Clinical trial NCT01215682: Vitamin D Supplementation and Upper Respiratory Tract Infections in Adolescent Swimmers
Official title: Vitamin D Supplementation, Upper Respiratory Tract Infections, Immune and Physical Functions in Adolescent Swimmers
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Upper Respiratory Tract Infections
Keywords: infections
immune system
vitamin D
sport
children
Lead sponsor: Sheba Medical Center
Sponsor class: OTHER_GOV
First posted: 2010-10-06
Enrollment: 82
Sex: ALL
Minimum age (years): 12
Maximum age (years): 18
Standard ages: CHILD
ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: PREVENTION

Brief summary: 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.


Eligibility criteria: 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

Primary outcomes:
measure: URI frequency
timeFrame: 3 months
measure: URI duration
timeFrame: 3 months
measure: UTI severity
timeFrame: 3 months
Secondary outcomes:
measure: plasma vitamin D levels
timeFrame: 3 months
measure: immune system function
timeFrame: 3 months
measure: physical function
timeFrame: 3 months
Other outcomes:
Locations:
city: Haifa
country: Israel
facility: Maccabi Haifa Swimming Club
city: Herzlyia
country: Israel
facility: Bnei Herzlyia Swimming Club
city: Hod Hasharon
country: Israel
facility: Hod Hasharon Swimming Club
city: Maccabim
country: Israel
facility: Maccabim-Reut Swimming Club
Study officials:
affiliation: Sheba Medical Center
name: Gal Dubnov-Raz, MD MSc
role: PRINCIPAL_INVESTIGATOR
affiliation: Hadassah Medical Organziation
name: Naama W Constantini, MD
role: PRINCIPAL_INVESTIGATOR
affiliation: Clalit Health Services
name: Avner Cohen, MD
role: PRINCIPAL_INVESTIGATOR
affiliation: Sheba Medical Center
name: Raz Somech, MD PhD
role: PRINCIPAL_INVESTIGATOR
References:
citation: Dubnov-Raz G, Rinat B, Hemila H, Choleva L, Cohen AH, Constantini NW. Vitamin D supplementation and upper respiratory tract infections in adolescent swimmers: a randomized controlled trial. Pediatr Exerc Sci. 2015 Feb;27(1):113-9. doi: 10.1123/pes.2014-0030. Epub 2014 Jul 15.