Trial Review

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Trial registered on ANZCTR


Registration number
ACTRN12620000896976
Ethics application status
Approved
Date submitted
17/07/2020
Date registered
11/09/2020
Date last updated
11/09/2020
Date data sharing statement initially provided
11/09/2020
Date results information initially provided
11/09/2020
Type of registration
Retrospectively registered

Titles & IDs
Public title
Effects of vitamin D supplementation in physically active adults
Scientific title
Effect of vitamin D supplementation on resting metabolic rate, body composition and strength in physically active adults
Secondary ID [1] 301777 0
None
Universal Trial Number (UTN)
U1111-1255-3010
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Muscle strength and body composition conditioning 318595 0
Increasing resting metabolic rate (RMR) 318596 0
Condition category
Condition code
Metabolic and Endocrine 316257 316257 0 0
Normal metabolism and endocrine development and function
Musculoskeletal 316615 316615 0 0
Normal musculoskeletal and cartilage development and function

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Participants completed two testing sessions (one pre-supplementation and another post-supplementation) over approximately 13 weeks. First, participants completed initial assessments, including an assessment of RMR, body composition, muscular strength and power, and hematological markers [total and free plasma 25(OH)VitD, Ca2+ and parathyroid hormone] between week 0 and 1. Data collection started after the summer season (March/April/May, Western Australia) to increase the chance of individuals being VitD sufficient at the baseline and to optimize the chance of participants reaching higher serum total concentration (= 120 nmol·L-1) at the end of the supplementation period. Following pre-testing, participants were matched for sunlight exposure and randomly allocated in a double-blind and counterbalanced manner to the VitD3 group (total n = 17, female n = 11; 50 IU·kg-1 body-mass [BM]·day-1 Elite Vitamin D3, Healthspan Ltd®, United Kingdom [UK], batch tested by Informed-Sport, LGC Limited, UK) or placebo (total n = 14, female n = 8; dextrose, Glucodin, iNova Pharmaceuticals, Australia) supplement group for 12 weeks. All doses were concealed in opaque gelatin capsules (oral supplementation) and organized in sequentially numbered envelopes to ensure that participants and the testing researcher were blinded to group allocations.
This dosing strategy was selected because it has been associated with a positive effect on strength performance in previous research. In the middle of the study (week 7) hematological markers were again assessed to measure VitD concentration and check for any possible adverse effects of supplementation. The frequency of the intervention administration was once a day for 12 weeks. Then, following 12 weeks of supplementation, participants repeated the pre-supplementation testing at the same time of day and referring back to their three-day food diary to ensure that they were similarly prepared to perform. Adequate and optimal VitD status were defined as 25(OH)D between 50-100nmol·L-1 and > 100 nmol·L-1, respectively, based on previous research that suggests that these concentrations may be related to optimal skeletal muscle outcomes. Participants were in contact with the main researcher weekly by personal text messages and email, to ensure training and supplementation adherence and report any perceived side-effects from the supplementation (self-report). Vitamin D3 supplementation was distributed to participants fortnightly and the capsules left were counted to determine compliance.
A three-day food diary will be kept to measure dietary intake through the whole study (pre, middle and post supplementation period). First, participants recorded the amount of food, fluid and supplements consumed during 3 consecutive days (2 weekdays and 1 day of the weekend), after having received detailed instructions about how to complete their dietary intake. This diet monitoring period is considered adequate for the estimation of habitual energy and macronutrient consumption. Then each food record was briefly reviewed by a nutritionist together with each participant to ensure that sufficient detail is captured. Food records were analysed using Foodworks® (V9, Xyris Australia). Each individual will be encouraged to follow similar eating patterns throughout the study to minimise deviations in macronutrients, and vitamin and mineral intake.

Intervention code [1] 318072 0
Treatment: Drugs
Comparator / control treatment
The placebo group was composed of n = 14, female and male n = 8. The composition of oral capsules supplementation was: (1/4 or ~0.4g of dextrose, Glucodin, iNova Pharmaceuticals, Australia) once a day for 12 weeks.
Control group
Placebo

Outcomes
Primary outcome [1] 324434 0
Muscular strength

Participants completed the test of 1-repetition maximum (1RM) for the bench press exercises following the procedures set out by Baechle and Earle to assess upper body strength. Briefly, participants had to lift progressively greater weights until a mass is identified that can only be lifted for one repetition for that exercise.
Timepoint [1] 324434 0
Pre supplementation period (week 0) and after the completion of 12 weeks supplementation period (week 12-13),
Primary outcome [2] 325081 0
Leg Power

