Is diabetes associated with cognitive impairment and cognitive decline among older women? Study of Osteoporotic Fractures Research Group.
BACKGROUND
The long-term effect of type 2 diabetes on cognitive function is uncertain.


OBJECTIVE
To determine whether older women with diabetes have an increased risk of cognitive impairment and cognitive decline.


METHODS
Prospective cohort study.


METHODS
Four research centers in the United States (Baltimore, Md; Portland, Ore; Minneapolis, Minn; and the Monongahela Valley, Pennsylvania).


METHODS
Community-dwelling white women 65 years and older (n = 9679).


METHODS
Physician-diagnosed diabetes and other aspects of health history were assessed by interview. Three tests of cognitive function, the Digit Symbol test, the Trails B test, and a modified version of the Mini-Mental State Examination (m-MMSE), were administered at baseline and 3 to 6 years later. Change in cognitive function was defined by the change in the score for each test. Major cognitive decline was defined as the worst 10th percentile change in the score for each test.


RESULTS
Women with diabetes (n = 682 [7.0%]) had lower baseline scores than those without diabetes on all 3 tests of cognitive function (Digit Symbol and Trials B tests, P<.01; m-MMSE, P = .03) and experienced an accelerated cognitive decline as measured by the Digit Symbol test (P<.01) and m-MMSE (P = .03). Diabetes was also associated with increased odds of major cognitive decline as determined by scores on the Digit Symbol (odds ratio = 1.63; 95% confidence interval, 1.20-2.23) and Trails B (odds ratio, 1.74; 95% confidence interval, 1.27-2.39) tests when controlled for age, education, depression, stroke, visual impairment, heart disease, hypertension, physical activity, estrogen use, and smoking. Women who had diabetes for more than 15 years had a 57% to 114% greater risk of major cognitive decline than women without diabetes.


CONCLUSIONS
Diabetes is associated with lower levels of cognitive function and greater cognitive decline among older women.
Gregg
E W
EW
Division of Diabetes Translation, National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control and Prevention, Atlanta, GA 30341, USA.
Yaffe
K
K
Cauley
J A
JA
Rolka
D B
DB
Blackwell
T L
TL
Narayan
K M
KM
Cummings
S R
SR
D000368:Aged; D000369:Aged, 80 and over; D003072:Cognition Disorders / Q000453:epidemiology* / Q000209:etiology; D015331:Cohort Studies; D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D011446:Prospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D014481:United States / Q000453:epidemiology