In a 25-year study on 3,381 people, 18- to 30-years-old, those with blood pressure, blood sugar and cholesterol levels slightly higher than the Association’s recommended guidelines, scored lower on cognitive function tests in their 40s and 50s. Standardized scores on three cognitive tests were between 0.06 to 0.30 points less, on average, for each standard deviation increase in cumulative exposure to these risk factors, which the researchers considered significant for this age group. Standard deviation is the amount of variation from the average.
“It’s amazing that as a young adult, mildly elevated cardiovascular risks seem to matter for your brain health later in life,” said Kristine Yaffe, M.D., study author and a neuropsychiatrist, epidemiologist and professor at the University of California-San Francisco. “We’re not talking about old age issues, but lifelong issues.”
This is one of the first comprehensive long-term studies looking at key heart disease and stroke risk factors’ effects on cognitive function in this age group. Prior research showed similar effects of mid-life and late-life cardiovascular health on brainpower in late life.
The study was part of the ongoing multi-center Coronary Artery Risk Development in Young Adults Study. Participants had their blood pressure, fasting blood sugar and cholesterol levels checked every two to five years. Researchers analyzed each person’s cumulative cardiovascular health over 25 years. The American Heart Association defines ideal cardiovascular health as systolic blood pressure <120 mm Hg, diastolic blood pressure <80 mm Hg, blood sugar <100 mg/dL, and cholesterol < 200 mg/dL.
At the end of the study, participants took three tests measuring memory, thinking speed and mental flexibility.
Elevated blood pressure, blood sugar and cholesterol are three major risk factors for atherosclerosis, the slow narrowing of arteries caused by a build-up of plaque in the artery walls leading to the brain and heart.
The narrowing of the arteries leading to and in the brain is the most likely explanation for the link between cardiovascular health and cognitive function, Yaffe said.
“Our study is hopeful, because it tells us we could maybe make a dent in the risks of Alzheimer’s and other forms of dementia by emphasizing the importance of controlling risk factors among younger people,” she said.
The study was funded in part by the National Heart, Lung, and Blood Institute and Kaiser Foundation Research Institute.
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