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 (cm³) and CBF (mL/100 g/min) in the total brain and gray matter as well as volume of white matter hyperintensities (cm³). 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 (β=–1.36; p = .04) and total brain (β=–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.