Subjects who meet initial pre-screening criteria will present for an on site screening visit and have a full medical history, brief physical exam, BMD and lab evaluation to confirm eligibility. Osteoporosis will be defined by DXA BMD T-Score < -2.5 at lumbar spine (at least 2 evaluable vertebrae between L1 and L4), or total hip or femoral neck. In addition, women with confirmed vertebral deformity on radiograph or lateral DXA image, or prior osteoporosis-related fracture at age >45 along with a DXA BMD T-Score < -1.5 at one or more skeletal sites will be eligible to participate.