Inclusion Criteria:

• Osteoporotic patients who meet any of the following condition:

  1. with at least one fragility fracture,
  2. above 70 year-old with bone mineral density below 70% young adult mean,
  3. with bone mineral density below 60% young adult mean
• Women three years or more after menopause or men

Exclusion Criteria:

• Current disorders such as primary hyperparathyroidism, Cushing’s syndrome,gonadal insufficiency, poorly controlled diabetes mellitus or other causes of secondary osteoporosis
• A history or suspicion of active urolithiasis at any time
• Use of bisphosphonates in the past 12 months
• Use of medications known to affect bone in the past 2 months
• Abnormal serum calcium, urinary calcium, serum creatinine or liver function tests