Undetected Bone Weakness Common in Older Women

Study: Nearly half of those beyond menopause have low density

TUESDAY, Dec. 11, 2001 (HealthDayNews) -- Nearly half of American women who've passed menopause have low bone density that may put them at increased risk of serious fractures, new research says.

Most of these women have bone mass that has not yet reached critical levels, and they may never get there. But the study of more than 200,000 women over age 50 -- without previously diagnosed brittle bones -- also found that 7 percent had osteoporosis that raised their risk of skeletal breaks almost four-fold compared with women with sturdier frames. The findings appear in the Dec. 12 issue of the Journal of the American Medical Association.

"If you, the primary care doctor, don't develop some strategies for eliciting risk factors [for osteoporosis from patients], you're not doing your job," says lead study author Dr. Ethel Siris, a Columbia University bone expert. "It's a silent disease, and if you don't look for it, you're not going to find it."

About 10 million Americans, 80 percent of whom are women, suffer from osteoporosis, and another 18 million Americans have low bone mass, reports the National Osteoporosis Foundation. Siris says one of two women will suffer an osteoporosis-related fracture in her lifetime.

The latest study, called the National Osteoporosis Risk Assessment, followed 200,160 postmenopausal women who were seen at doctors' offices in 13 states, with no previous diagnosis of osteoporosis. However, 22,000 had suffered an apparent osteoporosis-related fracture that hadn't been detected.

The women underwent a variety of portable, relatively inexpensive bone scans to measure bone mineral density -- a marker for skeletal strength -- at their fingers, heels and forearms. But they did not undergo a full-body, dual-energy X-ray absorptiometry (DXA) exam, which is the most thorough -- albeit the costliest and least accessible -- way to gauge bone mass.

Based on World Health Organization (WHO) criteria, 39.6 percent of the women had bone densities in the "low" range, a condition called osteopenia. And slightly more than 7 percent met the WHO's definition of osteoporosis, a bone mineral density at least 2.5 standard deviations below average on a particular machine. (A standard deviation is a statistical tool that helps scientists determine where a given value lies on a spectrum. It typically works out to about 10 percent.)

Neither osteopenia nor osteoporosis is a guarantee of fracture. But over a year of follow-up of roughly 164,000 of the women, those with osteopenia were 80 percent more likely to suffer a break than those with average bone density. Women with osteoporosis had a 350 percent greater chance of fracture, usually in the spine, hip or wrist.

"Even within one year after identification there were fractures, and those with the lowest scores were at the highest risk," Siris says.

Former or current smokers were, respectively, about 14 and 60 percent more likely to have osteoporosis than nonsmokers, the researchers found, confirming the harmful impact of tobacco on the skeleton. Asian-American and Hispanic women were significantly more likely to have the disease than whites, while African-American women were somewhat less prone to the disorder.

Women who had used steroids known to erode bone were at increased risk for osteoporosis, as were those with a family history of the disease. On the other hand, estrogen replacement therapy, exercise, being overweight and drinking more alcohol each cut the odds for the condition.

Siris says the study validates the use of the portable, "peripheral" bone scanners to predict fractures. She says the devices could easily be set up in a doctor's office to perform inexpensive readings. "It's a low-cost, quick test that serves as a screening and gives useful information," she says.

If a woman has extremely poor bone density, she can take drugs to strengthen her skeleton. Or if her score is merely low, she can do a wide range of things -- get more exercise, take vitamin D, stop smoking -- to slow the normal process of bone loss.

Yet some doctors expressed concern that the study was rich with conflicts of interest. Funding for the work came from Merck & Co., which makes the osteoporosis drug Fosamax and thus has an obvious interest in expanding the pool of women eligible to take the drug. Funding also came from the International Society for Clinical Densitometry, a group that receives money from Merck as well as the scanning industry.

And Dr. Charles Chestnut III, of the University of Washington in Seattle, acknowledges in an editorial accompanying the journal article that having more women considered candidates for osteoporosis treatment "would be to the sponsor's advantage."

But Chestnut says in an interview that he's "pretty comfortable" that there was nothing improper about the way the data were analyzed and presented.

What's more, Chestnut says even if Merck and other companies stand to gain from the findings, women will likely gain even more by increased awareness of osteoporosis. "On balance, the good far exceeds the small gain" that the pharmaceutical industry might reap, he says.

Dr. Phil Fontanarosa, the journal's executive editor, defends the article. "This paper, as with all scientific papers that we have, went through rigorous editorial evaluation and peer review" and was published on the basis of its "scientific merit," Fontanarosa says.

At the foot of the journal article is a lengthy disclosure that the editors felt was sufficient to explain the possible conflicts, Fontanarosa says. "While there may be interest in various organizations in these results for various reasons, what we have published there should lay out" those relationships.

Officials at Merck, based in Whitehouse Station, N.J., were not available for comment.

What To Do

Although some of the risk of osteoporosis is inherited, there are things you can do to build up your bones and reduce the chances of fractures. Most important of these is getting adequate calcium, especially early in life.

However, the U.S. Department of Agriculture says only 13.5 percent of girls and 36.3 percent of boys get enough of the mineral during adolescence.

"Osteoporosis is a pediatric disease with geriatric consequences," says Dr. Duane Alexander, director of the National Institute of Child Health and Human Development, in a statement announcing the agency's "Milk Matters" calcium-education campaign.

"Preventing this and other bone diseases begins in childhood. With low calcium intake levels during these important bone-growth periods, today's children and teens are certain to face a serious public health problem in the future," Alexander says.

For a definition of osteoporosis, check EndocrineWeb.

For more on how to maintain a healthy skeleton, try the National Osteoporosis Foundation or Milk Matters, from the National Institute of Child Health and Human Development.

SOURCES: Interviews with Ethel S. Siris, M.D., professor of clinical medicine, Columbia College of Physicians and Surgeons, New York City; Charles H. Chestnut III, M.D., director, Osteoporosis Research Group, University of Washington, Seattle; Phil Fontanarosa, M.D., executive editor, Journal of the American Medical Association; statement from Duane Alexander, M.D., director, National Institute of Child Health and Human Development, Bethesda, Md.; Dec. 12, 2001, Journal of the American Medical Association
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