Older Women with Healthy Bones May Need Osteoporosis Screening Less Often
Women, 67 years and older, with good bones may not need another osteoporosis screening for 10 years rather than every 2 years.
The current recommendations were set in 2002 by the U.S. Preventive Services Task Force. The recommendations state women ages 65 and older should be routinely screened for osteoporosis and suggested a 2-year screening interval.
Margaret L. Gourlay, MD, MPH of the University of North Carolina at Chapel Hill School of Medicine and colleagues presented the findings of a new study Sunday at the annual meeting of the American Society for Bone Mineral Research in Toronto which suggest women aged 67 years and older with normal bone mineral density scores may not need screening again for 10 years.
Screening of bone density is done using a densitometry or DXA scan. It is done to determine the presence or risk of osteoporosis. A bone density test uses X-rays to measure how many grams of calcium and other bone minerals are packed into a segment of bone. A bone density test is a fairly accurate predictor of your risk of fracture.
The length the screening interval has remained controversial and undecided, with no definitive scientific evidence to provide guidance. Gourlay and colleagues are attempting to find solid scientific evidence on which to base clinical guidelines.
"If a woman's bone density at age 67 is very good, then she doesn't need to be re-screened in two years or three years, because we're not likely to see much change," Gourlay said. "Our study found it would take about 16 years for 10 percent of women in the highest bone density ranges to develop osteoporosis."
Gourlay and study co-authors analyzed data from 5,035 women aged 67 years and older that were collected as part of the longest-running osteoporosis study in the U.S., the Study of Osteoporotic Fractures. These women were enrolled in the study from 1986 to 1988 when they were 65 years or older, and had bone mineral density (BMD) testing starting about two years later. All of the study participants had bone mineral density testing at least twice during the study period; some were tested up to five times over a period of 15 years.
For the analysis, women were categorized by BMD T-scores and women with osteoporosis (those with a T-score of -2.5 or lower) were excluded from the study.
The remaining women were placed in three groups according to their baseline BMD T-scores at the hip. The high risk group was women with T-scores ranging from -2.49 to -2.00, while the moderate risk group had T-scores from -1.99 to -1.50. The low risk group included two T-score ranges: T-scores -1.49 to -1.01, and normal BMD (those with T-scores of -1.00 or higher).
The researchers calculated estimated times for 10% of the women in each T-score group to transition to osteoporosis. For the high risk group, the estimated time was 1.26 years, while it was about 5 years for the moderate risk group and 16 years for the low risk group.
The study concluded that baseline BMD is the most important factor for doctors to consider in determining how often a patient should be screened. It also suggests that older postmenopausal women with a T-score of -2.0 and below will transition to osteoporosis more rapidly, while women with T-scores higher than -2.0 may not need screening again for 5 to 10 years, Gourlay said. "Doctors may adjust these time intervals for a number of reasons, but our results offer an evidence-based starting point for this clinical decision."