Vitamin D supplementation and risk of acute respiratory tract infection: systematic review and meta-analysis
Martineau, A.R., Jolliffe, D.A., Hooper, R.L.
Published in BMJ
Abstract
Vitamin D supplementation reduced the risk of acute respiratory tract infection among all participants.
Methodology
Systematic review and meta-analysis of individual participant data from 25 randomized controlled trials. Participants aged 0-95 years from 14 countries. Trials compared vitamin D supplementation against placebo for prevention of acute respiratory tract infection.
Key Findings
Vitamin D supplementation reduced risk of acute respiratory tract infection by 12% overall (adjusted OR 0.88, 95% CI 0.81-0.96) Protective effects were strongest in those with baseline 25(OH)D <25 nmol/L (adjusted OR 0.58, 95% CI 0.40-0.82) Daily or weekly dosing was more effective than monthly bolus doses No serious adverse events attributed to vitamin D supplementation Number needed to treat: 33 overall, 4 for those with severe deficiency
Conclusions
Vitamin D supplementation was safe and protected against acute respiratory tract infection overall. Patients who were very vitamin D deficient and those not receiving bolus doses experienced the most benefit. Results support public health recommendations for vitamin D supplementation to prevent respiratory infections.
Limitations
Heterogeneity between trials in dosing regimens, baseline vitamin D status, and infection definitions Most trials not originally designed to assess respiratory infections as primary outcome Limited data on optimal dosing and duration Difficulty distinguishing between bacterial and viral infections Variation in baseline vitamin D levels across populations
Supplements Studied
Vitamin D supplementation reduced the risk of acute respiratory tract infection among all participants.
Outcomes Measured
Vitamin D reduced acute respiratory infection risk overall, with the largest benefit in profoundly deficient participants
Vitamin D reduced acute respiratory infection risk overall, with the largest benefit in profoundly deficient participants
Vitamin D reduced acute respiratory infection risk overall, with the largest benefit in profoundly deficient participants
Study Details
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Disclosures
Funding
National Institute for Health Research, Queen Mary University of London
Conflicts of Interest
None declared. Authors report grants from various health research bodies but no conflicts related to vitamin D manufacturers.
This information is for educational purposes only. Always consult a healthcare professional before starting any supplement regimen.