Comparison of Calcium Metabolism in Caucasian and Asian Postmenopausal Women of Chinese Descent and the Use of Strontium as a Qualitative Marker of Calcium Metabolism

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).