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American Journal of Epidemiology Feb 2017Vitamin B12 (hereafter referred to as B12) deficiency in pregnancy is prevalent and has been associated with both lower birth weight (birth weight <2,500 g) and preterm... (Meta-Analysis)
Meta-Analysis Review
Associations of Maternal Vitamin B12 Concentration in Pregnancy With the Risks of Preterm Birth and Low Birth Weight: A Systematic Review and Meta-Analysis of Individual Participant Data.
Vitamin B12 (hereafter referred to as B12) deficiency in pregnancy is prevalent and has been associated with both lower birth weight (birth weight <2,500 g) and preterm birth (length of gestation <37 weeks). Nevertheless, current evidence is contradictory. We performed a systematic review and a meta-analysis of individual participant data to evaluate the associations of maternal serum or plasma B12 concentrations in pregnancy with offspring birth weight and length of gestation. Twenty-two eligible studies were identified (11,993 observations). Eighteen studies were included in the meta-analysis (11,216 observations). No linear association was observed between maternal B12 levels in pregnancy and birth weight, but B12 deficiency (<148 pmol/L) was associated with a higher risk of low birth weight in newborns (adjusted risk ratio = 1.15, 95% confidence interval (CI): 1.01, 1.31). There was a linear association between maternal levels of B12 and preterm birth (per each 1-standard-deviation increase in B12, adjusted risk ratio = 0.89, 95% CI: 0.82, 0.97). Accordingly, B12 deficiency was associated with a higher risk of preterm birth (adjusted risk ratio = 1.21, 95% CI: 0.99, 1.49). This finding supports the need for randomized controlled trials of vitamin B12 supplementation in pregnancy.
Topics: Birth Weight; Female; Humans; Infant, Low Birth Weight; Infant, Newborn; Pregnancy; Pregnancy Complications; Premature Birth; Risk Factors; Vitamin B 12; Vitamin B 12 Deficiency
PubMed: 28108470
DOI: 10.1093/aje/kww212 -
Human Reproduction Update 2009Adaptation of the maternal immune response to accommodate the semi-allogeneic fetus is necessary for pregnancy success, and disturbances in maternal tolerance are... (Review)
Review
BACKGROUND
Adaptation of the maternal immune response to accommodate the semi-allogeneic fetus is necessary for pregnancy success, and disturbances in maternal tolerance are implicated in infertility and reproductive pathologies. T regulatory (Treg) cells are a recently discovered subset of T-lymphocytes with potent suppressive activity and pivotal roles in curtailing destructive immune responses and preventing autoimmune disease.
METHODS
A systematic review was undertaken of the published literature on Treg cells in the ovary, testes, uterus and gestational tissues in pregnancy, and their link with infertility, miscarriage and pathologies of pregnancy. An overview of current knowledge on the generation, activation and modes of action of Treg cells in controlling immune responses is provided, and strategies for manipulating regulatory T-cells for potential applications in reproductive medicine are discussed.
RESULTS
Studies in mouse models show that Treg cells are essential for maternal tolerance of the conceptus, and that expansion of the Treg cell pool through antigen-specific and antigen non-specific pathways allows their suppressive actions to be exerted in the critical peri-implantation phase of pregnancy. In women, Treg cells accumulate in the decidua and are elevated in maternal blood from early in the first trimester. Inadequate numbers of Treg cells or their functional deficiency are linked with infertility, miscarriage and pre-eclampsia.
CONCLUSIONS
The potency and wide-ranging involvement of Treg cells in immune homeostasis and disease pathology indicates the considerable potential of these cells as therapeutic agents, raising the prospect of their utility in novel treatments for reproductive pathologies.
Topics: Abortion, Spontaneous; Animals; Cytokines; Dendritic Cells; Female; Humans; Immune Tolerance; Indoleamine-Pyrrole 2,3,-Dioxygenase; Infertility; Male; Mice; Models, Immunological; Ovary; Pregnancy; Pregnancy Complications; Prostaglandins; Semen; Signal Transduction; T-Lymphocytes, Regulatory; Testis; Toll-Like Receptors
PubMed: 19279047
DOI: 10.1093/humupd/dmp004 -
PloS One 2022Heme-oxygenase 1 (HMOX1) is a critical stress response gene that catalyzes the multistep oxidation of heme. A GT(n) repeat of variable length in the promoter in has been...
