm birth < 37 weeks' gestation or low birthweight (less than 2500 g). Additional rigorous high quality and larger randomised trials are required to evaluate the effects of vitamin D supplementation in pregnancy, particularly in relation to the risk of maternal adverse events.

A systematic review and meta-analysis of the response of serum 25-hydroxyvitamin D concentration to vitamin D supplementation from RCTs from around the globe

BACKGROUND/OBJECTIVES

Optimal doses of vitamin D (VitD) supplement in different populations are unclear. We aim to evaluate the relationship between VitD supplementation and post-intervention serum 25-hydroxyvitamin D [25(OH)D] concentration, to provide a recommended dosage of VitD for achieving an optimal 25(OH)D concentration for different populations.

SUBJECTS/METHODS

Literature search was conducted in Embase, etc. Randomized controlled trials about VitD supplemental intakes and their effect on 25(OH)D concentration were enrolled. The effect on 25(OH)D concentration between different supplementation doses in each population group was compared by meta-analysis. Multivariate meta-regression model is utilized to establish reference intake dosage of VitD.

RESULTS

A total of 136 articles were included about children (3-17 years), adults (18-64 years), postmenopausal women, the elderly ( >64 years), pregnant, or lactating women. Overall, intervention groups obtained higher 25(OH)D concentration than controls and there was obvious dose-response effect between intake dose and 25(OH)D concentration. Baseline 25(OH)D concentration and age were significant indicators for 25(OH)D concentration. To reach sufficient 25(OH)D concentration (75 nmol/L), the recommended VitD supplemental intakes was 1340 and 2250 IU/day for children and pregnant women, 2519 and 797 IU/day for European adults aged 18-64 and 65-85 years, 729, 2026, and 1229 IU/day for adults in North America, Asia and Middle East and Africa, respectively.

CONCLUSIONS

Regional- and age-specific recommended dosages of VitD supplements for population to achieve optimal 25(OH)D concentrations have been suggested.

Maternal vitamin D deficiency and developmental origins of health and disease (DOHaD)

Vitamin D is an essential nutrient that is metabolized in the body to generate an active metabolite (1,25(OH)2D) with hormone-like activity and highly diverse roles in cellular function. Vitamin D deficiency (VDD) is a prevalent but easily preventable nutritional disturbance. Emerging evidence demonstrates the importance of sufficient vitamin D concentrations during fetal life with deficiencies leading to long-term effects into adulthood. Here, we provide a detailed review and perspective of evidence for the role of maternal VDD in offspring long term health, particularly as it relates to Developmental Origins of Health and Disease (DOHaD). We focus on roles in neurobehavioral and cardiometabolic disorders in humans and highlight recent findings from zebrafish and rodent models that probe potential mechanisms linking early life VDD to later life health outcomes. Moreover, we explore evidence implicating epigenetic mechanisms as a mediator of this link. Gaps in our current understanding of how maternal VDD might result in deleterious offspring outcomes later in life are also addressed.

The effect of vitamin D supplementation on oxidative stress parameters: A systematic review and meta-analysis of clinical trials

Recent studies have shown that vitamin D supplementation beneficially decreases oxidative stress (OS) parameters; however, there is no consensus on this subject. In this systematic review and meta-analysis we aimed to investigate the effect of vitamin D supplementation on OS parameters. We searched electronic databases including Medline, Embase, Scopus, Web of Science and Cochrane Library up to July 2018 without any language restriction. Trials were reviewed using preferred reporting items for systematic reviews and meta-analyses (PRISMA) and Cochrane handbook. To compare the effects of vitamin D with placebo, standardized mean difference (SMD) with 95% confidence intervals (CI) were pooled using random effects model. Across thirteen clinical trials, we found that vitamin D supplementation increased serum levels of total antioxidant capacity (TAC) (SMD: 0.54 mmol/L, 95% CI: 0.29 to 0.79; I² = 65.4%, P = 0.001) and glutathione (GSH) (SMD: 0.33; 95% CI: 0.11 to 0.54, P = 0.003; I² = 61.2%, P = 0.001). Besides, malondialdehyde (MDA) concentration decreased significantly (SMD: -0.40 mmol/L, 95% CI: -0.60 to -0.21, P < 0.001) following vitamin D supplementation compared to placebo. However, its effects on nitric oxide (NO) was not significant (0.17, 95% CI: -0.10 to 0.45, I² = 71.1%, P = 0.21). Finally, we showed that vitamin D supplementation can improve OS parameters; however, this finding may not be clinically significant. Further large prospective clinical trials are needed to confirm the effect of vitamin D supplement on other OS parameters.

