Calcium DeficiencyEn-BoneNCT04823156
The Effect of Calcium Intake on Calcium and Bone Metabolism During Load Carriage in Women
A study testing Calcium in people with Calcium Deficiency, run by Army Health Branch, British Army at 1 site in United Kingdom.
Trial summary
This randomised trial will investigate the effect of calcium supplementation on bone and calcium metabolism in women during acute load carriage exercise. This study will test the hypothesis that calcium supplementation before load carriage exercise will attenuate the decline in serum ionised calcium and increase in… Read more about this study
- Who is it for?
- Ages 18 to 36 years, women onlyHealthy volunteers can take part
- Conditions the study is for
- Calcium Deficiency
- What is being tested?
- Calcium
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 40 participants
- Where
- 1 siteUnited Kingdom
- Study dates
- 24 Mar 2022to 19 May 2023
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 36 years
- Women only
- Healthy volunteers accepted
- Adult
Who may be able to join
- Female sex;
- Aged 18 to 36 years old;
- Maximal rate of oxygen uptake of ≥ 35 ml∙kg-1∙min-1;
- Weight stable (no change in self-reported body mass ≥ 5% over the previous 3 months);
- BMI between 18 and 30 kg∙m2;
- Not pregnant.
Who cannot join
- Evidence of disordered eating (≥ 20 on the EAT-26);
- Self-reported change in body mass of ≥ 5% over the previous 3 months;
- Vitamin D deficient (total 25(OH)D < 30 nmol∙L-1);
- Maximal rate of oxygen uptake of < 35 ml∙kg-1∙min-1;
- Total body BMD T-score of < -1;
- Evidence of menstrual disturbance (oligomenorrhoea: < 9 menstrual cycles in previous 12 months or amenorrhoea: ≤ 3 menstrual cycles in the previous 12 months);
Show all 13Show fewer
- Pregnant;
- Current smoker, or stopped smoking within the last three months;
- Taking any medications known to affect bone or calcium metabolism (e.g. treatment for thyroid disorders);
- Self-declared history of heart, liver or kidney disease, diabetes or thyroid disorder;
- Self-reported stress fracture or any other bone injuries in the previous 12 months;
- Anaemia (haemoglobin <12 g∙/dL-1).
- Currently using the implant, injection, or the progesterone-only pill ('mini pill').
Trial locations and contacts
1 site in 1 country.
Thomas J O'Leary, PhD contact
Charlotte V Coombs, PhD contact
United Kingdom1 site, 1 recruiting
- Recruiting
Army Health and Performance Laboratory
Camberley, Surry, GU15 4PQ
Thomas J O'Leary, PhD
About this study
Official title: The Effect of Calcium Intake on Calcium and Bone Metabolism During Load Carriage in Women: a Randomised Controlled Trial
This randomised trial will investigate the effect of calcium supplementation on bone and calcium metabolism in women during acute load carriage exercise. This study will test the hypothesis that calcium supplementation before load carriage exercise will attenuate the decline in serum ionised calcium and increase in parathyroid hormone and bone resorption.
Read the detailed description
Endurance exercise decreases serum ionised calcium and increases parathyroid hormone and bone resorption. These disturbances to calcium homeostasis can be attenuated by calcium supplementation before exercise. Military field exercises are characterised by high exercising energy expenditures, restricted dietary intake, and prolonged periods of load carriage. These exercise and nutritional challenges can result in impaired bone turnover, a negative calcium balance, and an increased risk of stress fracture. It is unknown if military load carriage disturbs calcium homeostasis and whether calcium supplementation before exercise can attenuate this disturbance. This crossover randomised controlled trial will investigate the effect of acute calcium supplementation on bone and calcium metabolism in women during acute load carriage exercise. Each participant will complete two 2 h load carriage trials. The trials will be performed after either consuming 1000 mg of calcium one hour before or with no treatment. During each experimental trial blood and urine will be sampled for markers of bone and calcium metabolism.
Primary Outcome: The absolute change in urine calcium balance (Ca44:Ca42) between pre- and post-load carriage will be compared between the non-supplemented (Control) and calcium supplemented trial (Supplement) using one-way ANCOVAs with pre-load carriage calcium balance (either as a ratio, or both the numerator and denominator) as the covariate, or a linear mixed model with the restricted maximum likelihood estimation to allow incorporation of incomplete data.
Secondary Outcomes: Circulating measures of bone turnover and calcium metabolism during load carriage will be compared between Control and Supplement using linear mixed models with the restricted maximum likelihood estimation to allow incorporation of incomplete data.
- Conditions
- Calcium Deficiency
- Being tested
- Calcium
- Keywords
- Military, Stress Fracture, Calcium, Bone Metabolism
- Medical subject headings
- Fractures, Stress
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
CalciumDietary supplement
Daily calcium food supplement.
| Study group | Role | What they receive |
|---|---|---|
| Calcium Supplementation | Experimental | 1000 mg of calcium carbonate one hour before exercise Receives: Dietary Supplement: Calcium |
| No Calcium Supplementation | No intervention | No calcium supplementation |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in calcium balance.
