Could High-Dose Vitamin D Supplementation Prevent Respiratory Infections?

High-dose vitamin D supplements do not prevent viral upper respiratory tract infections in young children, according to a recent study.

The study included 703 children from 1 to 5 years of age who were enrolled in the TARGet Kids! researcher network in Toronto, Canada. For a minimum of 4 winter months (between September and May), 349 participants were randomly assigned to receive a once daily high-dose 2000 IU oral vitamin D supplement, and 345 participants were randomly assigned to receive a once daily standard-dose oral vitamin D supplement.
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The number of laboratory-confirmed viral upper respiratory tract infections was assessed as the primary outcome. Secondary outcomes included the number of influenza infections, noninfluenza infections, parent-reported upper respiratory tract illnesses, time to upper respiratory tract infection, and serum 25-hydroxyvitamin D levels at the end of the study.

Overall, 699 participants (99.4%) completed the study.

The mean number of laboratory-confirmed upper respiratory tract infections per child was 1.05 in the high-dose group and 1.03 in the standard-dose group.

Additionally, the median time to first laboratory-confirmed infection was 3.95 months for the high-dose group and 3.29 months for the standard-dose group, and the number of parent-reported upper respiratory tract illnesses was 625 for the high-dose group and 600 for the standard-dose group.

There were no statistically significant differences in the number of laboratory-confirmed infections, the median time to first laboratory-confirmed infection, or in the number of parent-reported upper respiratory tract illnesses between groups.

At the end of the study, the serum hydroxyvitamin D levels was 48.7 ng/ml and 36.8 ng/ml for the high-dose group and standard-dose group, respectively.

“Among healthy children aged 1 to 5 years, daily administration of 2000 IU compared with 400 IU of vitamin D supplementation did not reduce overall wintertime upper respiratory tract infections,” the researchers concluded. “These findings do not support the routine use of high-dose vitamin D supplementation in children for the prevention of viral upper respiratory tract infections.”

—Melissa Weiss

Reference:

Aglipay M, Birken CS, Parkin PC, et al. Effect of high-dose vs standard-dose wintertime vitamin D supplementation on viral upper respiratory tract infections in young children [published online July 18, 2017]. JAMA. doi:10.1001/jama.2017.8708.