-
The American Journal of Clinical... Sep 2023Evidence is uncertain about the association between serum 25-hydroxyvitamin D (25(OH)D) concentration and health outcomes in people with type 2 diabetes. (Meta-Analysis)
Meta-Analysis
Serum 25(OH)D Concentration, Vitamin D Supplementation, and Risk of Cardiovascular Disease and Mortality in Patients with Type 2 Diabetes or Prediabetes: a Systematic Review and Dose-Response Meta-Analysis.
BACKGROUND
Evidence is uncertain about the association between serum 25-hydroxyvitamin D (25(OH)D) concentration and health outcomes in people with type 2 diabetes.
OBJECTIVES
We aimed to assess the association between vitamin D status and all-cause mortality and cardiovascular disease in people with type 2 diabetes.
METHODS
We did a systematic search in PubMed, Scopus, CENTRAL, and Web of Science until May 2022. We selected 1) cohort studies investigating the association between serum 25(OH)D concentration and mortality or cardiovascular disease in people with type 2 diabetes or prediabetes and 2) randomized trials of vitamin D supplementation in these patients. We used random-effects pairwise meta-analyses to calculate summary relative risks (RRs) and 95% confidence intervals (CI).
RESULTS
21 cohort studies and 6 randomized trials were included. Compared with sufficient vitamin D status (≥50 nmol/L), the RR of all-cause mortality was 1.36 (95% CI: 1.23, 1.49; n = 11 studies, GRADE = moderate) for vitamin D insufficiency (25 to <50 nmol/L), and 1.58 (1.33, 1.83; n = 16, GRADE = moderate) for deficiency (<25 nmol/L). Similar findings were observed for cardiovascular mortality and morbidity but not for cancer mortality. The certainty of evidence ranged from very low to moderate. Dose-response meta-analyses indicated nonlinear associations, with the lowest risk at 25(OH)D ∼60 nmol/L for all-cause and cardiovascular mortality. Supplementation with vitamin D did not reduce the risk of all-cause mortality (RR: 0.96, 95% CI: 0.79, 1.16; risk difference per 1000 patients: 3 fewer, 95% CI: 16 fewer, 12 more; n = 6 trials with 7316 participants; GRADE = low) or the risk of cardiovascular mortality and morbidity (very low- to low-certainty evidence).
CONCLUSIONS
Vitamin D deficiency and insufficiency are associated with a higher risk of all-cause and cardiovascular mortality in patients with type 2 diabetes or prediabetes. Vitamin D deficiency should be corrected in patients with type 2 diabetes to reach normal serum 25(OH)D concentrations, preferably 60 nmol/L.
SYSTEMATIC REVIEW REGISTRATION
This systemic review was registered at PROSPERO as CRD42022326429 (=https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=326429).
Topics: Humans; Cardiovascular Diseases; Diabetes Mellitus, Type 2; Prediabetic State; Vitamin D; Vitamins; Vitamin D Deficiency; Dietary Supplements
PubMed: 37467897
DOI: 10.1016/j.ajcnut.2023.07.012 -
Nutrients Aug 2023The coronavirus disease 2019 (COVID-19) pandemic caused by the Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) has become a global health crisis and pushed... (Meta-Analysis)
Meta-Analysis Review
The coronavirus disease 2019 (COVID-19) pandemic caused by the Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) has become a global health crisis and pushed researchers and physicians to discover possible treatments to improve the outcome of their patients. Vitamin D, known for its role in immune system function, has been hypothesized to play a role in COVID-19 treatment. A systematic review and meta-analysis were conducted to evaluate the efficacy of vitamin D supplementation in COVID-19, focusing on length of hospital stay (LOS), admission to the intensive care unit (ICU), and mortality. Thirteen randomized controlled trials (RCTs) were included, and the meta-analysis revealed that high-dose vitamin D supplementation showed potential benefits in reducing the length of hospital stay and ICU admission rates for patients with COVID-19. However, the overall effect on mortality did not reach statistical significance. While this systematic review suggests the potential benefits of high-dose vitamin D supplementation in reducing hospital stays and ICU admission in COVID-19 patients, caution is warranted due to the high heterogeneity and limitations of the included studies. Further large-scale randomized controlled trials with consistent study characteristics are needed to provide more robust evidence regarding the therapeutic benefits of vitamin D supplementation in COVID-19 outcomes.
