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Journal of the American Heart... Dec 2023Cardiovascular calcification, characterized by deposition of calcium phosphate in the arterial wall and heart valves, is associated with cardiovascular morbidity and...
BACKGROUND
Cardiovascular calcification, characterized by deposition of calcium phosphate in the arterial wall and heart valves, is associated with cardiovascular morbidity and mortality and is commonly seen in aging, diabetes, and chronic kidney disease. Whether evidence-based interventions could significantly attenuate cardiovascular calcification progression remains uncertain.
METHODS AND RESULTS
We conducted a systematic review of randomized controlled trials involving interventions, compared with placebo, another comparator, or standard of care, to attenuate cardiovascular calcification. Included clinical trials involved participants without chronic kidney disease, and the outcome was cardiovascular calcification measured using radiological methods. Quality of evidence was determined by the Cochrane risk of bias and Grading of Recommendations, Assessment, Development, and Evaluations assessment. Forty-nine randomized controlled trials involving 9901 participants (median participants 104, median duration 12 months) were eligible for inclusion. Trials involving aged garlic extract (n=6 studies) consistently showed attenuation of cardiovascular calcification. Trials involving 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (n=14), other lipid-lowering agents (n=2), hormone replacement therapies (n=3), vitamin K (n=5), lifestyle measures (n=4), and omega-3 fatty acids (n=2) consistently showed no attenuation of cardiovascular calcification with these therapies. Trials involving antiresorptive (n=2), antihypertensive (n=2), antithrombotic (n=4), and hypoglycemic agents (n=3) showed mixed results. Singleton studies involving salsalate, folate with vitamin B6 and 12, and dalcetrapib showed no attenuation of cardiovascular calcification. Overall, Cochrane risk of bias was moderate, and the Grading of Recommendations, Assessment, Development, and Evaluations assessment for a majority of analyses was moderate certainty of evidence.
CONCLUSIONS
Currently, there are insufficient or conflicting data for interventions evaluated in clinical trials for mitigation of cardiovascular calcification. Therapy involving aged garlic extract appears most promising, but evaluable studies were small and of short duration.
Topics: Humans; Antioxidants; Diabetes Mellitus; Disease Progression; Hypoglycemic Agents; Randomized Controlled Trials as Topic; Renal Insufficiency, Chronic; Vascular Calcification; Garlic; Phytotherapy; Plant Extracts
PubMed: 38014685
DOI: 10.1161/JAHA.123.031676 -
Cells Aug 2023There is an increasing interest in biomarkers of nitric oxide dysregulation and oxidative stress to guide management and identify new therapeutic targets in patients... (Meta-Analysis)
Meta-Analysis Review
There is an increasing interest in biomarkers of nitric oxide dysregulation and oxidative stress to guide management and identify new therapeutic targets in patients with chronic obstructive pulmonary disease (COPD). We conducted a systematic review and meta-analysis of the association between circulating metabolites within the arginine (arginine, citrulline, ornithine, asymmetric, ADMA, and symmetric, SDMA dimethylarginine), transsulfuration (methionine, homocysteine, and cysteine) and folic acid (folic acid, vitamin B, and vitamin B) metabolic pathways and COPD. We searched electronic databases from inception to 30 June 2023 and assessed the risk of bias and the certainty of evidence. In 21 eligible studies, compared to healthy controls, patients with stable COPD had significantly lower methionine (standardized mean difference, SMD = -0.50, 95% CI -0.95 to -0.05, = 0.029) and folic acid (SMD = -0.37, 95% CI -0.65 to -0.09, = 0.009), and higher homocysteine (SMD = 0.78, 95% CI 0.48 to 1.07, < 0.001) and cysteine concentrations (SMD = 0.34, 95% CI 0.02 to 0.66, = 0.038). Additionally, COPD was associated with significantly higher ADMA (SMD = 1.27, 95% CI 0.08 to 2.46, = 0.037), SDMA (SMD = 3.94, 95% CI 0.79 to 7.08, = 0.014), and ornithine concentrations (SMD = 0.67, 95% CI 0.13 to 1.22, = 0.015). In subgroup analysis, the SMD of homocysteine was significantly associated with the biological matrix assessed and the forced expiratory volume in the first second to forced vital capacity ratio, but not with age, study location, or analytical method used. Our study suggests that the presence of significant alterations in metabolites within the arginine, transsulfuration, and folic acid pathways can be useful for assessing nitric oxide dysregulation and oxidative stress and identifying novel treatment targets in COPD. (PROSPERO registration number: CRD42023448036.).
