Exposure to Infections Linked to Cognitive Decline

Preliminary research presented at the American Stroke Association’s International Stroke Conference 2014 revealed that exposure to common infections may be associated with a decline in memory and other cognitive performance.

The ongoing Northern Manhattan Study (NOMAS) has demonstrated evidence of a relationship between common infections and stroke, carotid atherosclerosis, and global cognitive function.

To determine whether past exposure to common infections is associated with cognitive performance and decline, researchers lead by Clinton B. Wright, MD, MS, Scientific Director, Evelyn F. McKnight Brain Institute, University of Miami, FL, examined a cohort of 588 participants (mean age, 71 years) of NOMAS.

Brain function tests were conducted among the participants, and blood samples were obtained to check for exposure to Chlamydia pneumoniae, Helicobacter pylori, cytomegalovirus, and herpes simplex viruses 1 and 2. Additional cognitive testing was performed in 287 individuals approximately 5 years later. Adjustments were made for age, sex, education, and diabetes, among others.

Researchers discovered that patients with higher antibody levels exhibited worse cognitive performance, including memory, planning, reasoning ability, speed of mental processing, and abstract thinking. This association was apparent even in individuals with infections that did not cause illness.

Wright explained in a press statement that the study does not explain why these infections were associated with worsening cognitive function, but he hypothesized that it could potentially be caused by an immune system response to the infections or it could be the result of the infection itself causing clinical damage. He also cautioned against treating these infections to avoid mental decline.

The study was funded by the National Institute of Neurological Disorders and Stroke.

-Meredith Edwards White

References

stroke.ahajournals.org/content/45/Suppl_1/A107.abstract?sid=894572a7-fc57-48cd-a7d3-16fdbe0868f0#aff-1

http://newsroom.heart.org/news/common-infections-may-increase-risk-for-memory-decline