Topics: Humans; COVID-19; SARS-CoV-2; Hospitalization; Intensive Care Units; Vitamins; Vitamin D; Dietary Supplements
PubMed: 37571407
DOI: 10.3390/nu15153470 -
Frontiers in Endocrinology 2023To evaluate the effect of vitamin D supplementation on pregnancy and ovulation in patients with polycystic ovary syndrome. (Meta-Analysis)
Meta-Analysis
OBJECTIVE
To evaluate the effect of vitamin D supplementation on pregnancy and ovulation in patients with polycystic ovary syndrome.
METHOD
We searched Pubmed, Medline (via Ovid, 1974 to 2020), EMBASE (via Ovid, 1974 to 2020), Cochrane Central Register of Controlled Trials (via Ovid), Web of Science, CNKI, WangFang and the Vip database from inception until April 2021. Two researchers independently screened articles, collected data and evaluated the quality, with Review manager 5.3 for meta-analysis.
RESULTS
Totally 20 randomized controlled studies with 1961 subjects were included. Meta analysis showed that pregnancy rate [RR=1.44 (1.28, 1.62), p<0.00,001], ovulation rate [RR=1.42 (1.14, 1.78), p=0.002] and matured oocytes rate [RR=1.08 (1.03, 1.13), p=0.002] of vitamin D supplementation group were significantly higher than those of control group. Meanwhile, early miscarriage rate [RR=0.44 (0.30, 0.66), p<0.00,001], androgen level [MD=-2.31 (-3.51, -1.11), p=0.0002], luteinizing hormone [MD=-1.47 (-2.57, -0.36), p=0.009], follicle stimulating hormone [MD=-0.15 (-0.24, -0.05), p=0.002], and premature delivery rate [RR=0.38, 95% CI (0.21, 0.70), p=0.002] were declined significantly than the controls. However, only one article suggested that the progesterone [MD=6.52 (4.52, 8.52), p<0.05] in the vitamin D intervention group was increased. There was no notable difference in the biochemical pregnancy rate [RR=0.95 (0.55, 1.63), p=0.84], gestational hypertension rate [RR=0.40, 95% CI (0.15, 1.11), p=0.08], gestational diabetes mellitus rate [RR=0.27, 95% CI (0.05, 1.39), p=0.11], fertilization rate [RR=1.05 (1.00, 1.10), p=0.04], cleavage rate [RR=1.03 (0.99, 1.06), p=0.17], high-quality embryo rate [RR=1.08 (0.98, 1.20), p=0.10], endometrial thickness [MD=0.10], 77 (-0.23, 1.77), p=0.13], estrogen level [MD=-0.34 (-1.55, 0.87), p=0.59], LH/FSH [MD=-0.14, 95% CI (-0.48, 0.20), p=1.00] and anti-Mullerian hormone [MD=-0.22 (-0.65, 0.21), p=0.32].
CONCLUSION
Vitamin D supplementation contribute to the higher pregnancy and ovulation rates, and lower androgen, LH, FSH and early miscarriage rates in women with PCOS, regardless of the use of ovulation induction drugs or assisted reproductive technologies. However, no significant improvement was observed in fertilization rate or cleavage rate. Due to the limitation in quality of involved studies, more high-quality RCTs are needed for further validation.
SYSTEMATIC REVIEW REGISTRATION
https://www.crd.york.ac.uk/PROSPERO, identifier CRD42021250284.
Topics: Female; Humans; Pregnancy; Abortion, Spontaneous; Androgens; Dietary Supplements; Follicle Stimulating Hormone, Human; Ovulation; Polycystic Ovary Syndrome; Vitamin D
PubMed: 37593349
DOI: 10.3389/fendo.2023.1148556 -
The American Journal of Clinical... Sep 2023Vitamin D supplements are widely used for improving bone health in children and adolescents, but their effects in vitamin D-deficient children are unclear. (Meta-Analysis)
Meta-Analysis
Vitamin D supplementation for improving bone density in vitamin D-deficient children and adolescents: systematic review and individual participant data meta-analysis of randomized controlled trials.
BACKGROUND
Vitamin D supplements are widely used for improving bone health in children and adolescents, but their effects in vitamin D-deficient children are unclear.
OBJECTIVES
This study aimed to examine whether the effect of vitamin D supplementation on bone mineral density (BMD) in children and adolescents differs by baseline vitamin D status and estimate the effect in vitamin D-deficient individuals.
