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The British Journal of Nutrition May 2023Vitamin A is an essential micronutrient, especially during pregnancy. We aimed to assess the prevalence of vitamin A deficiency in Brazilian women of childbearing age.... (Meta-Analysis)
Meta-Analysis Review
Vitamin A is an essential micronutrient, especially during pregnancy. We aimed to assess the prevalence of vitamin A deficiency in Brazilian women of childbearing age. We conducted a systematic review with meta-analysis of studies that assessed vitamin A deficiency in women of childbearing age following the registered protocol (CRD42020171856). Independent peer researchers selected the studies retrieved from MEDLINE, Embase, Scopus and other sources. Data from the eligible studies were extracted in pairs and assessed for methodological quality. The prevalence of vitamin A deficiency (< 0·70 µmol/l or <0·20 µg/dl) and 95 % CI was combined by meta-analysis, and heterogeneity was estimated by . Out of 3610 screened records, thirty-two studies were included, which assessed 12 577 women from 1965 to 2017, mostly in maternity hospitals. Main limitations of the studies were in sample frame (30/32) and sampling method (29/32). Deficiency occurred in 13 % (95 % CI 9·4, 17·2 %; = 97 %) of all women and was higher in pregnant women (16·1 %; 95 % CI 5·6, 30·6 %; = 98 %) than non-pregnant women (12·3 %; 95 % CI 8·4, 16·8 %; = 96 %). The prevalence increased according to the decade, from 9·5 % (95 % CI 1·9–21·6 %; = 98 %) up to 1990, 10·8 % (95 % CI 7·9, 14·2 %; = 86 %) in the 2000s and 17·8 % (95 % CI 8·7, 29·0 %; = 98 %) in the 2010s. Over 10 % of Brazilian women in childbearing age were deficient in vitamin A. Higher prevalence was observed in pregnant women, and deficiency seemed to be increasing over the decades. Low representativeness of the studies, mainly based on convenience sampling that included pregnant, postpartum, lactating and non-pregnant women, as well as high heterogeneity, limits the findings.
Topics: Humans; Female; Pregnancy; Vitamin A Deficiency; Brazil; Vitamin A; Lactation; Prevalence
PubMed: 35670044
DOI: 10.1017/S0007114522001714 -
Tropical Doctor Jan 2017Studies related to vitamin D deficiency and lower respiratory tract infections (LRTI) in children have inconsistent findings. The objective of this systematic review was... (Meta-Analysis)
Meta-Analysis Review
Studies related to vitamin D deficiency and lower respiratory tract infections (LRTI) in children have inconsistent findings. The objective of this systematic review was to assess the prevalence of vitamin D deficiency in children with LRTI, and to evaluate the correlation between vitamin D levels and the incidence and severity of LRTI. A total of 12 studies enrolling 2279 participants were included in our analysis. Children with LRTI were found to have significantly lower mean vitamin D levels as compared to controls There was likewise a correlation between vitamin D levels and incidence and severity of LRTI. Large randomised controlled trials are needed to evaluate effect of vitamin D supplementation for LRTI.
Topics: Child; Dietary Supplements; Humans; Prevalence; Respiratory Tract Infections; Vitamin D; Vitamin D Deficiency; Vitamins
PubMed: 27178217
DOI: 10.1177/0049475516644141 -
Medicine Jun 2021Current studies suggest that vitamin D deficiency during pregnancy can produce a certain effect for preterm birth (PTB), but there is no research showing whether vitamin... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Current studies suggest that vitamin D deficiency during pregnancy can produce a certain effect for preterm birth (PTB), but there is no research showing whether vitamin D deficiency has a consistent effect in different pregnancies; thus, we conducted a systematic review and meta-analysis of 24 observational studies, grouping them according to the gestational age at the time of serum sampling, to investigate whether vitamin D deficiency in different periods of gestation has different effects on PTB and to provide an evidence-based basis for pregnant women to measure and supplement vitamin D.
METHODS
The databases PubMed-Medline, EMBASE, the Cochrane Library, Web of Science, EBSCO, CBM, and CNKI were searched until February 2020. Two researchers independently assessed the eligibility and quality of studies, and STATA 12.0 software was used for meta-analysis.
RESULT
Seven cohort studies, 13 case-control studies, and 4 cross-sectional studies were included from 2500 articles by inclusion and exclusion criteria. After adjusting for age, race, and other confounding factors, meta-analysis results showed that vitamin D deficiency in the first trimester, the second trimester, and the third trimester did not increase the risk of PTB (odds ratio (OR) = 1.01, 95% confidence interval (CI) (0.88, 1.16), P = .867; OR = 1.12, 95%CI (0.92, 1.37), P = .249; OR = 1.05, 95%CI (0.87, 1.27), P = .602). However, there was moderate heterogeneity in the study of vitamin D deficiency in the second trimester, and subgroup analysis suggested that vitamin D deficiency in the second trimester may increase the risk of PTB (OR = 1.33, 95%CI (1.15, 1.54), P = .000). A sensitivity analysis of the second trimester showed that excluding any 1 study did not significantly change the results.
