An observational study in Vitamin D Deficiency, sponsored by University of Surrey. Completed at 2 sites in United Kingdom. Open to participants aged 18 Years to 30 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2018-11-16.
Sponsored by University of Surrey · Observational
Athletes and active individuals have been identified as an at-risk group for a low vitamin D status, specifically those residing in countries of higher latitude (such as the United Kingdom). This especially applies to those who train indoors for their sport, this is because Vitamin D is primarily produced following skin exposure to ultraviolet B (UVB) exposure. Vitamin D is essential for the maintenance of optimal bone and musculoskeletal health. It has also been suggested to play a role in the prevention of illness incidence, such as in upper respiratory tract infections (URTI). More recent research has indicated that an improved Vitamin D status may also play a role in enhancing exercise performance. Therefore, having a poor vitamin D status could negatively impact athletic training and competition. The purpose of this study is to evaluate the prevalence of vitamin D deficiency in university athletes and inactive controls in spring and autumn.
During this study the subjects will be asked to visit the labs on two occasions, at the beginning of the study for baseline measurements, and again on two occasions at the end of the study. Participants will have the following outcomes assessed: Sport performance (vertical jump height, muscular strength and aerobic fitness), peripheral Quantitative Computed Tomography (pQCT) scan of the bone mineral composition of the tibia, total body composition via Dual Energy X-ray Absorptiometry (DEXA),total and hip/femoral head bone mineral density and content to assess fracture risk via DEXA. Serum 25(OH)D levels (≈15ml of whole blood will be collected for these measurements. Dietary intake using self-reported food diaries. In addition illness and injury incidence will be recorded daily throughout the study in a booklet provided to the participants.Throughout the trial, the participants will be contacted via telephone/ email on a monthly basis to discuss any issues and maintain good communication.
During this study the subjects will be asked to visit the labs on 4 different occasions. There will be two occasions, at the beginning of the study for baseline measurements, and again on two occasions at the end of the study.
Data collection will take place across two testing sessions (separated by \~24 - 72 hrs) in the Autumn and Spring period.
Session 1
Session 2
Aerobic fitness will be tested using a VO2 max exercise protocol using a stationary cycle ergometer, the participants will be expected to perform this to maximal effort or exhaustion. The test will consist of progressive increments in cycling workload (power output, W) until volitional fatigue. The test will take about 8 - 12 minutes to complete and is dependent upon the fitness of the participants. This will take place in the Sport \& Exercise Science laboratories based in the Clinical Investigation Unit (22AX00). All subjects will be supervised during exercise at all times and will implement an adequate warm-up and cool-down to minimize the risk of injury. Staff will be on hand throughout the testing trained adequately in basic life support (including defibrillation).
Muscular strength assessments will be performed at the Surrey Human Performance Institute. Muscular strength of the knee extensor and handgrip muscles will be determined using an Isokinetic Dynamometer and a handgrip dynamometer respectively. For each assessment three maximal effort isometric contractions will be performed and peak torque (nM) and strength (kg) will be recorded. Muscular power will be assessed through performance of a countermovement jump (CMJ).
Body composition (absolute and relative amount of lean and fat mass), whole body bone mineral density and hip and femur bone mineral density will be measured with the use of DEXA (located in the Sport \& Exercise Science laboratories based in the Clinical Investigation Unit). Two scans will be performed: one for the assessment of whole body bone mineral density and body composition, and the other scan is performed to specifically assess fracture risk by scanning the hip and femoral head. Effective exposure doses for these scans are \~8uSv and \~4uSv respectively. The total effective dose is depending on the size ('thickness' \& height) of the volunteer and is approximately equivalent to the cosmic radiation exposure received in 45min of a transatlantic flight, or the radiation dose received on eating 80g of Brazil nuts (Health Protection Agency).
Bone mineral content of the tibia will be assessed using pQCT and this will be correlated to bone mineral density data obtained from DEXA. One scan will be performed and effective exposure doses will be between 1.5-1.8uSv which is comparable to 10 min on a transatlantic flight or one handful of Brazil nuts. The estimated total exposure dose for a single subject during the entire study is \~28uSv which is the same level of exposure as an average UK citizen is exposed to over the course of 4 days via background radiation.
Results of the body composition, bone mineral density, jump height, muscular strength, aerobic fitness (maximal oxygen uptake: VO2max) and dietary intake from the self-reported food diaries will be made available to the subjects upon request. The results from the blood analysis will be reported to the subject if there are any health concerns raised. If the results are within healthy ranges the participants will not be contacted unless specifically requested for this information. The investigators will not be contacting their GPs if there are any concerns raised in the study however it will be stressed that participants should contact a GP to discuss the results found.
