Vitamin D Supplementation Lowers Risk for Acute Respiratory Tract Infections

Observational evidence suggests that low blood concentrations of 25-hydroxyvitamin D are associated with susceptibility for acute respiratory tract infections. In this meta-analysis of 25 randomized, double-blind, placebo-controlled trials, researchers used individual participant data on about 11,000 children and adults to examine whether vitamin D supplementation lowered risk for acute respiratory tract infections (upper, lower, and unclassified location).

In all studies, vitamin D was administered orally: bolus doses every 1 to 3 months, weekly doses, daily doses, or a combination of bolus and daily doses. Vitamin D supplementation significantly lowered risk for acute respiratory tract infections (by 12%; adjusted odds ratio, 0.88). This p…