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Completed

NCT Number: NCT01215682

Vitamin D Supplementation and Upper Respiratory Tract Infections in Adolescent Swimmers

Background: The medical and economic burden of upper respiratory tract infections (URTIs) is extremely high, while prevention and treatment options are limited. Therefore, there is a constant need for new methods in order to significantly decrease such morbidity. Extensive evidence shows that vitamin D is associated with respiratory health, including in the prevention and treatment of URTIs. Competitive swimmers have a high prevalence of URTIs, and can serve as a model for research in this field.

The study hypothesis is that vitamin D supplementation to young swimmers with low vitamin D levels will reduce the frequency, length, and severity of URTIs and their accompanying functional impairment, while improving cellular immune function and physical function.

Methods: After screening 100 competitive adolescent swimmers to obtain ~60 with low serum levels of vitamin D, this study group will be randomized to receive either vitamin D supplementation (2000 IU/d) or placebo, given in a double blinded fashion for three months. Participants will fill a daily questionnaire regarding frequency, length and severity of URTIs symptoms and functional impairment. Blood will be drawn to evaluate changes in vitamin D status (25(OH)D) and immune function among study participants at the beginning of the study and after supplementation. Physical function on land and in water will also be assessed.

Expected results: Increase in serum 25(OH)D levels following supplementation will significantly decrease the frequency, length and severity of URTI's and their functional impairment, while enhancing the cellular immune system function and physical capacity.

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Key information

Conditions

Upper Respiratory Tract Infections Infections Respiratory Tract Diseases Respiratory Tract Infections

Age range

12 year–18 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Maccabi Haifa Swimming Club, Haifa, Israel

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Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • members of swimming team
  • training at least 15 hours/week
  • low vitamin D plasma levels (<30 ng/ml)
  • signed consent forms

Exclusion criteria

  • chronic health conditions
  • taking prescription medications
  • taking diet supplementations

Treatment and study plan

Vitamin D

Dietary Supplement

2000 IU/day of vitamin D3 as a once-daily dose

Placebo

Dietary Supplement

sweetened water

Primary outcomes

  1. URI frequency

    Time frame: 3 months

    URI frequency will be measured in both groups, starting 4 weeks after initiating the suplementation. Analysis will also assess differences by sex or initial vitamin D levels, as well as by immune function changes.

  2. URI duration

    Time frame: 3 months

    URI duration will be measured in both groups, starting 4 weeks after initiating the suplementation. Analysis will also assess differences by sex or initial vitamin D levels, as well as by immune function changes.

  3. UTI severity

    Time frame: 3 months

    URI severity will be measured in both groups, starting 4 weeks after initiating the suplementation. Analysis will also assess differences by sex or initial vitamin D levels, as well as by immune function changes.

Secondary outcomes

  1. plasma vitamin D levels

    Time frame: 3 months

  2. immune system function

    Time frame: 3 months

    T-cell receptor excision circles (TREC), T cell receptor repertoire, B-cell receptor excision circles (BREC). Comparison will be made with changes in vitamin D levels and with URI characteristics.

  3. physical function

    Time frame: 3 months

    absence from school or training, land and swimming fitness tests. Comparison will be made with changes in vitamin D levels.

Sponsors and collaborators

Lead sponsor

Sheba Medical Center

Other Gov

Registry information

Official study title

Vitamin D Supplementation, Upper Respiratory Tract Infections, Immune and Physical Functions in Adolescent Swimmers

Important dates

Study start
2010
Primary completion
2011
Study completion
2011
First posted
Oct 6, 2010
Registry last updated
Mar 26, 2012

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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