INTRODUCTION
Heme-oxygenase 1 (HMOX1) is a critical stress response gene that catalyzes the multistep oxidation of heme. A GT(n) repeat of variable length in the promoter in has been associated with a wide range of human diseases, including infections. This paper aims to summarise and systematically review associations between the length of the HMOX1 GT(n) promoter and infectious disease in humans.
METHODS
A search using relevant terms was performed in PubMED and EMBASE through to 15/01/21 identifying all research that studied an association between the HMOX1 GT(n) repeat polymorphism and the incidence and/or outcome of any human infectious disease. Citations were screened for additional studies. Potential studies were screened for inclusion by two authors. Data was extracted on allele frequency, genotype, strength of association, mechanism of genotyping, and potential biases. A narrative review was performed across each type of infection.
RESULTS
1,533 studies were identified in the search, and one via citation screening. Sixteen studies were ultimately included, seven in malaria, three in HIV, three in sepsis, and one each in pneumonia, hepatitis C, and acute respiratory distress syndrome (ARDS). Sample sizes for nearly all studies were small (biggest study, n = 1,646). Allelic definition was different across all included studies. All studies were at some risk of bias. In malaria, three studies suggested that longer alleles were associated with reduced risk of severe malaria, particularly malaria-induced renal dysfunction, with four studies identifying a null association. In sepsis, two studies suggested an association with longer alleles and better outcomes.
CONCLUSIONS
Despite the importance of HMOX1 in survival from infection, and the association between repeat length and gene expression, the clinical data supporting an association between repeat length and incidence and/or outcome of infection remain inconclusive.
Topics: Communicable Diseases; Genetic Predisposition to Disease; Heme; Heme Oxygenase-1; Humans; Polymorphism, Genetic; Sepsis
PubMed: 35551540
DOI: 10.1371/journal.pone.0267399 -
The American Journal of Clinical... Feb 2013Many randomized controlled trials (RCTs) and observational studies have provided information on the association between vitamin B-12 intake and biomarkers. The use of... (Meta-Analysis)
Meta-Analysis Review
Systematic review with dose-response meta-analyses between vitamin B-12 intake and European Micronutrient Recommendations Aligned's prioritized biomarkers of vitamin B-12 including randomized controlled trials and observational studies in adults and elderly persons.
BACKGROUND
Many randomized controlled trials (RCTs) and observational studies have provided information on the association between vitamin B-12 intake and biomarkers. The use of these data to estimate dose-response relations provides a useful means to summarize the body of evidence.
OBJECTIVE
We systematically reviewed studies that investigated vitamin B-12 intake and biomarkers of vitamin B-12 status and estimated dose-response relations with the use of a meta-analysis.
DESIGN
This systematic review included all RCTs, prospective cohort studies, nested case-control studies, and cross-sectional studies in healthy adult populations published through January 2010 that supplied or measured dietary vitamin B-12 intake and measured vitamin B-12 status as serum or plasma vitamin B-12, methylmalonic acid (MMA), or holotranscobalamin. We calculated an intake-status regression coefficient ( ) for each individual study and calculated the overall pooled and SE ( ) by using random-effects meta-analysis on a double-log scale.
RESULTS
The meta-analysis of observational studies showed a weaker slope of dose-response relations than the meta-analysis of RCTs. The pooled dose-response relation of all studies between vitamin B-12 intake and status indicated that a doubling of the vitamin B-12 intake increased vitamin B-12 concentrations by 11% (95% CI: 9.4%, 12.5%). This increase was larger for studies in elderly persons (13%) than in studies in adults (8%). The dose-response relation between vitamin B-12 intake and MMA concentrations indicated a decrease in MMA of 7% (95% CI: -10%, -4%) for every doubling of the vitamin B-12 intake. The assessment of risk of bias within individual studies and across studies indicated risk that was unlikely to seriously alter these results.
CONCLUSION
The obtained dose-response estimate between vitamin B-12 intake and status provides complementary evidence to underpin recommendations for a vitamin B-12 intake of populations.
