Stroke victims are more than twice as likely as other neurology patients to have had chronic infections in the mouth and lungs. The findings, reported in today's issue of Stroke, suggest that better dental and health care may have contributed to a decline in the number of stroke deaths worldwide in the last several decades. And some experts say that people already at risk for stroke should take better care to ward off infections.
Neurologist Armin Grau and colleagues at the University of Heidelberg in Germany set out to test whether chronic infections might be a risk factor, too. His group studied 130 people admitted to the hospital after a major stroke, and 36 people suffering from transient cerebral ischemia, or ministrokes that last less than 2 hours and appear to cause no permanent damage. The researchers took detailed medical histories and performed standard dental and ear-nose-and-throat examinations.
Both groups of stroke patients were twice as likely as controls--patients admitted for neurological disorders with no apparent links to infection, such as primary brain tumors and epileptic seizures--to have had frequent or chronic bronchitis, defined as two or more bouts in each of the last 2 years. And they were 2.5 times as likely to have poor dental hygiene, particularly periodontitis, a chronic inflammatory disease of the gums.
"It's an interesting observation," says Michael Walker, director of the division of stroke and trauma at the National Institute of Neurological Disorders and Stroke in Bethesda, Maryland. But, he adds, "it's a fairly weak association." Indeed, Grau cautions that "larger studies are needed to say anything definitive."
However, the findings do jibe with observations in other patients in Grau's research program, which has shown that smokers and diabetics are more likely to have infections--perhaps contributing to their elevated risk for stroke. Taking all the evidence into account, says Grau, people at risk for stroke "should take infections very seriously."