CONCLUSIONS
Vitamin D deficiency in early and late pregnancy may not be associated with PTB, while vitamin D deficiency in middle pregnancy is likely to have an important effect on PTB. Vitamin D levels should be measured in the second trimester of pregnancy, and vitamin D supplements should be provided if necessary.
Topics: Adult; Case-Control Studies; Cohort Studies; Cross-Sectional Studies; Dietary Supplements; Female; Gestational Age; Humans; Infant, Newborn; Pregnancy; Pregnancy Complications; Pregnancy Outcome; Pregnancy Trimesters; Premature Birth; Vitamin D; Vitamin D Deficiency; Vitamins
PubMed: 34128867
DOI: 10.1097/MD.0000000000026303 -
Pakistan Journal of Pharmaceutical... May 2015To identify the effect of Vitamin D in reducing the risk of preeclampsia in pregnant women. The review was conducted from December 2011 to March 2012 at the University... (Review)
Review
To identify the effect of Vitamin D in reducing the risk of preeclampsia in pregnant women. The review was conducted from December 2011 to March 2012 at the University of Sheffield. Studies were included from the Medline data base, Web of Science (Web of Knowledge), Ovid database and Google Scholar. Studies were limited to published literature only; published between January 1992 to March 2012. A total of seven studies were selected for this review based on the inclusion criteria. One was non-randomized clinical trial, three were cohort studies and three were nested case-control studies. The clinical trial showed a positive association between Vitamin D supplements and the reduction of preeclampsia risk in pregnant women. In addition, one large cohort and two nested case-control studies also showed a protective effect of vitamin D in preventing the risk of preeclampsia. However, the other two cohort studies and a nested case-control study could not find any association between vitamin D levels and the risk of preeclampsia in pregnant women. The studies included in this review show conflicting results about the association of vitamin D levels and the risk of preeclampsia. However, in this review more than half of the studies showed a positive link between Vitamin D deficiencies and Preeclampsia. There is a clear need for further trials and other robust studies to identify the effect of Vitamin D on preeclampsia.
Topics: Female; Humans; Hypertension, Pregnancy-Induced; Pre-Eclampsia; Pregnancy; Pregnancy Complications; Risk Factors; Vitamin D; Vitamin D Deficiency
PubMed: 26004709
DOI: No ID Found -
The Journal of Maternal-fetal &... Apr 2021The object of the present study was to estimate the relationship between maternal vitamin D deficiency during pregnancy and low birth weight by systematically review... (Meta-Analysis)
Meta-Analysis
OBJECTIVE
The object of the present study was to estimate the relationship between maternal vitamin D deficiency during pregnancy and low birth weight by systematically review prevalence studies.
METHODS
We collected data from relevant studies published up to April 2019 using predefined inclusion/exclusion criteria. And all the studies were searched in PubMed, Embase, Cochrane Library, and Web of Science.
RESULTS
A total of 16 studies met the criteria and were included in the meta-analysis. When compared with normal serum levels of vitamin D, the maternal vitamin D deficiency had an increased risk of low birth weight (OR = 2.39; 95%CI 1.25-4.57; = .008), and same results were found in the comparison of the mean (the total mean birth weight decreased by 0.08 kg; 95%CI -0.10 to -0.06; < .001).
CONCLUSION
The evidence from this meta-analysis indicates a consistent association between vitamin D deficiency during pregnancy and an increased risk of low birth weight, and preventing maternal vitamin D deficiency may be an important public health strategy to help decrease the risk of low birth weight.
Topics: Birth Weight; Female; Humans; Infant, Low Birth Weight; Infant, Newborn; Pregnancy; Pregnancy Complications; Pregnancy Outcome; Vitamin D; Vitamin D Deficiency
PubMed: 31122092
DOI: 10.1080/14767058.2019.1623780 -
Seminars in Thrombosis and Hemostasis Jul 2023Observational studies indicate a relationship between vitamin D deficiency and an increased risk of venous and arterial thrombotic events, but the underlying mechanisms...