The controversial role of vitamin D as an antioxidant: results from randomised controlled trials

Increased oxidative stress has been implicated as a potential causal factor in the development of several diseases. In the last decade, an extensive literature has been produced on vitamin D, not limited to its well-known function like a steroid hormone on skeletal tissue, but for its potential pleiotropic role in human health. Several researchers have suggested relationships between vitamin D intake and health outcomes such as cancer prevention and increased immunity, or possible role in preventing diabetes, and in inflammation. Little is known about its antioxidant effect. The aim of the present review was to explore major evidence regarding the potential scavenger capacity of vitamin D in high-evidence human studies. Studies considered by the present review suggest that the potential role of vitamin D as an antioxidant could not be confirmed. Current literature showed controversial effects about the ability of cholecalciferol to prevent or ameliorate oxidative stress biomarkers, and there is need of further and high-quality studies testing the antioxidant effect of vitamin D supplementation.

Association Between Vitamin D Supplementation During Pregnancy and Offspring Growth, Morbidity, and Mortality: A Systematic Review and Meta-analysis

IMPORTANCE

Whether vitamin D supplementation during pregnancy is beneficial and safe for offspring is unclear.

OBJECTIVE

To systematically review studies of the effects of vitamin D supplementation during pregnancy on offspring growth, morbidity, and mortality.

DATA SOURCES

Searches of Medline, Embase, and the Cochrane Database of Systematic Reviews were conducted up to October 31, 2017. Key search terms were vitamin D, pregnancy, randomized controlled trials, and offspring outcomes.

STUDY SELECTION

Randomized clinical trials of vitamin D supplementation during pregnancy and offspring outcomes.

DATA EXTRACTION AND SYNTHESIS

Two authors independently extracted data, and the quality of the studies was assessed. Summary risk ratio (RR), risk difference (RD) or mean difference (MD), and 95% CI were calculated using fixed-effects or random-effects meta-analysis.

MAIN OUTCOMES AND MEASURES

Main outcomes were fetal or neonatal mortality, small for gestational age (SGA), congenital malformation, admission to a neonatal intensive care unit, birth weight, Apgar scores, neonatal 25-hydroxyvitamin D (25[OH]D) and calcium concentrations, gestational age, preterm birth, infant anthropometry, and respiratory morbidity during childhood.

RESULTS

Twenty-four clinical trials involving 5405 participants met inclusion criteria. Vitamin D supplementation during pregnancy was associated with a lower risk of SGA (RR, 0.72; 95% CI, 0.52 to 0.99; RD, -5.60%; 95% CI, -0.86% to -10.34%) without risk of fetal or neonatal mortality (RR, 0.72; 95% CI, 0.47 to 1.11) or congenital abnormality (RR, 0.94; 95% CI, 0.61 to 1.43). Neonates with prenatal vitamin D supplementation had higher 25(OH)D levels (MD, 13.50 ng/mL; 95% CI, 10.12 to 16.87 ng/mL), calcium levels (MD, 0.19 mg/dL; 95% CI, 0.003 to 0.38 mg/dL), and weight at birth (MD, 75.38 g; 95% CI, 22.88 to 127.88 g), 3 months (MD, 0.21 kg; 95% CI, 0.13 to 0.28 kg), 6 months (MD, 0.46 kg; 95% CI, 0.33 to 0.58 kg), 9 months (MD, 0.50 kg; 95% CI, 0.01 to 0.99 kg), and 12 months (MD, 0.32 kg; 95% CI, 0.12 to 0.52 kg). Subgroup analysis by doses showed that low-dose vitamin D supplementation (≤2000 IU/d) was associated with a reduced risk of fetal or neonatal mortality (RR, 0.35; 95% CI, 0.15 to 0.80), but higher doses (>2000 IU/d) did not reduce this risk (RR, 0.95; 95% CI, 0.59 to 1.54).

