Background: Obesity is associated with lower concentrations of serum 25-hydroxyvitamin D; however, uncertainty exists as to the direction of causation. To date, meta-analyses of randomized controlled vitamin D-supplementation trials have shown no effect of raising circulating vitamin D on body weight, although several weight-loss-intervention trials have reported an increase in circulating vitamin D after weight reduction.
Objective: We undertook a systematic review and meta-analysis of randomized and nonrandomized controlled trials to determine whether weight loss compared with weight maintenance leads to an increase in serum 25-hydroxyvitamin D.
Design: A systematic search for controlled weight-loss-intervention studies published up to 31 March 2016 was performed. Studies that included participants of any age with changes in adiposity and serum 25-hydroxyvitamin D as primary or secondary outcomes were considered eligible.
Results: We identified 4 randomized controlled trials (n = 2554) and 11 nonrandomized controlled trials (n = 917) for inclusion in the meta-analysis. Random assignment to weight loss compared with weight maintenance resulted in a greater increase in serum 25-hydroxyvitamin D with a mean difference of 3.11 nmol/L (95% CI: 1.38, 4.84 nmol/L) between groups, whereas a mean difference of 4.85 nmol/L (95% CI: 2.59, 7.12 nmol/L) was observed in nonrandomized trials. No evidence for a dose-response effect of weight loss on the change in serum 25-hydroxyvitamin D was shown overall.
Conclusions: Our results indicate that vitamin D status may be marginally improved with weight loss in comparison with weight maintenance under similar conditions of supplemental vitamin D intake. Although additional studies in unsupplemented individuals are needed to confirm these findings, our results support the view that the association between obesity and lower serum 25-hydroxyvitamin D may be due to reversed causation with increased adiposity leading to suboptimal concentrations of circulating vitamin D. This trial was registered at www.crd.york.ac.uk/PROSPERO/ as CRD42015023836.
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http://dx.doi.org/10.3945/ajcn.116.136879 | DOI Listing |
Front Cell Infect Microbiol
January 2025
Laboratório de Imunidade Natural (LIN), Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia, Goiás, Brazil.
Background: The vitamin D pathway contributes to the microbicidal activity of macrophages against infection. In addition to induction of this pathway, interferon-gamma (IFNγ), interleukin (IL)-15, and IL32γ are part of a network of pro-inflammatory cytokines. The aim of this study was to evaluate single-nucleotide polymorphisms (SNPs) in the components of the vitamin D pathway and associated cytokine genes that could be related to resistance or susceptibility to American tegumentary leishmaniasis (ATL).
View Article and Find Full Text PDFBMJ Open
January 2025
Department of Obstetrics and Gynaecology, Uganda Martyrs University, Mother Kevin Postgraduate Medical School, Nsambya Campus, Kampala, Uganda.
Objective: There is a dearth of published data on the vitamin D status of the Ugandan population; the objective of the study was to determine the prevalence of vitamin D deficiency among pregnant women in Uganda and its associations with maternal characteristics and adverse foetal-maternal outcomes.
Study Design And Setting: We conducted a cross-sectional study on pregnant women admitted to a tertiary referral hospital in Kampala, Uganda for delivery during the study period from July to December 2023.
Participants: The study was conducted on 351 pregnant women aged ≥18 years who consented to participate in the study, who had a single intrauterine pregnancy and a gestational age greater than 26 weeks, and who delivered at St.
J Physiol Sci
January 2025
Department of Clinical Laboratory, Guangxi International Zhuang Medicine Hospital Affiliated to Guangxi University of Chinese Medicine, 530201, Nanning, Guangxi, China. Electronic address:
Establishing specific reference intervals (RIs) of serum 25-hydroxyvitamin D3 [25(OH)D] for children is essential for improving the accuracy of diagnosis and prognosis monitoring of diseases such as rickets and growth retardation. The study including 6,627 healthy children was conducted to establish specific RIs of 25(OH)D for children in Nanning area of China. The results showed that there were statistically significant differences among age, season, and gender of serum 25(OH)D levels, and the age-specific RIs of serum 25(OH)D were 20.
View Article and Find Full Text PDFFront Nutr
January 2025
Hebei Huiji Technology Co., Ltd., Shijiazhuang, Hebei, China.
Current evidence is inconsistent on whether vitamin D supplementation can prevent COVID-19 infection or improve its clinical outcomes. To better understand and look into the issue, we went through the background knowledge of COVID-19 and vitamin D, searched in Pubmed [by using key words in the title containing "randomized clinical trial", "COVID-19", and "vitamin D (25-hydroxyvitamin D, or cholecalciferol, or calcidiol, or calcifediol) supplementation"] for publications of studies on vitamin D/supplementation in COVID-19 patients, especially those about the randomized clinical trials (RCTs). After reviewing these papers, we did a short background review of vitamin D and the pathophysiology of COVID-19, summarized the key features of the 25 RCTs in text and tabulated in a table of some of the features, commented, compared and discussed the differences between RCTs (for example, change the serum 25-hydroxyvitamin D concentration from nmol/L to ng/mL, making the comparison easier).
View Article and Find Full Text PDFFront Endocrinol (Lausanne)
January 2025
Department of Pediatric Orthopaedics, ShengJing Hospital of China Medical University, Shenyang, China.
Objective: To explore the correlation between vitamin D levels, related endocrine/metabolic factors, and the risk of slipped capital femoral epiphysis (SCFE) in children and adolescents, and to assess whether vitamin D levels are associated with SCFE severity.
Methods: A retrospective case-control study was conducted from March 2014 to October 2023 in Shengjing hospital. Patients diagnosed with SCFE were categorized as the SCFE group.
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