Participants completed a counter-movement vertical jump test, (Vertec Yardstick Jumping Device, Swift Performance, Australia) to assess leg power.
Timepoint [2] 325081 0
Pre supplementation period (week 0) and after the completion of 12 weeks supplementation period (week 12-13),
Secondary outcome [1] 384640 0
Whole body composition (specifically lean and fat mass and bone mineral density) were assessed using dual energy X-ray absorptiometry (DXA; GE Lunar Prodigy, General Electric, USA) pre- and post-supplementation.
Timepoint [1] 384640 0
Before supplementation period (week 0) and after the completion of 12 weeks supplementation period (week 12-13),
Secondary outcome [2] 386800 0
Resting Metabolic Rate

Subjects were requested to abstain from any strenuous exercise for 24 h prior to the measurement. Subjects arrived at the laboratory after waking up from a 12h overnight fast, and will empty their bladder before being weighed. They had to rest in a supine position for 30 min, in a quiet room without noise and strong lights; before having their oxygen consumption assessed in the final 5 min of the period by metabolic cart (Parvo medics TrueOne 2400, Parvo medics, USA), using a mouthpiece and mixing chamber. These measurements were be used to determine RMR.
Timepoint [2] 386800 0
Before the supplementation period (week 0) and after the completion of 12 weeks supplementation period (week 12-13),
Secondary outcome [3] 386801 0
Total Vitamin D status

Participants attended an external pathology laboratory (PathWest Laboratories, Perth, Western Australia) pre-, mid- and post-supplementation, where a venous blood sample (~ 10 ml) was drawn to assess VitD status, Ca2+ and parathyroid hormone. Vitamin D status [25(OH)D] was determined using the Immunoassay method (Abbott Architect i2000sr analyser, USA)
Timepoint [3] 386801 0
Before supplementation period (week 0), middle supplementation (week 7) and after the completion of 12 weeks supplementation period (week 12-13),
Secondary outcome [4] 386803 0
Serum calcium

Participants attended an external pathology laboratory (PathWest Laboratories, Perth, Western Australia) pre-, mid- and post-supplementation, where a venous blood sample (~ 10 ml) was drawn to assess VitD status, Ca2+ and parathyroid hormone. Calcium was determined using the Arsenazo III method (Abbott, Spain).
Timepoint [4] 386803 0
Before supplementation period (week 0), middle supplementation (week 7) and after the completion of 12 weeks supplementation period (week 12-13),
Secondary outcome [5] 386804 0
Parathyroid hormone (PTH)
Participants attended an external pathology laboratory (PathWest Laboratories, Perth, Western Australia) pre-, mid- and post-supplementation, where a venous blood sample (~ 10 ml) was drawn to assess VitD status, Ca2+ and parathyroid hormone

Parathyroid hormone was analyzed using the chemiluminescent microparticle immunoassay methodology (Abbott, Spain).
Timepoint [5] 386804 0
Before supplementation period (week 0), middle supplementation (week 7), and after the completion of 12 weeks supplementation period (week 12-13),
Secondary outcome [6] 386805 0
Free Vitamin D status

Additionally, two small serum aliquots (1 ml) were separated and frozen to –80°C for subsequent measurement of the free 25(OH)D concentration. After thawing, concentrations of free 25(OH)D were measured by ELISA immunoassay (DIASource ImmunoAssays, Netherlands) following the procedure described previously.
Timepoint [6] 386805 0
Before the supplementation period (week 0) and after the completion of 12 weeks supplementation period (week 12-13),

Eligibility
Key inclusion criteria
- adults, 18-35 years old
-exercising at least three times per week with at least two of those sessions involving resistance training;
- no history of VitD3 supplementation in the last month;
- no current injuries that would prevent them from completing strength testing;
- no current use of multivitamins, medication, or other supplements that are related with VitD metabolism and body composition [including calcium, thyroxine, creatine and thermogenic supplements]).
- available to complete the tests at Curtin University and PathWest lab
Minimum age
18 Years
Maximum age
35 Years
Sex
Both males and females
Can healthy volunteers participate?
Yes
Key exclusion criteria

