OsteoporosisNCT02580604
PTH And Calcium Responses to Exercise in Older Adults Experiment 2 (PACE Sr. 2)
A study testing Calcium Chloride/Calcium Gluconate and Half-Normal Saline in people with Osteoporosis, run by University of Colorado, Denver at 1 site in United States.
Trial summary
Declines in serum calcium during exercise may cause increases in markers of bone resorption. This study will determine if preventing the decline serum ionized calcium experienced at the onset of exercise through the use of a "calcium clamp" also prevents increases in blood biomarkers associated with bone resorption. Read more about this study
- Who is it for?
- Ages 60 to 80 years, women onlyHealthy volunteers can take part
- Conditions the study is for
- Osteoporosis
- What is being tested?
- Calcium Chloride/Calcium Gluconate and Half-Normal Saline
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 12 participants
- Where
- 1 siteUnited States
- Study dates
- Nov 2015to 31 Jul 2025
- Phase
- Interventional
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
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 60 to 80 years
- Women only
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Healthy adults aged 60-80 y
- Currently taking a bisphosphonate medication
Who cannot join
- Use of medications (other than bisphosphonates) in the past 6 months known to affect bone metabolism (e.g., thiazide diuretics, oral glucocorticoids)
- Bone Mineral Density (BMD) t score < -3.0 at the total hip or lumbar spine
- Known disease or condition associated with intestinal malabsorption
- Moderate or severe renal impairment defined as an estimated glomerular filtration rate of <60 mL/min/1.73m2 based on the Modified Diet in Renal Disease (MDRD) equation
- Chronic hepatobiliary disease, defined as liver function tests (AST, ALT) >1.5 times the upper limit of normal; if such values are obtained on initial screening and thought to be transient in nature, repeated testing will be allowed
- Thyroid dysfunction, defined as an ultrasensitive TSH <0.5 or >5.0 mU/L; volunteers with abnormal TSH values will be re-considered for participation in the study after follow-up evaluation by the PCP with initiation or adjustment of thyroid hormone replacement
Show all 11Show fewer
- Serum calcium <8.5 or >10.3 mg/dL Serum 25(OH)D <20 ng/mL; volunteers with abnormal serum 25(OH)D values may be re-considered for participation in the study if serum 25(OH)D is >20 ng/mL after vitamin D supplementation
- Uncontrolled hypertension defined as resting systolic BP >150 mmHg or diastolic BP>90 mmHg; participants who do not meet these criteria at first screening will be re-evaluated, including after follow-up evaluation by the PCP with initiation or adjustment of anti-hypertensive medications
- History of type 1 or type 2 diabetes
- Cardiovascular disease; subjective or objective indicators of ischemic heart disease (e.g., angina, ST segment depression) or serious arrhythmias at rest or during the graded exercise test (GXT) without follow-up evaluation will be cause for exclusion; follow-up evaluation must include diagnostic testing (e.g., stress echocardiogram or thallium stress test) with interpretation by a cardiologist
- Diagnosis or history of asthma
Trial locations and contacts
1 site in 1 country.
United States1 site
University of Colorado Hospital
Aurora, Colorado, 80045
About this study
Declines in serum calcium during exercise may cause increases in markers of bone resorption. This study will determine if preventing the decline serum ionized calcium experienced at the onset of exercise through the use of a "calcium clamp" also prevents increases in blood biomarkers associated with bone resorption.
Read the detailed description
Participants will undergo two identical walking exercise sessions on a treadmill. One session will occur until continuous calcium infusion and the other will be under continuous saline infusion. C-telopeptide, parathyroid hormone, total calcium, and serum ionized calcium will be monitored to distinguish differences in bone activity under the two conditions.
- Conditions
- Osteoporosis
- Being tested
- Calcium Chloride/Calcium Gluconate, Half-Normal Saline
- Medical subject headings
- Osteoporosis
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Calcium Chloride/Calcium GluconateDrug
Calcium (as either calcium chloride or calcium gluconate in half normal saline) will be delivered via IV during exercise to keep serum ionized calcium levels above baseline. The clamp is modeled after the hyperglycemic glucose clamp.
Half-Normal SalineDrug
This is the placebo comparative infusion. Half-normal saline will be infused at the second collection visit following the identical infusion schedule determined during the calcium infusion visit.
| Study group | Role | What they receive |
|---|---|---|
| Calcium Infusion followed by Saline Infusion | Experimental | All participants will have a continuous calcium infusion during exercise at their first collection visit. The second collection visit will always be a volume-matched half-normal saline infusion. Receives: Drug: Calcium Chloride/Calcium Gluconate; Drug: Half-Normal Saline |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in Parathyroid Hormone (PTH)
Change in PTH will be measured from baseline to end of exercise
Measured: baseline, 60 minutes
Secondary outcomes (2)
Change in C-telopeptide (CTX)
Change in CTX will be measured from baseline to the end of 60 minutes of exercise
Measured: baseline, 60 minutes
Change in Ionized Calcium
Change in ionized calcium will be measured from baseline to the end of 60 minutes of exercise
Measured: baseline, 60 minutes
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted20 Oct 2015 (estimated)
- Study startNov 2015
- Primary completion31 Jul 2024
- Study completion31 Jul 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Other trials for OsteoporosisStudies of the same condition, open and under way.
