Alaska Natives Provide New Evidence Linking Common Infection to Heart Disease
Embargoed for Release: Monday, August 17, 4:00 pm ET
Contact: Lisbeth Pettengill (410)-955-6878 or [email protected]
In an autopsy study of Alaska Natives, researchers have found the strongest link yet between heart disease and Chlamydia pneumoniae (C. pneumoniae), a common bacterium responsible for chronic lung infections. The findings were reported in today's Circulation: Journal of the American Heart Association.
Other studies have reported finding C. pneumoniae in the atherosclerotic plaques (the fatty deposits that build up in the walls of blood vessels and lead to heart attacks and strokes) of some individuals, but the present study was the first to demonstrate that those individuals had been infected with C. pneumoniae long before their heart disease was diagnosed.
While the study did not confirm that the bacteria actually caused the atherosclerosis, it did provide substantial evidence on how the bacteria and the disease could be related. Early and persistent Chlamydia pneumoniae infection in people who later go on to develop atherosclerosis could mean that this organism plays an early role in the development of coronary heart disease, and that some forms of cardiovascular disease may eventually be prevented or treated by antibiotics or vaccination.
The scientists found C. pneumoniae not only in plaque samples obtained at autopsy from 60 Alaska Natives who had died from accidents, but also in blood samples that had been collected from 56 of the 60 individuals 7 to 26 years earlier, during screening programs for other diseases.
Lead author Michael Davidson, MD, MPH, a post-doctoral fellow at the Johns Hopkins School of Public Health, said, "The frozen archived blood samples provided evidence that these individuals were infected with Chlamydia pneumoniae long before a finding of the organism in either early or advanced heart lesions."
-more- The study found that if an individual's blood sample, an average of eight years earlier, showed a severe prior infection by C. pneumoniae, that person was nearly ten times more likely to have the bacteria in their arterial plaques at the time of death than were those with little or no evidence of an earlier infection.
Alaska Natives were studied because they have a lower risk of heart disease than the general population. The individuals studied died mainly from accidents between February 1989 and December 1992, and included 47 Eskimos, five Aleuts, and eight Indians (45 males and 15 females). Their ages at death ranged from 15 to 57 years.
C. pneumoniae causes about ten percent of the pneumonia in adults. Although related to the microorganism that causes the sexually transmitted disease commonly called chlamydia, C. pneumoniae is spread when an infected person coughs, not by sexual contact.
-end- The study was funded by the American Heart Association.
RSS