Vitamin D in the prevention of acute respiratory infection: systematic review of clinical studies

J Steroid Biochem Mol Biol. 2013 Jul;136:321-9. doi: 10.1016/j.jsbmb.2012.11.017. Epub 2012 Dec 7.

Abstract

Vitamin D metabolites enhance immunity to a wide range of respiratory pathogens in vitro. Numerous observational studies have investigated whether vitamin D deficiency is a risk factor for acute respiratory infection, and a number of clinical trials of vitamin D supplementation for the prevention of acute respiratory infection have recently been conducted. Syntheses of this literature are lacking. We therefore conducted a systematic review of clinical studies investigating the association between vitamin D deficiency and susceptibility to acute respiratory infection in humans. A total of 39 studies (4 cross-sectional studies, 8 case-control studies, 13 cohort studies and 14 clinical trials) satisfying review eligibility criteria were identified. Observational studies predominantly reported statistically significant associations between low vitamin D status and increased risk of both upper and lower respiratory tract infections. Results from randomised controlled trials were conflicting however, reflecting heterogeneity in dosing regimens and baseline vitamin D status in study populations. Further trials of vitamin D supplementation for the prevention of acute respiratory infection should be conducted in populations with a high prevalence of vitamin D deficiency at baseline, using doses sufficient to induce sustained elevation of serum 25-hydroxyvitamin D concentrations, and powered to detect clinically important sub-group effects. This article is part of a Special Issue entitled 'Vitamin D Workshop'.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review
  • Systematic Review

MeSH terms

  • Clinical Trials as Topic
  • Dietary Supplements
  • Disease Susceptibility
  • Epidemiologic Studies
  • Humans
  • Respiratory Tract Infections / blood
  • Respiratory Tract Infections / etiology
  • Respiratory Tract Infections / prevention & control*
  • Risk Factors
  • Vitamin D / blood
  • Vitamin D / pharmacology*
  • Vitamin D Deficiency / blood
  • Vitamin D Deficiency / complications
  • Vitamin D Deficiency / prevention & control

Substances

  • Vitamin D