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CompletedNCT03584256Updated Jul 12, 2018

Vitamin D Status Among Competitive Female Gymnast and Swimmers After Winter Time

An observational study in Vitamin D Deficiency, Injuries and Cardiovascular Risk Factor, sponsored by University of Ljubljana. Completed at 1 site in Slovenia. Open to female participants aged 12 Years and older. Per ClinicalTrials.gov, last updated 2018-07-12.

Sponsored by University of Ljubljana · Observational

Study type
Observational
Model
Cohort
Time perspective
Cross-sectional
Enrollment
31
Ages
12 Years and older
Sex
Female
01

Study summary

As indoor athletes, competitive gymnasts and swimmers can face the problem of a potential vitamin D deficiency. In the last decades, indoor sports participants have been faced with the problem of an institutionalized lifestyle and, in some places, a lower exposure to sun, which is also associated with the geographical area with a lower or higher UV index, especially in autumn, winter, and early spring (from October to April), when the day is shorter and the clock shifts to winter time. The problem with gymnasts and swimmers lies in daily trainings in the gym and pool and in the daily rest between two trainings, which can be spend more or less institutionally. The investigators wanted to examine the vitamin D status related to bone mineral density, body composition and various cardiovascular markers among young competitive gymnasts and swimmers after winter time. The investigators want to potentially give more solid but sensible recommendations for trainers, athletes, parents and sports doctors when it comes to vitamin D supplementations for indoor female athletes.

Read the detailed description

In this cross-sectional survey, the investigators will document vitamin D and the status of other micronutrients related to bone mineral density, body composition and a variety of risk factors for chronic non-communicable diseases.

The investigators hypothesize that there exists a serious problem of vitamin D deficiency among indoor athletes related to bone health, injuries and general health - especially when they are not using supplements. It is well known that vitamin D may improve athletic performance in vitamin D-deficient athletes.

International and national-level female gymnasts and swimmers that will be enrolled will sign an informed consent statement for the inclusion in this survey and the choice to participate in the study will be made by coaches and participants themselves and, in the event of females under 18 years of age, also by their parents, in accordance with the Helsinki declaration.

The investigators plan to enroll at least 30 female participants (15 gymnasts and 15 swimmers) who compete on an international and national level and are older than 12 years of age.

The investigators will measure the athletes' biochemistry in overnight fasted state (micronutrients, including vitamin D (25(OH)D), B12, Ca, Fe, Mg, K and P, lipids, liver enzymes, glucose, creatinine, etc.), their seated blood pressure status, bone mineral density (also segmental) and body composition, using Dual-energy X-ray absorptiometry (DXA), their dietary choice and nutrition intake status, using standardized Food frequency questionnaire (FFQ), their training characteristics, injury status and menstrual status. Athletes who are using vitamin D supplements or who have attended a one-month training camp in the southern geographical zone (Africa) will serve us as control group.

02

Conditions studied

  • Vitamin D Deficiency
  • Injuries
  • Cardiovascular Risk Factor
  • Nutritional Deficiency
03

In context

Vitamin D Deficiency

773 studies on the registry are indexed under Vitamin D Deficiency; 62 are open to participants now.

This study's enrollment of 31 is below the median of 139 across 184 observational studies indexed under Vitamin D Deficiency.

Browse Vitamin D Deficiency studies →

Lead sponsor

University of Ljubljana is the lead sponsor of 42 studies on the registry; 12 are open to participants now.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
12 Years and older
Sexes eligible
Female
Sampling method
Non-probability sample

Study population

Sport

Inclusion criteria

  • international and national level
  • Signed informed consent for participation in the study

Exclusion criteria

Exclusion Criteria:

-

05

Study design

Observational model
Cohort
Time perspective
Cross-sectional
Enrollment
31 participants (actual)
Patient registry
No

Groups and cohorts

  • gymnasts

    Female gymnasts, older than 13 years, with status of ineternational or national level,

  • swimmers

    Female swimmers, older than 12 years, with status of ineternational or national level,