METHODS
This is a systematic review and individual participant data (IPD) meta-analysis. We searched the Cochrane Central Register of Controlled Trials, MEDLINE, MBASE, CINAHL, AMED, and ISI Web of Science (until May 27, 2020) for randomized controlled trials (RCTs) of vitamin D supplementation reporting bone density outcomes after ≥6 mo in healthy individuals aged 1-19 y. We used two-stage IPD meta-analysis to determine treatment effects on total body bone mineral content and BMD at the hip, femoral neck, lumbar spine, and proximal and distal forearm after 1 y; examine whether effects varied by baseline serum 25-hydroxyvitamin D [25(OH)D] concentration, and estimate treatment effects for each 25(OH)D subgroup.
RESULTS
Eleven RCTs were included. Nine comprising 1439 participants provided IPD (86% females, mean baseline 25(OH)D = 36.3 nmol/L). Vitamin D supplementation had a small overall effect on total hip areal BMD (weighted mean difference = 6.8; 95% confidence interval: 0.7, 12.9 mg/cm; I = 7.2%), but no effects on other outcomes. There was no clear evidence of linear or nonlinear interactions between baseline 25(OH)D and treatment; effects were similar in baseline 25(OH)D subgroups (cutoff of 35 or 50 nmol/L). The evidence was of high certainty.
CONCLUSIONS
Clinically important benefits for bone density from 1-y vitamin D supplementation in healthy children and adolescents, regardless of baseline vitamin D status, are unlikely. However, our findings are mostly generalizable to White postpubertal girls and do not apply to those with baseline 25(OH)D outside the studied range or with symptomatic vitamin D deficiency (e.g., rickets). This study was preregistered at PROSPERO as CRD42017068772. https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42017068772.
Topics: Female; Adolescent; Child; Humans; Male; Bone Density; Randomized Controlled Trials as Topic; Vitamin D Deficiency; Vitamins; Vitamin D; Dietary Supplements
PubMed: 37661104
DOI: 10.1016/j.ajcnut.2023.05.028 -
Nutrients Oct 2023The combination of resistance exercise and creatine supplementation has been shown to decrease body fat percentage in adults ≥ 50 years of age. However, the effect on... (Meta-Analysis)
Meta-Analysis Review
The combination of resistance exercise and creatine supplementation has been shown to decrease body fat percentage in adults ≥ 50 years of age. However, the effect on adults < 50 years of age is currently unknown. To address this limitation, we systematically reviewed the literature and performed several meta-analyses comparing studies that included resistance exercise and creatine supplementation to resistance exercise and placebo on fat mass and body fat percentage Twelve studies were included, involving 266 participants. Adults (<50 years of age) who supplemented with creatine and performed resistance exercise experienced a very small, yet significant reduction in body fat percentage (-1.19%, = 0.006); however, no difference was found in absolute fat mass (-0.18 kg, = 0.76). Collectively, in adults < 50 years of age, the combination of resistance exercise and creatine supplementation produces a very small reduction in body fat percentage without a corresponding decrease in absolute fat mass.
Topics: Humans; Adult; Creatine; Resistance Training; Exercise; Dietary Supplements; Body Composition; Muscle, Skeletal; Muscle Strength
PubMed: 37892421
DOI: 10.3390/nu15204343 -
Nutrients Aug 2023β-alanine does not have an ergogenic effect by itself, but it does as a precursor for the synthesis of carnosine in human skeletal muscle. β-alanine and carnosine... (Review)
Review
β-Alanine Supplementation in Combat Sports: Evaluation of Sports Performance, Perception, and Anthropometric Parameters and Biochemical Markers-A Systematic Review of Clinical Trials.
