University of North Carolina at Chapel Hill researchers are co-leading a national study to examine whether middle-aged people's physical health influences their risk of dementia later in life.

The study aims to determine what role vascular risk factors- including hypertension, diabetes and lifestyle - experienced in middle age may play in the development of dementia (vascular or due to Alzheimer's disease) and cognitive decline in the elderly.

UNC's Gillings School of Global Public Health's Collaborative Studies Coordinating Center will lead the neurocognitive study, which builds on its Atherosclerosis Risk in Communities (ARIC) study, a large epidemiologic investigation of the risk factors for heart disease and stroke that has been collecting data for more than 20 years.

The new neurocognitive study is funded through a $26 million grant over four years from the National Institutes of Health to five collaborating institutions: UNC, the University of Mississippi Medical Center, the University of Minnesota, along with Johns Hopkins and Wake Forest universities. UNC receives $4.6 million from the grant.

The study, a comprehensive examination of thousands of patients, will include detailed neurocognitive testing and brain imaging, said Diane Catellier, Dr.P.H., research associate professor of biostatistics and the principle investigator from UNC.

"Using the new exam data and the wealth of information collected during ARIC's 20-plus years, we expect to find out more about the causes of dementia and less severe symptoms of mild cognitive impairment," Catellier said. "We hope to get a unique view into early physiological changes that eventually culminate in dementia. The findings may help identify at-risk individuals who may benefit from early interventions targeting modifiable risk factors."

The original study has followed a group of roughly 16,000 participants for more than 20 years, from middle age into late life. Over the years, participants have been extensively evaluated for diseases and factors including heart disease, hypertension and cognitive function.

"The new ARIC Neurocognitive Study will be one of the most comprehensive investigations to date into the role of vascular and related mid-life risk factors in Alzheimer's and cognitive decline," said Thomas Mosley, M.D., University of Mississippi Medical Center professor of geriatric medicine and one of the new study's lead investigators.

Mosley said he believes Alzheimer's disease likely isn't caused by a single factor, but rather by a complex process involving multiple factors interacting and accumulating over decades.

"Understanding the risk factors involved in this complex process may lead to new targets for treatment," he said. "It could also allow us to intervene at an earlier point with people who are at high risk for dementia, a time when preventive treatments may be most effective."

Recent research has found African Americans may have a twofold or greater risk for Alzheimer's compared to whites. With one of the largest and most extensively evaluated African-American study subgroups, the study will help illuminate the role of ethnic differences in relative risk for dementia.

Previous findings from the long-term study have indicated the importance of vascular risk factors in predicting decline in cognitive functions such as memory and processing speed. Using brain imaging, researchers have also shown brain changes, such as atrophy and silent strokes, are surprisingly common, even in middle-age adults. They have also found that these brain abnormalities begin to affect cognitive functions as early as middle age.

The new neurocognitive study is co-funded by three NIH institutes: the National Heart, Lung and Blood Institute; the National Institute of Neurological Disorders and Stroke; and the National Eye Institute.

Source:
University of North Carolina at Chapel Hill