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Fertility and Sterility Aug 2014To report an update on the role of vitamin D (VD) in ovarian physiology with a focus on genes involved in steroidogenesis, follicular development, and ovarian reserve,... (Review)
Review
OBJECTIVE
To report an update on the role of vitamin D (VD) in ovarian physiology with a focus on genes involved in steroidogenesis, follicular development, and ovarian reserve, as well as ovulatory dysfunction associated with polycystic ovary syndrome (PCOS), and ovarian response to assisted reproductive technology (ART).
DESIGN
Systematic review.
SETTING
Not applicable.
PATIENT(S)
Human, animal, and cell culture models.
INTERVENTION(S)
Pubmed literature search.
MAIN OUTCOME MEASURE(S)
Granulosa cell function, serum antimüllerian hormone (AMH), AMH and its receptor gene expression, soluble receptor for advanced glycation end-products (sRAGE), PCOS parameters, and ART outcome.
RESULT(S)
In human granulosa cells, VD alters AMH signaling, FSH sensitivity, and progesterone production and release, indicating a possible physiologic role for VD in ovarian follicular development and luteinization. In the serum, 25-hydroxyvitamin D (25OH-D) is positively correlated with AMH, and appropriate VD supplementation in VD-depleted women can suppress the seasonal changes that occur in serum AMH. In VD-deficient women with PCOS, VD supplementation lowers the abnormally elevated serum AMH levels, possibly indicating a mechanism by which VD improves folliculogenesis. The antiinflammatory sRAGE serum levels significantly increase in women with PCOS after VD replacement. Although follicular fluid 25OH-D correlates with IVF outcomes, there is a lack of data pertaining to the impact of VD supplementation on pregnancy rates following IVF.
CONCLUSION(S)
This review underscores the need for understanding the mechanistic actions of VD in ovarian physiology and the critical need for randomized trials to elucidate the impact of VD supplementation on controlled ovarian hyperstimulation/IVF outcome and ovulatory dysfunction associated with PCOS.
Topics: Animals; Dietary Supplements; Female; Fertility; Humans; Infertility, Female; Male; Ovarian Follicle; Ovary; Polycystic Ovary Syndrome; Pregnancy; Reproductive Techniques, Assisted; Signal Transduction; Treatment Outcome; Vitamin D; Vitamin D Deficiency
PubMed: 24933120
DOI: 10.1016/j.fertnstert.2014.04.046 -
Nutrients Mar 2018Observational studies have indicated an inverse association between vitamin D levels and the risk of diabetes, yet evidence from population interventions remains... (Meta-Analysis)
Meta-Analysis Review
Observational studies have indicated an inverse association between vitamin D levels and the risk of diabetes, yet evidence from population interventions remains inconsistent. PubMed, EMBASE, Cochrane Library and ClinicalTrials.gov were searched up to September 2017. Data from studies regarding serum 25(OH)D, fasting blood glucose (FBG), hemoglobin A1c (HbA1c), fasting insulin and homeostasis model assessment of insulin resistance (HOMA-IR) were pooled. Twenty studies ( = 2703) were included in the meta-analysis. Vitamin D supplementation resulted in a significant improvement in serum 25(OH)D levels (weighted mean difference (WMD) = 33.98; 95%CI: 24.60-43.37) and HOMA-IR (standardized mean difference (SMD) = -0.57; 95%CI: -1.09~-0.04), but not in other outcomes. However, preferred changes were observed in subgroups as follows: short-term (WMD = -8.44; 95%CI: -12.72~-4.15), high dose (WMD = -8.70; 95%CI: -12.96~-4.44), non-obese (SMD = -1.80; 95%CI: -2.66~-0.95), Middle Easterners (WMD = -10.43; 95%CI: -14.80~-6.06), baseline vitamin D deficient individuals (WMD = -5.77; 95%CI: -10.48~-1.05) and well-controlled HbA1c individuals (WMD = -4.09; 95%CI: -15.44~7.27). Vitamin D supplementation was shown to increase serum 25(OH)D and reduce insulin resistance effectively. This effect was especially prominent when vitamin D was given in large doses and for a short period of time, and to patients who were non-obese, Middle Eastern, vitamin D deficient, or with optimal glycemic control at baseline.