Topics: Humans; Cysteine; Nitric Oxide; Metabolomics; Arginine; Methionine; Racemethionine; Folic Acid; Homocysteine; Vitamins
PubMed: 37681911
DOI: 10.3390/cells12172180 -
The Cochrane Database of Systematic... 2000Pyridoxine (vitamin B6) contributes to the development of the central nervous system and may influence brain development and cognitive function. It may also prevent... (Review)
Review
BACKGROUND
Pyridoxine (vitamin B6) contributes to the development of the central nervous system and may influence brain development and cognitive function. It may also prevent dental caries and protect the placental vascular bed.
OBJECTIVES
The objective of this review was to assess the effects of vitamin B6 supplementation during pregnancy and labour.
SEARCH STRATEGY
We searched the Cochrane Pregnancy and Childbirth Group trials register.
SELECTION CRITERIA
Randomised trials of pyridoxine administration compared to a control group.
DATA COLLECTION AND ANALYSIS
Trial quality was assessed and data were extracted by two reviewers.
MAIN RESULTS
One trial involving 371 women was included. Pyridoxine supplementation either as oral capsules (odds ratio 0.63, 95% confidence interval 0. 41 to 0.95) or lozenges (odds ratio 0.33, 95% confidence interval 0. 22-0.51) was associated with decreased incidence of dental decay in pregnant women.
REVIEWER'S CONCLUSIONS
There is not enough evidence to evaluate pyridoxine supplementation during pregnancy, although the results of one trial suggest that it may have a beneficial effect on dental decay.
Topics: Dietary Supplements; Female; Humans; Pregnancy; Pyridoxine
PubMed: 10796172
DOI: 10.1002/14651858.CD000179 -
Drugs & Aging May 2019Vitamin B deficiency and elevated total plasma homocysteine have been associated with cognitive impairment and dementia in later life, although it is unknown if... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Vitamin B deficiency and elevated total plasma homocysteine have been associated with cognitive impairment and dementia in later life, although it is unknown if treatment with these vitamins improves cognitive outcomes.
OBJECTIVES
The objectives of this study were to examine the efficacy of treatment with vitamin B, vitamin B, or folic acid in slowing cognitive decline amongst older adults with and without cognitive impairment.
METHODS
We summarized findings from previous systematic reviews of clinical trials and performed a new systematic review and meta-analysis of 31 English-language, randomized placebo-controlled trials of B-vitamin supplementation of individuals with and without existing cognitive impairment.
RESULTS
Previous reviews have generally reported no effect of B vitamins on cognitive function in older adults with or without cognitive impairment at study entry, although these vitamins effectively lowered total plasma homocysteine levels in participants. Ten randomized placebo-controlled trials of 1925 participants with pre-existing cognitive impairment and 21 trials of 15,104 participants without cognitive impairment have been completed to date but these generally confirmed findings from previous reviews with the exception of two trials that showed a modest but clinically uncertain benefit for vitamins in people with elevated plasma homocysteine. B-vitamin supplementation did not show an improvement in Mini-Mental State Examination scores for individuals with (mean difference 0.16, 95% confidence interval - 0.18 to 0.51) and without (mean difference 0.04, 95% confidence interval - 0.10 to 0.18) cognitive impairment compared to placebo.
CONCLUSIONS
Raised total plasma homocysteine is associated with an increased risk of cognitive impairment and dementia, although available evidence from randomized controlled trials shows no obvious cognitive benefit of lowering homocysteine using B vitamins. Existing trials vary greatly in the type of supplementation, population sampled, study quality, and duration of treatment, thereby making it difficult to draw firm conclusions from existing data. Findings should therefore be viewed in the context of the limitations of the available data and the lack of evidence of effect should not necessarily be interpreted as evidence of no effect.
Topics: Aged; Cognition; Cognition Disorders; Dementia; Dietary Supplements; Female; Folic Acid; Homocysteine; Humans; Male; Vitamin B 12; Vitamin B 6; Vitamin B Complex
PubMed: 30949983
DOI: 10.1007/s40266-019-00649-w -
The Cochrane Database of Systematic... Apr 2006Vitamin B6 plays vital roles in numerous metabolic processes in the human body, such as nervous system development and functioning. It has been associated with some... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Vitamin B6 plays vital roles in numerous metabolic processes in the human body, such as nervous system development and functioning. It has been associated with some benefits in non-randomised studies, such as higher Apgar scores, higher birthweights, and reduced incidence of pre-eclampsia and preterm birth. Recent studies also suggest a protection against certain congenital malformations.
OBJECTIVES
To evaluate the clinical effects of vitamin B6 supplementation during pregnancy and/or labour.
SEARCH STRATEGY
We searched the Cochrane Pregnancy and Childbirth Group Trials Register (30 December 2005).
SELECTION CRITERIA
We included randomised controlled trials comparing vitamin B6 administration in pregnancy and/or labour with: placebos, no supplementations, or supplements not containing vitamin B6.