Topics: Adult; Aged; Aging; Biomarkers; European Union; Evidence-Based Medicine; Humans; Methylmalonic Acid; Nutrition Policy; Nutritional Requirements; Transcobalamins; Vitamin B 12; Vitamin B 12 Deficiency
PubMed: 23269815
DOI: 10.3945/ajcn.112.033951 -
The Cochrane Database of Systematic... Jul 2005Vitamin B12 deficiency is common and rises with age. Most people with vitamin B12 deficiency are treated in primary care with intramuscular vitamin B12 which is a... (Review)
Review
BACKGROUND
Vitamin B12 deficiency is common and rises with age. Most people with vitamin B12 deficiency are treated in primary care with intramuscular vitamin B12 which is a considerable source of work for health care professionals. Several case control and case series studies have reported equal efficacy of oral administration of vitamin B12 but it is rarely prescribed in this form, other than in Sweden and Canada. Doctors may not be prescribing oral formulations because they are unaware of this option or have concerns regarding effectiveness.
OBJECTIVES
To assess the effectiveness of oral vitamin B12 versus intramuscular vitamin B12 for vitamin B12 deficiency.
SEARCH STRATEGY
Searches were undertaken of The Cochrane Library, MEDLINE, EMBASE and Lilacs in early 2005. The bibliographies of all relevant papers identified using this strategy were searched. In addition we contacted authors of relevant identified studies and Vitamin B12 research and pharmaceutical companies to enquire about other published or unpublished studies and ongoing trials.
SELECTION CRITERIA
Randomised controlled trials (RCTs) examining the use of oral or intramuscular vitamin B12 to treat vitamin B12 deficiency.
DATA COLLECTION AND ANALYSIS
All abstracts or titles identified by the electronic searches were independently scrutinised by two reviewers. When a difference between reviewers arose, we obtained and reviewed a hard copy of the papers and made decisions by consensus. We obtained a copy of all pre-selected papers and two researchers independently extracted the data from these studies using piloted data extraction forms. The whole group checked whether inclusion and exclusion criteria were met, and disagreement was decided by consensus. The methodological quality of the included studies was independently assessed by two researchers and disagreements were brought back to the whole group and resolved by consensus.
MAIN RESULTS
Two RCT's comparing oral with intramuscular administration of vitamin B12 met our inclusion criteria. The trials recruited a total of 108 participants and followed up 93 of these from 90 days to four months. High oral doses of B12 (1000 mcg and 2000 mcg) were as effective as intramuscular administration in achieving haematological and neurological responses.
AUTHORS' CONCLUSIONS
The evidence derived from these limited studies suggests that 2000 mcg doses of oral vitamin B12 daily and 1000 mcg doses initially daily and thereafter weekly and then monthly may be as effective as intramuscular administration in obtaining short term haematological and neurological responses in vitamin B12 deficient patients.
Topics: Administration, Oral; Aged; Humans; Injections, Intramuscular; Randomized Controlled Trials as Topic; Vitamin B 12; Vitamin B 12 Deficiency; Vitamin B Complex
PubMed: 16034940
DOI: 10.1002/14651858.CD004655.pub2 -
Indian Pediatrics Jan 2012To evaluate the effect of clofibrate for unconjugated hyperbilirubinemia in neonates. (Meta-Analysis)
Meta-Analysis Review
OBJECTIVE
To evaluate the effect of clofibrate for unconjugated hyperbilirubinemia in neonates.
METHODS
A systematic review with meta-analysis of randomized controlled trials or quasi-randomized controlled trials was conducted to evaluate the clofibrate treatment in neonates with unconjugated hyperbilirubinemia. We followed the guidelines from the Cochrane review group and the PRISMA statement.
RESULTS
Of 148 studies identified, a total of 13 studies on 867 infants were included. A single oral administration of clofibrate was associated with decreased need of phototherapy (RR:.38, 95% CI: 0.21 to 0.68), shortened duration of phototherapy (mean duration: 23.88 h, 95% CI: 33.03 to -14.72 h) and reduced peak total serum bilirubin (mean duration: -1.62 mg/dL, 95% CI: 2.13 to -1.11 mg/dL). These effects were especially obvious in term infants and infants without hemolytic diseases. Data regarding mortality or kernicterus were not available from included studies.