Topics: Adult; Aged; Biomarkers; Blood Glucose; Diabetes Mellitus, Type 2; Dietary Supplements; Female; Glycated Hemoglobin; Humans; Insulin Resistance; Male; Middle Aged; Treatment Outcome; Vitamin D; Vitamin D Deficiency
PubMed: 29562681
DOI: 10.3390/nu10030375 -
The Journal of Steroid Biochemistry and... Oct 2014Vitamin D deficiency is a major public health problem worldwide in all age groups, even in those residing in countries with low latitude, where it was generally assumed... (Review)
Review
Vitamin D deficiency is a major public health problem worldwide in all age groups, even in those residing in countries with low latitude, where it was generally assumed that UV radiation was adequate enough to prevent this deficiency, and in industrialized countries, where vitamin D fortification has been implemented now for years. However, most countries are still lacking data, particularly population representative data, with very limited information in infants, children, adolescents and pregnant women. Since the number of recent publications is escalating, with a broadening of the geographic diversity, the objective of the present report was to conduct a more recent systematic review of global vitamin D status, with particular emphasis in at risk groups. A systematic review was conducted in PubMed/Medline in April-June 2013 to identify articles on vitamin D status worldwide published in the last 10 years in apparently healthy individuals. Only studies with vitamin D status prevalence were included. If available, the first source selected was population-based or representative samples studies. Clinical trials, case-control studies, case reports or series, reviews, validation studies, letters, editorials, or qualitative studies were excluded. A total of 103 articles were eligible and included in the present report. Maps were created for each age group, providing an updated overview of global vitamin D status. In areas with available data, the prevalence of low vitamin D status is a global problem in all age groups, in particular in girls and women from the Middle East. These maps also evidenced the regions with missing data for each specific population groups. There is striking lack of data in infants, children and adolescents worldwide, and in most countries of South America and Africa. In conclusion, vitamin D deficiency is a global public health problem in all age groups, particularly in those from the Middle East. This article is part of a Special Issue entitled '16th Vitamin D Workshop'.
Topics: Dietary Supplements; Global Health; Humans; Public Health; Vitamin D Deficiency
PubMed: 24239505
DOI: 10.1016/j.jsbmb.2013.11.003 -
Reviews in Endocrine & Metabolic... Oct 2022Vitamin D deficiency is associated with an increase in the occurrence of cardiometabolic events, but the evidence of this relationship in adolescence is still limited.... (Meta-Analysis)
Meta-Analysis Review
Vitamin D deficiency is associated with an increase in the occurrence of cardiometabolic events, but the evidence of this relationship in adolescence is still limited. Thus, we analyzed the association between vitamin D deficiency and cardiometabolic risk factors in adolescents. Observational studies were searching in PubMed/Medline, Embase, Scopus, Web of Science, Science Direct, Lilacs, and Google Scholar database. Random effects models were used to summarize standardized mean differences for as a summary measure. The certainty of the evidence was verified using the Cochrane recommendations. A total of 7537 studies were identified, of which 32 were included in the systematic review and 24 in the meta-analysis.Vitamin D deficiency was associated with increased systolic pressure (SMD = 0.22; 95%CI = 0.10; 0.34), diastolic pressure (SMD = 0.23; 95%CI = 0.10; 0.35), glycemia (SMD = 0.13; 95%CI = 0.05; 0.12), and insulin (SMD = 0.50; 95%CI = 0.15; 0.84), an increase in the HOMA index (SMD = 0.48; 95%CI = 0.36; 0.60), high triglyceride values (SMD = 0.30; 95%CI = 0.11; 0.49), and reduced HDL concentrations (SMD= -0.25; 95%CI = -0.46; -0.04). No statistically significant association was observed for glycated hemoglobin, LDL cholesterol, and total cholesterol. Most of the studies presented low and moderate risks of bias, respectively. The certainty of the evidence was very low for all the outcomes analyzed. Vitamin D deficiency was associated with increased exposure to the factors linked to the occurrence of cardiometabolic diseases in adolescents. Systematic Review Registration: PROSPERO (record number 42,018,086,298).
