The carotid arteries are essential for supplying blood to the brain. In a study published online in the journal Alzheimer’s & Dementia, researchers from Inserm, in collaboration with those involved in the Three Cities Study (3C), have focused on the relationships between atherosclerosis and the risk of dementia in older subjects.

Atherosclerosis is characterised by the deposition of plaque essentially composed of lipids (known as atheroma) on the walls of arteries. These plaques can be highly unstable and cause a stroke when they become detached. Previous studies have shown a link between cardiovascular risk factors and the occurrence of dementia. Atherosclerosis, which reflects lifelong exposure to these factors, can be measured noninvasively by ultrasound of the carotid arteries, making it possible to detect the presence of atheroma plaques.

In this study, researchers from the “Cardiovascular Epidemiology and Sudden Death”[1] and “Hormones and Cardiovascular Disease”[2] teams analysed data from the Three Cities (3C) French multicentre cohort. The association between carotid atherosclerosis and the occurrence of dementia after 7 years of monitoring was measured in 6,025 men and women aged from 65 to 86 years, who were initially free from dementia and non-institutionalised.

“Subjects showing carotid plaques at enrolment had a nearly 2-fold higher risk of dementia than those free of carotid atheroma,” explains Matthieu Plichart, who co-authored this work.

For the first time, the study examines the utility of measuring carotid atherosclerosis. The researchers suggest that taking carotid plaques into account might be useful in predicting the individual risk of developing these “mixed/vascular” dementias, i.e. those resulting from a combination of vascular lesions in the brain and neurodegenerative lesions. They are the second most important cause of dementia, the leading cause being Alzheimer’s disease, which is a purely neurodegenerative process.