PTH And Calcium Responses to Exercise in Older Adults Experiment 2 (PACE Sr. 2)

NCT02580604 | Completed Results

• 2 other identifiers: 15-0878UM1TR004399
• Study Type: interventional
• Target: 12
• Locations: 1 country
• Sites: 1

Brief 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.

Conditions

Osteoporosis

Outcome Measures

Primary Outcomes (1)

• Change in Parathyroid Hormone (PTH)

  Change in PTH will be measured from baseline to end of exercise

  baseline, 60 minutes

Secondary Outcomes (2)

• Change in C-telopeptide (CTX)

  baseline, 60 minutes

• Change in Ionized Calcium

  baseline, 60 minutes

Study Arms (1)

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.

Drug: Calcium Chloride/Calcium Gluconate; Drug: Half-Normal Saline

Interventions

Calcium Chloride/Calcium Gluconate DRUG

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.

Calcium Infusion followed by Saline Infusion

Half-Normal Saline DRUG

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.

Calcium Infusion followed by Saline Infusion

Eligibility Criteria

• Age: 60 Years - 80 Years
• Sex: female
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Healthy adults aged 60-80 y
• Currently taking a bisphosphonate medication

You may not qualify if:

• 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
• 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
• Diagnosis or history of asthma

Sponsors & Collaborators

• University of Colorado, Denver: lead
• National Center for Advancing Translational Sciences (NCATS): collaborator

Study Sites (1)

University of Colorado Hospital

Aurora, Colorado, 80045, United States

Location

MeSH Terms

Conditions

Osteoporosis

Interventions

Calcium Chloride; Calcium Gluconate

Condition Hierarchy (Ancestors)

Bone Diseases, Metabolic; Bone Diseases; Musculoskeletal Diseases; Metabolic Diseases; Nutritional and Metabolic Diseases

Intervention Hierarchy (Ancestors)

Calcium Compounds; Inorganic Chemicals; Chlorides; Hydrochloric Acid; Chlorine Compounds; Gluconates; Sugar Acids; Acids, Acyclic; Carboxylic Acids; Organic Chemicals; Hydroxy Acids; Carbohydrates

Results Point of Contact

• Title: Dr. Sarah Wherry
• Organization: University of Colorado Anschutz Medical Campus

sarah.wherry@cuanschutz.edu

303-724-1927

Study Officials

• Sarah J Wherry, PhD

  University of Colorado, Denver

  PRINCIPAL INVESTIGATOR

Publication Agreements

• PI is Sponsor Employee: Yes

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NON RANDOMIZED
• Masking: NONE
• Purpose: PREVENTION
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: October 16, 2015
• First Posted: October 20, 2015
• Study Start: November 1, 2015
• Primary Completion: July 31, 2024
• Study Completion: July 31, 2025
• Last Updated: August 13, 2025
• Results First Posted: August 13, 2025

Record last verified: 2025-08

Locations

US (1)