Topics: Adolescent; Cardiometabolic Risk Factors; Cardiovascular Diseases; Cholesterol, LDL; Glycated Hemoglobin; Humans; Insulin; Risk Factors; Triglycerides; Vitamin D; Vitamin D Deficiency
PubMed: 35713809
DOI: 10.1007/s11154-022-09736-7 -
Nutrition Reviews Feb 2022Epidemiological studies suggest an association between vitamin D deficiency and anemia. Evidence of this relationship in pregnant women, however, is scarce. (Meta-Analysis)
Meta-Analysis
CONTEXT
Epidemiological studies suggest an association between vitamin D deficiency and anemia. Evidence of this relationship in pregnant women, however, is scarce.
OBJECTIVE
The aim of this systematic review was to investigate the association between vitamin D deficiency and gestational anemia through observational studies.
DATA SOURCES
The PubMed, Scopus, Web of Science, ScienceDirect, Embase, and Virtual Health Library databases were searched from inception to April 2021.
STUDY SELECTION
Original articles reporting observational studies that investigated the association between vitamin D deficiency and gestational anemia were included. Articles that did not have an abstract, as well as reviews articles, experimental studies, and editorials, were excluded. Two reviewers independently performed study selection, data extraction, and assessment of study quality. Disagreements between the reviewers were resolved by a third reviewer.
DATA EXTRACTION
Study quality was assessed by 2 scales. Data were extracted from eligible studies and arranged in a 2 × 2 table. Odds ratios with 95% confidence intervals for the risk of the outcome were estimated using a fixed-effect model.
RESULTS
In total, 985 studies were retrieved, of which 17 were included in the systematic review: 11 cohort studies, 3 case-control studies, and 3 cross-sectional studies. For the meta-analysis, 8 studies with a total of 6530 women were included. There was a 61% increase in the odds of anemia in pregnant women with vitamin D deficiency (OR = 1.61; 95%CI, 1.41-1.83; I2 = 48%).
CONCLUSIONS
Vitamin D deficiency may be a risk factor for anemia in pregnant women.
SYSTEMATIC REVIEW REGISTRATION
PROSPERO registration no. CRD42020182697.
Topics: Anemia; Cross-Sectional Studies; Female; Humans; Pregnancy; Pregnant Women; Vitamin D; Vitamin D Deficiency
PubMed: 34969067
DOI: 10.1093/nutrit/nuab114 -
Nutrients Sep 2019A systematic review and meta-analysis was undertaken to examine and quantify the effects of B vitamin supplementation on mood in both healthy and 'at-risk' populations.... (Meta-Analysis)
Meta-Analysis
A systematic review and meta-analysis was undertaken to examine and quantify the effects of B vitamin supplementation on mood in both healthy and 'at-risk' populations. A systematic search identified all available randomised controlled trials (RCTs) of daily supplementation with ≥3 B group vitamins with an intervention period of at least four weeks. Random effects models for a standardized mean difference were used to test for overall effect. Heterogeneity was tested using the I statistic. Eighteen articles (16 trials, 2015 participants) were included, of which 12 were eligible for meta-analysis. Eleven of the 18 articles reported a positive effect for B vitamins over a placebo for overall mood or a facet of mood. Of the eight studies in 'at-risk' cohorts, five found a significant benefit to mood. Regarding individual facets of mood, B vitamin supplementation benefited stress ( = 958, SMD = 0.23, 95% CI = 0.02, 0.45, = 0.03). A benefit to depressive symptoms did not reach significance ( = 568, SMD = 0.15, 95% CI = -0.01, 0.32, = 0.07), and there was no effect on anxiety ( = 562, SMD = 0.03, 95% CI = -0.13, 0.20, = 0.71). The review provides evidence for the benefit of B vitamin supplementation in healthy and at-risk populations for stress, but not for depressive symptoms or anxiety. B vitamin supplementation may particularly benefit populations who are at risk due to (1) poor nutrient status or (2) poor mood status.
