Researchers of a new study found that extended exposure to common infections increases the risk of memory decline, even if the infection does not cause any illness.
Findings of this new study were presented at the American Stroke Association's International Stroke Conference 2014. University of Miami researchers found that an index of antibody levels caused by exposure to infections like Chlamydia pneumoniae, Helicobacter pylori, cytomegalovirus, and herpes simplex viruses 1 and 2 reduced cognitive performance, including memory decline, reduction in speed of mental processing, lower abstract thinking, planning and reasoning ability.
"We were very interested in what were the risk factors for cognitive performance and decline," said Clinton Wright, M.D., M.S., the study's lead researcher in a statement.
The study was conducted as an attempt to determine whether past exposure to these infections affected performance in memory tests, thinking speed and other brain functions. Previous studies have established that exposure to certain infections increase the risk of Alzheimer's disease and strokes. The researchers collected blood samples from 588 people and then conducted brain function tests on the participants. Five years later, half of the participants were asked to take another cognitive test.
Researchers noted that along with an increased risk of stroke, participants exposed to these common infections were also at a higher risk of atherosclerosis and inflammation. However, the reason behind this was not determined.
"It could be caused by an immune system response to the infections or the infection itself could result in clinical damage that we're not aware of," Wright said. "There is no evidence yet that treating these infections is beneficial. It would be great if treatment prevented these bad outcomes, but we're very far away from having that type of evidence." The study authors also said that exposure to viruses much earlier may result in gradual decline later on in life.
Since 70 percent of the study participants were Hispanic, Wright said that further studies need to be conducted to see if similar trends are observed in other populations too. The study was funded by the National Institute of Neurological Disorders and Stroke.
