Cardiovascular illness linked to poor brain health in middle age: Research

"Cardiovascular diseases such as heart disease and stroke have been associated with an increased risk for cognitive impairment and dementia in older adults, but less is known about how having these diseases before age 60 impacts cognition and brain health over the course of life," said study author Xiaqing Jiang, PhD, of the University of California, San Francisco. "Our study found that cardiovascular events earlier in life are associated with worse cognition, accelerated cognitive decline and poor brain health in middle age." (Also read: Pneumonia triggers heart attack. Here are its symptoms and prevention tips )

3,146 participants were examined for the study. The study's participants, who ranged in age from 18 to 30 at the outset, were monitored for up to 30 years. They were on average 55 years old at the conclusion of the study.

Early cardiovascular disease was defined as having coronary heart disease, stroke, congestive heart failure, carotid artery disease, or peripheral arterial disease before the age of 60 and affected 147 participants, or 5 per cent of the total. A first cardiovascular incident often occurred around age 48.

After being followed for three decades, participants were given five cognitive tests. The tests measured thinking and memory skills including global cognition, processing speed, executive function, delayed verbal memory and verbal fluency.

Researchers found that people with early cardiovascular disease performed worse than those without on five out of five tests. In a test of recalling a list of words after 10 minutes where scores ranged from zero to 15, those with early cardiovascular disease compared to those without had an average score of 6.4 versus an average score of 8.5. In a test assessing global cognition where scores ranged from zero to 30, those with early cardiovascular disease had an average score of 21.4 compared to others without cardiovascular disease who had an average score of 23.9. A score of 26 or higher is considered typical, while people with mild cognitive impairment have an average score of 22.

Of the total participants, 656 people had brain scans to look at white matter hyperintensities and white matter integrity. White matter hyperintensities typically indicate vascular injury to the brain's white matter. After adjusting for cardiovascular risk factors such as diabetes and high blood pressure, researchers found that early cardiovascular disease was associated with more white matter hyperintensities in the brain as well as higher white matter mean diffusivity, which indicates a decrease in brain tissue integrity.

For participants who had two sets of cognitive tests 25 and 30 years into the study, researchers found the early cardiovascular disease was associated with a three times greater likelihood of accelerated cognitive decline over five years, with 13 per cent of people with early cardiovascular disease experiencing accelerated cognitive decline compared to 5 per cent people who did not have the disease.

"Our research suggests that a person's 20s and 30s are a crucial time to begin protecting brain health through cardiovascular disease prevention and intervention," Jiang said. "Preventing these diseases may delay the onset of cognitive decline and promote a healthier brain throughout life."

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