CT-Based Changes in Bone and Marrow Among Patients on Oral Steroids

Inclusion Criteria: * Inclusion (all subjects): * Diagnosis of severe, persistent asthma (defined as using both a long-acting beta-agonist AND a high-dose inhaled steroid) * Age 25-45 * Inclusion (oral steroid group): * Chronic treatment with oral steroids for at least 45 days but less than 1 year Exclusion Criteria: * Exclusion (all subjects): * Pregnant or breastfeeding * History of any cancer, excluding non-melanoma skin cancer * Currently receiving dialysis * History of any lower extremity fracture * Hip or knee replacement * Non-ambulatory * Greater than 10 pack-year smoking history * BMI \> 50 * Age \< 25 or \> 45 * Current or past use of FDA-approved medication for osteoporosis: Bisphosphonates (Alendronate/Fosamax, Ibandronate/Boniva, Risedronate/Actonel/Atelvia, Zoledronic Acid/Reclast) Calcitonin (Fortical, Miacalcin) Selective Estrogen Receptor Modulator (Raloxifene/Evista) Parathyroid Hormone Analogue (Teriparatide/Forteo) Monoclonal Antibody (Denosumab/Prolia)