CONCLUSIONS AND RELEVANCE

Vitamin D supplementation during pregnancy is associated with a reduced risk of SGA and improved infant growth without risk of fetal or neonatal mortality or congenital abnormality. Vitamin D supplementation with doses of 2000 IU/d or lower during pregnancy may reduce the risk of fetal or neonatal mortality.

Vitamin D in the Middle East and North Africa

PURPOSE

The Middle East and North Africa (MENA) region registers some of the lowest serum 25‑hydroxyvitamin D [25(OH)D] concentrations, worldwide. We describe the prevalence and the risk factors for hypovitaminosis D, completed and ongoing clinical trials, and available guidelines for vitamin D supplementation in this region.

METHODS

This review is an update of previous reviews published by our group in 2013 for observational studies, and in 2015 for randomized controlled trials (RCTs) from the region. We conducted a comprehensive search in Medline, PubMed, and Embase, and the Cochrane Library, using MeSH terms and keywords relevant to vitamin D, vitamin D deficiency, and the MENA region, for the period 2012-2017 for observational studies, and 2015-2017 for RCTs. We included large cross-sectional studies with at least 100 subjects/study, and RCTs with at least 50 participants per arm.

RESULTS

We identified 41 observational studies. The prevalence of hypovitaminosis D, defined as a 25‑hydroxyvitamin D [25(OH)D] level below the desirable level of 20 ng/ml, ranged between 12-96% in children and adolescents, and 54-90% in pregnant women. In adults, it ranged between 44 and 96%, and the mean 25(OH)D varied between 11 and 20 ng/ml. In general, significant predictors of low 25(OH)D levels were female gender, increasing age and body mass index, veiling, winter season, use of sun screens, lower socioeconomic status, and higher latitude.We retrieved 14 RCTs comparing supplementation to control or placebo, published during the period 2015-2017: 2 in children, 8 in adults, and 4 in pregnant women. In children and adolescents, a vitamin D dose of 1000-2000 IU/d was needed to maintain serum 25(OH)D level at target. In adults and pregnant women, the increment in 25(OH)D level was inversely proportional to the dose, ranging between 0.9 and 3 ng/ml per 100 IU/d for doses ≤2000 IU/d, and between 0.1 and 0.6 ng/ml per 100 IU/d for doses ≥3000 IU/d. While the effect of vitamin D supplementation on glycemic indices is still controversial in adults, vitamin D supplementation may be protective against gestational diabetes mellitus in pregnant women. In the only identified study in the elderly, there was no significant difference between 600 IU/day and 3750 IU/day doses on bone mineral density. We did not identify any fracture studies.The available vitamin D guidelines in the region are based on expert opinion, with recommended doses between 400 and 2000 IU/d, depending on the age category, and country.

CONCLUSION

Hypovitaminosis D is prevalent in the MENA region, and doses of 1000-2000 IU/d may be necessary to reach a desirable 25(OH)D level of 20 ng/ml. Studies assessing the effect of such doses of vitamin D on major outcomes, and confirming their long term safety, are needed.

Vitamin D and gestational diabetes mellitus: a systematic review based on data free of Hawthorne effect

BACKGROUND

Gestational diabetes mellitus (GDM) is an increasingly prevalent disorder, associated with low blood vitamin D level.

OBJECTIVES

To evaluate the relationship between vitamin D and GDM.

SEARCH STRATEGY

EMBASE, MEDLINE, Cochrane Library and China Biology Medicine disc were searched up to May 2017. The references of previous studies were screened.

SELECTION CRITERIA

Observational studies on the relationship between vitamin D and GDM free from Hawthorne effect and randomised controlled trials of vitamin D supplementation during pregnancy for preventing or treating GDM were included.

