Presented by: Joy Wu, MD, PhD
Assistant Professor, Medicine (Endocrinology)
February 25, 2016
Most people are aware that as they age, their bones aren’t as strong as when they were young. But many don’t realize how common osteoporosis is.
“A pretty significant proportion of the American population has some degree of bone loss,” said Joy Wu, MD, PhD, at a presentation for the Stanford Health Library. “Half of all women over 50 are going to have a fracture from osteoporosis.” Men have a lower but not insignificant lifetime risk of about 20 percent, she said.
Osteoporosis is defined as having “porous bones,” with a decrease in bone mass that leads to fractures. When low bone mass is less severe, it is called osteopenia. Either condition can leave bones vulnerable to fracture.
Altogether, osteoporosis leads to about 1.5 million fractures a year in the United States. About half a million people end up in the hospital.
“That’s a lot of fractures every day in this country. And many of them are sadly preventable,” said Dr. Wu, who is an assistant professor of medicine in the division of endocrinology, gerontology and metabolism at Stanford University Medical Center.
The most frequent fractures from osteoporosis are in the spine, the wrist or hip.
—Spine fractures, which are the most common, account for more than a quarter of fractures. About half are asymptomatic. They may be found on an X-ray or an MRI. Sometimes they are identified when people realize they’ve lost 3 to 4 inches of height, which signals spinal compression fractures. The other half of spinal fractures are very symptomatic—with severe back pain.
“Somebody might be bending over a bathtub or picking something up from the floor,” Dr. Wu said. “Suddenly there’s a pop, and they feel excruciating back pain.”
—The second-most common site for osteoporosis fractures is the wrist. Typically it happens when people extend their hands to break a fall. Dr. Wu has seen many patients during winter snowstorms when they slip on ice and fall. “It’s very, very painful,” she said.
—Hip fractures are the third-most common osteoporosis fracture, and the most serious. “They are devastating,” Dr. Wu said. Hip fractures can leave people unable to walk for a long time. “Many people end up in nursing homes for a prolonged time,” Dr. Wu said. Some people never really recover.
“The number I find most shocking is, after a hip fracture, the estimates are that 20 percent to 30 percent of people will die within a year,” Dr. Wu said. “Half of people never walk again.”
The risk for hip fracture peaks late in life, at about age 75. Spine and shoulder fractures are evenly spread among ages over 50. In contrast, wrist fractures are most common in people age 50 to 60, Dr. Wu said.
Dr. Wu has come to see a wrist fracture in a 50-something woman as a warning sign the woman is more likely to get a hip fracture in her 70s—unless she gets preventive treatment.
In recent years, doctors have begun to realize that men can get osteoporosis as well. About one-third of all hip fractures occur in men, Dr. Wu said. Men getting hip fractures are twice as likely to die within a year as women, a death rate Dr. Wu called alarmingly high. “The consequences, if anything, can be even worse,” Dr. Wu said. “Some of that is because men are older when they get a hip fracture.”
For men and women, these fractures are preventable—if they get treatment. The decision to start treatment is based on whether a person has one or more of the following risk factors:
- Previous fracture
- Getting glucocorticoid therapy
- Family history of osteoporosis, fractures
- Low body weight
- Cigarette smoking
- Excessive alcohol (more than two drinks/day for women, three/day for men)
- Rheumatoid arthritis
- Taking drugs known to increase fracture risk (including some heartburn drugs)
For each person, it’s the combination of all of these risk factors that determine if they should start treatment, Dr. Wu said. “If you’ve ever had a fracture, you’re at much higher risk for having more fractures.”
Before initiating treatment, many people get a test of their bone density, called a DXA scan. Dr. Wu recommends that women over age 65 and men over age 70 get this test. The test is also recommended for anyone over age 50 who has other risk factors, or who has had a previous fracture not due to trauma after age 50.
DXA scans typically measure bone density in the hips and spine, presenting the results as a “T score.” In general, T scores fall into these categories:
- A score of -2.5 or lower indicates osteoporosis
- A score of -1.0 to -2.5 indicates osteopenia (some weakening of bones)
- A score of -1.0 or higher is normal, with 0.0 normal for age 30
T score doesn’t tell the whole story, however. The other number that tells doctors whether to recommend treatment is age.
“Your fracture risk is very much dependent on both your bone density and your age,” Dr. Wu said. Even those with normal bone density can have a higher fracture risk at an advanced age.
Using the T score and age, doctors can estimate a person’s 10-year probability of fracture, which estimates how likely it is that someone will get a fracture in the next 10 years. The threshold for starting treatment, under current medical guidelines, is a 10-year probability of hip fracture of 3 percent or higher.
That means that T scores alone don’t determine whether a doctor recommends treatment, Dr. Wu said. A woman with a -2.5 T score at age 55 is below the threshold for treatment, but the same score when she is age 65 puts her right on the edge of the threshold. A woman age 75 with the same score should be treated. Still other risk factors can also influence whether treatment is warranted.
“Bone density scan is not a crystal ball,” Dr. Wu said. Even when it’s used to estimate the probability of a fracture, that remains a probability—not a certainty. Many women get fractures even when their T scores don’t indicate osteoporosis. In fact, half of all fractures occur in women whose bones show only the milder weakness called osteopenia rather than full osteoporosis.
Drug treatment can prevent fractures by blocking the breakdown of bone, or by promoting bone formation. The first category includes the most commonly prescribed drugs, the bisphosphonates (Fosamax, Reclast, Boniva), and denosumab (Prolia); the second group includes a newer drug, teriparatide (Forteo).
Many women considering treatment for osteoporosis are concerned about safety, Dr. Wu said. A common side effect of the bisphosphonates is heartburn, which usually can be minimized. Rare side effects include atypical fractures in the thigh bone, or osteonecrosis of the jaw. Dr. Wu said studies have shown 97 percent of the jaw problems have occurred in patients getting much higher doses of bisphosphonates prescribed for cancer rather than the lower doses for osteoporosis. The benefits of treating osteoporosis for five years or less “far, far” outweigh the risks of treatment, Dr. Wu said.
Apart from treatment, people can also make changes in lifestyle to improve their bone health:
- Be physically active to keep bones strong
- Avoid falls at home by moving slippery throw rugs out of the way
- Maintain a healthy weight
- Avoid smoking
- Limit alcohol drinking
- Get enough calcium and vitamin D from food and/or taking supplements
To keep bones strong, most women need 1,000 to 1,200 mg. of calcium per day. Milk, yogurt, cheddar cheese and fortified orange juice are all good sources. But someone would have to drink 3 or 4 glasses of milk a day to get enough calcium—which most adults find difficult—so supplements can help meet the daily goal. For vitamin D, many people rely on supplements to get the recommended 600-800 IUs per day. Taking higher doses of vitamin D isn’t recommended because it can increase the risk for kidney stones, Dr. Wu said.
Taking these lifestyle steps can help maintain strong bones, but they may not prevent fractures in people who already have weak bones, however. “Lifestyle changes can slow—but not reverse—osteoporosis,” Dr. Wu said. “Treatment, when used properly, can be safe.”
About the speaker
Joy Wu, MD, PhD, received her medical degree from Duke University and completed her medical residency at Brigham and Women’s Hospital and her clinical fellowship in endocrinology at Massachusetts General Hospital, both at Harvard Medical School. She is board-certified in internal medicine and a member of the Endocrine Society and the American Society for Bone and Mineral Research. Her medical interests include osteoporosis, metabolic bone disease and disorders of mineral metabolism.
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