The women who would benefit the most from a screening test for osteoporosis are the least likely to get it, a new study shows.

Forty percent of white women aged 50 and older will fracture their hip, wrist or spine due to the bone-thinning disease at some point in their lives, Dr. Joan M. Neuner of the Medical College of Wisconsin in Milwaukee and colleagues write in the Journal of the American Geriatric Society.

They note that a hip fracture can be particularly disabling, with more than half of sufferers never fully recovering. Twenty percent of women who fracture a hip will wind up in a nursing home.

The risk of osteoporosis and fracture rises as women get older, Neuner and her team add; while less than one-fifth of women aged 65 to 74 have osteoporosis, more than half of women older than 85 do.

Osteoporosis screening is important, the researchers write, because drug or hormone treatment can help restore bone strength and reduce the risk of fractures. The US Preventive Services Task Force recommends bone density testing for every woman 65 and older, and Medicare covers the test every two years for post-menopausal women.

To see how often older women were actually having the test, the researchers looked at nearly 44,000 women 66 and older, all of whom were covered by Medicare, during the first three years after the insurer began paying for bone density testing.

Between 1999 and 2001, 23 percent had the test at least once. Ironically, the older the woman, the less likely she was to be screened. Among women 66 to 70, 27 percent underwent the screening test, compared to less than 10 percent of women aged 80 to 90.

While more women may be getting screened today, the researchers write, “the differences in testing by age are troubling.”

Physicians may be unaware of new guidelines on osteoporosis screening, Neuner and her colleagues say, and they may also not understand that their older female patients often have many more years to live, making osteoporosis treatment worthwhile.

The researchers also point to a survey of women 75 and older, 80 percent of whom said they would “rather die” than be put in a nursing home after a hip fracture. “Preventive care for older patients must be performed with an understanding of their life expectancy and values,” the researchers conclude.

SOURCE; Journal of the American Geriatrics Society, March 2006.