Steven Boonen, MD, PhD, is professor of medicine at the Leuven University Department of Experimental Medicine, clinical director of the Leuven University Center for Metabolic Bone Diseases, and consultant in geriatric medicine at the Leuven University Division of Internal Medicine. As a Steering Committee member for both the 2301 and 2310 trials, he has been intimately involved in the clinical development of zoledronic acid in osteoporosis. His main research activities focus on the pathogenetic mechanisms involved in age-related osteoporosis, in particular the role of selected endocrine deficiencies as determinants of skeletal fragility. Additional areas of expertise include trial design, osteoporosis in old age, male osteoporosis and strategies to reduce fracture risk. Dr. Boonen has published widely on these topics in journals such as Annals of Internal Medicine, Arthritis and Rheumatism, Journal of Bone and Mineral Research, Journal of Clinical Endocrinology and Metabolism, Journal of the American Geriatrics Society, Osteoporosis International and The New England Journal of Medicine. He has authored more than 125 peer-reviewed original research papers, along with a number of editorials, reviews and book chapters. Dr. Boonen is a member of the Committee of Scientific Advisors of the International Osteoporosis Foundation (IOF) and serves on the Editorial Boards of Osteoporosis International and Calcified Tissue International. From 2003-2007, Dr. Boonen served as president of the BBC.