Study Finds Cold Sore Virus May Cause Memory Problems
Miller School researchers led by Ralph L. Sacco, M.D., M.S., professor and Chair of Neurology, collaborated on a study that found the virus that causes cold sores, along with other viral or bacterial infections, may be associated with cognitive problems. Published March 26 in Neurology, the medical journal of the American Academy of Neurology, the study shows that people with higher levels of infection in their blood, which indicates exposure over years to various pathogens such as the herpes simplex type 1 virus that causes cold sores, were more likely to have cognitive problems than people with lower levels of infection in the blood.
For the study, “Infectious burden and cognitive function: The Northern Manhattan Study,” researchers, including Clinton Wright, M.D., associate professor of neurology and Scientific Director of the Evelyn F. McKnight Brain Institute, tested the cognitive function and memory of 1,625 people who averaged 69 years of age and lived in northern Manhattan, where Sacco established the Northern Manhattan Study before joining the UM faculty. Study participants provided blood samples that were tested for herpes simplex type 1, herpes simplex type 2, cytomegalovirus, Chlamydophila pneumoniae, which is bacterium that causes respiratory infection, and Helicobacter pylori, bacterium found in the stomach.
The study found that the people who had higher levels of infection were more likely to score lower on thinking and memory tests compared with those with lower levels of infection. They specifically were 25 percent more likely to receive a low score on a common cognition test called the mini-mental state examination.
“We have reported that infectious burden, as well as inflammation, is an important contributor to stroke and cardiovascular risk,” said Sacco, who is also the Olemberg Family Chair in Neurological Disorders and Executive Director of the McKnight Brain Institute. “This study extends these findings to include cognitive impairment and opens up new possibilities for prevention and treatment of cognitive decline.”
Researchers tested the memory and cognition of study participants every year for an average of eight years, but infection was not associated with changes in memory and thinking abilities over time.
Senior author of the study is Mira Katan, M.D., with the Northern Manhattan Study at Columbia University Medical Center. The study was supported by the National Institute of Neurological Disorders and Stroke, the Swiss National Science Foundation and the Leducq Foundation.