Cerebrovascular and brain morphologic correlates of mild cognitive impairment in the national heart, lung, and blood institute twin study

Objective: To evaluate the relative risk (RR) of mild cognitive impairment (MCI) associated with cerebrovascular risk factors and cerebrovascular-rela ted brain changes. Design: Mild cognitive impairment was determined for the subjects of the pr ospective National Heart, Lung, and Blood Institute Twin Study. Quantitativ e measures of brain, white matter hyperintensity, cerebral infarction, apol ipoprotein E genotype, and psychometric testing were obtained. Results: Subjects with MCI were older (73.5 +/-3.0 vs 72.1 +/-2.8 years), c onsumed less alcohol (3.7 +/-5.8 vs 7.0 +/- 10.7 drinks per week), had grea ter white matter hyperintensity volumes (0.56%+/-0.82% vs 0.25%+/-0.34% of cranial volume), and had an increased prevalence of apolipoprotein E4 genot ype (31.4% vs 19.2%) than normal subjects. White matter hyperintensity and the presence of the apolipoprotein E4 genotype were associated with a signi ficantly increased risk for MCI. When all subjects were included in the ana lysis, alcohol consumption was associated with a reduced risk for MCI (RR=0 .93, P<.05). When subjects with a history of symptomatic cerebrovascular di sease were excluded from the analysis, elevated midlife diastolic blood pre ssure was associated with an increased risk for MCI (RR=1.70, P<.05). Conclusions: Elevated midlife blood pressures, and the resulting increased white matter hyperintensities, increase the risk for MCI in a group of comm unity-dwelling older men to at least the same degree as apolipoprotein E4 g enotype. Given the common occurrence of elevations in midlife blood pressur e, early and effective treatment may be warranted to prevent late-life brai n abnormalities and MCI. Moreover, since many individuals with MCI progress to clinical dementia, longitudinal evaluations of this cohort will be impo rtant.