Osteoporosis

What Is Osteoporosis?

Osteoporosis is a condition marked by weak and brittle bones. People with osteoporosis are more likely to fracture their bones. For many adults, a fracture is the initial presentation of osteoporosis.

Eight million women (and 2 million men) have osteoporosis in the United States, and an estimated 44 million Americans have osteopenia, which is low bone density placing them at increased risk to develop osteoporosis and fractures. One in two women and up to one in four men will have a low-impact (fragility) fractures of the spine, hip, pelvis and wrist in their lifetime. Many fractures that are caused by osteoporosis can be prevented with prompt diagnosis and treatment of osteoporosis.

What Are the Causes and Risk Factors of Osteoporosis?

Your bones are always rebuilding, but at the same time old bone is broken down. The balance between new bone generation and old bone decay changes as you age.

When you are young, your body makes new bone faster than it breaks down old bone, and your bone mass increases. The balance starts to tip as you enter your early to mid-20s, and most people reach their peak bone mass by 30 years of age. After that, you may start losing bone faster than it is generated.

How likely you are to develop osteoporosis depends partly on how much bone mass you built in your youth. Peak bone mass is somewhat inherited and varies also by ethnic group. The higher your peak bone mass, the more bone you have "in the bank" and the less likely you are to develop osteoporosis as you age.

Some of the common risk factors for developing osteoporosis include:

• Are female
• Over the age of 50
• Are of white or Asian descent
• Have family history of osteoporosis, especially if your mother or father fractured a hip
• Have low body weight
• Have low levels of sex hormones (low estrogen in women, low testosterone in men)
• Have too much thyroid hormone (hyperthyroidism)
• Are chronically on certain medications such as steroids

There are other factors though that influence the likelihood of developing osteoporosis. You are at risk for osteoporosis if one or more of the following apply to you. You can remember these factors by using the mnemonic SLENDER^®.

• Slim build
• Low calcium intake or little exercise
• Early menopause or even a history of irregular periods
• No pregnancies
• Dermatologic / ethnic background (very light-skinned people are at greater risk than darker-skinned people)
• External factors, such as smoking, excess alcohol consumption, drugs such as steroids and anti-seizure medication or excess thyroid hormone. Certain acid-inhibiting drugs and diabetes drugs (called TZDs) increase fracture risk as well
• Relatives with osteoporosis (particularly your mother, father or sibling)

There are also factors that make you more likely to have a fracture. These can be remembered by the mnemonic FAR TRIP^®. They include:

• Frailty (such as inability to get out of a chair without help)
• Age (older people are more likely to fracture)
• Relatives who have fractured
• Tendency to fall, particularly to the side
• Radiologic (x-ray) evidence of deformity of the spine, including partial painless fracture of the spine
• Increased length of the part of the hip called the femoral neck, which can be seen in people of Asian descent
• Prior history of fracture

Other conditions and diseases can increase the risk of developing osteoporosis. These include certain types of cancer, some organ transplantations, types of liver or kidney diseases, prolonged use of the blood thinner heparin or mast cell disease, inflammatory arthritis and certain endocrine diseases.

What Are the Symptoms of Osteoporosis?

Although most people are not aware that they may have osteoporosis until they experience a fracture, there are some signs and symptoms that you may experience in later stages of the condition. They include:

• Back pain (in the presence of vertebral compression fracture)
• Loss of height over time (this will be gradual)
• A stooped posture
• Low-impact bone fracture, especially of the spine, wrist, or hip

How Is Osteoporosis Diagnosed?

A health care provider can check your bone density to determine if you have osteoporosis or are at higher risk of bone fractures. The test is done using a machine that emits low levels of X-rays. It is painless and usually only a few bones are examined, mainly the hip and spine and sometimes the forearm.

The test results are usually shown in two different ways. For post-menopausal women (and older men), a result called a T-score is interpreted. The number describes the number of units (called standard deviations) your bone density is above or below the average of a normal, healthy young adult of your sex. Specifically:

• T-score of -1 and above: normal bone density
• T-score between -1 and -2.5: below normal density – osteopenia
• T-score of -2.5 and below: osteoporosis

For young adults, women who are pre-menopausal and men under the age of 50, a Z-score is used. The result is similar, but in this case bone density is compared to the average number for someone of the same age, sex, weight and ethnic or racial origin. If your Z-score is significantly lower than the average, it may suggest that something other than aging is causing abnormal bone loss.

If you have symptoms of osteoporosis or have been recently diagnosed, find endocrine care in your area.

How Is Osteoporosis Treated?

You should begin treatment for osteoporosis if you have been diagnosed, are at high risk for fractures or have suffered a low-impact fracture. In addition to exercise, calcium and vitamin D supplements, you may also require one of the following medications:

• Bisphosphonates (alendronate, risedronate, ibandronate, zolendronic acid) to slow down excessive bone loss, stabilize BMD (bone mineral density) and reduce fracture risk. These medications continue to work after stopped, so a “drug holiday” is often considered after using these medications for 3 years (i.e. zolendronic acid) or 4-5 years (i.e. alendronate).
• Denosumab to indirectly reduce bone loss. It is important to get this medication every 6 months, since stopping can be associated with rapid bone loss. However, if stopped, treatment with another medication would be recommend to prevent bone loss after discontinuing this medication. Denosumab may be helpful in patients who cannot tolerate other forms of treatment such as the bisphosphonates, for example due to significant kidney dysfunction.
• Romosozumab to reduce fracture risk and increase new bone formation in post-menopausal women. This may increase the risk of heart attack, stroke and cardiovascular death so it’s important to carefully select patients for this therapy, which includes avoiding use in patients who have had a heart attack or stroke within the previous year. It has been approved by the FDA for use for 12 months. After completing this medication, an anti-resorptive agent should be started to prevent loss of bone after this is discontinued.
• Estrogen to reduce fracture risk if post-menopausal. When the estrogen is discontinued, however, bone loss can increase as it happens in menopause.
• Selective estrogen receptor modulator or SERM (raloxifene) to reduce spine fractures. It may have beneficial effects on other tissues.
• Teriparatide and abaloparatide are agents being used to treat osteoporosis. They are once-a-day shots under the skin. They are known to build bone, hence their classification as anabolic agents. However, you can lose bone very quickly upon completion of therapy. Treatment with these agents is limited to a total of two years by the FDA. After stopping an anabolic agent, an anti-resorptive agent will need to be started immediately. If you qualify for treatment, you or a family member will need to learn how to administer these shots at home.
• Calcitonin to slow down excessive bone activity and reduces fracture risk in the spine. It can also reduce pain from acute spinal fractures. Long-term use of the drug may not be recommended as evidence suggests it can lead to tumor growth.

Some of these drugs, may result in atypical fractures (especially of the femur or thigh bone) with longer term use (i.e. bisphopshonates and denosumab). Decay in the jaw (osteonecrosis) can be seen in <1% of patients using bisphosphonates or denosumab especially in the setting of invasive dental procedures, such as tooth extractions. Check with your doctor about when to discontinue these medications.

Can You Prevent Osteoporosis?

There are lifestyle and dietary modifications you can make to help reduce the likelihood of developing osteoporosis and prevent fractures:

• Don’t smoke or stop smoking if possible, as it can increase how quickly your bone loses mass
• Avoid excessive alcohol, which can decrease bone formation if consuming more than two drinks a day
• Prevent falls by wearing low-heeled shoes with nonslip soles. You can also make sure that your home is tidy, and you are able to walk around easily (removing loose electrical cords, area rugs and covering slippery surfaces, ensure adequate night lighting)
• Make sure you are getting enough calcium in your diet, as this is important for bone formation.