Cause

During childhood and teen years, new bone grows faster than existing bone is absorbed by the body. After age 30, this process begins to reverse. As a natural part of aging, bone dissolves and is absorbed faster than new bone is made, and bones become thinner. You are more likely to have osteoporosis if you did not reach your ideal bone thickness (bone mineral density) during your childhood and teenage years.

In women, bone loss increases around menopause, when ovaries decrease production of estrogen, a hormone that protects against bone loss. Likewise, testosterone protects men from bone loss. Osteoporosis is typically seen in men older than 65, when production of this hormone declines. In both men and women: The older you get, the more likely you are to have osteoporosis. See a picture of healthy bone versus bone weakened by osteoporosis.

Not getting enough calcium and vitamin D contributes to bone thinning. Also, a tendency for lower bone mass may pass from parent to child.

Symptoms

In the early stages of osteoporosis, you probably will not have symptoms. As the disease progresses, you may have symptoms related to weakened bones, including:

• Back pain.
• Loss of height and stooped posture.
• A curved upper back (dowager's hump).
• Broken bones (fractures) that might occur with a minor injury, especially in the hip, spine, and wrist.
• Compression fractures in the spine that may cause severe back pain. But sometimes these fractures cause only minor symptoms or no symptoms at all.