Takeaway
This meta-analysis found a small but significant protective effect of vitamin D supplementation on the risk of having ≥1 acute respiratory infections (ARIs) vs placebo, but there was evidence of significant heterogeneity of effect across trials.
Protection was associated with administration of daily doses of 400-1000 international units (IU) for up to 12 months and age at enrolment of 1.00-15.99 years.
Why this matters
A 2017 meta-analysis of data from 25 randomised controlled trials (RCTs) of vitamin D supplementation for the prevention of ARIs showed a protective effect of this intervention.
The relevance of these findings to COVID-19 is not known and requires further investigation.
Study design
Meta-analysis of 43 RCTs including 49,419 participants.
Funding: None.
Key results
A significantly lower proportion of participants in the vitamin D supplementation group had ≥1 ARIs vs placebo group (61.3% vs 62.3%; OR, 0.92; 95% CI, 0.86-0.99; 37 studies; I²=35.6%; Pheterogeneity=.018).
No significant effect of vitamin D supplementation on the risk of having ≥1 ARIs was seen for any of the subgroups defined by baseline 25(OH)D concentration.
A significant protective effect of vitamin D supplementation was seen in trials in which vitamin D was given (OR; 95% CI):
in a daily dosing regimen (0.78; 0.65-0.94; 19 studies; I²=53.5%, Pheterogeneity=.003);
at daily dose equivalents of 400-1000 IU (0.70; 0.55-0.89; 10 studies; I²=31.2%, Pheterogeneity=.16);
for a duration of ≤12 months (0.82; 0.72-0.93; 29 studies; I²=38.1%; Pheterogeneity=.021); and
to participants aged 1.00-15.99 years at enrolment (0.71; 0.57-0.90; 15 studies; I²=46.0%; Pheterogeneity=.027).
No significant interaction was seen between allocation to the vitamin D
supplementation group vs the placebo group and dose, dose frequency, study duration, or age.
Limitations
Heterogeneity across trials.
Risk of bias.
This clinical summary originally appeared on Univadis, part of the Medscape Professional Network.
© 2021 WebMD, LLC
Any views expressed above are the author's own and do not necessarily reflect the views of WebMD or Medscape.
Cite this: Sarfaroj Khan. Vitamin D in Moderation Reduces Risk of Acute Respiratory Infections - Medscape - Apr 07, 2021.
Comments