DATA COLLECTION AND ANALYSIS
Two authors independently extracted data and assessed trials for methodological quality. We used relative risk and weighted mean difference with 95% confidence intervals.
MAIN RESULTS
Five trials (1646 women) were included. Four trials used blinding. One had adequate method of randomisation and allocation concealment; four did not report this. Three trials had large losses to follow up. Vitamin B6 as oral capsules or lozenges resulted in decreased risk of dental decay in pregnant women (capsules: relative risk (RR) 0.84; 95% confidence interval (CI) 0.71 to 0.98; one trial, n = 371; lozenges: RR 0.68; 95% CI 0.56 to 0.83; one trial, n = 342). A small trial showed reduced mean birthweights with vitamin B6 supplementation (weighted mean difference -0.23 kg; 95% CI -0.42 to -0.04; n = 33; one trial). We did not find any statistically significant differences in the risk of eclampsia (capsules: n = 1242; three trials; lozenges: n = 944; one trial), pre-eclampsia (capsules n = 1197; two trials; lozenges: n = 944; one trial) or low Apgar scores at one minute (oral pyridoxine: n = 45; one trial), between supplemented and non-supplemented groups. No differences were found in Apgar scores at one or five minutes, or breastmilk production between controls and women receiving oral (n = 24; one trial) or intramuscular (n = 24; one trial) loading doses of pyridoxine at labour.
AUTHORS' CONCLUSIONS
There were few trials, reporting few clinical outcomes and mostly with unclear trial methodology and inadequate follow up. There is not enough evidence to detect clinical benefits of vitamin B6 supplementation in pregnancy and/or labour other than one trial suggesting protection against dental decay. Future trials assessing this and other outcomes such as orofacial clefts, cardiovascular malformations, neurological development, preterm birth, pre-eclampsia and adverse events are required.
Topics: Dietary Supplements; Female; Humans; Pregnancy; Pregnancy Outcome; Pyridoxine; Randomized Controlled Trials as Topic
PubMed: 16625530
DOI: 10.1002/14651858.CD000179.pub2 -
Journal of Thrombosis and Thrombolysis Nov 2012A homocysteine-independent role for B-group vitamins on venous thrombosis (VT) development has been reported. However, related research findings remain inconsistent.... (Meta-Analysis)
Meta-Analysis Review
A homocysteine-independent role for B-group vitamins on venous thrombosis (VT) development has been reported. However, related research findings remain inconsistent. PUBMED, EMBASE, and COCHRANE databases were searched to collect information on all eligible studies to make a meta-analysis about the relationship between B-group vitamins and VT. Literature search results did not suggest a correlation between thiamin, pantothenic acid, niacin, or riboflavin with VT. Based on their correlations in the literature, folic acid, vitamin B12, B6 were considered in the meta-analysis and systematic review. Significant standardized mean differences were obtained for plasma folic acid (-0.55; 95% CI, -0.75 to -0.36) and vitamin B12 (-0.34; 95% CI, -0.55 to -0.13). Reduced levels of folic acid and vitamin B12 may be independent risk factors of VT. Moreover, a qualitative systematic review indicated that low level of vitamin B6 was an independent risk factor of VT. Randomized clinical studies of B-group vitamins supplementation showed varying results on VT prevention. Multivitamin supplementation for VT prevention, regardless of homocysteine level, would be of interest. Further prospective clinical studies are needed to provide additional evidence on the clinical benefits of B-group vitamin supplementation for VT.
Topics: Female; Homocysteine; Humans; Male; PubMed; Randomized Controlled Trials as Topic; Risk Factors; Venous Thrombosis; Vitamin B Complex
PubMed: 22743781
DOI: 10.1007/s11239-012-0759-x -
Clinical Chemistry and Laboratory... Nov 2020
PubMed: 33554504
DOI: 10.1515/cclm-2020-1684 -
The Cochrane Database of Systematic... 2002The use of mega-vitamin intervention began in the early 1950's with the treatment of schizophrenic patients. Pyroxidine (vitamin B6) was first used with children... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
The use of mega-vitamin intervention began in the early 1950's with the treatment of schizophrenic patients. Pyroxidine (vitamin B6) was first used with children diagnosed with "autism syndrome" when speech and language improvement was observed in some children as a result of large doses of B6. A number of published studies attempted to assess the effects of vitamin B6-Mg (Mg was found to reduce undesirable side effects from B6) on a variety of characteristics such as verbal communication, non-verbal communication, interpersonal skills, and physiological function, in individuals with autism.
OBJECTIVES
To determine the efficacy of vitamin B6 and magnesium (B6-Mg) for treating social, communication and behavioural responses of children and adults with autism.
