There is equivocality regarding the interaction between vitamin D and insulin-like growth factor-1 (IGF-1). Thus, the aim of this study was to elucidate the effect of vitamin D supplementation on serum levels of IGF-1 by conducting a systematic review and meta-analysis of randomized controlled trials (RCTs).
PubMed, Scopus, and ISI Web of Science databases were searched up to May 2019 for RCTs that evaluated the effect of vitamin D supplementation on IGF-1 levels. Mean and standard deviation changes of IGF-1 in each treatment group were considered for analysis and pooled using random-effect model. Risk of bias for included studies was assessed by the Cochrane scale and the NutriGrade approach was applied to evaluate the quality of evidence.
Six trials (n= 773 participants) were included in the meta-analysis. Compared with control group, vitamin D supplementation yielded no significant effect on serum level of IGF-1 (weighted mean difference [WMD] = 4.66 ng/ml, 95% CIs: -6.72 to 16.03, P=0.42, I2= 74.8, P-heterogeneity= 0.001). Additionally, no meaningful changes were observed in subgroup analyses.
The evidence from the limited number of published trials does not convincingly show that vitamin D supplementation elicits any clinically relevant effects on IGF-1 levels. More high-quality studies are needed to reach a consensual conclusion in this area.
Bibliographical noteNOTICE: this is the author’s version of a work that was accepted for publication in Complementary Therapies in Medicine,. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Complementary Therapies in Medicine, 50 (2020)
© 2020, Elsevier. Licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nc-nd/4.0/
- Growth factor
- Insulin-Like growth Factor-1
- Vitamin D
ASJC Scopus subject areas
- Complementary and Manual Therapy
- Complementary and alternative medicine
- Advanced and Specialised Nursing