Bones are living tissue made up of calcium and other minerals. In people with osteoporosis, bone tissue breaks down faster than it is replaced. The bones become thinner and brittle (lose mass) and are more likely to break (fracture) with pressure or after a fall. Bone loss happens without any warning signs. This is why osteoporosis is called a “silent disease.”

Bone tissue is replaced regularly in a process called bone turnover. From childhood into young adulthood, the body produces more than enough cells to replace those that die, resulting in stronger, denser bones. By age 25, bones are at peak bone mass and cell turnover remains fairly stable for several years. At about age 40, bone cells start to die at a more rapid rate than new cells are produced. This starts a slow decline in bone mass, and may lead to the development of osteoporosis.

Any bone in the body can be affected by osteoporosis. However, the spine, hips, ribs and wrists are the most commonly fractured when a person with osteoporosis falls.  Osteoporosis can also cause a hump in the upper back or loss of height.

Osteoporosis is different from osteoarthritis, a form of arthritis in which joint cartilage, the rubbery material that covers the ends of bones, wears away.

Who’s Affected?

More than 10 million people have osteoporosis. Each year, this disease contributes to more than 1.5 million fractures of the back, wrists and hips. Approximately 34 million people are at risk for low bone density (osteopenia). Osteoporosis is more common in women.  It is the main cause of bone fractures in post-menopausal women and the elderly. However, men can also get osteoporosis.

Several studies have shown that men and women who take antidepressants have an increased risk of osteoporosis-related fractures compared with people who don't take these kinds of medications. The association seems to be particularly strong in a class of antidepressants known as selective serotonin reuptake inhibitors, or SSRIs.