Upon commencing the study, the participants will be required to track their incidence of illness and training habits during the 20-week experimental period between baseline and conclusion measurements. Throughout this period the incidence of illness and days trained during the months must be recorded in a check-list booklet, which will be provided. An email reminder will be sent to prompt all participants to complete these booklets on a daily basis during the experimental period, this should only take 1-2 minutes every evening. Throughout the duration of the trial, the participants will be contacted via telephone/ email on a monthly basis to discuss any issues and maintain good communication.
Participants will be recruited from the university population in Surrey during term-time
University athlete inclusion criteria:
Control group inclusion criteria:
Exclusion Criteria:
DEXA, pQCT, lifestyle questionnaire, muscular strength measurements, aerobic fitness, blood draw and finger prick test.
Radiation: DEXA · Radiation: pQCT · Other: Lifestyle Questionnaire · Other: Aerobic Fitness · Other: Muscular Strength · Biological: Blood draw and finger prick test · Other: Muscular Power
DEXA, pQCT, lifestyle questionnaire, muscular strength measurements, aerobic fitness, blood draw and finger prick test.
Radiation: DEXA · Radiation: pQCT · Other: Lifestyle Questionnaire · Other: Aerobic Fitness · Other: Muscular Strength · Biological: Blood draw and finger prick test · Other: Muscular Power
DEXA, pQCT, lifestyle questionnaire, muscular strength measurements, aerobic fitness, blood draw and finger prick test.
Radiation: DEXA · Radiation: pQCT · Other: Lifestyle Questionnaire · Other: Aerobic Fitness · Other: Muscular Strength · Biological: Blood draw and finger prick test · Other: Muscular Power
Dual energy X-ray absorptiometry (DEXA): a total of two scans will be performed, one for the assessment of whole body bone mineral density and body composition, and the other scan is performed to specifically assess fracture risk by scanning the hip and femoral head. Effective exposure doses for these scans are \~8uSv and \~4uSv respectively.
Also known as: DXA
A total of one scan will be performed on the non-dominant Tibia, the effective exposure dose will be between 1.5-1.8uSV.
Participants are required to record their lifestyle, diet (5-day self reported), physical activity (IPAQ questionnaire), injury and illness incidence.
Aerobic fitness will be tested using a VO2 max exercise protocol using a stationary cycle ergometer, the participants will be expected to perform this to maximal effort or exhaustion.
Muscular strength of the knee extensor and handgrip muscles will be determined using an Isokinetic Dynamometer and a handgrip dynamometer respectively.
15ml of whole blood will be collected for the measurement of fasting serum 25(OH)D levels, parathyroid hormone, C-terminal telopeptide (CTX) and full blood count
Muscular power will be determined using an optical measurement system consisting of a transmitting and receiving bar to determine jump height through the interpretation of jump flight of the participant (reported in cm). The equipment used is an Optojump.
Seasonal Change in the Number of Participants with Deficiency in Vitamin D (according to government cut-off points in the UK and USA) in University Athletes and their Healthy Controls.
This will be assessed by measuring serum 25(OH)D levels in participants during Autumn and Spring. Vitamin D status will be measured in nmol/L
Time frame: 1 year
Seasonal Change in the Incidence of Injury in University Athletes
Self reported questionnaire
Time frame: 1 year
Seasonal Change in Bone Mineral Density in University Athletes
mg/cm
Time frame: 1 year
Seasonal Change in Bone Mineral Content in University Athletes
mg/cm
Time frame: 1 year
The change in vitamin D status due to participation in indoor or outdoor training in university level athletes between Autumn and Spring.
hours and nmol/L
Time frame: 1 year
Change between autumn and spring and the effects of high, medium and low impact sports on bone mineral density in university athletes
mg/cm
Time frame: 1 year
Changes from baseline in muscular power throughout an academic sporting season
Vertical jump: cm
Time frame: 1 year
Changes from baseline in muscular strength throughout an academic sporting season
hand-grip strength: kg, knee extensor muscular strength: nM
Time frame: 1 year
Changes from baseline in aerobic fitness throughout an academic sporting season
ml/kg/min-1
Time frame: 1 year
Change from baseline in the incidence of injury and illness and its correlation with vitamin D status
Days of illness reported or missed training due to injury
Time frame: 1 year
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University of Surrey