Weili Xu (Department of Epidemiology and Biostatistics, School of Public Health, Tianjin Medical University, Tianjin, China) and colleagues report in the Journal of the American College of Cardiology that people with a higher risk of developing cardiovascular disease have increased cognitive decline, including an increase in typical markers of Alzheimer’s disease. This suggests that monitoring and controlling for heart disease may be key to maintaining and improving cognitive health later in life.
Xu et al sought to compare Framingham General Cardiovascular Risk Scores (FGCRS), which incorporate demographic information with traditional cardiovascular risk factors to assess future risk, to an individual’s long-term decline in global and domain specific cognitive function.
They followed 1,588 dementia-free participants from the Rush Memory and Aging Project for 21 years. The average age was 79.5 years. Their FGCRS was assessed at baseline and categorised into lowest, middle and highest groups according to heart disease risk. Each year 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) was assessed using 19 tests to derive a composite score.
At the end of the study period, Xu et al found that having a higher cardiovascular risk burden was associated with faster decline in episodic memory, working memory and perceptual speed. They also looked at MRI data for a subset of patients and found that higher FGCRS was associated with smaller volumes of hippocampus, cortical grey matter and total brain. Decreases in hippocampal and grey matter are typical markers of Alzheimer’s dementia-related neurodegeneration. MRIs also showed a greater volume of white matter hyperintensities, which are white spots on the brain that cause an area to decline in functionality.
Episodic memory and working memory were related to hippocampal volume, but perceptual speed was associated with white matter hyperintensities in the study, showing that results from the memory tests and the MRI were complementary.
Xu says: “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. Given the progressive increase in the number of dementia cases worldwide, our findings have both clinical and public health relevance.”