Some potentially bad news for people who get cold sores -- the virus that causes those pesky, itchy sores might also be linked with thinking problems.
A new study in the journal Neurology shows an association between having higher infection levels in the blood and risk of cognitive problems.
"While this association needs to be further studied, the results could lead to ways to identify people at risk of cognitive impairment and eventually lower that risk," study researcher Dr. Mira Katan, M.D., of the Northern Manhattan Study at Columbia University Medical Center, said in a statement. "For example, exercise and childhood vaccinations against viruses could decrease the risk for memory problems later in life."
The study included 1,625 people from northern Manhattan with an average age of 69. Researchers gathered blood samples from the study participants, which were then analyzed for infection with Helicobacter pylori, chlamydia pneumoniae and herpes simplex virus (types 1 and 2; type 1 causes cold sores). The study participants also took a cognitive test called the Mini-Mental State Examination each year for an average of eight years.
Researchers found an association between infection levels in the blood (which was determined by the participants' antibody levels) and scores on the cognitive test. Specifically, people with the higher infection levels were 25 percent more likely to score low on the test, compared with people with lower infection levels.
Of course, the researchers only found an association -- not a causal relationship -- so take the findings with a grain of salt. But this isn't the first time the cold sore virus has been linked with cognitive problems. In 2010, a study in the journal Schizophrenia Research showed that exposure to the cold sore virus is linked with cognitive impairment and even brain shrinking among people with schizophrenia.
And past research has drawn a link between the cold sore-causing virus and Alzheimer's disease.