DATA COLLECTION AND ANALYSIS

Data and information of included articles were extracted by duplicate using piloted tables. Newcastle-Ottawa Scale and Cochrane Handbook were used for quality assessment. Random-effects models were used for meta-analyses. Heterogeneity tests, sensitivity analysis and analysis of publication bias were conducted.

MAIN RESULTS

Eighty-seven observational studies and 25 randomised controlled trials involving 55 859 and 2445 women, respectively, were included. Low blood vitamin D level during pregnancy was associated with a higher risk of GDM (OR 1.850, 95% CI 1.471-2.328). Blood vitamin D level for women with GDM were lower than in the control women. Blood vitamin D level was associated with fasting plasma glucose (FPG) and homeostasis model of assessment for insulin resistance index (HOMA-IR) (r = -0.100 and r = -0.351), whereas the correlation between blood vitamin D level and fasting insulin (FINS) might be concealed by publication bias. Vitamin D intervention during pregnancy could change the blood levels of vitamin D, FINS, FPG, HOMA-IR, glutathione, C-reactive protein and lipid.

CONCLUSIONS

Low blood vitamin D level could increase the risk of GDM, and vitamin D supplementation during pregnancy could ameliorate the condition of GDM.

TWEETABLE ABSTRACT

Low blood vitamin D increases gestational diabetes mellitus (GDM) risk. Vitamin D supplementation ameliorates GDM condition.

Clinical Trial on the Effects of Vitamin D Supplementation on Metabolic Profiles in Diabetic Hemodialysis

The current study was conducted to assess the effects of vitamin D supplementation on insulin metabolism, lipid fractions, biomarkers of inflammation, and oxidative stress in diabetic hemodialysis (HD) patients. This randomized double-blind placebo-controlled clinical trial was carried out among 60 diabetic HD patients. Subjects were randomly allocated into two groups to intake either oral vitamin D3 supplements at a dosage of 50 000 IU (n=30) or placebo (n=30) every 2 weeks for 12 weeks. After 12 weeks of intervention, subjects who received vitamin D supplements compared with the placebo had significantly decreased serum insulin concentrations (-3.4±3.7 vs. +2.0±4.2 μIU/ml, p<0.001), homeostasis model of assessment-estimated insulin resistance (HOMA-IR) (-1.2±1.8 vs. +0.9±2.3, p<0.001), and improved quantitative insulin sensitivity check index (QUICKI) (+0.02±0.03 vs. -0.01±0.02, p<0.001). In addition, compared with the placebo, vitamin D supplementation led to significant reductions in serum high-sensitivity C-reactive protein (hs-CRP) (-1.4±2.5 vs. +1.4±4.8 mg/l, p=0.007), plasma malondialdehyde (MDA) (-0.1±0.2 vs. +0.1±0.2 μmol/l, p=0.009) and a significant increase in plasma total antioxidant capacity (TAC) concentrations (+33.8±56.7 vs. -2.0±74.5 mmol/l, p=0.04). We did not see any significant effect of vitamin D supplementation on lipid profiles and other biomarkers of inflammation and oxidative stress compared with the placebo. Overall, we found that vitamin D supplementation had beneficial effects on serum insulin, HOMA-IR, QUICKI, serum hs-CRP, plasma MDA, and TAC levels among diabetic HD patients for 12 weeks. CLINICAL REGISTRATION:: http://www.irct.ir: IRCT201611155623N92.

Vitamin D, pre-eclampsia, and preterm birth among pregnancies at high risk for pre-eclampsia: an analysis of data from a low-dose aspirin trial

OBJECTIVE

To examine the relation between maternal vitamin D status and risk of pre-eclampsia and preterm birth in women at high risk for pre-eclampsia.

DESIGN

Analysis of prospectively collected data and blood samples from a trial of prenatal low-dose aspirin.

SETTING

Thirteen sites across the USA.

POPULATION

Women at high risk for pre-eclampsia.