- More trials run by University of Colorado, DenverThe sponsor's other registered studies.
- 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
- Non-randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Enrolment
- 12 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Colorado, Denver
- Sponsor type
- University, hospital or other
- Collaborators
- National Center for Advancing Translational Sciences (NCATS)
- Responsible party
- Sponsor
- Investigators
- Sarah J Wherry, PhD, Principal investigator, University of Colorado, Denver
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT02580604
- Sponsor's protocol ID
- 15-0878
- Other IDs
- UM1TR004399
- Status last verified
- Aug 2025
- First submitted
- 16 Oct 2015
- Last updated
- 13 Aug 2025
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- No
Study at a glance
From the registry record, last updated by the sponsor on 13 Aug 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- PTH And Calcium Responses to Exercise in Older Adults Experiment 2 (PACE Sr. 2)
- ClinicalTrials.gov ID
- NCT02580604
- Acronym / sponsor ID
- 15-0878
- Conditions
- Osteoporosis
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 12 participants (actual)
- Lead sponsor
- University of Colorado, DenverUniversity, hospital or other
- Collaborators
- National Center for Advancing Translational Sciences (NCATS)
- Study start
- Nov 2015 (actual)
- Primary completion
- 31 Jul 2024 (actual)
- Study completion
- 31 Jul 2025 (actual)
- First posted
- 20 Oct 2015 (estimated)
- Results
- Posted 13 Aug 2025
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Declines in serum calcium during exercise may cause increases in markers of bone resorption. This study will determine if preventing the decline serum ionized calcium experienced at the onset of exercise through the use of a "calcium clamp" also prevents increases in blood biomarkers associated with bone resorption.
Detailed description
Participants will undergo two identical walking exercise sessions on a treadmill. One session will occur until continuous calcium infusion and the other will be under continuous saline infusion. C-telopeptide, parathyroid hormone, total calcium, and serum ionized calcium will be monitored to distinguish differences in bone activity under the two conditions.
Study design
- Primary purpose
- Prevention
- Allocation
- Non-randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Calcium Infusion followed by Saline Infusion | Experimental | Drug: Calcium Chloride/Calcium Gluconate, Drug: Half-Normal SalineAll participants will have a continuous calcium infusion during exercise at their first collection visit. The second collection visit will always be a volume-matched half-normal saline infusion. |
Who may qualify
- Ages
- 60 to 80 years
- Sex
- Female only
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (2 listed)
- Healthy adults aged 60-80 y
- Currently taking a bisphosphonate medication
Key exclusion criteria (11 listed)
- Use of medications (other than bisphosphonates) in the past 6 months known to affect bone metabolism (e.g., thiazide diuretics, oral glucocorticoids)
- Bone Mineral Density (BMD) t score < -3.0 at the total hip or lumbar spine
- Known disease or condition associated with intestinal malabsorption
- Moderate or severe renal impairment defined as an estimated glomerular filtration rate of <60 mL/min/1.73m2 based on the Modified Diet in Renal Disease (MDRD) equation
- Chronic hepatobiliary disease, defined as liver function tests (AST, ALT) >1.5 times the upper limit of normal; if such values are obtained on initial screening and thought to be transient in nature, repeated testing will be allowed
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 |
|---|---|---|
| Calcium Chloride/Calcium GluconateCalcium (as either calcium chloride or calcium gluconate in half normal saline) will be delivered via IV during exercise to keep serum ionized calcium levels above baseline. The clamp is modeled after the hyperglycemic glucose clamp. | Drug | Calcium Infusion followed by Saline Infusion |
| Half-Normal SalineThis is the placebo comparative infusion. Half-normal saline will be infused at the second collection visit following the identical infusion schedule determined during the calcium infusion visit. | Drug | Calcium Infusion followed by Saline Infusion |
Primary outcome
Change in Parathyroid Hormone (PTH)
Time frame: baseline, 60 minutes
Change in PTH will be measured from baseline to end of exercise
2 secondary outcomes
Change in C-telopeptide (CTX)
Time frame: baseline, 60 minutes
Change in Ionized Calcium
Time frame: baseline, 60 minutes
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 13 Aug 2025.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
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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.
Sarah J Wherry, PhD principal investigator
University of Colorado, Denver
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 Chloride/Calcium Gluconate and Half-Normal Saline in people with Osteoporosis, run by University of Colorado, Denver at 1 site in United States.
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 2 inclusion and 11 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: finished, as of the sponsor's last update on 13 Aug 2025. 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 States. 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?
Yes. Results are posted in the registry (first posted 13 Aug 2025). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in Parathyroid Hormone (PTH) (time frame: baseline, 60 minutes). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
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 13 Aug 2025.