CONCLUSIONS
Clofibrate may have short-term benefits for the infants with hyperbilirubinaemia, especially for population of term infants and infants without hemolytic diseases. Large RCTs with long-term followup are required to verify the safety of clofibrate and assess its long-term effects.
Topics: Bilirubin; Clofibrate; Humans; Hyperbilirubinemia, Neonatal; Infant, Newborn; Phototherapy; Treatment Outcome
PubMed: 22318100
DOI: 10.1007/s13312-012-0012-x -
Arquivos de Gastroenterologia 2021The vitamin B12 absorption can be affected in patients with nonalcoholic fatty liver disease (NAFLD), and low serum vitamin B12 levels has been related to the high... (Meta-Analysis)
Meta-Analysis
BACKGROUND
The vitamin B12 absorption can be affected in patients with nonalcoholic fatty liver disease (NAFLD), and low serum vitamin B12 levels has been related to the high homocysteine (HCY) levels and to the degree of NAFLD.
OBJECTIVE
To carry out a systematic review and metanalysis of serum vitamin B12 and HCY levels in patients with NAFLD.
METHODS
Original studies including serum vitamin B12 and HCY levels in humans with NAFLD were included. The searches were performed in four databases.
RESULTS
159 studies were identified, and after excluding the duplicates and non-eligible titles, eight original articles were included. Six out of eight showed higher B12 levels in NAFLD patients (404.9±136.2 pg/mL in relation to controls 353.91±117.3 pg/mL). Seven of the eight studies also showed higher HCY levels in NAFLD patients (14.2±3.44 umol/L in relation to controls 11.05±3.6 umol/L). The results for serum vitamin B12 and HCY levels were submitted to metanalysis, showing no difference in the vitamin B12 levels between patients with NAFLD and controls. However, the levels of Hcy were higher in NAFLD patients than in controls.
CONCLUSION
There was no relashionship between the vitamin B12 levels and NAFLD. The levels of HCY were significantly higher in patients with NAFLD, suggesting this could be a potential marker for liver damage.
Topics: Biomarkers; Folic Acid; Homocysteine; Humans; Non-alcoholic Fatty Liver Disease; Vitamin B 12
PubMed: 34287533
DOI: 10.1590/S0004-2803.202100000-42 -
Genes Oct 2021The maternal environment during the periconceptional period influences foetal growth and development, in part, via epigenetic mechanisms moderated by one-carbon... (Review)
Review
The maternal environment during the periconceptional period influences foetal growth and development, in part, via epigenetic mechanisms moderated by one-carbon metabolic pathways. During embryonic development, one-carbon metabolism is involved in brain development and neural programming. Derangements in one-carbon metabolism increase (i) the short-term risk of embryonic neural tube-related defects and (ii) long-term childhood behaviour, cognition, and autism spectrum disorders. Here we investigate the association between maternal one-carbon metabolism and foetal and neonatal brain growth and development. Database searching resulted in 26 articles eligible for inclusion. Maternal vitamin B, vitamin B, homocysteine, and choline were not associated with foetal and/or neonatal head growth. First-trimester maternal plasma folate within the normal range (>17 nmol/L) associated with increased foetal head size and head growth, and high erythrocyte folate (1538-1813 nmol/L) with increased cerebellar growth, whereas folate deficiency (<7 nmol/L) associated with a reduced foetal brain volume. Preconceptional folic acid supplement use and specific dietary patterns (associated with increased B vitamins and low homocysteine) increased foetal head size. Although early pregnancy maternal folate appears to be the most independent predictor of foetal brain growth, there is insufficient data to confirm the link between maternal folate and offspring risks for neurodevelopmental diseases.
Topics: Brain; Carbon; Embryonic Development; Female; Fetal Development; Fetus; Folic Acid; Humans; Pregnancy; Vitamin B 12
PubMed: 34681028
DOI: 10.3390/genes12101634 -
Cellular Physiology and Biochemistry :... 2018Indoleamine 2,3-dioxygenase 1 (IDO1) is a heme-containing enzyme catalyzing the initial and rate-limiting steps in the kynurenine pathway, which converts tryptophan into... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND/AIMS
Indoleamine 2,3-dioxygenase 1 (IDO1) is a heme-containing enzyme catalyzing the initial and rate-limiting steps in the kynurenine pathway, which converts tryptophan into kynurenine. Upregulation of IDO1 decreases tryptophan levels and increases the accumulation of kynurenine and its metabolites. These metabolites can affect the proliferation of T cells. Increasing evidence has shown that IDO1 is highly expressed in various cancer types and associated with poor prognosis of cancer patients. However, the results were inconsistent.
