Osteoporosis

What is osteoporosis?

Osteoporosis is a disease that causes loss of bone density and strength, which increases the risk of fractures. Osteoporosis does not cause symptoms unless it causes a bone fracture.

Osteoporosis is more common in women than men. This is mainly due to declining estrogen levels that occur with menopause.

Aging is the most common risk factor for osteoporosis. Throughout life, bones undergo a continuous maintenance cycle called remodeling, in which they are simultaneously broken down and rebuilt. But with age, bones break down faster than they can rebuild. Eventually, bones can become so thin, weak, and brittle that a fall or stress on the bone can cause a fracture.

You are more likely to develop osteoporosis if you:

• are female
• are age 50 or older
• are postmenopausal
• consume a diet low in bone-building calcium and vitamin D, which help the body absorb dietary calcium
• lead a sedentary lifestyle
• are thin
• take certain medications, such as corticosteroids
• are Caucasian or of Asian descent
• smoke
• drink more than a moderate amount of alcohol
• have a family history of osteoporosis.

Many medical conditions are associated with bone loss and can increase the risk of osteoporosis. Some examples include:

• digestive diseases like celiac disease and inflammatory bowel disease
• rheumatoid arthritis
• chronic liver disease
• kidney disease
• hyperthyroidism (an overactive thyroid)
• diabetes (type 1 and 2)
• anorexia nervosa or other cause of malnutrition
• kidney disease
• liver disease
• premature menopause.

Some medications also may cause bone loss. These include:

• anticonvulsants
• aromatase inhibitors
• glucocorticoids
• gonadotropic-releasing hormone agonists.

How is osteoporosis diagnosed?

A bone density measurement is the gold standard test for diagnosing osteoporosis. You may also be diagnosed with osteoporosis if you have a "fragility fracture" — a broken bone that results from no trauma or only minor trauma, such as falling from standing height.

The most accurate and widely used bone density test is a dual-energy X-ray absorptiometry (DEXA) scan. This test is painless, takes only 10 to 15 minutes, and uses minimal radiation (similar to other bone x-rays and only about 1/100th of the radiation as a standard chest X-ray).

Scans are generally performed on the lumbar spine (in the lower back), total hip (at a specific site near the hip joint), and femoral neck (at the top of the thigh bone or femur).

The results of a DEXA scan are assigned a number called a T-score, which represents how close you are to peak bone density. T-scores are classified as follows:

• -1 or greater means normal bone density
• -1 to -2.5 indicates osteopenia (a precursor to osteoporosis)
• lower than -2.5 indicates osteoporosis.

The Bone Health and Osteoporosis Foundation recommends people be tested with DEXA if they are:

• a woman age 65 or older or a man age 70 or older
• a postmenopausal woman under age 65 or a man aged 50 to 69 with risk factors for osteoporosis
• a woman or man who has had a fracture at age 50 or older
• a woman or man who has a medical condition or is taking a medication associated with bone loss.

Many doctors recommend that people get a FRAX score in addition to a DEXA scan. A fracture risk assessment (FRAX) score uses the DEXA score and other key risk factors for a fracture to estimate the percent probability that a person will break or fracture a bone within 10 years.

Treatment with osteoporosis medications

Bisphosphonates are the first-choice drug to treat osteoporosis. ​​They slow bone loss and may lead to a modest increase in bone density. Commonly prescribed drugs in this class include the following:

• Alendronate (Fosamax) is FDA-approved to prevent and treat osteoporosis in men and postmenopausal women, as well as to treat glucocorticoid-induced osteoporosis. It comes in several formulations: pill, liquid, or tablet that you dissolve in water.
• Ibandronate (Boniva) is used to prevent and treat postmenopausal osteoporosis. It is available in a monthly tablet or quarterly IV infusion.
• Risedronate(Actonel) is approved for preventing and treating osteoporosis in postmenopausal women and men. The drug is available as a daily, weekly, or monthly tablet.
• Zoledronic acid (Reclast) is given annually as a 15-minute infusion to treat osteoporosis or every other year to prevent bone loss.

It's important to follow instructions carefully when taking bisphosphonate drugs to avoid unpleasant side effects such as heartburn, nausea, or difficulty swallowing. A bisphosphonate pill should be taken first thing in the morning, on an empty stomach, with a large glass of water. (For liquid versions, check the written instructions to make sure you drink enough water with each dose.) Remain upright for at least 30 minutes (60 minutes for once-a month ibandronate). During this time, avoid eating, drinking, or taking another medication. Take the pill versions with water, rather than coffee or orange juice, which can interfere with your body's ability to absorb and use the drug. Most people tolerate these medications well when they take them as instructed.

A relatively small number of people may develop side effects such as bone, joint, or muscle pain. These symptoms resolve for most people after they stop using the medication.

Two other bisphosphonate side effects are worth noting. The first is increased risk of thighbone fracture. In very rare cases, some women on long-term treatment with bisphosphonates have experienced unusual fractures of the thighbone (atypical femoral fractures). These fractures are a type of stress fracture that occurs with little or no injury. The cause of these fractures remains unclear. When considering these medications, the very small chance of a bisphosphonate-induced atypical fracture needs to be weighed against the likelihood of improving bone density and preventing painful and disabling fractures.

Another rare side effect seen in people taking bisphosphonates over the long term is damage to bone tissue (osteonecrosis) in the jaw. Symptoms include pain, swelling, or infection of the gums or jaw; infected or injured gums that aren't healing; loose teeth; and numbness in the jaw. Although the risk is real, it is very small. According to one estimate, for every 10,000 to 100,000 people who take a bisphosphonate for a year to treat bone loss, one may develop osteonecrosis in the jaw.

Other classes of medications for osteoporosis include:

• monoclonal antibodies
• parathyroid hormone-related medications
• estrogen-related medications.

Protecting your bones with exercise

Regular exercise can be helpful to treat and prevent osteoporosis. Exercise places stress on your bones, stimulating the body to deposit calcium into the bones and increasing density. Additionally, exercise boosts the activity of bone-forming cells, further strengthening your bones.

An osteoporosis-based exercise program should include weight-bearing, balance, and flexibility exercises.

• Weight-bearing exercises force your body to work against gravity, which helps to strengthen bones. Examples include walking, climbing stairs, playing tennis, and dancing, as well as strength training like lifting free weights, using a weight machine, working with resistance bands, and body-weight exercises.
• Balance and flexibility exercises improve your ability to hold yourself upright and keep your muscles limber and joints mobile, which also helps reduce the risk of falls. Examples include tai chi, yoga, and stretching.

If you have had a previous fracture or any health concerns regarding your ability to safely exercise, it's a good idea to check with your doctor before starting an exercise program, and consider getting guidance from an experienced physical therapist or trainer.

What's the difference between osteoporosis and osteopenia?

Osteopenia is a precursor to osteoporosis. With osteopenia, bone density is lower than normal but not low enough to be diagnosed as osteoporosis. A bone density score between -1 and -2.5 indicates osteopenia, while a T-score lower than -2.5 indicates osteoporosis.

People with osteopenia do not always develop osteoporosis. The following steps can help prevent this progression:

• doing weight-bearing exercise
• increasing intake of bone-building calcium and vitamin D
• taking bone-strengthening medication if prescribed
• not smoking
• drinking alcohol only in moderation.