β-alanine does not have an ergogenic effect by itself, but it does as a precursor for the synthesis of carnosine in human skeletal muscle. β-alanine and carnosine together help improve the muscles' functionality, especially in high-intensity exercises such as combat sports. Therefore, β-alanine could be considered a nutritional ergogenic aid to improve sports performance in combat athletes. We aimed to critically review clinical trial evidence on the impact of β-alanine supplementation on sports performance, perception, and anthropometric parameters, as well as circulating biochemical markers in combat athletes. This systematic review was conducted following the specific methodological guidelines of the Preferred Report Items for Systematic Reviews and Meta-Analyses guidelines (PRISMA), the PICOS question model, the Critical Review Form of McMaster, and the PEDro scale. Furthermore, the Cochrane risk-of-bias assessment tool was used. The search was carried out in the SCOPUS, Web of Science (WOS), and Medline (PubMed) databases for studies published from the beginning of the database until July 31, 2023. Of the 41 registers identified, only 7 met the established criteria and were included in this systematic review. Overall, performance parameters related to strength, power, total exercise work capacity, and combat-specific parameters were significantly improved ( < 0.05). Perception parameters increased non-significantly ( > 0.05). Regarding biochemical parameters, carnosine increased significantly ( < 0.05), pH decreased non-significantly ( > 0.05), and the results for blood bicarbonate and blood lactate were heterogeneous. Finally, there was a non-significant ( > 0.05) improvement in the anthropometric parameters of lean mass and fat mass. β-alanine supplementation appears to be safe and could be a suitable nutritional ergogenic aid for combat athletes.
Topics: Humans; Athletes; Athletic Performance; Carnosine; Dietary Supplements; Perception; Performance-Enhancing Substances; Clinical Trials as Topic
PubMed: 37686787
DOI: 10.3390/nu15173755 -
Advances in Nutrition (Bethesda, Md.) Nov 2023Overweight and obesity are highly prevalent worldwide and are associated with cardiovascular disease (CVD) risk factors, including systematic inflammation, dyslipidemia,... (Meta-Analysis)
Meta-Analysis Review
Effect of Alpha-Linolenic Acid Supplementation on Cardiovascular Disease Risk Profile in Individuals with Obesity or Overweight: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.
Overweight and obesity are highly prevalent worldwide and are associated with cardiovascular disease (CVD) risk factors, including systematic inflammation, dyslipidemia, and hypertension. Alpha-linolenic acid (ALA) is a plant-based essential polyunsaturated fatty acid associated with reduced CVD risks. This systematic review and meta-analysis aimed to investigate the effects of supplementation with ALA compared with the placebo on CVD risk factors in people with obesity or overweight (International Prospective Register of Systematic Reviews Registration No. CRD42023429563). This review included studies with adults using oral supplementation or food or combined interventions containing vegetable sources of ALA. All studies were randomly assigned trials with parallel or crossover designs. The Cochrane Collaboration tool was used for assessing the risk of bias (Version 1). PubMed, Web of Science, Embase, and Cochrane library databases were searched from inception to April 2023. Nineteen eligible randomized controlled trials, including 1183 participants, were included in the meta-analysis. Compared with placebo, dietary ALA supplementation significantly reduced C-reactive protein concentration (standardized mean difference [SMD] = -0.38 mg/L; 95% confidence interval [CI]: -0.72, -0.04), tumor necrosis factor-α concentration (SMD = -0.45 pg/mL; 95% CI: -0.73, -0.17), triglyceride in serum (SMD = -4.41 mg/dL; 95% CI: -5.99, -2.82), and systolic blood pressure (SMD = -0.37 mm Hg; 95% CI: -0.66, -0.08); but led to a significant increase in low-density lipoprotein cholesterol concentrations (SMD = 1.32 mg/dL; 95% CI: 0.05, 2.59). ALA supplementation had no significant effect on interleukin-6, diastolic blood pressure, total cholesterol, or high-density lipoprotein cholesterol (all P ≥ 0.05). Subgroup analysis revealed that ALA supplementation at a dose of ≥3 g/d from flaxseed and flaxseed oil had a more prominent effect on improving CVD risk profiles, particularly where the intervention duration was ≥12 wk and where the baseline CVD profile was poor.
