OBJECTIVE: To test the hypothesis that bone mineral density (BMD), a marker
of cumulative estrogen exposure, is associated with cognitive function in
nondemented older women.
DESIGN: A prospective cohort study.
SETTING: Clinical centers in Baltimore, Maryland, Minneapolis, Minnesota, t
he Monongahela Valley near Pittsburgh, Pennsylvania, and Portland, Oregon.
PARTICIPANTS: We evaluated 8333 older community-dwelling women enrolled in
the Study of Osteoporotic Fractures who mere not taking estrogen replacemen
t.
MEASUREMENTS: Calcaneal and hip BMD were measured at baseline and at follow
-up (4-6 years later);vertebral fractures were ascertained radiologically a
t year 6. Women were administered a modified Mini-Mental State Exam, Trails
B, and Digit Symbol at baseline and at follow-up.
RESULTS: Compared with women with higher bone mineral density, women with l
ow baseline BMD had up to 8% worse baseline cognitive scores (P = .001) and
up to 6% worse repeat cognitive scores (P = .001), even after multivariate
adjustments. For 1 SD decrease in baseline hip BMD or calcaneal BMD, women
had a 32% (95% CI, 19-47%) or a 33% (95% CI, 20-48%) greater odds of cogni
tive deterioration (worst 10th percentile of change). Women with vertebral
fractures had lower cognitive test scores and a greater odds of cognitive d
eterioration than those without fractures (OR = 1.29; 95%CI, 1.03-1.60).
CONCLUSIONS: Women with osteoporosis, whether measured by baseline BMD, red
uctions in BMD, or vertebral fractures, have poorer cognitive function and
greater risk of cognitive deterioration. Our findings suggest a link betwee
n two of the most common conditions affecting older women. Further understa
nding of this association may be important for new treatment and prevention
directions.