Calcium Metabolism
Conditions
Keywords
Calcium metabolism, Osteoporosis, Postmenopausal women
Brief summary
This study aims to: 1) quantitatively assess parameters of bone calcium balance in healthy postmenopausal Asian women of Chinese descent; 2) assess possible ethnic differences in calcium metabolism by direct comparison of acquired data in Chinese postmenopausal women with those acquired earlier in Caucasian postmenopausal women using the same methodology; 3) assess differences in calcium and strontium metabolism in parallel to evaluate if strontium stable isotopes can be used for tracing bone calcium metabolism qualitatively
Detailed description
The study will follow closely the protocol that was used previously by the PI at ETH Zurich to study calcium metabolism in healthy postmenopausal women. Calcium metabolism will be studied after a single oral administration of a calcium tracer (Ca-41) and by following the excretion of the tracer in urine over 6 months. Obtained data will be used to assess parameters of calcium metabolism (flux rates and sizes of body calcium compartments) by kinetic modelling. A strontium tracer (Sr-84) will be administered in parallel and its urinary excretion pattern compared to Ca-41 excretion to determine if strontium tracers can be used to assess calcium metabolism qualitatively. Subjects will be supplemented with Vit D throughout the study. Vit D supplementation will commence 1 month before isotope administration.
Interventions
OTHERCa-41(isotope tracer)
Ca-41 is given orally in the form of (Ca-41)Cl3 in citrate-buffered solution. Tracer will be used to determine parameters of calcium metabolism based on tracer excretion data.
OTHERSr-84 (isotope tracer)
Sr-84 is given orally in the form of (Sr-84)Cl2 in aqueous solution.Tracer will be used to determine parameters of strontium metabolism based on tracer excretion data.
DIETARY_SUPPLEMENTVitamin D
One tablet daily (400IU per tablet)
Sponsors
National University of Singapore
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
BASIC_SCIENCE
Masking
NONE
Eligibility
Sex/Gender
FEMALE
Age
50 Years to 75 Years
Healthy volunteers
Yes
Inclusion criteria
1. Last menstrual bleeding was at least 5 years ago. 2. Between the ages of 50 and 75 years old. 3. Both parents and 4 grandparents are/were of Chinese descent. It is not a necessity for the participant, participant's parents and grandparent's to be born and raised in Singapore to participate in this study. 4. BMI above 16 and below 30
Exclusion criteria
1. Diagnosed with osteoporosis 2. Presence of significant liver disease, malignancy (excluding myeloma in the study group), malabsorption syndrome, hypoparathyroidism, hyperparathyroidism, sarcoidosis or hyperthyroidism (from toxic multinodular goitre or Graves disease), Paget's disease osteosarcoma, acromegaly, Cushing's syndrome, hypopituitarism, diabetes mellitus or severe chronic obstructive pulmonary disease. 3. Current smoking and an alcohol intake exceeding one standard drink per day 4. Undergoing treatment with any of the following drugs (within the last 12 months) i) adrenocorticoid steroids (3 months or longer at anytime or \>10 days of treatment within the previous 12 months) ii) anticonvulsant therapy iii) pharmacological doses of thyroid hormone (causing decline of TSH below normal) iv) bisphosphonates v) calcitonin vi) synthetic parathyroid hormone vii) selective estrogen receptor modulators viii) strontium ranelate ix) estrogen therapy x ) chemotherapeutic agents xi) sodium fluoride (any history of treatment with fluoride) xii) medications known to affect calcium metabolism (diuretics, antacids, calcium channel blockers etc.). 5. Presence of any other chronic illnesses. 6. Any other significant medical, psychiatric and/or social issue as determined by the investigator that would compromise subject's safety and/or compliance with trial procedure. 7. Any other clinically significant screening laboratory abnormality (as determined by the investigators).
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Time changes in urinary tracer excretion (Ca-41 and Sr-84) | 6 months post dose | Urine samples collected from participants are analysed for calcium and strontium content as well as Ca-41 and Sr-84 excretion. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Flux rates and relative compartment sizes (mineralized bone, exchangeable bone calcium, plasma calcium) of the study population | 6 months post dose | Flux rates (mg/day) and calcium distribution between compartments (% body calcium) will be obtained by compartmental modelling of urinary tracer data. Obtained data will be compared to a mirroring study conducted earlier in Caucasian postmenopausal women. |
| Comparison between flux rates and relative compartment sizes for calcium and strontium in each individual subject | 6 months post dose | Flux rates (mg/day), and calcium and strontium distribution between compartments (% body calcium and strontium ) will be obtained by compartmental modelling of urinary tracer data |
Countries
Singapore
Outcome results
None listed