October 9, 2015
Scientists have uncovered more evidence that what’s bad for the heart is bad for the brain. Researchers at the University of Southern California report that many of the risk factors for heart disease, such as drinking, smoking, obesity and diabetes, are tied to shrinkage of brain regions critical for memory and thinking skills.
Scientists already knew that diseases that damage blood vessels, including those in the brain, can lead to problems with memory and thinking skills and increase the risk for Alzheimer’s disease and other forms of dementia. And other studies have shown that having high blood pressure and fat around the belly area in midlife may increase your risk of Alzheimer’s as well.
“But our findings give us a more concrete idea about the relationship between specific vascular risk factors and brain health,” said Dr. Kevin S. King, M.D., a study author and professor of radiology at the Keck School of Medicine at U.S.C. The study was published in the journal Radiology.
For the study, Dr. King and his colleagues analyzed data from 1,629 men and women enrolled in the Dallas Heart Study, a large and ongoing study of risk factors for heart disease. About half of the participants were under 50.
They evaluated the participants’ risk factors for heart disease at the start of the study. Seven years later, the participants underwent brain scans and tests of memory to assess whether they were developing early signs of Alzheimer’s disease. They also examined three areas of the brain critical for memory and thinking skills: the hippocampus, the precuneus and the posterior cingulate cortex. Loss of gray matter in those areas may predict the impending onset of Alzheimer’s disease.
The researchers found that various risk factors for heart disease, namely alcohol consumption, smoking, diabetes, and obesity, were linked to shrinkage in areas of the brain tied to Alzheimer’s. They also found that low scores on tests of memory and thinking skills correlated with lower brain volumes in each area.
Alcohol use and diabetes were associated with smaller total brain volume, a known risk factor for Alzheimer’s disease. Smoking and obesity were linked with reduced volumes of the posterior cingulate cortex, an area of the brain connected with memory as well as emotional and social behavior.
Shrinkage of some brain areas was more prominent after age 50, and depletion in other areas was more common in younger individuals. Dr. King believes that additional studies will provide the ability to better identify the impact of specific cardiovascular risk factors on the brain.
He also notes that the tests that were used in this study are readily available at medical centers across the country. One day, such tests may routinely provide useful information about who is at risk for Alzheimer’s when the tests are performed at a relatively young age, when the disease might be prevented.
“We currently do not have effective treatments for Alzheimer’s disease, so the focus is on prevention,” he said. “In the future, we may be able to provide patients with useful and actionable information about the impact different risk factors may be having on their brain health during routine clinical imaging.”
Source: Rajiv N. Srinivasa, M.D., Heidi C. Rossetti, Ph.D., Mohit K. Gupta, M.D., et al: “Cardiovascular Risk Factors Associated with Smaller Brain Volumes in Regions Identified as Early Predictors of Cognitive Decline.” Radiology July 2015.