PURLS / PEER REVIEWED

Can Vitamin D Prevent Acute Respiratory Infections?

Clinician Reviews. 2019 September;29(9):4e-5e

References

1. Martineau AR, Jolliffe DA, Hooper RL, et al. Vitamin D supplementation to prevent acute respiratory tract infections: systematic review and meta-analysis of individual participant data. BMJ. 2017;356:i6583.
2. Renati S, Linder JA. Necessity of office visits for acute respiratory infections in primary care. Fam Pract. 2016,33:312-317.
3. CDC National Center for Health Statistics. National Health Care Surveys. www.cdc.gov/nchs/dhcs.htm. Accessed September 5, 2019.
4. Grijalva CG, Nuorti JP, Griffin MR. Antibiotic prescription rates for acute respiratory tract infections in US ambulatory settings. JAMA. 2009;302:758-766.
5. Rees JR, Hendricks K, Barry EL, et al. Vitamin D3 supplementation and upper respiratory tract infections in a randomized, controlled trial. Clin Infect Dis. 2013;57:1384-1392.
6. Murdoch DR, Slow S, Chambers ST, et al. Effect of vitamin D3 supplementation on upper respiratory tract infections in healthy adults: the VIDARIS randomized controlled trial. JAMA. 2012;308:1333-1339.
7. Laaksi I, Ruohola J-P, Mattila V, et al. Vitamin D supplementation for the prevention of acute respiratory tract infection: a randomized, double-blinded trial among young Finnish men. Infect Dis. 2010;202:809-814.
8. Bergman P, Norlin A-C, Hansen S, et al. Vitamin D3 supplementation in patients with frequent respiratory tract infections: a randomised and double-blind intervention study. BMJ Open. 2012;2:e001663.

WHAT’S NEW

A more accurate snapshot

Previous studies of vitamin D and respiratory tract infections were mostly observational in nature. Those that were RCTs used variable doses of vitamin D, had variable baseline 25(OH)D levels, and employed various methods to monitor ARTI symptoms/incidence.^5-8 This is the first systematic review and meta-analysis of randomized, double-blind, placebo-controlled trials with supplementation using vitamin D₃ or D₂ that used individual participant-level data, which gives a more accurate estimate of outcomes when compared with traditional meta-analyses.

CAVEATS

Only the most deficient benefit?

Vitamin D supplementation was safe and protected against ARTIs overall, but the greatest effect was noted in those who were most severely vitamin D deficient (those with circulating 25(OH)D levels < 10 ng/mL [NNT, 4] and those with circulating 25(OH)D levels 10-28 ng/mL [NNT, 15]). There was no demonstrable effect once circulating 25(OH)D levels reached 30 ng/mL.

CHALLENGES TO IMPLEMENTATION

Breaking tradition

The study found that both daily and weekly doses of vitamin D were effective in reducing the incidence of ARTIs. However, the doses studied were much lower than those commonly used (10,000 to 50,000 IU bolus), which were ineffective in reducing ARTIs in this meta-analysis. Changing from bolus dosing may prove challenging, as it is an ingrained practice for many providers.

In addition, the authors of the study suggest that one way to provide this level of vitamin D is through food fortification. But this method is often complicated by emotional and/or political issues that could thwart implementation.

ACKNOWLEDGEMENT

The PURLs Surveillance System was supported in part by Grant Number UL1RR024999 from the National Center For Research Resources, a Clinical Translational Science Award to the University of Chicago. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Center For Research Resources or the National Institutes of Health.

Reprinted with permission from the Family Physicians Inquiries Network and The Journal of Family Practice (2019;68[4]:230-231).