METHODS

We measured 25-hydroxyvitamin D [25(OH)D] concentrations in stored maternal serum samples drawn at 12-26 weeks' gestation (n = 822). We used mixed effects models to examine the association between 25(OH)D and risk of pre-eclampsia and preterm birth, controlling for confounders including prepregnancy BMI and race.

MAIN OUTCOME MEASURES

Pre-eclampsia and preterm birth.

RESULTS

Twelve percent of women were vitamin D deficient [25(OH)D <30 nmol/l]. Women with 25(OH)D <30 versus ≥75 nmol/l had a 2.4-fold (95% CI 1.0-5.6) higher risk of early-onset pre-eclampsia (<35 weeks' gestation) after confounder adjustment. Women with 25(OH)D <50 nmol/l had a 1.8-fold (95% CI 1.0-3.2) increased risk of preterm birth at <35 weeks compared with women who had 25(OH)D ≥75 nmol/l, which was driven by indicated preterm births at <35 weeks' gestation [25(OH)D <50 versus ≥75 nmol/l adjusted RR 2.5 (95% CI 1.1-5.8)]. There was no association between vitamin D status and pre-eclampsia or preterm birth at <37 weeks.

CONCLUSION

Maternal vitamin D status in the second trimester was inversely associated with risk of early-onset pre-eclampsia and preterm birth at <35 weeks in women at high risk for pre-eclampsia.

TWEETABLE ABSTRACT

Vitamin D is inversely related to risk of pre-eclampsia and preterm birth at <35 weeks in high-risk pregnancies.

Vitamins supplementation affects the onset of preeclampsia

Preeclampsia may affect between 2-8% of all pregnancies. It seriously affects maternal health after pregnancy. This meta-analysis was performed to define the efficacy of vitamins supplementation on the risk of preeclampsia. Potential articles were systematically searched on the databases of Pubmed, Embase and Web of Science up to May 2016. Relative risk (RR) and 95% confidence intervals (95%CIs) were used to analyze the relationship of vitamins supplementation with risk of preeclampsia. Cochran Q test was used to test inter-study heterogeneity. Begg's funnel plot was adopted to assess the potential publication bias. 28 eligible studies were selected. Pooled results indicated that vitamins supplementation could reduce the risk of preeclampsia (RR = 0.74, 95%CI = 0.64-0.86). The studies with non-randomized controlled trial (RCT) analysis also suggested the significant relationship of vitamins supplementation with risk of preeclampsia (RR = 0.60, 95%CI = 0.42-0.85). However, negative results were observed in studies with RCT analysis. Subgroup analysis by vitamin type was performed among the studies with RCT analysis. The results indicated that vitamin D supplementation could significantly reduce the risk of preeclampsia (RR = 0.41, 95%CI = 0.22-0.78). Similar results were observed in the studies with multivitamins supplementation (RR = 0.69, 95%CI = 0.51-0.93). Vitamins supplementation could reduce the onset of preeclampsia.

Effect of Two Different Doses of Vitamin D Supplementation on Metabolic Profiles of Insulin-Resistant Patients with Polycystic Ovary Syndrome: A Randomized, Double-Blind, Placebo-Controlled Trial

