The influence of vitamin D supplementation on IGF-1 levels in humans: A systematic review and meta-analysis

Kord-Varkaneh H 1 , Rinaldi G 2 , Hekmatdoost A 3 , Fatahi S 4 , Tan SC 5 , Shadnoush M 1 Show all authors , Khani V 6 , Mousavi SM 7 , Zarezadeh M 8 , Salamat S 9 , Bawadi H 10 , Rahmani J 11

Affiliations 

  • 1 Department of Clinical Nutrition and Dietetics, Student Research Committee, Faculty of Nutrition and Food Technology, Shahid Beheshti University of Medical Sciences, Tehran, Iran
  • 2 St.George's Hospital, London, United Kingdom
  • 3 Department of Pediatrics, BC Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
  • 4 Student Research Committee, Department of Nutrition, School of Public Health, Iran University of Medical Sciences, Tehran, Iran
  • 5 UKM Medical Molecular Biology Institute, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
  • 6 Department of Radiology, Taleghani Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran
  • 7 Department of Community Nutrition, Students' Scientific Research Center (SSRC), School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences (TUMS), Tehran, Iran
  • 8 Department of Clinical Nutrition, Student Research Committee, Nutrition Research Center, School of Nutrition and Food Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
  • 9 Department of Nutrition, Student Research Committee, Faculty of Para-Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran; Department of health, Arvand Petrochemical Company, Mahshahr, Iran
  • 10 College of Health Sciences, QU-health, Qatar University, Doha, Qatar. Electronic address: hbawadi@qu.edu.qa
  • 11 Department of Community Nutrition, Students' Scientific Research Center (SSRC), School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences (TUMS), Tehran, Iran. Electronic address: Jrahmani@sbmu.ac.ir
Ageing Res Rev, 2020 01;57:100996.
PMID: 31816443 DOI: 10.1016/j.arr.2019.100996

Abstract

BACKGROUND: Inconsistencies exist with regard to influence of vitamin D supplementation on IGF-1 levels. The inconsistencies could be attributed to several factors, such as dosage and duration of intervention, among others. To address these inconsistencies, this study was conducted to determine the impact of vitamin D supplementation on IGF-1 levels through a systematic review and meta-analysis of randomized controlled trials (RCTs).

METHODS: A comprehensive systematic search was carried out in PubMed/MEDLINE, Web of Science, SCOPUS and Embase for RCTs that investigated the impact of vitamin D intake on circulating IGF-1 levels from inception until June 2019. Weighted mean difference (WMD) with the 95 % CI were applied for estimating combined effect size. Subgroup analysis was performed to specify the source of heterogeneity among studies.

RESULTS: Pooled results from eight studies demonstrated an overall non-significant increase in IGF-1 following vitamin D supplementation (WMD: 4 ng/ml, 95 % CI: -4 to 11). However, a significant degree of heterogeneity among studies was observed (I2 = 66 %). The subgroup analyses showed that vitamin D dosage of ≤1000 IU/day (WMD: 10 ng/ml) significantly increased IGF-1 compared to the vitamin D dosage of <1000 IU/day (WMD: -1 ng/ml). Moreover, intervention duration ≤12 weeks (WMD: 11 ng/ml) significantly increased IGF-1 compared to intervention duration <12 weeks (WMD: -3 ng/ml). In the epidemiological cohort study, participants under 60 years of age with a higher dietary vitamin D intake had significantly higher IGF-1 levels when compared to those with lower dietary vitamin D intake in second categories.

CONCLUSION: The main results indicate a non-significant increase in IGF-1 following vitamin D supplementation. Additionally, vitamin D dosages of <1000 IU/day and intervention durations of <12 weeks significantly raised IGF-1 levels.

* Title and MeSH Headings from MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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