Topics: Adult; Humans; Cardiovascular Diseases; alpha-Linolenic Acid; Overweight; Randomized Controlled Trials as Topic; Cholesterol, HDL; Obesity; Dietary Supplements
PubMed: 37778442
DOI: 10.1016/j.advnut.2023.09.010 -
Nutrition Research (New York, N.Y.) Aug 2023The relationship between anthocyanin intake and obesity-related inflammatory markers remains unclear in existing research. To investigate this, we hypothesized that... (Meta-Analysis)
Meta-Analysis Review
The relationship between anthocyanin intake and obesity-related inflammatory markers remains unclear in existing research. To investigate this, we hypothesized that anthocyanin supplementation could reduce plasma concentrations of inflammatory markers, including C-reactive protein (CRP), tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), vascular cell adhesion molecule-1, and other cytokines in obesity. We conducted a systematic search of PubMed, Web of Science, Scopus, SinoMed, and other related literature and identified 16 randomized controlled trials that met our inclusion criteria. Our findings showed that anthocyanin intake was significantly associated with a reduction in vascular cell adhesion molecule-1 mean plasma concentrations (-53.56 ng/mL; 95% confidence interval [CI], -82.10 to -25.03). We also observed a modest decrease in CRP (-0.27 ng/mL; 95% CI, -0.58 to 0.05), TNF-α (-0.20 ng/mL; 95% CI, -0.54 to 0.15), and IL-6 (-0.53 ng/mL; 95% CI, -1.16 to 0.10) mean plasma concentrations. Subgroup analysis revealed that anthocyanin intake tended to decrease CRP and IL-6 concentrations in overweight or dyslipidemic individuals. Additionally, the intervention duration subgroup analysis showed that anthocyanin supplementation had a stronger effect on plasma IL-6 and TNF-α in participants after 8 to 12 weeks of intervention. In conclusion, our meta-analysis indicated that anthocyanin supplementation can effectively reduce obesity-related inflammatory markers associated with chronic low-grade inflammation.
Topics: Humans; Anthocyanins; Interleukin-6; Tumor Necrosis Factor-alpha; Vascular Cell Adhesion Molecule-1; Randomized Controlled Trials as Topic; Obesity; C-Reactive Protein; Inflammation; Dietary Supplements
PubMed: 37320946
DOI: 10.1016/j.nutres.2023.05.009 -
Neuromuscular Disorders : NMD Nov 2023We conducted a systematic literature review and meta-analysis on the effectiveness of vitamin D supplementation in maintaining or restoring vitamin D levels in Duchenne... (Meta-Analysis)
Meta-Analysis Review
We conducted a systematic literature review and meta-analysis on the effectiveness of vitamin D supplementation in maintaining or restoring vitamin D levels in Duchenne muscular dystrophy. Due to a lack of randomised controlled trials, cross-sectional and retrospective and prospective cohort studies were taken as the best available evidence. Inclusion criteria included reporting mean serum vitamin D levels in a supplement-taking group. After screening 102 records; 13 were included in a narrative synthesis and eight of these in a meta-analysis. We show that current dosing regimens are preventing severe deficiency but are not effective at maintaining sufficient vitamin D levels within the Duchenne population. Despite high levels of daily vitamin D supplementation (>1000 International Units), at least 20 % of people with Duchenne remain vitamin D deficient. No significant association between dose and serum vitamin D levels was found (r = 0.3, p = 0.237). A meta-analysis of mean serum vitamin D levels across eight studies also revealed substantial variability in response to vitamin D supplementation and high heterogeneity (I = 99.59 %). These data could impact on an individual's risk and severity of osteoporosis and vertebral fractures.
Topics: Humans; Muscular Dystrophy, Duchenne; Retrospective Studies; Prospective Studies; Cross-Sectional Studies; Vitamin D; Vitamins; Dietary Supplements
PubMed: 37932186
DOI: 10.1016/j.nmd.2023.10.008 -
Brain Sciences Oct 2023β-carotene is a powerful antioxidant and dietary precursor of vitamin A whose role in maintaining mental health and cognitive performance, either alone or in... (Review)
Review
β-carotene is a powerful antioxidant and dietary precursor of vitamin A whose role in maintaining mental health and cognitive performance, either alone or in combination with other dietary compounds, has been a topic of recent research. However, its effectiveness is still unclear. This systematic review, conducted according to the PRISMA guideline and assisted by the MySLR platform, addressed this issue. A total of 16 eligible original research articles were identified. Dietary intake or β-carotene serum levels were associated with improved measures of cognitive function in 7 out of 10 epidemiological studies included. In intervention studies, β-carotene consumption alone did not promote better cognitive function in the short term, but only in a long-term intervention with a mean duration of 18 years. However, all but one intervention study suggested the beneficial effects of β-carotene supplementation at doses ranging from 6 mg to 50 mg per day in combination with a multicomplex such as vitamin E, vitamin C, zinc, or selenium for a period of 16 weeks to 20 years. Despite the current limitations, the available evidence suggests a potential association between β-carotene dietary/supplementary intake and the maintenance of cognitive function. The β-carotene most probably does not act alone but in synergy with other micronutrients.
PubMed: 37891835
DOI: 10.3390/brainsci13101468