The D-BIICEP Study
Condition: Vitamin D Deficiency
MeSH terms: Vitamin D Deficiency
Study type: Observational

Summary: 
      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.
    

Detailed description: 
      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

        -  Peripheral Quantitative Computed Tomography (pQCT) scan of the bone mineral composition
           of the tibia.

        -  Total and percentage lean and fat mass and total bone mineral density via Dual Energy
           X-ray Absorptiometry (DEXA).

        -  Sport performance: Vertical jump height and maximal oxygen uptake (VO2 max) test.

      Session 2

        -  Fasting serum 25(OH)D levels, lipid profile, glucose, insulin, serum calcium, albumin,
           parathyroid hormone, C- terminal telopeptide (CTX), full blood count, kidney, thyroid
           and liver function (≈15ml of whole blood will be collected for these measurements).

        -  Collection of self-reported food diaries to assess dietary intake

        -  Sport performance: muscular strength

      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.
    

Intervention name(s): DEXA; pQCT; Lifestyle Questionnaire; Aerobic Fitness; Muscular Strength; Blood draw and finger prick test; Muscular Power
Intervention type(s): Radiation; Radiation; Other; Other; Other; Biological; Other
Intervention description(s): 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.; 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.
Other intervention name(s): DXA
Observational model: Case-Control
Time perspective: Cross-Sectional
Sampling method: Probability Sample
Study population: 
        Participants will be recruited from the university population in Surrey during term-time
      
Biospecimen description: 
      Plasma and Serum samples obtained at baseline and visit 2
    
Keywords: Physical Performance; Bone; Illness; Injury