PaTH Study: Parathyroid Hormone and Alendronate for Osteoporosis

Inclusion Criteria: * Aged between 55 and 85 years * Postmenopausal (have not had any menses in the last 5 years) * Have a bone mineral density scan (DXA) that can be evaluated at the spine AND at the hip with a T-score equal to or below -2.5 at the spine or the femoral neck or total hip OR T-score equal to or below -2.0 at the spine or the femoral neck or total hip and have at least one of the following risk factors for fracture: (a) age \> 65 years; (b) history of postmenopausal fracture (nonvertebral or vertebral); or (c) maternal history of hip fracture * Willing and able to self-administer daily injections Exclusion Criteria: * Have used estrogen (oral or patch) for more than 1 month in the last 6 months or more than 12 months in the last 2 years * History of more than 12 months of bisphosphonate use ever, or any use (\> 4 weeks) within the past 12 months * History of rhPTH (recombinant human PTH) use * Any major life-threatening illnesses * Type 1 or uncontrolled type 2 diabetes mellitus (defined as hemoglobin A1C \> 10.0), or currently using insulin * Vitamin D level \< 15 nanograms/ml * History of kidney disease (creatinine \> 2.0 mg/dl) * Renal insufficiency (creatinine clearance \< 40 mg/min) * Any history of kidney stones * Any history of hypercalciuria or currently have urine calcium/creatinine \>300 mg * History of hypercalcemia, sarcoidosis, or hyperparathyroidism * History of active or treated tuberculosis or other granulomatous disorders * History of breast cancer, melanoma, or hematologic malignancy that has required treatment within the last 10 years * History of bone cancer or any other metabolic bone disease that has required treatment within the last 10 years * History of any other nonskin cancer that has required treatment within the last 10 years * History of symptomatic esophageal reflux, achalasia or esophageal stricture * Currently taking \> 7.5 mg systemic prednisone or equivalent per day * Currently using \> two puffs, four times/day of inhaled steroids * Currently taking anticoagulants or anticonvulsants * Have used Calcitonin within the past 3 months * Have used Raloxifene in the last 6 months or for more than 12 months in the last 2 years * Have used Tamoxifen in the last 6 months or for more than 12 months in the last 2 years * Have used fluoride for at least a month within the past 5 years * Currently taking \> 1000 IU/day vitamin D or vitamin D analogues or metabolites * Currently taking thyroid hormone replacement AND have a TSH \< 0.1mIU/L