Common Infections May Raise Stroke Risk

Exposure to some common pathogens (infectious organisms) may raise the risk of having a stroke, according to a study published in the Archives of Neurology. The study, led by Mitchell Elkind, M.D., associate professor of neurology at Columbia University Medical Center in New York City, found that the pathogens Chlamydia pneumoniae, Helicobacter pylori, cytomegalovirus and herpes simplex virus 1 and 2 may contribute to accelerating arterial disease (artherosclerosis), which could increase the risk of stroke.

Although it's not clear how these pathogens adversely affect arterial function, one possibility, say study researchers, is that chronic infection leads to inflammation in the blood vessels, which can restrict blood flow. Another possibility is that the pathogens disrupt the normal functioning of the arterial walls. Strokes occur when there is a disruption in the blood supply to the brain, such as blockage in an artery or other blood vessel, depriving brain tissue of oxygen and nutrients. When this happens, brain cells begin to die within minutes, causing brain damage that may result in loss of speech, movement or memory or even death.

Dr. Elkind's findings coincides with earlier studies looking at the role of pathogens in cardiovascular disease, which found that untreated gum disease and other oral infections can spread and cause heart disease. In Dr. Elkind's study, 1,625 adults in New York City were tracked for over seven-in-a-half years. During that time, 67 patients suffered a first stroke. Even when other risk factors such as high blood pressure and diabetes were taken into account, the majority of the patients tested positive for one or more of the suspected pathogens.

According to Dr. Elkind, it's too early to know which specific pathogens contributed to the strokes and whether other pathogens not included in the study might also be involved. It's also too early to know what to do clinically to reduce the pathogens' effect on the cardiovascular system. One possibility may be that if scientists conclusively determine that pathogens do cause strokes years after people have been exposed to them, treating them with antibiotics for a longer period of time may help.

How to Lower Your Risk for Stroke

According to the Centers for Disease Control and Prevention, stroke is the third leading cause of death in the U.S. and the leading cause of serious long-term disability. You can reduce your risk for stroke by:

  • Preventing and controlling high blood pressure; and high cholesterol
  • Preventing and controlling diabetes
  • Quitting smoking
  • Maintaining a health weight
  • Being physically active
  • Eating a healthy diet