Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Meta-Analysis
. 2022 Feb 15;14(4):818.
doi: 10.3390/nu14040818.

Efficacy of Vitamin D Supplements in Prevention of Acute Respiratory Infection: A Meta-Analysis for Randomized Controlled Trials

Hae-Eun Cho  1 , Seung-Kwon Myung  2   3   4 , Herim Cho  1
Affiliations
Meta-Analysis

Efficacy of Vitamin D Supplements in Prevention of Acute Respiratory Infection: A Meta-Analysis for Randomized Controlled Trials

Hae-Eun Cho et al. Nutrients. .

Abstract

Background: Previous systematic reviews and meta-analyses of randomized controlled trials (RCTs) have reported inconsistent results regarding the efficacy of vitamin D supplements in the prevention of acute respiratory infections (ARIs).

Methods: We investigated these efficacy results by using a meta-analysis of RCTs. We searched PubMed, EMBASE, and the Cochrane Library in June 2021.

Results: Out of 390 trials searched from the database, a total of 30 RCTs involving 30,263 participants were included in the final analysis. In the meta-analysis of all the trials, vitamin D supplementation showed no significant effect in the prevention of ARIs (relative risk (RR) 0.96, 95% confidence interval (CI) 0.91-1.01, I2 = 59.0%, n = 30). In the subgroup meta-analysis, vitamin D supplementation was effective in daily supplementation (RR 0.83, 95% CI, 0.73-0.95, I2 = 69.1%, n = 15) and short-term supplementation (RR 0.83, 95% CI, 0.71-0.97, I2 = 66.8%, n = 13). However, such beneficial effects disappeared in the subgroup meta-analysis of high-quality studies (RR 0.89, 95% CI, 0.78-1.02, I2 = 67.0%, n = 10 assessed by the Jadad scale; RR 0.87, 95% CI, 0.66-1.15, I2 = 51.0%, n = 4 assessed by the Cochrane's risk of bias tool). Additionally, publication bias was observed.

Conclusions: The current meta-analysis found that vitamin D supplementation has no clinical effect in the prevention of ARIs.

Keywords: acute respiratory infections; meta-analysis; randomized controlled trial; vitamin D supplements.

PubMed Disclaimer

Conflict of interest statement

All authors declare no conflict of interest.

Figures

Figure 1
Figure 1
Flow Diagram for selection of relevant clinical trials.
Figure 2
Figure 2
Efficacy of vitamin D supplements in prevention of acute respiratory infections in a meta-analysis of randomized controlled trials (n = 30) [13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42]. RR, relative risk; CI, confidence interval; A, trial of vitamin D supplementation for prevention of Influenza (ViDiFlu); B, vitamin D3 supplementation in patients with chronic obstructive pulmonary disease (ViDiCO); C, vitamin D3 supplementation in adults with asthma (ViDiAs).
Figure 3
Figure 3
Efficacy of daily supplementation of vitamin D in prevention of acute respiratory infections and its efficacy in subgroup meta-analysis by quality of the study assessed by the Jadad scale [13,14,15,16,18,20,21,22,23,24,27,28,32,35,36]. RR, relative risk; CI, confidence interval.
Figure 4
Figure 4
Efficacy of daily supplementation of vitamin D in prevention of acute respiratory infections in subgroup meta-analysis by quality of the study assessed by Cochrane’s risk of bias tool [13,14,15,16,18,20,21,22,23,24,27,28,32,35,36]. RR, relative risk; CI, confidence interval.
Figure 5
Figure 5
Begg’s funnel plot and Egger’s test for identifying publication bias of randomized controlled trials. RR, relative risk; S.E, standard error.
See this image and copyright information in PMC

References

    1. Grief S.N. Upper respiratory infections. Prim. Care Clin. Off. Pract. 2013;40:757–770. doi: 10.1016/j.pop.2013.06.004. - DOI - PMC - PubMed
    1. Barrett B.T., Goldman R.B. Chapter 337: The common cold. In: Goldman L., Schafer A.I., editors. Cecil Medicine. 26th ed. Elsevier; Amsterdam, The Netherlands: 2019. pp. 2150–2152.
    1. Musher D.M. Chapter 91: Overview of pneumonia. In: Goldman L., Schafer A.I., editors. Cecil Medicine. 26th ed. Elsevier; Amsterdam, The Netherlands: 2019. pp. 592–603.
    1. Troeger C., Forouzanfar M., Rao P.C., Khalil I., Brown A., Swartz S., Fullman N., Mosser J., Thompson R.L., Reiner R.C., Jr., et al. Estimates of the global, regional, and national morbidity, mortality, and aetiologies of lower respiratory tract infections in 195 countries: A systematic analysis for the Global Burden of Disease Study 2015. Lancet Infect. Dis. 2017;17:1133–1161. doi: 10.1016/S1473-3099(17)30396-1. - DOI - PMC - PubMed
    1. Mousa H.A. Prevention and Treatment of Influenza, Influenza-Like Illness, and Common Cold by Herbal, Complementary, and Natural Therapies. J. Evid. Based Complementary Altern. Med. 2017;22:166–174. doi: 10.1177/2156587216641831. - DOI - PMC - PubMed

Publication types

MeSH terms