Study
Shows
Vitamin D Preventing
Influenza
On March 12, 2010, the American Journal of Clinical Nutrition published a multicenter, randomized, double-blind, placebo controlled trial of schoolchildren showing that vitamin D prevents influenza. A secondary finding was that asthmatic children on placebo had six times more asthma attacks than did children on vitamin D.
For further information, contact lead author Dr. Mitsuyoshi Urashima at urashima@jikei.ac.jp
Urashima M, Segawa T, Okazaki M, Kurihara M, Wada Y, Ida H. Randomized trial of vitamin D supplementation to prevent seasonal influenza A in schoolchildren. Am J Clin Nutr. Epub 2010 Mar 10.
Division of Molecular Epidemiology Jikei University School of Medicine Minato-ku Tokyo Japan.
Background
: To our knowledge, no rigorously designed clinical trials have evaluated the relation between vitamin D and physician-diagnosed seasonal influenza.
Objective
: We investigated the effect of vitamin D supplements on the incidence of seasonal influenza A in schoolchildren.
Design
: From December 2008 through March 2009, we conducted a randomized, double-blind, placebo-controlled trial comparing vitamin D(3) supplements (1200 IU/d) with placebo in schoolchildren. The primary outcome was the incidence of influenza A, diagnosed with influenza antigen testing with a nasopharyngeal swab specimen.
Results
: Influenza A occurred in 18 of 167 (10.8%) children in the vitamin D(3) group compared with 31 of 167 (18.6%) children in the placebo group [relative risk (RR), 0.58; 95% CI: 0.34, 0.99; P = 0.04]. The reduction in influenza A was more prominent in children who had not been taking other vitamin D supplements (RR: 0.36; 95% CI: 0.17, 0.79; P = 0.006) and who started nursery school after age 3 y (RR: 0.36; 95% CI: 0.17, 0.78; P = 0.005). In children with a previous diagnosis of asthma, asthma attacks as a secondary outcome occurred in 2 children receiving vitamin D(3) compared with 12 children receiving placebo (RR: 0.17; 95% CI: 0.04, 0.73; P = 0.006).
Conclusion
: This study suggests that vitamin D(3) supplementation during the winter may reduce the incidence of influenza A, especially in specific subgroups of schoolchildren. This trial was registered at http://list.netatlantic.com/t/51059679/75015860/126222/0/ as UMIN000001373.
PMID: 20219962 [PubMed – as supplied by publisher]
– John Cannell, MD
Author
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