Carotid Intima-Media Thickness and Markers of Brain Health in a Biracial Middle-Aged Cohort: CARDIA Brain MRI Sub-study

Background: We investigated whether carotid intima-media thickness is associated with measures of cerebral blood flow (CBF), white matter hyperintensities, and brain volume in a biracial cohort of middle-aged individuals. Methods: We performed a cross-sectional cohort study based on data from a multicenter, population-based study Coronary Artery Risk Development in Young Adults. Using linear and logistic regression, we estimated the association of the composite intima-media thickness measured in three segments of carotid arteries (common carotid artery, carotid artery bulb, and internal carotid artery) with volume (cm(3)) and CBF (mL/100 g/min) in the total brain and gray matter as well as volume of white matter hyperintensities (cm(3)). Results: In the analysis, 461 participants (54% women, 34% African Americans) were included. Greater intima-media thickness was associated with lower CBF in gray matter (beta=-1.36; p = .04) and total brain (beta=-1.26; p = .04), adjusting for age, sex, race, education, and total brain volume. The associations became statistically nonsignificant after further controlling for cardiovascular risk factors. Intima-media thickness was not associated with volumes of total brain, gray matter, and white matter hyperintensities. Conclusions: This study suggests that lower CBF in middle age is associated with markers of atherosclerosis in the carotid arteries. This association may reflect early long-term exposure to traditional cardiovascular risk factors. Early intervention on atherosclerotic risk factors may modulate the trajectory of CBF as people age and develop brain pathology.