The ratio of the calcium isotopes Ca44:Ca42 in spot urine samples.
Measured: Before and immediately after exercise.
Secondary outcomes (4)
Circulating calcium isotopes during load carriage.
The ratio of the calcium isotopes Ca44 and Ca42 (Ca44:Ca42) in blood.
Measured: Before and immediately after exercise.
Bone turnover during load carriage.
Circulating concentration of procollagen type 1 N-terminal propeptide (P1NP), beta carboxy-terminal cross-linking telopeptide of type 1 collagen (βCTX), osteocalcin, and sclerostin.
Measured: 0, 20, 40, 60, 80, 100, and 120 minutes during, and 15, 30, 60 and 90 minutes following, exercise.
Calcium metabolism during load carriage.
Circulating concentration of ionized calcium, phosphate, and intact parathyroid hormone.
Measured: 0, 20, 40, 60, 80, 100, and 120 minutes during, and 15, 30, 60 and 90 minutes following, exercise.
Dermal calcium loss.
Concentrations of total calcium and the ratio of the calcium isotopes Ca44 and Ca42 (Ca44:Ca42) in sweat.
Measured: During exercise.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted30 Mar 2021
- Study start24 Mar 2022
- Primary completion19 May 2023 (estimated)
- Study completion19 May 2023 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (2)Papers the sponsor has linked to this study.
- Other trials for Calcium DeficiencyStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- Crossover randomised controlled trial.
- Masking
- None (open label)
- Enrolment
- 40 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Army Health Branch, British Army
- Sponsor type
- Other government
- Collaborators
- University of East Anglia, Osteolabs, GEOMAR
- Responsible party
- Principal investigator, Dr. Thomas O'Leary, Army Health Branch, British Army
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04823156
- Sponsor's protocol ID
- 1021/MODREC/19
- Acronym
- En-Bone
- Status last verified
- Apr 2023
- First submitted
- 7 Jul 2020
- Last updated
- 21 Apr 2023
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Data will be owned by UK Ministry of Defence, not the Principal Investigator. Data will be made available where possible by the Principal Investigator assuming the appropriate approvals are granted by the UK Ministry of Defence.
Publications
Coombs CV, Greeves JP, Young CD, Irving AS, Eisenhauer A, Kolevica A, Heuser A, Tang JCY, Fraser WD, O'Leary TJ. The effect of calcium supplementation on bone calcium balance and calcium and bone metabolism during load carriage in women: a randomized controlled crossover trial. J Bone Miner Res. 2025 Jun 3;40(6):753-765. doi: 10.1093/jbmr/zjaf004.
PubMed 39804018Coombs CV, Wardle SL, Shroff R, Eisenhauer A, Tang JCY, Fraser WD, Greeves JP, O'Leary TJ. The effect of calcium supplementation on calcium and bone metabolism during load carriage in women: protocol for a randomised controlled crossover trial. BMC Musculoskelet Disord. 2023 Jun 16;24(1):496. doi: 10.1186/s12891-023-06600-w.
PubMed 37328859
Study at a glance
From the registry record, last updated by the sponsor on 21 Apr 2023. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Effect of Calcium Intake on Calcium and Bone Metabolism During Load Carriage in Women: a Randomised Controlled Trial
- ClinicalTrials.gov ID
- NCT04823156
- Acronym / sponsor ID
- En-Bone / 1021/MODREC/19
- Conditions
- Calcium Deficiency
- Keywords
- Military, Stress Fracture, Calcium, Bone Metabolism
- Study type
- Interventional
- Recruitment status
- Unknown status
- Enrolment
- 40 participants (estimated)
- Lead sponsor
- Army Health Branch, British ArmyOther government
- Collaborators
- University of East Anglia, Osteolabs, GEOMAR
- Study start
- 24 Mar 2022 (actual)
- Primary completion
- 19 May 2023 (estimated)
- Study completion
- 19 May 2023 (estimated)
- First posted
- 30 Mar 2021 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This randomised trial will investigate the effect of calcium supplementation on bone and calcium metabolism in women during acute load carriage exercise. This study will test the hypothesis that calcium supplementation before load carriage exercise will attenuate the decline in serum ionised calcium and increase in parathyroid hormone and bone resorption.