SEARCH STRATEGY
We searched the Cochrane Controlled Trials Register (Cochrane Library, Issue 2, 2002), MEDLINE (1966- January 2002), EMBASE (1980-January 2002), PsychINFO (1887 - January 2002), Dissertation Abstracts International (1861 - January 2002). The search engine FirstSearch was also used (January 2002). Reference lists for all the obtained studies and other review articles were examined for additional studies.
SELECTION CRITERIA
All studies in which the participants were randomly allocated prior to intervention and in which outcomes were compared to either a placebo or non-treated group were included.
DATA COLLECTION AND ANALYSIS
Two reviewers independently evaluated all potential studies identified as indicated above for inclusion.
MAIN RESULTS
Two trials were included in the review. Both studies used a double-blind crossover design. One study (Tolbert 1993) provided insufficient data to conduct an analysis. The senior author was contacted for supporting data but was unable to provide the needed information. The remaining study (Findling, 1997) yielded no significant differences between treatment and placebo group performances following the B6 intervention on measures of social interaction, communication, compulsivity, impulsivity, or hyperactivity.
REVIEWER'S CONCLUSIONS
Due to the small number of studies, the methodological quality of studies, and small sample sizes, no recommendation can be advanced regarding the use of B6-Mg as a treatment for autism.
Topics: Adult; Autistic Disorder; Child; Drug Therapy, Combination; Humans; Magnesium; Vitamin B 6
PubMed: 12519599
DOI: 10.1002/14651858.CD003497 -
BMJ Clinical Evidence Jun 2009More than half of pregnant women suffer from nausea and vomiting, which typically begins by the 4th week and disappears by the 16th week of pregnancy. The cause of... (Review)
Review
INTRODUCTION
More than half of pregnant women suffer from nausea and vomiting, which typically begins by the 4th week and disappears by the 16th week of pregnancy. The cause of nausea and vomiting in pregnancy is unknown, but may be due to the rise in human chorionic gonadotrophin concentration. In 1 in 200 women, the condition progresses to hyperemesis gravidarum, which is characterised by prolonged and severe nausea and vomiting, dehydration, and weight loss.
METHODS AND OUTCOMES
We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of treatment for nausea and vomiting in early pregnancy? What are the effects of treatments for hyperemesis gravidarum? We searched: Medline, Embase, The Cochrane Library, and other important databases up to May 2008 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA).
RESULTS
We found 30 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions.
CONCLUSIONS
In this systematic review we present information relating to the effectiveness and safety of the following interventions: acupressure; acupuncture; antihistamines; corticosteroids; corticotrophins; diazepam; dietary interventions other than ginger; domperidone; ginger; metoclopramide; ondansetron; phenothiazines; and pyridoxine (vitamin B6).
Topics: Acupressure; Administration, Oral; Domperidone; Female; Humans; Metoclopramide; Nausea; Phytotherapy; Pregnancy; Single-Blind Method; United States Food and Drug Administration; Vomiting
PubMed: 21726485
DOI: No ID Found -
Archives of Gerontology and Geriatrics 2009Hyperhomocysteinemia (HHcy) is supposed to be one of the modifiable risk factors that, if treated, may delay the onset of Alzheimer's disease (AD). The relation between... (Review)
Review
Hyperhomocysteinemia (HHcy) is supposed to be one of the modifiable risk factors that, if treated, may delay the onset of Alzheimer's disease (AD). The relation between serum homocysteine (Hcy) and vitamin levels during AD and its preclinical phase was systematically reviewed. Searches through large literature and trial databases were conducted. Data were extracted from studies and, after quality assessment, analyzed using a meta-analysis software package. Nine qualitatively good case-control studies were identified. The pooled standardized mean difference (PSMD) of Hcy levels (631 patients, 703 controls) was 1.04 (0.44-1.63), indicating higher Hcy levels in AD patients. Levels of folate (PSMD=0.65) (0.34-0.95) (387 patients, 312 controls) and vitamin B(12) (PSMD=0.50) (-0.05-1.06) (387 patients, 312 controls) were lower in AD patients. Vitamin B(6) levels were evaluated in 1 case-control study and were not significantly lower in AD patients. Analysis of prospective cohort studies (2569 subjects) revealed a pooled relative risk for AD in HHcy of 2.5 (1.38-4.56, p<0.01). No specific randomized controlled trials (RCTs) concerning Hcy-lowering therapy and AD-risk were identified. Prospective studies on the relation between folate, vitamins B(6) and B(12) levels and the risk of developing AD are warranted, preferably in the form of RCTs.
Topics: Alzheimer Disease; Folic Acid; Humans; Hyperhomocysteinemia; Risk Factors; Vitamin B 12; Vitamin B 6
PubMed: 18479766
DOI: 10.1016/j.archger.2008.03.009