METHODS
We searched the Web of Science, PubMed, Embase and Cochrane library databases to identify studies evaluating the prognostic value of IDO1 in cancer patients. Pooled hazard ratios (HRs) or odds ratios (ORs) with 95% confidence intervals (CIs) were calculated by using fixed-effects/random-effects models.
RESULTS
This systematic review and meta-analysis included 2706 patients from 24 articles. The results indicated a shorter overall survival in patients with high expression of IDO1 (hazard ratio [HR] = 2.03, 95% confidence interval [CI]: 1.56-2.63). Furthermore, disease-free survival was worse in patients with high expression of IDO1 (HR = 2.47, 95% CI: 1.46-4.20). Additionally, the pooled odds ratios (ORs) showed that increased IDO1 was significantly associated with tumor differentiation (OR = 1.81, 95% CI: 1.05-3.12), distant metastasis (OR = 1.45, 95% CI: 1.02-2.06), and poor clinical stage (OR = 1.89, 95% CI: 1.13-3.17). However, no significant correlation was observed of increased IDO1 expression with age, sex, lymph node metastasis, and tumor size.
CONCLUSION
High expression of IDO1 is associated with poor clinical outcomes. IDO1 could serve as a biomarker of prognosis and a potential predictive factor of clinicopathology in various cancers. Further studies should be performed to verify the clinical utility of IDO1 in human solid tumors.
Topics: Biomarkers, Tumor; Databases, Factual; Disease-Free Survival; Humans; Indoleamine-Pyrrole 2,3,-Dioxygenase; Neoplasm Metastasis; Neoplasms; Prognosis; Proportional Hazards Models; Survival Rate
PubMed: 30134237
DOI: 10.1159/000492849 -
BMJ Open Gastroenterology Oct 2020Over the last few years, epidemiological studies have shown that infection with has a major effect on micronutrient deficiency as well as on adverse pregnancy outcomes.... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Over the last few years, epidemiological studies have shown that infection with has a major effect on micronutrient deficiency as well as on adverse pregnancy outcomes. Importantly, there are gaps in understanding the linkage of infection with micronutrients deficiency in pregnant women.
OBJECTIVE
We conducted a systematic review and meta-analysis to estimate the association between infection and micronutrient deficiencies in pregnant women.
METHODS
A systematic literature search was conducted for relevant articles using PubMed, Web of Science, and Scopus database from inception to March 2020. The OR with 95% CIs was determined by meta-analysis of data extracted from the selected studies.
RESULTS
From 2384 primary articles, 6 studies were selected for systematic reviews and 4 studies distinctively (with 1274 participants: 553 cases and 721 controls) were selected for meta-analysis. The meta-analysed fixed effect model estimated the odds of having infection was not significantly higher among pregnant women with micronutrient deficiencies than those without deficiencies (OR=1.12, 95% CI 0.88 to 1.42, p=0.37). In the subgroup analysis, no correlation was found between infection and vitamin B (OR=0.74, 95% CI 0.45 to 1.21, p=0.22), folate (OR=1.07, 95% CI 0.73 to 1.58, p=0.73), and ferritin (OR=0.81, 95% CI 0.51 to 1.31, p=0.4). However, a positive correlation was found between iron-deficiency anaemia (IDA) and infection (OR=16.23, 95% CI 4.19 to 62.93, p<0.0001) during pregnancy.
CONCLUSION
infection is associated with increased risk of IDA but not with deficiency of other micronutrients in pregnancy.
PROSPERO REGISTRATION NUMBER
CRD42019135683.
Topics: Adolescent; Adult; Anemia, Iron-Deficiency; Case-Control Studies; Data Management; Female; Folic Acid; Helicobacter Infections; Helicobacter pylori; Humans; Malnutrition; Micronutrients; Observational Studies as Topic; Pregnancy; Pregnancy Outcome; Risk Factors; Vitamin B 12; Young Adult
PubMed: 33093020
DOI: 10.1136/bmjgast-2020-000490