The study is published in the Aug. 2 issue of Neurology, the journal of the American Academy of Neurology.
“This study provides evidence that identifying these risk factors early in middle age could be useful in screening people at risk of dementia and in encouraging them to make changes in their lifestyles before it’s too late,” said Charles DeCarli, a professor of neurology in the UC Davis School of Medicine and director of the UC Davis Alzheimer’s Disease Center.
The study examined the relationships between midlife vascular risk factors and markers for brain aging based on magnetic resonance imaging (MRI). The indicators are associated with cognitive decline and dementia later in life.
The current study was conducted with data from participants in the Framingham Offspring Cohort Study, a multi-site, prospective cohort study comprised of three generations of the offspring and spouses of participants in the Framingham Heart Study. Some 1,352 of the study participants were included in the current research. The study subjects had an average age of 54.
Study participants have been followed since 1978 to identify vascular disease risk factors, and were repeatedly assessed for those risk factors, which included an elevated body mass index, hypertension, obesity, diabetes and smoking.
Beginning in 1999, the researchers obtained measures of vascular disease such as the volume of white matter hyperintensities, or areas on MRI that appear bright white that are associated with increased vascular damage. Other measurements included changes in total brain volume and changes in cognitive tests of verbal and spatial memory and decision-making capabilities.
The study found that people with high blood pressure developed white matter hyperintensities at a faster rate than those with normal blood pressure and had a more rapid decline in scores on tests of executive function, or planning and decision making. Participants who were obese were more likely to be in the top 25 percent of people with a greater rate of decline in scores on tests of executive functioning abilities later in life.
The study also found that participants with diabetes in mid-life had lost brain volume in the hippocampus brain region at a faster rate than those without diabetes when they were older. Study subjects who smoked lost overall brain volume faster than non-smokers and also were more likely to have a rapid increase in white matter hyperintensities.
“These factors appeared to cause the brain to lose volume, to develop lesions secondary to presumed vascular injury, and also appeared to affect the brain’s ability to plan and make decisions as quickly as it had 10 years earlier,” said DeCarli, who is a fellow of the American Academy of Neurology.
Other study authors include Stephanie Debette, Sudha Seshadri, Alexa Besier, Jayandra Jung Himali, Carole Palumbo and Philip A. Wolf, all of Boston University.
The study was funded by grants from the National Heart Lung and Blood Institute, the National Institute of Neurological Disorders and Stroke and the National Institute on Aging of the National Institutes of Health.
The UC Davis Alzheimer’s Disease Center is one of only 29 research centers designated by the National Institutes of Health’s National Institute on Aging. The center’s goal is to translate research advances into improved diagnosis and treatment for patients while focusing on the long-term goal of finding a way to prevent or cure Alzheimer’s disease. Also funded by the state of California, the center allows researchers to study the effects of the disease on a uniquely diverse population. For more information, visit alzheimer.ucdavis.edu.