Posted on May 17, 2016, 6 a.m.
Physiological changes in specific brain regions associated with memory may be precipitated by vascular risk factors.
A number of previous studies suggest that cardiovascular risk factors may contribute to cognitive decline. Kevin S. King, from the University of Southern California (USC; California, USA), and colleagues assessed data collected on 1,629 men and women, enrolled in the Dallas Heart Study. Participants were divided into two age groups: 805 subjects under age 50 years, and 824 ages 50 years and older. The researchers analyzed data from the initial baseline visit, which included laboratory and clinical analysis, and the follow-up visit seven years later consisting of a brain MRI and cognitive test, measuring mild cognitive impairment and preclinical Alzheimer's disease. By comparing the initial visit in which cardiovascular risk factors were identified to the MRI results and cognitive scores, the team was able to distinguish the specific risk factors of alcohol consumption, smoking, diabetes, and obesity and their relationship to smaller volumes in the three targeted regions of the brain. The results confirmed that lower cognitive test scores correlated with lower brain volumes in each area. Data analysis revealed that risk factors of alcohol use and diabetes were associated with smaller total brain volume, while smoking and obesity were linked with reduced volumes of the posterior cingulate corte – the area of the brain connected with memory retrieval as well as emotional and social behavior. In addition, lower hippocampal mass was linked to both alcohol consumption and smoking whereas alcohol use, obesity and high fasting blood glucose numbers correlated with reduced precuneus size. The findings also suggest that in patients age 50 and older, diminished hippocampal and precuneus volumes may be early risk indicators for cognitive decline, while smaller posterior cingulate volumes are better predictors in patients under age 50. The study authors submit that: “Smaller volumes in specific brain regions considered to be early markers of dementia risk were associated with specific cardiovascular disease risk factors and cognitive deficits.”
Rajiv N. Srinivasa, Heidi C. Rossetti, Mohit K. Gupta, Roger N. Rosenberg, Myron F. Weiner, Ronald M. Peshock, Roderick W. McColl, Linda S. Hynan, Richard T. Lucarelli, Kevin S. King. “Cardiovascular Risk Factors Associated with Smaller Brain Volumes in Regions Identified as Early Predictors of Cognitive Decline,” Radiology, July 28, 2015.