The current study was conducted to evaluate the effects of 2 different doses of vitamin D supplementation on metabolic profiles of insulin-resistant patients with polycystic ovary syndrome (PCOS). This randomized double-blind, placebo-controlled trial was performed on 90 insulin-resistant patients with PCOS according to the Rotterdam criteria aged 18-40 years old. Participants were randomly allocated into 3 groups to receive either 4 000 IU of vitamin D (n=30) or 1 000 IU of vitamin D (n=30) or placebo (n=30) per day for 12 weeks. Vitamin D supplementation (4 000 IU), compared with vitamin D (1 000 IU) and placebo, led to reduced fasting plasma glucose (-4.3±8.6 vs. -4.7±7.1 and +0.1±6.7 mg/dl, respectively, p=0.02), serum insulin concentrations (-2.7±2.7 vs. -1.4±4.2 and -0.1±4.1 μIU/ml, respectively, p=0.02), and HOMA-IR (-0.6±0.6 vs. -0.4±1.0 and -0.1±0.9, respectively, p=0.02). In addition, we found significant decreases in mean change of serum triglycerides (-10.3±7.3 vs. -3.6±14.5 and +6.9±23.8 mg/dl, respectively, p=0.001), VLDL- (-2.0±1.5 vs. -0.7±2.9 and +1.4±4.8 mg/dl, respectively, p=0.001), total- (-14.0±9.5 vs. -6.2±24.0 and +7.1±29.7 mg/dl, respectively, p=0.002), LDL- (-10.8±8.3 vs. -5.7±21.9 and +6.8±28.2 mg/dl, respectively, p=0.005), and total-/HDL-cholesterol ratio (-0.2±0.3 vs. -0.1±0.6 and +0.2±0.7 mg/dl, respectively, p=0.003) in the high-dose vitamin D group compared with low-dose vitamin D and placebo groups. Overall, vitamin D supplementation at a dosage of 4 000 IU/day for 12 weeks in insulin-resistant patients with PCOS had beneficial effects of glucose metabolism and lipid profiles compared with 1 000 IU/day of vitamin D and placebo groups.

Vitamin D and its impact on maternal-fetal outcomes in pregnancy: A critical review

The role of vitamin D beyond its classical function in calcium homeostasis has been of significant interest in recent years. There has been expanding research on the pleiotropic role of vitamin D in pregnancy and the implications of its deficiency on maternal-fetal outcomes. Several studies have associated low maternal vitamin D status to adverse outcomes in pregnancy, including preeclampsia, gestational diabetes, preterm births, low birth weight, and others. Several randomized controlled clinical trials of Vitamin D supplementation during pregnancy have also been conducted. Though some of the studies found improvement in pregnancy outcomes with vitamin D supplementation, others have not shown any association. In this article, we have critically reviewed the observational and interventional studies, published primarily within the past two years (January 2014 to February 2016) on the influence of vitamin D deficiency on pregnancy and the impact of its supplementation. The potential underlying mechanisms of vitamin D in regulating each of the outcomes have also been discussed.

Vitamin D replacement in children, adolescents and pregnant women in the Middle East and North Africa: A systematic review and meta-analysis of randomized controlled trials

INTRODUCTION

Hypovitaminosis D affects one-third to two-thirds of children and pregnant women from the Middle East and North Africa (MENA) region.

OBJECTIVE

To evaluate in infants, children, adolescents and pregnant women, from the MENA region, the effect of supplementation with different vitamin D doses on the change in 25-hydroxyvitamin D [25(OH)D] level reached, and other skeletal and non-skeletal outcomes.

METHODS

This is a systematic review of randomized controlled trials of vitamin D supplementation conducted in the MENA region. We conducted a comprehensive literature search in 7 databases, without language or time restriction, until November 2016. Two reviewers abstracted data from the included studies, independently and in duplicate. We calculated the mean difference (MD) and 95% CI of 25(OH)D level reached when at least 2 studies were eligible in each comparison (low (<800IU), intermediate (800-2000IU) or high (>2000IU) daily dose of vitamin D, or placebo). We pooled data using RevMan version 5.3.

RESULTS

We identified a total of 15 eligible trials: one in infants, 4 in children and adolescents and 10 in pregnant women. In children and adolescents, an intermediate vitamin D dose (1901IU/d), resulted in a mean difference in 25(OH)D level of 13.5 (95% confidence interval (CI) 8.1-18.8) ng/ml, compared to placebo, favoring the intermediate dose (p<0.001). The proportion of children and adolescents reaching a 25(OH)D level≥ 20ng/ml was 74% in the intermediate dose group. In pregnant women, four trials started supplementation at 12-16weeks of gestation and continued until delivery, and six trials started supplementation at 20-28weeks' gestation and stopped it at delivery. The MD in 25(OH)D level reached was 8.6 (95% CI 5.3-11.9) ng/ml (p<0.001) comparing the high dose (3662IU/d) to the intermediate dose (1836IU/d), and 12.3 (95% CI 6.4-18.2) ng/ml (p<0.001), comparing the high dose (3399IU/d) to the low dose (375IU/d). Comparing the intermediate (1832IU/d) to the low dose (301IU/d), the MD in 25(OH)D level achieved was 7.8 (95% CI 4.5-10.8) ng/ml (p<0.001). The proportion of pregnant women reaching a 25(OH)D level≥20ng/ml was 80%-90%, 73% and 27%-43% in the high, intermediate, and low dose groups, respectively. The risk of bias in the included studies, for children, adolescents and pregnant women, ranged from low to high across all doamins.

