Few question the value of bone density screening for women 65 and older, with timely repetitions of the exam determined by the initial results. The test is painless and noninvasive, and involves a level of radiation 50 times lower than that of a mammogram, Dr. Margaret L. Gourlay, research associate professor of family medicine at the University of North Carolina, told me. There is also solid evidence that treatment with a bone-preserving or bone-building drug is beneficial when a bone density test reveals a level of bone loss defined as osteoporosis in the spine or a hip.
“Bone density testing also has a place for women younger than 65,” Dr. Gourlay said. The question is, for which women and how often should it be done? The task force concluded that the need for an initial test is best determined by first examining a woman’s risk factors, a process that Dr. Gourlay said could consume half the time of a typical doctor visit.
There are three such screening tools currently available.
The most popular and most time-consuming risk assessment tool is called FRAX. It involves a list of about a dozen factors that can influence a person’s risk of osteoporosis, and estimates the chances of a major osteoporotic fracture occurring in the next 10 years. The factors include age, sex, weight, height, previous fracture, parental fracture history, smoking, alcohol consumption and the use of steroids. If the FRAX assessment deems a woman’s risk is 3 percent or higher for a hip fracture or 20 percent or higher for a fracture on the forearm, shoulder or spine, she is likely to be urged to get a bone density test if she is 40 or older.
Another somewhat simpler risk assessment is called SCORE. It calculates risk based on race, rheumatoid arthritis, fracture history, age, estrogen use and weight. And a third, called OST, involves only age and weight and may be as good or better than more complicated risk tools. In an editorial accompanying the task force report, Dr. Gourlay wrote that “multiple observational studies have demonstrated that age and weight are as strongly associated with osteoporosis and fracture outcomes as more complicated risk tools.”
Dr. Jane A. Cauley, epidemiologist at the University of Pittsburgh who also wrote an editorial about the task force report, said in an interview that, in the Women’s Health Initiative Study of women aged 50 through 64, the OST tool identified 80 percent of women who had a bone density reading in the osteoporotic range. In contrast, she said, the SCORE tool identified 74 percent of such women, but both OST and SCORE did a better job than FRAX.
So, ladies, if you are past menopause and thin, consider getting your bone density checked. The lower your weight, the less benefit weight-bearing activities like walking will have on the strength of your bones. Also, women who lose weight by dieting lose bone along with fat and may consider getting checked for bone density, Dr. Gourlay suggested.
Dr. Cauley said she was “disappointed” that the task force issued no recommendations for testing men. “Men age 70 and older who have a high probability of an osteoporotic fracture based on any one of the assessment tools should get a bone density scan,” she said. “One in five men will experience an osteoporotic fracture, and bone density screening is warranted if the risk is relatively high given that there is a good screening method and effective treatment for bone loss.”