Carotid Artery Atherosclerosis and Cognitive Decline: An Ultrasound-Based Studies of Southall and Brent Revisited (SABRE) and the National Survey of Health and Development

Abstract

This thesis explores the relationship between carotid artery atherosclerosis and cognitive function across different ethnic groups and age cohorts, using a combina-tion of systematic reviews, meta-analyses, and cohort studies. Introduction Carotid artery atherosclerosis is a significant risk factor for cognitive decline, yet the extent and nature of this relationship remain unclear. This research aims to elucidate these connections, considering diverse ethnicities and age groups. Hypothesis The hypothesis is that carotid artery atherosclerosis is associated with cognitive decline and that these associations vary across ethnic groups and age cohorts. Methodology A systematic Review and Meta-Analysis was conducted using elec-tronic databases to identify studies linking carotid atherosclerosis with cognitive function assessed by the Mini-Mental State Examination (MMSE). Data extraction and statistical analyses were performed to assess the strength of these associa-tions. The SABRE study involved participants from the Southall and Brent Revisited study, examining carotid atherosclerosis using ultrasound and assessing cognitive function and brain health through standardized tests. Blood and urine samples were analysed for cardiovascular risk factors. Generalized linear models were used to evaluate associations. Data from the MRC National Survey of Health and Development (NSHD) was used to assess carotid intima-media thickness and plaque via ultrasound in relation to cognitive function at multiple life stages. Regression models analysed the relation-ships, adjusting for confounders. Results The systematic Review and Meta-Analysis found inconsistent evidence regarding the association between carotid artery atherosclerosis and cognitive function, highlighting the need for more longitudinal studies. The SABRE Study revealed significant ethnic differences in carotid plaque preva-lence, with African-Caribbean individuals showing lower rates than Europeans and South Asians. Initial associations between carotid plaque and cognitive perfor-mance weakened after adjusting for confounders, though neuroimaging indicated increased white matter lesion volume with carotid plaque. NSHD Cohort: Longitudinal data did not show strong associations between carotid atherosclerosis and cognitive decline, suggesting the influence of other factors over time. Conclusion The thesis underscores the complex relationship between carotid ar-tery atherosclerosis and cognitive function. While some associations were ob-served, they were generally weak and confounded by other factors. The findings emphasize the need for ongoing research, incorporating comprehensive assess-ments and considering social and psychological factors, to develop targeted inter-ventions and public health policies for managing cardiovascular and cognitive dis-eases. A multidisciplinary approach is essential to address the challenges of cogni-tive decline in aging populations.