CONCLUSION

In children, adolescents and pregnant women from the MENA, an intermediate vitamin D dose of 1000-2000IU daily may be necessary to allow for the majority of the population to reach a desirable 25(OH)D level of 20ng/ml. Further high quality RCTs are required to confirm/refute the beneficial impact of vitamin D supplementation on various clinically important outcomes.

The effects of vitamin D supplementation on wound healing and metabolic status in patients with diabetic foot ulcer: A randomized, double-blind, placebo-controlled trial

OBJECTIVE

This study was conducted to evaluate the effects of vitamin D supplementation on wound healing and metabolic status in patients with diabetic foot ulcer (DFU).

METHODS

This randomized, double-blind, placebo-controlled trial was performed among 60 patients with grade 3 DFU according to "Wagner-Meggitt's" criteria. Participants were randomly divided into two groups (each 30 participants) and received either 50,000IU vitamin D supplements every 2weeks for 12weeks (group A) or placebo (group B). Fasting blood samples were taken at study baseline and after 12-week intervention to determine related markers.

RESULTS

After 12weeks of intervention, compared with the placebo, vitamin D supplementation resulted in a significant reduction in ulcer length (-2.1±1.1 vs. -1.1±1.1cm, P=0.001), width (-2.0±1.2 vs. -1.1±1.0cm, P=0.02) and depth (-1.0±0.5 vs. -0.5±0.5cm, P<0.001), and erythema rate (100% vs. 80%, P=0.01). In addition, in supplemented patients changes in serum insulin concentration (-3.4±9.2 vs. +2.8±9.3 μIU/mL, P=0.01), homeostasis model of assessment-estimated insulin resistance (-1.5±4.1 vs. +1.7±5.1, P=0.01), the quantitative insulin sensitivity check index (+0.006±0.02 vs. -0.006±0.02, P=0.03) and HbA1c (-0.6±0.6 vs. -0.1±0.5%, P=0.004) were significantly different from those of patients in the placebo group. Additionally, following supplementation with vitamin D, significant reductions in serum total- (-15.8±18.9 vs. +5.3±31.8mg/dL, P=0.003), LDL- (-17.2±19.8 vs. +2.2±28.6mg/dL, P=0.003), total-/HDL-cholesterol ratio (-1.1±0.8 vs. -0.2±1.1, P=0.001), high sensitivity C-reactive protein (hs-CRP) (-0.4±2.5 vs. +1.9±4.2μg/mL, P=0.01), erythrocyte sedimentation rate (ESR) (-34.7±32.4 vs. -18.0±26.6mm/h, P=0.03) and plasma malondialdehyde (MDA) concentrations (-0.7±0.9 vs. -0.2±0.5μmol/L, P=0.008) were seen compared with the placebo.

CONCLUSIONS

Overall, vitamin D supplementation for 12weeks among patients with DFU had beneficial effects on glucose homeostasis, total-, LDL-, total-/HDL-cholesterol, ESR, hs-CRP and MDA levels. In addition, vitamin D may have played an indirect role in wound healing due to its effect on improved glycemic control.

