Two-Year Bone Density Screening Unnecessary for Women with Normal T-scores

  Margaret L. Gourlay
  Margaret L. Gourlay

Since 2002, the U.S. Preventive Services Task Force has recommended that
women ages 65 years and older be routinely screened for osteoporosis and has
suggested that a 2-year screening interval might be appropriate. However, what
length the screening interval should be is a topic that remains controversial
and undecided, with no definitive scientific evidence to provide guidance.

Now a new study led by Margaret L. Gourlay, MD, MPH, of the University
of North Carolina at Chapel Hill School of Medicine, finds that women aged 67
years and older with normal bone mineral density scores may not need screening
again for 10 years.

“If a woman’s bone density at age 67 is very good, then she
doesn’t need to be re-screened in 2 years or 3 years, because we’re
not likely to see much change,” Gourlay stated in a press release.
“Our study found it would take about 16 years for 10% of women in the
highest bone density ranges to develop osteoporosis.”

Gourlay, an assistant professor in UNC’s Department of Family
Medicine, presented these results at the annual meeting of the American Society
for Bone Mineral Research (ASBMR) in Toronto.

In the study, 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 2 years later. All 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, which compare
a person’s bone mineral density to the expected bone density of a healthy
young adult (about age 30). Women with osteoporosis (those with a T-score of
-2.5 or lower) were excluded because current guidelines recommend treatment for
all women in that group. 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, while the moderate risk group had
T-scores from -1.99 to -1.5. 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 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 and below
will transition to osteoporosis more rapidly, while women with T-scores higher
than -2 may not need screening again for 5 to 10 years, Gourlay stated.
“Doctors may adjust these time intervals for a number of reasons, but our
results offer an evidence-based starting point for this clinical

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