Observational studies indicate a relationship between vitamin D deficiency and an increased risk of venous and arterial thrombotic events, but the underlying mechanisms behind this association are uncertain. This systematic review explores if there is an association between decreased vitamin D levels and a prothrombotic profile. The systematic literature search initially identified 3,214 studies (published until December 21, 2021) investigating the relationship between vitamin D and numerous hemostatic parameters. After the screening process, 18 observational and intervention studies fulfilled the inclusion criteria and were included in this systematic review. Parameters of primary hemostasis, secondary hemostasis, and fibrinolysis were investigated in six, thirteen, and fifteen of these studies, respectively. Most of the eligible studies did not identify significant associations between decreased vitamin D levels and hemostatic parameters. Some conflicting results were found between decreased vitamin D levels and thrombin generation parameters and the tissue factor pathway inhibitor. Conflicting results were also found between decreased vitamin D levels and fibrinolytic parameters, although the evidence may point toward weak associations with some regulators of fibrinolysis, mostly decreased tissue type plasminogen activator. Overall, our systematic review did not identify any definitive link between vitamin D deficiency and a prothrombotic profile, which might otherwise help explain the observed association between vitamin D deficiency and increased risk of thrombotic events. Moreover, there is no clinical evidence to confirm or refute a possible antithrombotic effect of vitamin D. Larger high-quality randomized controlled trials are needed to better elucidate the link between vitamin D deficiency and a prothrombotic risk profile.
Topics: Humans; Fibrinolysis; Hemostasis; Vitamin D Deficiency; Thrombosis; Vitamin D; Hemostatics
PubMed: 36174611
DOI: 10.1055/s-0042-1756701 -
Current Diabetes Reviews 2023Type 2 diabetes mellitus is one of the most globally common chronic diseases. Metformin is the most popular prescribed medication for the treatment of diabetes. Studies...
BACKGROUND
Type 2 diabetes mellitus is one of the most globally common chronic diseases. Metformin is the most popular prescribed medication for the treatment of diabetes. Studies suggest that metformin is associated with vitamin B12 deficiency, which may impart adverse health complications.
OBJECTIVE
This review screens the literature to clarify the effect of metformin on vitamin B12 deficiency among type 2 diabetes mellitus patients.
METHODS
Google Scholar, PubMed, Research Gate, and Semantic Scholar, were searched for the association between metformin intake and vitamin B12 deficiency in type 2 diabetes mellitus patients using relevant keywords and their combinations. Selected studies were those conducted on patients taking metformin with no vitamin B12 supplement. Nineteen studies (fifteen observational studies and four randomized controlled trials) met the inclusion criteria. These studies were assessed for design, setting, study population, and overall quality.
RESULTS
There is a positive correlation between metformin intake and vitamin B12 deficiency. This has been accompanied by increased homocysteine and decreased folate levels. Despite the refuting of the findings, most studies showed that higher doses of metformin were strongly associated with lower vitamin B12 levels, while the duration of treatment was not.
CONCLUSION
Regular measurement of vitamin B12 levels during long-term metformin treatment is recommended. A clear policy should be in place to illuminate the importance of this screening in preventing vitamin B12 deficiency complications. Taking therapeutic supplements or injections of vitamin B12 along with a vitamin B12-rich diet may decrease the incidence of its deficiency in diabetic patients taking metformin.
Topics: Humans; Metformin; Diabetes Mellitus, Type 2; Hypoglycemic Agents; Vitamin B 12 Deficiency; Vitamin B 12
PubMed: 35440313
DOI: 10.2174/1573399818666220418080959 -
Otolaryngology--head and Neck Surgery :... Nov 2020The role of vitamin D deficiency has been linked with recurrent upper respiratory tract infections, but its impact on the frequency of tonsillitis is not yet fully... (Meta-Analysis)
Meta-Analysis
OBJECTIVES
The role of vitamin D deficiency has been linked with recurrent upper respiratory tract infections, but its impact on the frequency of tonsillitis is not yet fully understood. The objective of this study is to determine the association between vitamin D deficiency and recurrent tonsillitis based on current literature.
DATA SOURCE
A systematic review was performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline. Data were collected from online medical databases (PubMed, MEDLINE, EMBASE, and Cochrane Collaboration Registry of Controlled Trials).
REVIEW METHODS
All studies addressing the association of vitamin D deficiency and recurrent tonsillitis prior to March 2019. The data were collected in different phases: screening review using search words and controlled vocabularies followed by detailed review of screened articles based on inclusion and exclusion criteria, then a full review that included screening the references of selected articles.
RESULTS
Fifty-three studies were potentially eligible; of these, 4 publications met the inclusion criteria and were included in the quantitative synthesis. There was a statistically significant reduction of vitamin D levels in patients with recurrent tonsillitis as compared to healthy controls (mean difference, -10.71; 95% CI, -19.12 to -2.31; = .01). The odds of vitamin D insufficiency were significantly higher in patients with recurrent tonsillitis as compared to the control group (odds ratio, 4.37; 95% CI, 2.78-6.88; < .001).
