By Lori Solomon, Medical Tribune News Service
Osteoporosis and cognitive decline are two common conditions
affecting older women, and for the first time there is evidence
that these two conditions are linked.
Researchers led by Dr. Kristine Yaffe of the University of
California, San Francisco, reported in the October issue of the
Journal of the American Geriatric Society that women with osteoporosis
have poorer cognitive function and are at greater risk for
cognitive deterioration than women with higher bone mineral
density. Bone mineral density, a marker for osteoporosis, may prove
to be a significant indicator of multiple health conditions in
older women.
The UCSF researchers studied more than 8,000 women age 65 and
older. At the start of the study, the women with the lowest bone
mineral density scored 8 percent lower on cognitive tests than did
the women with the highest bone quality, even when differences in
age, education and general health status were taken into account.
This pattern persisted when the women were re-tested six years
later.
At follow-up, the women with low bone mineral density showed
greater decline in cognitive performance over the study period than
did the women with higher bone quality. For each
one-standard-deviation decrease in bone mineral density, the women
had 32 percent greater odds of cognitive deterioration.
The investigators concluded that women with osteoporosis --
whether measured by baseline bone density, reduction in bone
density or vertebral fracture -- have poorer cognitive function and
are at greater risk of cognitive deterioration. The researchers
believe that this relationship between bone density and cognitive
function is the result of some mediating factor, most likely, low
levels of estrogen.
``Osteoporosis is not causing cognitive decline,'' said Diane
Jacobs, assistant professor of neuropsychology at the College of
Physicians and Surgeons of Columbia University, New York. ``It is
something related to both. At the top of the list [of possible
factors] is estrogen,'' she said.
``Estrogen replacement in postmenopausal women decreases the
risk of osteoporosis and increases bone density,'' said Jacobs.
``There is mounting evidence that hormone replacement is involved
in the relative maintenance of cognitive function and decreases the
risk of dementias, such as Alzheimer's disease.''
Most of the support for the beneficial effects of estrogen
replacement therapy are from observational data, and researchers
are awaiting the results of ongoing randomized, clinical trials.
``The decision to use estrogen replacement therapy is a personal
one each woman makes with her health care provider,'' said Jacobs.
``There are certainly many benefits, but there are also some
potentially serious side effects.''
Jacobs explained that there is a new treatment option: a drug
class known as SERMs or selective estrogen receptor modulators.
These drugs are an alternative to hormone replacement therapy in
that they are tissue specific. These drugs may offer the same
benefits as estrogen on the skeletal and cardiovascular systems
while blocking estrogen's effects on the uterus and breasts.
