Source: DGNews  |  Posted 5 years ago

By Crystal Phend

CHICAGO, I.L. -- May 4, 2006 -- Low bone mineral density (BMD) in postmenopausal women may be associated with cognitive impairment, and estrogen metabolism may be the cause, researchers said here at the American Geriatrics Society 2006 Annual Scientific Meeting (AGS).

This association may also help explain the relationship between Alzheimer's disease and osteoporosis, said presenting author Nicola Napoli, MD, research fellow, Washington University, St. Louis, Missouri, in a presentation on May 4[^]th[].

The dominant factor in postmenopausal bone loss is known to be estrogen metabolism, but the relationship of cognitive performance is less clear.

"Although data from laboratory studies support the important role of estrogen on brain function," he said, "epidemiologic and population studies have yielded conflicting results."

Dr. Napoli and colleagues studied 62 women and 26 men who had previously participated in a genetic study to determine whether they had a polymorphism for increased metabolic breakdown of estrogen (CYP1A1 C4887A).

The participants received follow-up bone mineral testing using dual energy x-ray absorptiometry (DEXA) scans and a battery of cognitive function tests, including the modified Mini Mental State Examination (MMSE), a word fluency test, and Trail Making Tests A and B.

Cognitive function as measured by MMSE was significantly associated with BMD of the total femur in all subjects. Word fluency was also significantly correlated with BMD of the total femur, intertrochanter, and spine in all participants.

In women, fluency correlated positively with BMD at all skeletal sites measured, but Trail Making Tests A and B did not correlate with BMD.

In men, none of the cognitive function tests were correlated with BMD.

Lower BMD and worse cognitive function as measured by Trail Making Test A scores were associated with higher sex hormone binding globulin levels and lower levels of free estradiol.

Women with the polymorphism that reduces available estrogen took significantly longer to finish the Trail Making Test A than those without it (about 60 seconds vs about 40 seconds). Those with the polymorphism also tended to take longer on the Trail Making Test B and to have lower word fluency test scores.

Since both osteoporosis and Alzheimer's disease increase in incidence after menopause, estrogen deficiency has been suggested as a common underlying mechanism, which Dr. Napoli said the results of this study may support.

[Presentation title: Low BMD Is Predictive of Poor Cognitive Performance in Postmenopausal Women. Abstract A61]