Stroke risk factors and loss of high cognitive function.
BACKGROUND
Modifiable stroke risk factors may contribute to age-associated declines in cognitive function. Individuals with high levels of cognitive function after midlife may have less exposure to these stroke risk factors or may be less susceptible to their effects on cognition.


METHODS
The Cardiovascular Health Study (CHS)* is a population-based, longitudinal cohort study of 5,888 people age 65 years and older. Participants (n = 4,129) who were free of dementia, stroke, or TIA at the time of baseline cranial MRI were selected for analysis. High cognitive function at baseline was defined by performance at or above midlife norms on the Modified Mini-Mental State Examination (3MS).


RESULTS
The odds of having high cognitive function at baseline decreased by quartile of stroke risk (highest vs lowest risk quartile, adjusted odds ratio [OR] 0.68; 95% CI 0.52 to 0.88; p for trend = 0.005). Stroke risk was a predictor of decline on the 3MS in those with typical levels of cognitive function at baseline, even in the absence of incident stroke or TIA (highest vs lowest risk quartile for 3MS decline, adjusted OR 2.11; 95% CI 1.42 to 3.13; p for trend < 0.001). In contrast, stroke risk was not associated with decline on the 3MS in those with high cognitive function at baseline (p = 0.03 for interaction).


CONCLUSIONS
In a cohort of older adults without stroke, TIA, or dementia, cognitive function and incident cognitive decline were associated with risk for stroke. Additional studies are needed to determine whether modification of stroke risk factors can reduce the cognitive decline that is often attributed to normal aging.
Elkins
J S
JS
University of California, San Francisco, CA 94143-0114, USA.
O'Meara
E S
ES
Longstreth
W T
WT
Carlson
M C
MC
Manolio
T A
TA
Johnston
S C
SC
D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000523:psychology; D003072:Cognition Disorders / Q000453:epidemiology*; D015331:Cohort Studies; D015897:Comorbidity; D005260:Female; D005500:Follow-Up Studies; D006613:Higher Nervous Activity; D006801:Humans; D015994:Incidence; D008297:Male; D018570:Risk Assessment; D012307:Risk Factors; D012494:Sampling Studies; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D020521:Stroke / Q000453:epidemiology*; D014481:United States / Q000453:epidemiology