CHICAGO, Dec 11, 2001 (United Press International via COMTEX) -- Researchers say almost half of the postmenopausal women enrolled in a large national study had undetected low bone mineral density, including 7 percent with osteoporosis.

The research, published in the Dec. 12 issue of the Journal of the American Medical Association, finds that these women are at increased risk of having a bone fracture within one year.

"When a woman reaches menopause and loses estrogen, she can lose a good deal of bone density faster than it can be replaced and as a result have fragile bones and fractures," Dr. Ethel S. Siris, of Columbia University College of Physicians and Surgeons in New York City, told United Press International. "The study found that nearly 40 percent of postmenopausal women in the United States have undetected low bone mass, placing them at serious risk for osteoporotic fracture as they age."

Siris and Dr. Charles H. Chesnut III, professor of radiology and medicine at the University of Washington in Seattle, reported their findings from the National Osteoporosis Risk Assessment. NORA is the largest study of osteoporosis conducted to date in the United States, recruiting some 200,160 postmenopausal women ages 50 and older with no previous diagnosis of osteoporosis The women came from 4,236 primary care physicians in 34 states.

Given the economic and social costs of osteoporotic fractures -- women often experience complications following a hip or spine fracture that results in death -- strategies to identify and manage osteoporosis in the primary-care setting need to be established and implemented, according to Siris.

"We advocate that women be screened for bone density by age 60 but there is a lack of awareness on the part of both physicians and patients to do the scans," Dr. Felcia Cosman, assistant professor of medicine at Columbia University, said. "The test uses a very minimal amount of radiation so patients should ask for the test each year because there are now four drugs that can reduce the amount of bone loss."

Cosman said physicians and patients may not be motivated to screen for bone density loss because up to five years ago there was no real treatment except estrogen replacement, but since then four drugs have been produced that reduce the amount of postmenopausal rapid bone loss.

The NORA study was funded by pharmaceutical company Merck, which manufactures Fosamax, one of the drugs used to reduce the amount of bone loss.

"I don't know why there's such a low level of bone density screening, but in medicine like in everything else you have to hammer things into people, physicians as well," said Dr. Robert P. Heaney, professor of medicine at the Osteoporosis Research Center at Creighton University in Omaha, Neb.

Osteoporosis is thinning of the bones with a reduction in bone mass due to depletion of calcium and bone protein. People with osteoporosis are more likely to experience fractures that are often slow to heal. A condition known as osteopenia represents low bone mass, but not to the severe extent of osteoporosis. Both osteoporosis and osteopenia can be diagnosed by bone density scans.

"Among the 163,979 participants with follow-up study information, osteoporosis was associated with a fracture rate approximately four times that of normal bone mineral density and osteopenia was associated with a 1.8-fold higher rate," the report said.

Siris said dual energy X-ray absorptiometry of the hip and spine currently is the "gold standard" for measurement of BMD. It a large machine costing up to $100,000 and often not found in doctor's offices because of the size and cost. The machine usually is found in radiology centers and costs the patient $200 to $400 per test.

However, smaller portable machines that cost about $20,000 -- about $30 to $50 per test for patients -- also can identify people at risk, Siris said.

Although 90 percent of the participants were white, more than 18,000 minority women were included and the study found 32 percent of black women had osteopenia and 4 percent had osteoporosis.

However, black women are not as much at risk for low bone density because they have different bone shape and have 6 percent to 10 percent more bone mass than white women, according to Heaney.

"Men do not experience the same amount of bone density loss because they have heavier bones to begin with, they consume more calcium during their lifetime and they don't lose estrogen as women do at menopause," Heaney said. "However, slighter men and men living longer lives can also experience osteoporosis."

Age, personal or family history of fracture, Asian or Hispanic heritage, smoking and cortisone use were associated with significantly increased likelihood of osteoporosis, according to Siris. Higher body mass index, African-American heritage, estrogen or diuretic use, exercise and alcohol consumption significantly decreased the likelihood of loss of bone density.

"The large survey size of more than 200,000 women makes the NORA findings a critical wake-up call to the nearly 40 million American women in this country in midlife to make healthy bone behaviors a part of their daily routine," said Sandra C. Raymond, executive director of the National Osteoporosis Foundation in Washington. "NOF has consistently advised women to consume enough calcium and vitamin D in their daily diets, engage in weight-bearing exercise, avoid smoking and, when appropriate, take daily or weekly medications and get regular bone density tests."

　　From Healthy.net