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Vitamin D supplementation to prevent acute respiratory tract infections: systematic review and meta-analysis of individual participant data
IPD meta-analysis of 25 RCTs (10,933 participants): vitamin D supplementation reduced acute respiratory tract infection odds (adjusted OR 0.88, 95% CI 0.81–0.96); strongest protective signals appeared with daily/weekly dosing without large boluses and among baseline 25(OH)D <25 nmol/L.
Design
- IPD obtained for 25 RCTs (10,933 of 11,223 randomised participants)
- Intervention: oral vitamin D vs placebo or lower-dose control
Primary pooled result (adjusted)
- Any acute respiratory tract infection: adjusted OR 0.88 (95% CI 0.81–0.96; P < 0.001)
Dose-regimen heterogeneity (major theme)
- Daily or weekly dosing without intermittent very large boluses showed stronger protection in subgroup models
- Participants with baseline 25(OH)D <25 nmol/L derived larger relative benefits in analyses reported in the abstract
Evidence hygiene
Acute infection prevention is not the same endpoint family as fracture or falls—keep vitamin D rows distinct by outcome when cross-linking sunlight protocols.
Publication
Martineau AR, Jolliffe DA, Hooper RL, et al. BMJ. 2017 Feb 15;356:i6583. PMID 28202713.
Outcomes
- Any acute respiratory tract infection: adjusted odds ratio 0.88 (95% CI 0.81–0.96; P<0.001) for vitamin D supplementation vs control across 25 RCTs with individual participant data (n=10,933).