Topic Overview

The risk of getting osteoporosis increases with age as bones naturally become thinner. After age 30, the rate at which your bone tissue dissolves and is absorbed by the body slowly increases, while the rate of bone building decreases. So overall you lose a small amount of bone each year after age 30.

In women, bone loss is more rapid and usually begins after monthly menstrual periods stop, when a woman's production of the hormone estrogen slows down (usually between the ages of 45 and 55). A man's bone thinning typically starts to develop gradually when his production of the hormone testosterone slows down, at about 45 to 50 years of age. Women typically have smaller and lighter bones than men. As a result, women develop osteoporosis far more often than men. Osteoporosis usually does not have a noticeable effect on people until they are 60 or older.

Whether a person develops osteoporosis depends on the thickness of the bones (bone density) in early life, as well as health, diet, and physical activity later in life. Factors that increase the risk for osteoporosis in both men and women include:

• Having a family history of osteoporosis. If your mother, father, or a sibling has been diagnosed with osteoporosis or has experienced broken bones from a minor injury, you are more likely to develop osteoporosis.
• Lifestyle factors. These include:
  • Smoking. People who smoke lose bone density faster than non-smokers.
  • Alcohol use. Heavy alcohol use can decrease bone formation, and it increases the risk of falling. Osteoporosis Canada recommends drinking no more than 2 alcohol drinks a day. See pictures of standard alcoholic drinks.
  • Getting little or no exercise. Weight-bearing exercises—such as walking, jogging, stair climbing, dancing, or lifting weights—keep bones strong and healthy by working the muscles and bones against gravity. Exercise may improve your balance and decrease your risk of falling.
  • Being small-framed or thin. Thin people and those with small frames are more likely to develop osteoporosis. But being overweight puts women at risk for other serious medical conditions, including type 2 diabetes, high blood pressure, and coronary artery disease (CAD). For more information, see the topic Weight Management.
  • A diet low in foods containing calcium and vitamin D.
• Breaking a bone after age 40 doing something that wouldn't normally cause a broken bone, such as a simple fall from standing-height or less.
• Having certain medical conditions. Some medical conditions, such as hyperthyroidism or hyperparathyroidism, put you at greater risk for osteoporosis.
• Taking certain medicines. Several medicines, such as corticosteroids used for long periods, cause bone thinning.
• Having certain surgeries, such as having your ovaries removed before menopause.

Other risk factors for osteoporosis may include:

• Being of European and Asian ancestry, the people most likely to have osteoporosis.
• Being inactive or bedridden for long periods of time.
• Excessive dieting or having an eating disorder, such as anorexia nervosa.
• Being a female athlete, if you have infrequent menstrual cycles due to low body fat.

Women who have completed menopause have the greatest risk for osteoporosis because their levels of the estrogen hormone drop. Estrogen protects women from bone loss. Likewise, women who no longer have menstrual periods—either because their ovaries are not working properly or because their ovaries have been surgically removed—also can have lower estrogen levels.