Coker, Laura H.

Background and Purpose— The relationships between cerebrovascular lesions visible on imaging and cognition are complex. We explored the possibility that the cerebral cortical volume mediated these relationships. Methods— Total of 1906 nondemented participants (59% women; 25% African–American; mean age, 76.6 years) in the Atherosclerosis Risk in Communities (ARIC) study underwent cognitive assessments, risk factor assessments, and quantitative MRI for white matter hyperintensities (WMH) and infarcts. The Freesurfer imaging analysis pipeline was used to determine regional cerebral volumes. We examined the associations of cognitive domain outcomes with cerebral volumes (hippocampus and separate groups of posterior and frontal cortical regions of interest) and cerebrovascular imaging features (presence of large or small cortical/subcortical infarcts and WMH volume). We performed mediation pathway analyses to assess the hypothesis that hippocampal and cortical volumes mediated the associations between cerebrovascular imaging features and cognition. Results— In unmediated analyses, WMH and infarcts were both associated with worse psychomotor speed/executive function. In mediation analyses, WMH and infarct associations on psychomotor speed/executive function were significantly attenuated, but not abolished, by the inclusion of the posterior cortical regions of interest volume in the models, and the infarcts on psychomotor speed/executive function association were attenuated, but not abolished, by inclusion of the frontal cortical regions of interest volume. Conclusions— Both WMH and infarcts were associated with cortical volume, and both lesions were also associated with cognitive performance, implying shared pathophysiological mechanisms. Although cross-sectional, our findings suggest that WMH and infarcts could be proxies for clinically covert processes that directly damage cortical regions. Microinfarcts are 1 candidate for such a clinically covert process.

Background and purposeTo evaluate the association between systolic, diastolic and pulse pressure, and increase in ventricular size (VS). Observations in laboratory animals suggest intraventricular pulse pressure (systolic–diastolic) may play a role in ventricular enlargement.MethodsInitial magnetic resonance (MR) scans and vascular risk factors evaluation were performed in 1812 Atherosclerosis Risk in Communities participants in 1994–1995. In 2004–2006, 1130 participants underwent repeat MR. VS was rated using a validated nine‐point scale. Multiple logistic regression analysis assessed association between blood pressure measures and pulse pressure, and the change between the MR scans of VS controlling for age, sex and race.ResultsAt baseline 1112 participants (385 black women, 200 black men, 304 white women and 223 white men) had a mean age of 61.7 ± 4.3 years. In adjusted models pulse pressure at baseline was associated with an increase in VS [odds ratio (OR) 1.19, 95% confidence interval (CI) 1.01–1.40], as was systolic pressure (OR 1.28, 95% CI 1.03–1.58).ConclusionsSystolic pressure and pulse pressure are associated with future development of increased VS. The findings are consistent with the animal literature that increased pulse pressure predisposes to risk of future increased VS. High pulse pressure might play a role in the pathogenesis of normal pressure hydrocephalus.

BackgroundStrokes, vascular risk factors, and apolipoprotein E (APOE) genotype are associated with cognitive decline in the elderly, but definitive evidence that these affect cognition as early as middle age is limited.ObjectiveWe describe the relationships of APOE genotype, stroke, and vascular risk factors with cognitive change over a 14‐year follow‐up in the Atherosclerosis Risk in Communities (ARIC) Study cohort recruited while in middle age.MethodsParticipants included a subset of the ARIC Study who underwent assessments of cognitive function and vascular risk factors. Four cognitive assessments were performed between 1990–1992 and 2004–2006. Cognitive assessments included the Delayed Word Recall (DWR) Test, the Digit Symbol Substitution (DSS) Test, and the Word Fluency (WF) Test. Vascular risk factors were assessed during the baseline visit in 1990–1992. Incident stroke was recorded over the 14 years of follow‐up.ResultsThere were 1130 participants (mean age, 59 ± 4.3 [SD] years; 62% women; 52% African‐American) with longitudinal data. In multivariate, random‐effects linear models adjusted for age, education, gender, and race, the risk factors diabetes and APOE ɛ4 genotype were independently associated with a decline in performance on the DSS test (both P < .005), whereas hypertension and stroke were not. For DWR, stroke and APOE ɛ4 genotype were independent predictors of decline (both P < .001). For the WF test, metabolic syndrome, hypertension, and stroke were independently associated with decline (all P < .005). No evidence of differential effects of risk factors on cognitive decline by race, gender, or interactions between risk factors was found.ConclusionsThe vascular risk factors diabetes and hypertension, a history of stroke itself, and APOE ɛ4 genotype independently contribute to cognitive decline in late middle age and early elderly years.