Vitamin D supplementation and upper respiratory tract infections in adolescent swimmers: A randomized controlled trial

Gal Dubnov-Raz, Barak Rinat, Harri Hemilä, Lauryn Choleva, Avner H. Cohen, Naama W. Constantini

Research output: Contribution to journalArticlepeer-review

Abstract

Observational studies identified associations between vitamin D insufficiency (serum 25(OH)D < 30ng·ml-1) and risk of upper respiratory infection (URI). Swimmers are highly prone to URIs, which might hinder their performance. The aim of this study was to examine if vitamin D3 supplementation reduces URI burden in vitamin D-insufficient swimmers. Fifty-five competitive adolescent swimmers with vitamin D insufficiency were randomized to receive vitamin D3 (2,000IU·d.1) or placebo for 12 winter weeks. A URI symptom questionnaire was completed weekly. Serum 25(OH)D concentrations were measured by radio-immunoassay before and after supplementation. We used linear regression to examine the relation between the change in 25(OH)D concentrations during the trial, and the duration and severity of URIs. There were no between-group differences in the frequency, severity, or duration of URIs. Exploratory analyses revealed that in the placebo group only, the change in 25(OH)D concentrations during the trial was highly associated with the duration of URIs (r = -0.90, p < .001), and moderately associated with the severity of URIs (r = -0.65,p = .043). The between-group differences for duration were highly significant. Vitamin D3 supplementation in adolescent swimmers with vitamin D insufficiency did not reduce URI burden. However, larger decreases in serum 25(OH)D concentrations were associated with significantly longer and more severe URI episodes.

Original languageEnglish
Pages (from-to)113-119
Number of pages7
JournalPediatric Exercise Science
Volume27
Issue number1
DOIs
StatePublished - 1 Feb 2015
Externally publishedYes

Keywords

  • Athletes
  • Cholecalciferol
  • Cold
  • Pediatrics
  • Swimming

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