According to a recent study, people with a higher risk of cardiovascular disease (CVD) demonstrate an increase in cognitive decline, including a rise in the typical markers of Alzheimer disease. Furthermore, results of the research suggest that monitoring and controlling for CVD may be critical to maintaining and improving cognitive health later in life.1

Currently, there exists no effective method for treating dementia, yet 50 million people were affected by it in 2017, with the WHO predicting that this number will increase to 82 million people by 2030. For these reasons, the identification of modifiable risk factors that could delay or prevent dementia onset has been a critical field of research in recent years, according to the study.1

In prior studies, researchers assessed the role of smaller volumes of specific brain regions, such as white matter, gray matter, and hippocampus in relation to CVD, but the results remained inconsistent.1

Due to these inconsistencies, the authors of the current study sought to compare Framingham General Cardiovascular Risk Scores (FGCRS), which incorporate demographic information with traditional CVD risk factors in order to assess future risk, to the long-term decline in global and domain-specific cognitive function in patients.1

The study observed 1588 dementia-free participants over a period of 21 years, with an average age of 79.5 years, from the Rush Memory and Aging Project. Their FGCRS were assessed at baseline before being categorized into lowest, middle, and highest CVD risk groups.1

Throughout the 21-year period, participants' episodic memory (memory of everyday events), semantic memory (long-term memory), working memory (short-term memory), visuospatial ability (capacity to identify visual and spatial relationships among objects), and perceptual speed (ability to accurately and completely compare letters, numbers, objects, pictures, or patterns) were assessed each year. The researchers then used 19 tests to derive a composite score for these areas.1

The results of the data demonstrated that a higher CVD risk burden was associated with an increased rate of decline in episodic memory, working memory, and perceptual speed.1

MRI data for a subset of patients also showed that higher FGCRS were associated with smaller volumes of hippocampus, cortical gray matter, and total brain. This is relevant because a decrease in hippocampal and gray matter is typically a marker of Alzheimer dementia-related neurodegeneration. The MRIs of these participants also demonstrated a higher volume of white matter hyperintensities, which are white spots on the brain that cause an area to decline in functionality.1

Since episodic memory and working memory are associated with hippocampal volume and perceptual speed is associated with white matter hyperintensities, the researchers were able to ascertain that the results of both the memory tests and the MRI were complimentary.1

"In the absence of effective treatments for dementia, we need to monitor and control cardiovascular risk burden as a way to maintain patient's cognitive health as they age," said Weili Xu, PhD, Department of Epidemiology and Biostatistics, School of Public Health, Tianjin Medical University, Tianjin, China, in a press release. "Given the progressive increase in the number of dementia cases worldwide, our findings have both clinical and public health relevance."2

The researchers noted that study limitations did exist due to the participants being generally well-educated volunteers who performed relatively well on cognitive tests. The researchers explained that for this reason, the observed association between CVD risk and cognitive decline may be an underestimation of the association among the general population.1

REFERENCES
  1. Song R, Xu H, Dintica CS, et al. Associations Between Cardiovascular Risk, Structural Brain Changes, and Cognitive Decline. Journal of the American College of Cardiology. 2020;75(20):2525. doi: 10.1016/j.jacc.2020.03.053.
  2. Maintaining heart health may protect against cognitive decline [news release]. American College of Cardiology; May 18, 2020. sciencedaily.com/releases/2020/05/200518144842.htm. Accessed June 8, 2020.