Common Infections Can Increase the Risk of Having a Stroke

Stroke is the third leading cause of death and the leading cause of serious disability in the USA.  Risk factors include high blood pressure, heart disease, high cholesterol, and smoking.  But some victims have none of these risk factors.  One possibility is infection, or a series of infections.  A group of physicians have investigated this, and reported in the Archives of Neurology.

The study included 1,625 healthy stroke-free men and women of average age 68 living in Manhattan, New York.  They were followed for an average of 7.6 years.  Baseline samples of their blood were examined for antibodies to 5 common infection-causing biological agents: Chlamydia pneumoniae, Helicobacter pylori, cytomegalovirus, and herpes simplex virus 1 and 2.

During the follow-up period, 67 of the volunteers had a stroke.  Analysis showed that each of these 5 infections was positively linked with an increased risk of a stroke (although the increased risk was not statistically significant).  When the total infective burden was calculated for each volunteer (e.g. whether they had one, two, three or more infections), there was a significantly increased risk of stroke in those with the greatest burden.  After making allowances for known risk factors, and excluding those subjects with coronary heart disease, the increased risk amounted to 50%.      

As the authors of the report state: “Further studies are needed to confirm these findings and to further define optimal measures of infectious burden as a stroke risk factor”.  And then one should see if clearing up such infections can have a protective influence . . .