Osteoporosis

Osteoporosis, or "porous bones," is a disease that causes bones to become weak and brittle. It can weaken their structure to such a degree that a fall or even mild impact like a cough can cause a fracture. In many cases, bones weaken when you have low levels of calcium and other minerals in your bones.

A common result of osteoporosis is fractures — most of them occur in the spine, hip or wrist. Although it's often thought of as a women's disease, osteoporosis affects men too. And aside from people who have osteoporosis, many others have low bone density, putting them at risk of developing osteoporosis. It's never too late — or too early — to do something about osteoporosis. You can take steps to keep bones strong and healthy throughout life.

Scientists don't yet know exactly why osteoporosis occurs, but they do know that the normal bone remodeling process is disrupted. Your bone is continuously changing — new bone is made and old bone is broken down (resorption) — a process called remodeling or bone turnover. When you're young, your body makes new bone faster than it breaks down old bone and your bone mass increases. You reach your peak bone mass around age 30. After that, bone remodeling continues, but you lose slightly more than you gain.

How likely you are to develop osteoporosis depends on how much bone mass you attained in your 20s and early 30s (peak bone mass) and how rapidly you lose it later. The higher your peak bone mass, the more bone you have "in the bank" and the less likely you are to develop osteoporosis as you age. The strength of your bones depends on their size and density; bone density depends in part on the amount of calcium, phosphorus and other minerals bones contain. When your bones contain fewer minerals than normal, they're less strong and eventually lose their internal supporting structure.

Other factors, such as hormone levels, also affect bone density. In women, when estrogen levels drop at menopause, bone loss increases dramatically. In men, low estrogen and testosterone levels can cause a loss of bone mass.

Three factors essential for keeping your bones healthy throughout your life are:

• Adequate amounts of calcium
• Adequate amounts of vitamin D
• Regular exercise

If you keep these three items in mind, your chance of developing osteoporosis drops to almost zero.

A number of factors can increase the likelihood that you'll develop osteoporosis — some you can change, others you cannot.

Risk factors you can change

• Low calcium intake. A lifelong lack of calcium plays a major role in the development of osteoporosis. Low calcium intake contributes to diminished bone density, early bone loss and an increased risk of fractures.
• Tobacco use. The exact role tobacco plays in osteoporosis isn't clearly understood, but researchers do know that tobacco use contributes to weak bones.
• Eating disorders. Women and men with anorexia nervosa or bulimia are at higher risk of lower bone density.
• Sedentary lifestyle. People who spend a lot of time sitting have a higher risk of osteoporosis than their more-active counterparts. Any weight-bearing exercise is beneficial for your bones, but walking, running, jumping, dancing and weightlifting seem particularly helpful for creating healthy bones.
• Excessive alcohol consumption. Regular consumption of more than two alcoholic drinks a day increases your risk of osteoporosis, possibly because alcohol can interfere with the body's ability to absorb calcium.
• Corticosteroid medications. Long-term use of corticosteroid medications, such as prednisone, cortisone, prednisolone and dexamethasone, is damaging to bone. These medications are common treatments for chronic conditions, such as asthma, rheumatoid arthritis and lupus, and you may not be able to stop taking them to lessen your risk of osteoporosis. If you need to take a steroid medication for long periods, your doctor should monitor your bone density and recommend other drugs to help prevent bone loss.
• Other medications. Long-term use of aromatase inhibitors to treat breast cancer, the antidepressant medications called selective serotonin reuptake inhibitors (SSRIs), the cancer treatment drug methotrexate, some anti-seizure medications, the acid-blocking drugs called proton pump inhibitors and aluminum-containing antacids are all associated with an increased risk of osteoporosis.

Risk factors you can't change

• Being a woman. Fractures from osteoporosis are almost twice as common in women as they are in men.
• Getting older. The older you get, the greater your risk of osteoporosis.
• Race. You're at greatest risk of osteoporosis if you're white or of Asian descent.
• Family history. Having a parent or sibling with osteoporosis puts you at greater risk, especially if you also have a family history of fractures.
• Frame size. Men and women who are exceptionally thin (with a body mass index of 19 or less) or have small body frames tend to have a higher risk because they may have less bone mass to draw from as they age.
• Thyroid hormone. Too much thyroid hormone also can cause bone loss. This can occur either because your thyroid is overactive (hyperthyroidism) or because you take excess amounts of thyroid hormone medication to treat an underactive thyroid (hypothyroidism).
• Medical conditions and procedures that affect bone health. Stomach surgery (gastrectomy) and weight-loss surgery can affect your body's ability to absorb calcium. So can conditions such as Crohn's disease, celiac disease, hyperparathyroidism and Cushing's disease — a rare disorder in which your adrenal glands produce excessive corticosteroid hormones.