Stiffness of the aorta, the largest artery in the body, may be a significant risk factor for developing dementia, according to new research from the University of Pittsburgh.
The study, published in the Journal of Alzheimer’s Disease, draws on data collected from hundreds of elderly adults for more than 15 years.
“As the large arteries get stiffer, their ability to cushion the pumping of blood from the heart is diminished, and that transmits increased pulsing force to the brain, which contributes to silent brain damage that increases dementia risk,” said senior author Rachel Mackey, Ph.D., M.P.H., assistant professor of epidemiology, University of Pittsburgh Graduate School of Public Health.
“Although arterial stiffness is associated with markers of silent, or subclinical, brain damage and cognitive decline, until now, it was not clear that arterial stiffness was associated with the risk of dementia.”
The good news is that arterial stiffness can often be reduced by antihypertensive drugs and lifestyle interventions, and therefore at-risk patients may have the power to prevent or delay the onset of dementia.
For the study, the authors investigated the link between arterial stiffness and dementia in 356 older adults, with an average age of 78, who were part of the Cardiovascular Health Study Cognition Study (CHS-CS), a long-term study to identify dementia risk factors. This study is unique because it had 15 years of almost complete follow-up of cognitive status and outcomes for older participants.
All study subjects were dementia-free when the research began in 1998. During this time period, participants were tested for aortic stiffness with pulse wave velocity (PWV), a noninvasive measure of the speed at which the blood pressure pulse travels through the arteries. Study participants also had MRI scans of their brains to measure signs of subclinical brain disease.
The findings show that participants with high PWV readings were 60 percent more likely to develop dementia during the following 15 years compared to those with lower PWV values.
Although arterial stiffness is associated with subclinical brain disease and risk factors for cardiovascular disease, these confounding variables did not explain the results.
“It’s very surprising that adjusting for subclinical brain disease markers didn’t reduce the association between arterial stiffness and dementia at all,” said Chendi Cui, M.S., first author on the paper and doctoral student at Pitt Public Health.
“We expect that arterial stiffness increases the risk of dementia partly by increasing subclinical brain damage. However, in these older adults, arterial stiffness and subclinical brain damage markers appeared to be independently related to dementia risk.”
These findings are promising as there hasn’t been much evidence showing it is possible to reverse subclinical brain disease; however, arterial stiffening can be reduced by antihypertensive medication and perhaps also healthy lifestyle changes such as exercise.
For example, the study shows that exercise at an average age of 73 is tied to lower PWV five years later. So, if elderly patients get flagged with a high PWV reading or marker of subclinical brain damage, they may still have the chance to ward off dementia.
“What’s exciting to think about is that the strong association of arterial stiffness to dementia in old age suggests that even at age 70 or 80, we might still be able to delay or prevent the onset of dementia,” Mackey said.