none

Study design
Purpose of the study
Prevention
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
1. sealed opaque envelopes (a specific ID was generated for each participant).
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Simple randomization using procedures as coin-tossing was used.
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s
The people administering the treatment/s
The people assessing the outcomes
Intervention assignment
Parallel
Other design features
Phase
Not Applicable
Type of endpoint/s
Statistical methods / analysis
Categorical data were summarized using frequency distributions. Depending on normality, continuous variables were summarized by means and standard deviations [age, free 25(OH)D, weekly sunlight exposure and daily calcium intake] or medians and interquartile ranges (IQR) [BMI, total 25(OH)D, parathyroid hormone (PTH), Ca+2 and total training load]. Participants’ main characteristics at pre- and post-supplementation were compared between groups using Chi-squared tests for categorical data and t-tests or non-parametric Mann-Whitney U tests for continuous data. Based on previous research considering strength as the main outcome, a sample size of 30 has 99% power to detect a standardized mean difference of 0.60 in a mixed-model ANOVA in two groups across two time points with, an a value of 0.05. However, due to the ability to adjust for factors, linear mixed modelling was used for the main analyses considering random subject intercepts. Effects of free and total serum 25(OH)D on pre-post supplementation differences in strength, RMR and body composition outcomes, within and between intervention groups, were assessed by linear mixed models (LMM), adjusting for gender, sunlight exposure, training load, protein, carbohydrate, fat and total energy intake. LMM were also used to assess total and serum 25(OH)D concentration within and between groups differences pre and post supplementation. This model uses maximum likelihood estimation methods which parametrize all longitudinal data regardless of missing data points. Results are summarized as estimated marginal means, mean differences and 95% confidence intervals. Statistical significance was as accepted at p < 0.05. Analyses were conducted using STATA/IC 16.0 (StataCorp LLC, College Station, USA).

Recruitment
Recruitment status
Completed
Date of first participant enrolment
Anticipated
Actual
23/03/2019
Date of last participant enrolment
Anticipated
Actual
27/05/2019
Date of last data collection
Anticipated
Actual
4/09/2019
Sample size
Target
42
Accrual to date
Final
31
Recruitment in Australia
Recruitment state(s)
WA

Funding & Sponsors
Funding source category [1] 306207 0
University
Name [1] 306207 0
Curtin University
Country [1] 306207 0
Australia
Primary sponsor type
University
Name
Curtin University
Address
BLDG 305 – CHIRI
KENT ST
BENTLEY, WA 6102,
AUSTRALIA
Country
Australia
Secondary sponsor category [1] 306725 0
University
Name [1] 306725 0
Torrens University Australia
Address [1] 306725 0
196 Flinders St, Melbourne VIC 3000
Country [1] 306725 0
Australia

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 306419 0
Curtin University Human Research Ethics Committee
Ethics committee address [1] 306419 0
KENT ST
BENTLEY, WA 6102,
AUSTRALIA
Ethics committee country [1] 306419 0
Australia
Date submitted for ethics approval [1] 306419 0
09/01/2019
Approval date [1] 306419 0
22/01/2019
Ethics approval number [1] 306419 0
HRE2019-0028

Summary
Brief summary
Most of our vitamin D comes from spending time in the sun, but also a little comes from our diet. Importantly, research suggests that the amount of vitamin D that you have may affect the health of your muscles and therefore your strength, body composition and the amount of energy that your body uses at rest. However, we don’t know lots of things about this relationship and therefore we need to investigate it further. This is important because vitamin D may assist people to achieve a healthier body composition and perhaps help with the progression of exercise training (e.g., increasing muscle strength). The results of this study will help health professionals to clarify if higher levels of vitamin D are beneficial for achieving optimal muscle function and body composition.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 103810 0
Dr Kagan J Ducker
Address 103810 0
Faculty of Health Sciences, Curtin University, Kent St, Bentley WA 6102
Country 103810 0
Australia
Phone 103810 0
+61 8 9266 9443
Fax 103810 0
Email 103810 0
kagan.ducker@curtin.edu.au
Contact person for public queries
Name 103811 0
Dr Kagan J Ducker
Address 103811 0
Faculty of Health Sciences, Curtin University, Kent St, Bentley WA 6102
Country 103811 0
Australia
Phone 103811 0
+61 8 9266 9443
Fax 103811 0
Email 103811 0
kagan.ducker@curtin.edu.au
Contact person for scientific queries
Name 103812 0
Dr Kagan J Ducker
Address 103812 0
Faculty of Health Sciences, Curtin University, Kent St, Bentley WA 6102
Country 103812 0
Australia
Phone 103812 0
+61 8 9266 9443
Fax 103812 0
Email 103812 0
kagan.ducker@curtin.edu.au

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No
No/undecided IPD sharing reason/comment
Not available in order to maintain confidentiality for publication of results only and guarantee that the all the terms are being followed according to ethics approval.


What supporting documents are/will be available?




Results publications and other study-related documents

Documents added manually
No documents have been uploaded by study researchers.

Documents added automatically
SourceTitleYear of PublicationDOI
EmbaseVitamin d supplementation does not impact resting metabolic rate, body composition and strength in vitamin d sufficient physically active adults.2020https://dx.doi.org/10.3390/nu12103111
N.B. These documents automatically identified may not have been verified by the study sponsor.