Bone Diseases: Keeping Bones Strong, and What Can Go Wrong

Bones let you move, give your body its shape and hold it up. They are living tissue that rebuilds itself throughout life. In childhood and the teenage years, the body adds new bone faster than it removes old bone; after about age 20, you can start losing bone faster than you make it.

Keeping bones strong

To build strong bones when young and limit bone loss later, you need enough:

• calcium;
• vitamin D;
• exercise.

It also helps to avoid smoking and drinking too much alcohol.

Kinds of bone disease

Bone diseases can make bones break easily. They include:

• low bone density and osteoporosis, which weaken bones and make them more likely to break;
• osteogenesis imperfecta, which makes bones brittle;
• Paget's disease of bone, which weakens them;
• cancer and infections of the bone;
• other bone diseases caused by poor nutrition, genetics, or problems with how fast bone grows or rebuilds.

Osteoporosis

In osteoporosis, bones become weak and likely to fracture, as bone mineral density and bone mass fall or bone structure and strength change. The body constantly breaks down old bone and replaces it; osteoporosis develops when more is broken down than replaced, which can happen with age. It is called a "silent" disease because it usually causes no symptoms — you may not know you have it until a bone breaks, most often in the hip, spine or wrist. Anyone can develop it, but it is more common in women, especially after menopause, in people over 50, and in people who are slim and thin-boned, and more likely if a parent had osteoporosis or broke a hip.

Osteogenesis imperfecta

Osteogenesis imperfecta (OI) is a genetic disorder in which bones break easily, sometimes for no known reason. Faulty genes affect how the body makes collagen, a protein that helps make bones strong. It can also cause weak muscles, brittle teeth, a curved spine and hearing loss. It ranges from mild to severe: a person may have a few fractures in a lifetime, or several hundred. There is no cure, but exercise, pain medicine, physical therapy, wheelchairs, braces and surgery can help manage it.

Paget's disease of bone

Normally bones break down and regrow in balance. In Paget's disease, a chronic disorder, the breakdown and regrowth are excessive, so bones regrow too fast and end up bigger and softer than normal — sometimes misshapen and easily broken. It usually affects one or a few bones and gets worse slowly, without spreading to normal bones. Many people with it have no symptoms; when there are symptoms, they can resemble arthritis, and include pain, headaches and hearing loss when the skull is affected, and hip pain when the pelvis or thighbone is. It is more common in older people, in people of northern European heritage, and in those with a close relative who has it.

Sources

• MedlinePlus, U.S. National Library of Medicine, "Bone Diseases," drawing on the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS). https://medlineplus.gov/bonediseases.html
• MedlinePlus summaries "Osteoporosis," "Osteogenesis Imperfecta" and "Paget's Disease of Bone," also drawing on NIAMS, used for the three sections on those diseases: https://medlineplus.gov/osteoporosis.html, https://medlineplus.gov/osteogenesisimperfecta.html, https://medlineplus.gov/pagetsdiseaseofbone.html
• Rewritten in hubnx's own words.