Carotid disease at age 73 and cognitive change from age 70 to 76 years: A longitudinal cohort study

Abstract

Cognitive decline and carotid artery atheroma are common at older ages. In community-dwelling subjects, we assessed cognition at ages 70, 73 and 76 and carotid Doppler ultrasound at age 73, to determine whether carotid stenosis was related to cognitive decline. We used latent growth curve models to examine associations between four carotid measures (internal carotid artery stenosis, velocity, pulsatility and resistivity indices) and four cognitive ability domains (memory, visuospatial function, crystallised intelligence, processing speed) adjusted for cognitive ability at age 11, current age, gender and vascular risk factors. Amongst 866 participants, carotid stenosis (median 12.96%) was not associated with cognitive abilities at age 70 or cognitive decline from age 70 to 76. Increased ICA pulsatility and resistivity indices were associated with slower processing speed (both P < 0.001) and worse visuospatial function (P = 0.036, 0.031, respectively) at age 70, and declining crystallised intelligence from ages 70 to 76 (P = 0.008, 0.006, respectively). The findings suggest that vascular stiffening, rather than carotid luminal narrowing, adversely influences cognitive ageing and provides a potential target for ameliorating age-related cognitive decline.

Association between carotid atheroma and cerebral cortex structure at age 73 years

“…Linear regression modeling confirmed a negative association, as found in our previous analysis, between carotid stenosis and fluid intelligence at age 73 years (maximum carotid stenosis: standardized beta coefficient = −0.151, p = 0.001; mean carotid stenosis: standardized beta coefficient = −0.131, p = 0.003; Table ). Controlling for sex, VRFs, education years, and IQ‐11 made only minor differences to the strength of these associations.…”

“…A negative relationship following a linear monotonic model was demonstrated between carotid stenosis and cortical thickness independent of other carotid measures, VRFs, WMHs, and IQ‐11. As in our prior analysis, we confirmed a significant negative association between measures of fluid intelligence and carotid stenosis at age 73 years. Having previously excluded any mediation by WMHs, our novel finding is that this association was partly mediated by carotid stenosis–related thinning of cerebral cortex.…”

“…As in our prior analysis, we confirmed a significant negative association between measures of fluid intelligence and carotid stenosis at age 73 years. Having previously excluded any mediation by WMHs, our novel finding is that this association was partly mediated by carotid stenosis–related thinning of cerebral cortex. A further significant and novel finding is that the carotid stenosis–cortical thickness association was present in all vascular territories, including the regions supplied by the carotid and vertebrobasilar arteries, irrespective of the side of carotid stenosis, with no lateralizing difference in cortical thickness in subjects with a unilateral carotid stenosis.…”

“…Similarly, the Framingham study reported poorer performance on executive functioning tasks in individuals with carotid stenosis ≥ 50% . However, using a 6‐year longitudinal design, a study of the LBC1936 with a larger sample than the one included in the current analyses (it was not restricted to subjects with available MRI) did not report an association between changes in cognitive function and mean (average) carotid stenosis after controlling for VRFs and IQ‐11 . Conversely, parameters of carotid wall stiffness (including pulsatility and resistivity indices) were found to associate with slower processing speed and worse visuospatial function at age 70 years, in addition to declining crystallized intelligence from age 70 to 76 years .…”

“…However, using a 6‐year longitudinal design, a study of the LBC1936 with a larger sample than the one included in the current analyses (it was not restricted to subjects with available MRI) did not report an association between changes in cognitive function and mean (average) carotid stenosis after controlling for VRFs and IQ‐11 . Conversely, parameters of carotid wall stiffness (including pulsatility and resistivity indices) were found to associate with slower processing speed and worse visuospatial function at age 70 years, in addition to declining crystallized intelligence from age 70 to 76 years . In the current study, we adopted an independent strategy to analyze the cognitive data compared to Wardlaw et al We focused on examining the relationship between a PCA‐derived measure of fluid intelligence and carotid stenosis at age 73 years due to the previously documented steeper decline of fluid intelligence with age .…”