New research may go a long way
towards settling an old feud between the World Health
Organization (WHO) and the US National Osteoporosis Foundation
(NOF). It's old news that one of the consequences of osteopenia
is the tendency for fragile bones to fracture under stress
that usually leaves non-osteopenic bones unscathed. Both
WHO and NOF recognize this risk. They've separately devised
a scoring system (T score) that relates a patient's bone
mineral density (BMD) to that of a model 30-year-old whose
bones are in tip-top shape. But, the quantitative devil
is in the details. It turns out that a T score between
-1.0 (a good score) and -2.5 (a bad score) is an imprecise
grey zone. In that zone, WHO and NOF disagree on what
score should jumpstart risk-reducing treatments, like
a diet change or prescription drug use.
Fortunately a study in the May
24 issue of the Archives of Internal Medicine
goes a long way to clearing the muddy waters of the
-1.0 to -2.5 grey zone.
The investigative team headed by
Dr Paul Miller, of the Colorado Center for Bone Research
in Lakewood, analyzed data from over 57,000 postmenopausal
osteopenic women who had bone mineral density T scores
in the range of -1.0 to -2.5. The women were followed
for one year and those who were unfortunate enough to
sustain a fracture served as fertile research fodder.
Thirty two risk factors for fracture were used in a
number crunching exercise to come up with a predictive
tool.
Of the 57,421 women, 1,130 had
a fracture during the year-long study. Using the mathematical
formula they'd developed, the researchers found that
55% of these 1,130 women were at increased risk of another
fracture. The factors that made this unwanted repeat
more likely were the occurrence of the previous fracture,
a T score of -1.8 or less at a site like the heel or
forearm, the self-perception of poor health and difficulty
in movement.
Just how good was this tool at
predicting fractures? Seventy four percent of the women
who were predicted to be at risk for a second fracture,
actually did sustain one. So, the classification tool
"accurately identified postmenopausal women with
peripheral T scores ... who are at increased risk of
fracture within 12 months," conclude the authors.
"It can be used in clinical practice to guide assessment
and treatment decisions."
This is welcome news. Not least
because, as Dr Daniel Mazanec of the Cleveland Clinic
Foundation writes in an accompanying editorial, "Osteoporosis
clearly qualifies for screening as a societal health
problem of enormous and increasing magnitude."
Clarifying risk factors, as Dr Miller's study has done,
should simplify predicting the likelihood for that next
fracture in osteopenic women.
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