A number of factors can increase the likelihood that you'll develop osteoporosis including your age, race, lifestyle choices, and medical conditions and treatments.

Unchangeable risks

Some risk factors for osteoporosis are out of your control, including:

• Your sex. Women are much more likely to develop osteoporosis than are men.
• Age. The older you get, the greater your risk of osteoporosis.
• Family history. Having a parent or sibling with osteoporosis puts you at greater risk, especially if your mother or father fractured a hip.
• Body frame size. Men and women who have small body frames tend to have a higher risk because they might have less bone mass to draw from as they age.

Hormone levels

Osteoporosis is more common in people who have too much or too little of certain hormones in their bodies. Examples include:

• Sex hormones. Lowered sex hormone levels tend to weaken bone. The fall in estrogen levels in women at menopause is one of the strongest risk factors for developing osteoporosis. Treatments for prostate cancer that reduce testosterone levels in men and treatments for breast cancer that reduce estrogen levels in women are likely to accelerate bone loss.
• Thyroid problems. Too much thyroid hormone can cause bone loss. This can occur if your thyroid is overactive or if you take too much thyroid hormone medicine to treat an underactive thyroid.
• Other glands. Osteoporosis has also been associated with overactive parathyroid and adrenal glands.

Dietary factors

Osteoporosis is more likely to occur in people who have:

• Low calcium intake. A lifelong lack of calcium plays a role in the development of osteoporosis. Low calcium intake contributes to diminished bone density, early bone loss and an increased risk of fractures.
• Eating disorders. Severely restricting food intake and being underweight weakens bone in both men and women.

Lifestyle choices

Some bad habits can increase your risk of osteoporosis. Examples include:

• Sedentary lifestyle. People who spend a lot of time sitting have a higher risk of osteoporosis than do those who are more active. Any weight-bearing exercise and activities that promote balance and good posture are good for your bones, but walking, running; jumping, dancing and weightlifting seem particularly helpful.
• Excessive alcohol consumption. Regular consumption of more than two alcoholic drinks a day increases the risk of osteoporosis.
• Tobacco use. The exact role tobacco plays in osteoporosis isn't clear, but it has been shown that tobacco use contributes to weak bones.

Bone breaks, particularly in the spine or hip, are the most serious complications of osteoporosis. Hip fractures often are caused by a fall and can result in disability and even an increased risk of death within the first year after the injury.

In some cases, broken bones in the spine can occur even if you haven't fallen. The bones that make up your spine, called vertebrae, can weaken to the point of collapsing, which can result in back pain, lost height and a hunched-forward posture.

Good nutrition and regular exercise are essential for keeping your bones healthy throughout your life.

Calcium

Men and women between the ages of 18 and 50 need 1,000 milligrams of calcium a day. This daily amount increases to 1,200 milligrams when women turn 50 and men turn 70.

Good sources of calcium include:

• Low-fat dairy products.
• Dark green leafy vegetables.
• Canned salmon or sardines with bones.
• Soy products, such as tofu.
• Calcium-fortified cereals and orange juice.

Your bone density can be measured by a machine that uses low levels of X-rays to determine the proportion of mineral in your bones