The Effects of Vitamin D-K-Calcium Co-Supplementation on Endocrine, Inflammation, and Oxidative Stress Biomarkers in Vitamin D-Deficient Women with Polycystic Ovary Syndrome: A Randomized, Double-Blind, Placebo-Controlled Trial

The current study was conducted to assess the effects of vitamin D-K-calcium co-supplementation on endocrine, inflammation, and oxidative stress biomarkers in vitamin D-deficient women with polycystic ovary syndrome (PCOS). This randomized double-blind, placebo-controlled trial was performed on 60 vitamin D-deficient women diagnosed with PCOS aged 18-40 years old. Participants were randomly allocated into 2 groups to intake either 200 IU vitamin D, 90 μg vitamin K plus, 500 mg calcium supplements (n=30), or placebo (n=30) twice a day for 8 weeks. Endocrine, inflammation, and oxidative stress biomarkers were quantified at the beginning and the end of the study. After 8 weeks of intervention, compared with the placebo, vitamin D-K-calcium co-supplementation resulted in a significant reduction in serum-free testosterone (- 2.1±1.6 vs.+0.1±1.0 pg/ml, p<0.001) and dehydroepiandrosterone sulfate (DHEAS) levels (- 0.8±1.0 vs.-0.1±0.5 μg/ml, p=0.006). In addition, a significant increase in plasma total antioxidant capacity (TAC) (+ 75.7±126.1 vs.-80.4±242.8 mmol/l, p=0.005) and a significant difference in plasma malondialdehyde (MDA) concentrations (+ 0.03±0.6 vs.+1.4±2.4 μmol/l, p=0.005) was observed following the supplementation with vitamin D-K-calcium compared with the placebo. A trend toward a greater decrease in luteinizing hormone was observed in vitamin D-K-calcium co-supplement group compared to placebo group (- 7.0 vs.-1.2 IU/l, p=0.09). We did not find any significant effect of vitamin D-K-calcium co-supplementation on prolactin, follicle-stimulating hormone, 17-OH progesterone, inflammatory markers, and glutathione levels. Overall, vitamin D-K-calcium co-supplementation for 8 weeks among vitamin D-deficient women with PCOS had beneficial effects on serum DHEAS, free testosterone, plasma TAC, and MDA levels.

Vitamin D and Evening Primrose Oil Administration Improve Glycemia and Lipid Profiles in Women with Gestational Diabetes

Limited data are available assessing the effects of vitamin D and evening primrose oil (EPO) administration on markers of insulin resistance and lipid concentrations in gestational diabetes mellitus (GDM). This study was designed to evaluate the effects of vitamin D and EPO administration on insulin resistance and lipid concentrations among women with GDM. In this prospective randomized, double-blind, placebo-controlled clinical trial, 60 participants with GDM were divided into 2 groups of either 1000 IU vitamin D3 and 1000 mg EPO or placebo for 6 weeks. At the beginning and end of the study, fasting blood samples were obtained from the participants to measure related variables. After 6 weeks of intervention, changes in fasting plasma glucose (-3.6 ± 7.5 vs. +1.5 ± 11.4 mg/dL, P = 0.04), serum insulin concentrations (-2.0 ± 5.3 vs. +4.6 ± 10.7 µIU/mL, P = 0.004), homeostasis model of assessment (HOMA) insulin resistance (-0.5 ± 1.1 vs. +1.1 ± 2.5, P = 0.003), HOMA-B cell function (-7.7 ± 23.3 vs. +17.4 ± 42.9, P = 0.007) and the quantitative insulin sensitivity check index (+0.01 ± 0.02 vs. -0.01 ± 0.02, P = 0.007) in the vitamin D plus EPO group were significantly different from the placebo group. In addition, compared with the placebo, vitamin D and EPO supplementation resulted in significant reductions in serum TAG (-20.0 ± 54.3 vs. +34.3 ± 38.2 mg/dL, P < 0.001), VLDL (-4.0 ± 10.9 vs. +6.9 ± 7.6 mg/dL, P < 0.001), TC (-22.1 ± 32.6 vs. +5.3 ± 20.1 mg/dL, P < 0.001), LDL concentrations (-18.0 ± 25.5 vs. +1.8 ± 15.7 mg/dL, P = 0.001) and TC/HDL (-0.3 ± 0.4 vs. +0.3 ± 0.5 mg/dL, P < 0.001). We did not observe any significant effect of vitamin D and EPO supplementation on serum HDL concentrations.

CLINICAL TRIAL REGISTRATION NUMBER

http://www.irct.ir : IRCT201509115623N52.