Topics: Adolescent; Adult; Affect; Aged; Aged, 80 and over; Anxiety; Depression; Dietary Supplements; Female; Humans; Male; Middle Aged; Nutritional Status; Randomized Controlled Trials as Topic; Risk Assessment; Risk Factors; Stress, Psychological; Treatment Outcome; Vitamin B Complex; Vitamin B Deficiency; Young Adult
PubMed: 31527485
DOI: 10.3390/nu11092232 -
Autoimmunity Reviews Feb 2024Vitamin D plays a critical role in immunomodulation, and its deficiency is implicated in the pathogenesis of several autoimmune diseases. Nevertheless, its relationship... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Vitamin D plays a critical role in immunomodulation, and its deficiency is implicated in the pathogenesis of several autoimmune diseases. Nevertheless, its relationship with non-infectious uveitis (NIU), an inflammatory ocular disorder, remains inconclusive.
METHODS
A systematic search was conducted in three databases from database inception until May 8, 2023, to investigate the potential relationship between vitamin D deficiency and NIU. We included observational studies reporting the measurement of vitamin D levels in patients with NIU and healthy controls without restriction of language or date of publication. Three pairs of authors independently screened the title and abstracts for potential eligibility and then in full text. A third author resolved disagreements. Three pairs of independent reviewers abstracted the data from the fully reviewed records and evaluated the risk of bias. We followed The MOOSE and PRISMA guidelines. Random effects meta-analyses were used for primary analysis. Studies not included in the meta-analysis were summarized descriptively. This review was registered in PROSPERO: CRD42022308105.
FINDINGS
Of 933 records screened, 11 studies were included, and five were meta-analyzed, encompassing 354 cases and 5728 controls (mean participant age ranging from 7.1 to 58.9 years). Patients with vitamin D deficiency exhibited an Odds Ratio of 2.04 (95% CI = 1.55-2.68, P < 0.00001) for developing NIU compared to controls. Overall, potential sources of bias were low across most studies.
INTERPRETATION
Our findings suggest that vitamin D may play an essential role in the pathophysiology of NIU. While the included studies demonstrated generally low potential bias, additional rigorous prospective studies are necessary to confirm these findings and further elucidate the underlying mechanisms involved. Vitamin D supplementation could represent a possible therapeutic strategy for preventing or managing NIU if substantiated. Clinicians should consider screening for and addressing vitamin D deficiency in patients with or at risk for NIU.
Topics: Humans; Uveitis; Vitamin D; Vitamin D Deficiency
PubMed: 38052262
DOI: 10.1016/j.autrev.2023.103497 -
International Health Nov 2023Vitamin A deficiency (VAD) during pregnancy is a public health challenge in low-income countries. There are inconsistent findings that can affect policy in planning... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Vitamin A deficiency (VAD) during pregnancy is a public health challenge in low-income countries. There are inconsistent findings that can affect policy in planning appropriate intervention. This systematic review and meta-analysis were conducted to summarize the evidence in order to identify existing gaps and propose strategies to reduce VAD during pregnancy in Ethiopia.
METHODS
This study included published and unpublished observational studies searched from different databases (PubMed, CINHAL [EBSCO], Embase, Google Scholar, Directory of Open Access Journals, Web of Sciences, MEDLINE, Cochrane Library, Scopus, Google Search and MedNar). Statistical analysis was conducted using Stata version 14 software. Heterogeneity and publication bias were assessed. Forest plots were used to present the pooled prevalence using the random effects model.
RESULTS
A total of 37 618 pregnant women from 15 studies were included. The overall pooled prevalence of VAD was 29% (95% confidence interval 21 to 36) with I2=99.67% and p<0.001. Socio-economic and sociodemographic factors were identified as affecting vitamin A deficiencies among pregnant women.
CONCLUSIONS
Nearly one-third of pregnant women in Ethiopia had VAD. Strengthening intervention modalities that aimed to increase the uptake of vitamin A-rich foods can avert VAD among pregnant women in Ethiopia.