06

What researchers measure

Primary outcomes

  1. Differences between female gymnasts and swimmers of vitamin D status

    Serum 25(OH)D (ng/ml) status after winter time

    Time frame: April 2018

Secondary outcomes

  1. Differences between female gymnasts and swimmers of bone mineral density status

    Bone mineral density status (g/cm3) using DEXA

    Time frame: April 2018

Other outcomes

  1. Differences between female gymnasts and swimmers of body composition status

    Lean and fat tissue mass (%) assessed dy DEXA

    Time frame: April 2018

07

Study locations

1 site
  • Faculty of Sport
    Ljubljana, 1000, Slovenia
08

References and documents

Publications

  • Bjelakovic G, Gluud LL, Nikolova D, Whitfield K, Wetterslev J, Simonetti RG, Bjelakovic M, Gluud C. Vitamin D supplementation for prevention of mortality in adults. Cochrane Database Syst Rev. 2014 Jan 10;2014(1):CD007470. doi: 10.1002/14651858.CD007470.pub3. PubMed 24414552 ↗
  • Fuleihan Gel-H, Bouillon R, Clarke B, Chakhtoura M, Cooper C, McClung M, Singh RJ. Serum 25-Hydroxyvitamin D Levels: Variability, Knowledge Gaps, and the Concept of a Desirable Range. J Bone Miner Res. 2015 Jul;30(7):1119-33. doi: 10.1002/jbmr.2536. Epub 2015 May 7. PubMed 25952470 ↗
  • Holick MF. Vitamin D deficiency. N Engl J Med. 2007 Jul 19;357(3):266-81. doi: 10.1056/NEJMra070553. No abstract available. PubMed 17634462 ↗
  • Bannert N, Starke I, Mohnike K, Frohner G. [Parameters of mineral metabolism in children and adolescents in athletic training]. Kinderarztl Prax. 1991 May;59(5):153-6. German. PubMed 1921165 ↗
  • Lovell G. Vitamin D status of females in an elite gymnastics program. Clin J Sport Med. 2008 Mar;18(2):159-61. doi: 10.1097/JSM.0b013e3181650eee. PubMed 18332692 ↗
  • De Keyzer W, Dekkers A, Van Vlaslaer V, Ottevaere C, Van Oyen H, De Henauw S, Huybrechts I. Relative validity of a short qualitative food frequency questionnaire for use in food consumption surveys. Eur J Public Health. 2013 Oct;23(5):737-42. doi: 10.1093/eurpub/cks096. Epub 2012 Jul 26. PubMed 22843611 ↗
  • Geiker NRW, Hansen M, Jakobsen J, Kristensen M, Larsen R, Jorgensen NR, Hansen BS, Bugel S. Vitamin D Status and Muscle Function Among Adolescent and Young Swimmers. Int J Sport Nutr Exerc Metab. 2017 Oct;27(5):399-407. doi: 10.1123/ijsnem.2016-0248. Epub 2017 May 30. PubMed 28556690 ↗
  • Jakse B, Jakse B, Cuk I, Sajber D. Body Composition, Training Volume/Pattern and Injury Status of Slovenian Adolescent Female High-Performance Gymnasts. Int J Environ Res Public Health. 2021 Feb 19;18(4):2019. doi: 10.3390/ijerph18042019. PubMed 33669675 ↗

Individual participant data

Plan to share: Undecided

09

Updates

Tracking since Sep 25, 2026
No changes since tracking began. The registry record was last updated on Jul 12, 2018, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
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Registry details

Key details

Study ID
NCT03584256
Lead sponsor
University of Ljubljana
Collaborators
Barbara Jakše s.p.
Responsible party
Sponsor
First posted
Jul 12, 2018
Start date
Apr 5, 2018
Primary completion
Apr 6, 2018
Completion
Apr 6, 2018
Last update
Jul 12, 2018

Study contacts

Ivan Čuk
principal investigator · University of Ljubljana, Faculty of Sport, Slovenia

Oversight

Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

Not currently enrolling

This study is completed, as verified in Jul 2018. You cannot join it, but the record below documents what was studied.

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