Inclusion Criteria:

• Able and willing to provide informed consent.
• Postmenopausal women (FSH > 20 IU/L).
• Aged 50-80 years old.
• Lean control subjects:  BMI < 25, Hemoglobin A1c 
• Obese, non-diabetic subjects:  BMI ≥ 30, Hemoglobin A1c 
• Obese, T2DM subjects:  BMI ≥ 30, Hemoglobin A1c > 6.5% (for at least the past 5 years).

Exclusion Criteria:

• Clinical significant abnormality in any of the screening laboratory studies (see below).
• Presence of (documented clinical diagnosis of any of the following):
  • Significant liver or renal disease;
  • Malignancy (including myeloma);
  • Malabsorption (as defined by clinical diagnosis);
  • Hypoparathyroidism (as defined by clinical diagnosis);
  • Hyperparathyroidism (as defined by clinical diagnosis);
  • Acromegaly;
  • Cushing’s syndrome;
  • Hypopituitarism;
  • Severe chronic obstructive pulmonary disease;
  • History of cardiac failure;
  • Bleeding disorders or current use of therapeutic doses of anticoagulants other than aspirin.
• Undergoing treatment with any medications that affect bone turnover, including the following:
  • corticosteroids > 3 months at any time (inhaled steroids acceptable unless used year-round);
  • anticonvulsant therapy for seizures (carbamazepine or phenytoin within the previous year);
  • pharmacological doses of:
    • thiazolidinediones;
    • thyroid hormone (causing decline of thyroid stimulating hormone below normal);
    • Bisphosphonates (within the past 3 years);
    • denosumab, estrogen therapy or treatment with a selective estrogen receptor modulator, or teriparatide (within the past year).
  • Any history of fracture prior to screening.