CONCLUSION
Vitamin D deficiency was present in patients with recurrent tonsillitis and might be associated with an increase in the risk of recurrent tonsillitis. There is a need to explore these findings via clinical trials based on large populations.
Topics: Adult; Bacterial Infections; Child; Humans; Tonsillitis; Vitamin D Deficiency
PubMed: 32689892
DOI: 10.1177/0194599820935442 -
Vitamin D deficiency is associated with the severity of COPD: a systematic review and meta-analysis.International Journal of Chronic... 2015To explore the association between host serum 25-hydroxyvitamin D (25(OH)D) and the susceptibility and severity of COPD. (Meta-Analysis)
Meta-Analysis Review
PURPOSE
To explore the association between host serum 25-hydroxyvitamin D (25(OH)D) and the susceptibility and severity of COPD.
METHODS
Previous studies on the association between host 25(OH)D and the susceptibility and severity of COPD were collected on the basis of a systematic literature search of PubMed and Web of Science up to June 2015. Continuous variable data were presented as standard mean difference (SMD) or weighted mean difference with 95% confidence interval (CI). The dichotomous variable data were analyzed as relative ratio (RR) or odds ratio with 95% CI for cohort and case-control studies. A systematic review was conducted to understand the curative and side effects of vitamin D intake.
RESULTS
A total of 18 studies including eight cohort, five case-control, and five randomized studies met the inclusion criteria. The serum level of 25(OH)D in COPD patients was comparable with controls with a pooled SMD of 0.191 (95% CI: -0.126 to 0.508, P=0.237) based on pooled analyses of cohort studies. However, the serum level of 25(OH)D in COPD patients was lower with a pooled SMD of 0.961 (95% CI: 0.476-1.446, P<0.001) compared with controls based on pooled analyses of case-control studies. The deficiency rates of 25(OH)D were comparable between controls and COPD patients with a pooled RR of 0.955 (95% CI: 0.754-1.211, P=0.705) based on analyses of cohort studies, and the same results were observed based on pooled analyses of case-control studies. Interestingly, the deficiency rate of 25(OH)D was significantly lower in moderate or severe COPD patients with a pooled RR of 0.723 (95% CI: 0.632-0.828, P<0.001) compared with that in mild COPD patients. The same results were obtained from the pooled analysis between moderate and severe COPD patients. The four randomized studies showed that vitamin D intake provided benefit for COPD patients.
CONCLUSION
Low serum levels of 25(OH)D were not associated with COPD susceptibility, but the high deficiency rate of 25(OH)D was associated with COPD severity. Vitamin D supplementation may prevent COPD exacerbation.
Topics: Dietary Supplements; Disease Progression; Humans; Pulmonary Disease, Chronic Obstructive; Severity of Illness Index; Vitamin D; Vitamin D Deficiency
PubMed: 26392765
DOI: 10.2147/COPD.S89763 -
Nutrients Mar 2018This narrative systematic review evaluates growing evidence of an association between low maternal vitamin D status and increased risk of hypertensive disorders. The... (Review)
Review
This narrative systematic review evaluates growing evidence of an association between low maternal vitamin D status and increased risk of hypertensive disorders. The inclusion of interventional, observational, and dietary studies on vitamin D and all hypertensive disorders of pregnancy is a novel aspect of this review, providing a unique contribution to an intensively-researched area that still lacks a definitive conclusion. To date, trial evidence supports a protective effect of combined vitamin D and calcium supplementation against preeclampsia. Conflicting data for an association of vitamin D with gestational hypertensive disorders in observational studies arises from a number of sources, including large heterogeneity between study designs, lack of adherence to standardized perinatal outcome definitions, variable quality of analytical data for 25-hydroxyvitamin D (25(OH)D), and inconsistent data reporting of vitamin D status. While evidence does appear to lean towards an increased risk of gestational hypertensive disorders at 25(OH)D concentrations <50 nmol/L, caution should be exercised with dosing in trials, given the lack of data on long-term safety. The possibility that a fairly narrow target range for circulating 25(OH)D for achievement of clinically-relevant improvements requires further exploration. As hypertension alone, and not preeclampsia specifically, limits intrauterine growth, evaluation of the relationship between vitamin D status and all terms of hypertension in pregnancy is a clinically relevant area for research and should be prioritised in future randomised trials.
Topics: Female; Humans; Hypertension, Pregnancy-Induced; Pregnancy; Vitamin D; Vitamin D Deficiency
PubMed: 29494538
DOI: 10.3390/nu10030294