Osteoporosis (pronounced oss-tee-oh-pour-OH-sis) is, very simply, weak and brittle bones caused by bone loss. As we get older, we lose more bone than our bodies can make. This loss weakens the bones and can cause fractures in the hip, wrist, spine, or elsewhere.
Bone is living tissue, just like any other tissue in the body. Old bone is replaced by new bone all the time. Every day, cells called osteoclasts break bone down, and another type of cell known as osteoblasts, try to repair the damage by forming new, healthy bone. Throughout our life, the speed of this process changes: Up until our early 30’s, the osteoblasts make more bone than is lost. These are the years when the body builds the skeleton up to hold the greatest amount of bone. From our 30’s to our 50’s, we lose old bone and make new bone at about the same rate. When women each menopause and men reach their 50’s, the process changes again. Now, our bodies always make less bone than we lose. At some point, this bone loss may cause the bone to fracture.
Bone is not just solid tissue. In fact, the spongy type of bone found in the spine looks like a honeycomb inside, with a network of curved plates and rods. The thicker the plates and rods, the stronger the bone. When this honeycomb becomes thinner, the bone weakens.
A healthy bone and one weakened by osteoporosis might look exactly the same on the outside. Only if you looked at the inside would you see the ruins of the honeycomb within the bone.
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Michael Pazianas, MD, is a nephrologist by training and his main area of interest is metabolic bone diseases including osteoporosis. During his tenure at the University of London (Charing Cross Hospital & Westminster Medical School — St George’s Hospital Medical School), University of Pennsylvania and currently at Oxford, Dr Pazianas has published over 100 papers, including authoritative review articles and chapters. He is also co-author of a book entitled “Therapy of Osteoporosis”.
See bibliography (479KB PDF) for full details.
Dr. Pazianas has served as a Member of the Grant Review Committee of the NIH, as well as the Endocrinology / Bone Grant Review and Career Development Award Committees of the US Department of Veteran’s Affair’s Research Program. Dr Pazianas is a member of the Editorial Board of the Journal of Spine and also a reviewer for highly rated journals including Nature, the New England Journal of Medicine, Proceedings of the National Academy of Science, Blood, Journal of Bone and Mineral Research and the American Journal of Physiology.
He is presently working in conjunction with the Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, which is part of the University Medical School, where you can find his departmental profile page.