Aging is a global phenomenon of damage accumulation throughout the body. Different people age at modestly different rates due to their lifestyle choices and environment, so correlations between different manifestations of the aging process are easy to pull from the data even if there is no obvious way in which the known causative processes are linked. Yet since many bodily systems do in fact influence one another, that aging is global doesn't necessarily mean that any given set of age-related conditions are independent - so a correlation may be meaningful.
Atherosclerosis is a condition in which fat, cholesterol and other substances collect in the arteries, forming a substance called plaque that can build up, limiting blood flow. It can occur in any artery of the body, including the carotid, which supplies blood to the brain, coronary arteries and the aorta, which carries oxygenated blood from the heart through the abdomen to the rest of body. In a study of nearly 2,000 adults, researchers found that a buildup of plaque in the body's major arteries was associated with mild cognitive impairment. "It is well established that plaque buildup in the arteries is a predictor of heart disease, but the relationship between atherosclerosis and brain health is less clear. Our findings suggest that atherosclerosis not only affects the heart but also brain health."
In the study, researchers analyzed the test results of 1,903 participants (mean age, 44 years) in the Dallas Heart Study. The participants included both men and women who had no symptoms of cardiovascular disease. Study participants completed the Montreal Cognitive Assessment (MoCA), a 30-point standardized test for detecting mild cognitive impairment, and underwent magnetic resonance imaging (MRI) of the brain to identify white matter hyperintensity (WMH) volume. Bright white spots known as high signal intensity areas on a brain MR images indicate abnormal changes within the white matter.
Study participants also underwent imaging exams to measure the buildup of plaque in the arteries in three distinct vascular areas of the body: MRI to measure wall thickness in the carotid arteries and the abdominal aorta, and computed tomography (CT) to measure coronary artery calcium, or the amount of calcified plaque in the arteries of the heart. Using the results, researchers performed a statistical regression to correlate the incidence of atherosclerosis and mild cognitive impairment.