Topics: Female; Pregnancy; Humans; Pregnant Women; Vitamin A Deficiency; Ethiopia; Vitamin A; Prevalence; Observational Studies as Topic
PubMed: 37264928
DOI: 10.1093/inthealth/ihad038 -
BMC Public Health Aug 2023The association between vitamin D deficiency and lipid profiles in adults with overweight or obesity remains unclear and inconsistent. The aim of our study was to... (Meta-Analysis)
Meta-Analysis
OBJECTIVE
The association between vitamin D deficiency and lipid profiles in adults with overweight or obesity remains unclear and inconsistent. The aim of our study was to determine the relationship between lipid profiles and vitamin D deficiency in the overweight and obese adults.
METHODS
Four databases, including PubMed, the Web of Science, EMBASE and the Cochrane Library, were used to identify all studies on vitamin D status and lipid levels, including the serum levels of triglycerides (TGs), total cholesterol (TC), low-density lipoprotein cholesterol (LDL), and high-density lipoprotein cholesterol (HDL). The Weighted mean difference (WMD) with 95% confidence intervals (CIs) using random-effects models was used to assess the association between the lipid profile and vitamin D deficiency.
RESULTS
Twenty-one articles that included a total of 7952 adults with overweight or obesity (BMI ≥ 25 kg/m2) were included. The overall results revealed that compared with the controls, individuals with vitamin D deficiency showed higher levels of TG (WMD = 15.01; 95%CI, 2.51-27.52) and TC (WMD = 8.61; 95%CI, 1.31-15.92). Moreover, vitamin D deficiency was related to an increased level of LDL (WMD = 6.12; 95%CI, 0.02-12.23). HDL level was inversely associated with the vitamin D deficiency status (WMD = -2.57; 95%CI, -4.26, -0.88).
CONCLUSIONS
Among the adults with overweight or obesity, the vitamin D deficient group displayed impaired lipid profiles, including increased TG, TC and LDL levels and reduced HDL level.
Topics: Adult; Humans; Overweight; Obesity; Vitamin D Deficiency; Vitamin D; Cholesterol, HDL
PubMed: 37644450
DOI: 10.1186/s12889-023-16447-4 -
Clinical Cardiology Jul 2023Vasovagal syncope (VVS) is the most prevalent type of syncope and its management includes pharmacologic and non-pharmacologic interventions. Recently, studies have... (Meta-Analysis)
Meta-Analysis Review
Vasovagal syncope (VVS) is the most prevalent type of syncope and its management includes pharmacologic and non-pharmacologic interventions. Recently, studies have investigated vitamin D levels in VVS patients. In this systematic review and meta-analysis, we aim to review these studies to find possible associations between vitamin D deficiency and vitamin D levels with VVS. International databases including Scopus, Web of Science, PubMed, and Embase were searched with keywords related to "vasovagal syncope" and "vitamin D." Studies were screened and the data were extracted from them. Random-effect meta-analysis was conducted to calculate the standardized mean difference (SMD) and 95% confidence interval (CI) for vitamin D levels in comparison to VVS patients and controls. Also, VVS occurrence was measured and the odds ratio (OR) and 95% CI were calculated for comparison of vitamin D deficient cases and nondeficient individuals. Six studies were included with 954 cases investigated. Meta-analysis showed that patients with VVS had significantly lower vitamin D serum levels in comparison to non-VVS cases (SMD -1.05, 95% CI -1.54 to -0.57, p-value < .01). Moreover, VVS occurrence was higher in vitamin D-deficient individuals (OR 5.43, 95% CI 2.40 to 12.27, p-value < .01). Our findings which show lower vitamin D levels in VVS patients can have clinical implications in order for clinicians to pay attention to this when approaching VVS. Further randomized controlled trials are certainly warranted to assess the role of vitamin D supplementation in individuals with VVS.
Topics: Humans; Tilt-Table Test; Syncope, Vasovagal; Syncope; Vitamin D Deficiency; Vitamin D
PubMed: 37226313
DOI: 10.1002/clc.24035