Detailed description
Endurance exercise decreases serum ionised calcium and increases parathyroid hormone and bone resorption. These disturbances to calcium homeostasis can be attenuated by calcium supplementation before exercise. Military field exercises are characterised by high exercising energy expenditures, restricted dietary intake, and prolonged periods of load carriage. These exercise and nutritional challenges can result in impaired bone turnover, a negative calcium balance, and an increased risk of stress fracture. It is unknown if military load carriage disturbs calcium homeostasis and whether calcium supplementation before exercise can attenuate this disturbance. This crossover randomised controlled trial will investigate the effect of acute calcium supplementation on bone and calcium metabolism in women during acute load carriage exercise. Each participant will complete two 2 h load carriage trials. The trials will be performed after either consuming 1000 mg of calcium one hour before or with no treatment. During each experimental trial blood and urine will be sampled for markers of bone and calcium metabolism.
Primary Outcome: The absolute change in urine calcium balance (Ca44:Ca42) between pre- and post-load carriage will be compared between the non-supplemented (Control) and calcium supplemented trial (Supplement) using one-way ANCOVAs with pre-load carriage calcium balance (either as a ratio, or both the numerator and denominator) as the covariate, or a linear mixed model with the restricted maximum likelihood estimation to allow incorporation of incomplete data.
Secondary Outcomes: Circulating measures of bone turnover and calcium metabolism during load carriage will be compared between Control and Supplement using linear mixed models with the restricted maximum likelihood estimation to allow incorporation of incomplete data.
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Number of arms
- 2
- Model description
- Crossover randomised controlled trial.
| Arm | Type | Receives |
|---|---|---|
| Calcium Supplementation | Experimental | Dietary Supplement: Calcium1000 mg of calcium carbonate one hour before exercise |
| No Calcium Supplementation | No intervention | –No calcium supplementation |
Who may qualify
- Ages
- 18 to 36 years
- Sex
- Female only
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (6 listed)
- Female sex;
- Aged 18 to 36 years old;
- Maximal rate of oxygen uptake of ≥ 35 ml∙kg-1∙min-1;
- Weight stable (no change in self-reported body mass ≥ 5% over the previous 3 months);
- BMI between 18 and 30 kg∙m2;
Key exclusion criteria (13 listed)
- Evidence of disordered eating (≥ 20 on the EAT-26);
- Self-reported change in body mass of ≥ 5% over the previous 3 months;
- Vitamin D deficient (total 25(OH)D < 30 nmol∙L-1);
- Maximal rate of oxygen uptake of < 35 ml∙kg-1∙min-1;
- Total body BMD T-score of < -1;
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| CalciumDaily calcium food supplement. | Dietary supplement | Calcium Supplementation |
Primary outcome
Change in calcium balance.
Time frame: Before and immediately after exercise.
The ratio of the calcium isotopes Ca44:Ca42 in spot urine samples.
4 secondary outcomes
Circulating calcium isotopes during load carriage.
Time frame: Before and immediately after exercise.
Bone turnover during load carriage.
Time frame: 0, 20, 40, 60, 80, 100, and 120 minutes during, and 15, 30, 60 and 90 minutes following, exercise.
Calcium metabolism during load carriage.
Time frame: 0, 20, 40, 60, 80, 100, and 120 minutes during, and 15, 30, 60 and 90 minutes following, exercise.
Dermal calcium loss.
Time frame: During exercise.
Results and safety
Results are not available in the source record.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 21 Apr 2023.
- Derived from this study: PubMed 39804018Coombs CV, Greeves JP, Young CD, Irving AS, Eisenhauer A, Kolevica A, Heuser A, Tang JCY, Fraser WD, O'Leary TJ. The effect of calcium supplementation on bone calcium balance and calcium and bone metabolism during load carriage in women: a randomized controlled crossover trial. J Bone Miner Res. 2025 Jun 3;40(6):753-765. doi: 10.1093/jbmr/zjaf004.
- Derived from this study: PubMed 37328859Coombs CV, Wardle SL, Shroff R, Eisenhauer A, Tang JCY, Fraser WD, Greeves JP, O'Leary TJ. The effect of calcium supplementation on calcium and bone metabolism during load carriage in women: protocol for a randomised controlled crossover trial. BMC Musculoskelet Disord. 2023 Jun 16;24(1):496. doi: 10.1186/s12891-023-06600-w.
- Individual participant dataSharing planned: No. Data will be owned by UK Ministry of Defence, not the Principal Investigator. Data will be made available where possible by the Principal Investigator assuming the appropriate approvals are granted by the UK Ministry of Defence.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Thomas J O'Leary, PhD contact
Charlotte V Coombs, PhD contact
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Calcium in people with Calcium Deficiency, run by Army Health Branch, British Army at 1 site in United Kingdom.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 6 inclusion and 13 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: status not confirmed, as of the sponsor's last update on 21 Apr 2023. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United Kingdom. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
Results are not available in the source record.
How can a doctor refer a patient or contact the research team?
Contact Thomas J O'Leary, PhD (thomas.oleary100@mod.gov.uk), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in calcium balance. (time frame: Before and immediately after exercise.). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT04823156, which also lists 2 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 21 Apr 2023.