They may not seem to share much in common, but similar mechanisms could be driving the two conditions.
In recent years, researchers have documented an intriguing connection between heart disease risk factors and cognitive decline; those with poorer circulation who were at higher risk of developing heart disease also seemed to show more signs of dementia and cognitive problems than those with healthier hearts. In the latest study on the association, published in the journal, Neurology, scientists from the French National Institute of Health and Medical Research found that tests for heart disease were better at predicting memory problems than those that measured dementia.
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At the beginning of the study, the researchers calculated the heart disease and dementia risk scores for 7,830 men and women around age 55 using three different tests. They used two measures of heart disease and stroke risk, which factored in age, blood pressure, high blood pressure treatment, levels of HDL, LDL and total cholesterol, smoking, diabetes and the presence of an irregular heart beat.
The dementia risk score, called the Cardiovascular Risk Factors, Aging and Dementia (CAIDE) included age, education, blood pressure, BMI, total cholesterol, how much exercise the participants received and whether they had a gene associated with dementia. Over 10 years, the scientists tested the volunteers three times on cognitive abilities that assessed their reasoning, memory, verbal fluency, vocabulary and global cognition.
At the end, all three of the risk scores — for heart disease, stroke and dementia — successfully predicted decline in cognitive tests over 10 years. Those with higher heart disease risk showed a 14 point drop in cognitive abilities in all areas except for memory when compared to those with lower risk for heart disease. But the dementia risk test did not foretell declines in memory or other cognitive functions. That suggests that the heart disease and stroke tests, which measure blood circulation and brain aging, may be better markers of cognitive function than the dementia test, which takes into account education and possible brain reserves that could compensate for declining brain function.
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“The CAIDE dementia and Framingham risk scores predict cognitive decline in late middle age, but the Framingham risk scores may have an advantage over the dementia risk score for use in primary prevention for assessing risk of cognitive decline and targeting of modifiable risk factors,” the authors write.
Proper circulation may play an important role in maintaining brain function beginning in middle age, they say, since the blood provides nutrients and other components that nerve cells need to thrive. So some of the factors that may put the heart at risk, including high cholesterol, the build up of plaque in the vessels, and high blood pressure, could also adversely affect cognitive functions. For patients, that means that maintaining a healthy heart could also preserve brain function into old age, and that interventions to treat heart disease might help to improve memory and other cognitive skills. And if risk for heart disease is detected early, then it’s possible that cognitive decline can be identified at its beginning stages and treated as well.