A new study suggests that an easily measurable marker of atherosclerosis and cardiovascular risk may also be an early warning sign of cognitive decline in older adults — and potentially dementia.
For the study, a research team from Flinders University in Australia and the University of Aberdeen in the U.K. focused on a certain blood marker known as asymmetric dimethylarginine (ADMA) and investigated its effects on cognition in a group of older adults. Data for the study was taken from the 1936 Aberdeen Birth Cohort.
ADMA has been associated with atherosclerosis (build-up of fats and other deposits on artery walls) and cardiovascular disease (disease involving the heart or blood vessels) in epidemiological studies.
The researchers say the findings could support the search for novel preventative and therapeutic treatments for dementia.
Previous studies on this topic have primarily focused on a set of abnormalities found in diseased brains. However, observational studies and clinical trials targeting these changes have been disappointing, suggesting the urgent need to better understand the causes of dementia and identify novel markers of disease.
Unlike other human aging study groups, participants in the 1936 Aberdeen Birth Cohort were also given childhood intelligence tests at age 11, a key predictor of intelligence and health in old age.
In the first part of the study, ADMA levels measured in the year 2000 (when participants were 63 years) were associated with decline in cognitive performance assessments after four years, said Flinders University Professor Arduino Mangoni.
“Therefore the results of this study suggest, that ADMA, an easily measurable marker of atherosclerosis and cardiovascular risk, could be an early indicator of cognitive decline in old age — and possibly dementia,” said Mangoni, head of Clinical Pharmacology at Flinders.
Alzheimer’s disease (AD), a neurodegenerative disorder characterized by a rapid decline in cognition and significant disability in old age, currently affects more than 5 million Americans. In Australia, it affects more than 342,000 residents, and this number is expected to increase to 400,000 in less than a decade. The causes of late onset AD are largely unknown and despite extensive research, there is still no clear consensus on robust biomarkers to predict disease onset and progression and the response to therapies.
U.K. researcher Dr. Deborah Malden said the results of the new study should be approached with caution and that more extensive investigations would be needed with larger study groups.
“We should be cautious about emphasizing the results with the 93 participants’ results here,” she said. “We would know much more after repeating this study in a large-scale cohort, potentially tens of thousands of individuals, and perhaps a genetic MR (Mendelian randomization) study.”
Even so, if the initial study findings are confirmed in large-scale testing, the research team hopes the results could pave the way for population-wide dementia risk categorization and perhaps future development of therapeutic strategies to reduce ADMA levels and/or slow the progression of cognitive decline in old age.
The new article is published in the International Journal of Geriatric Psychiatry.
Source: Flinders University