Atherosclerosis, the build-up of plaque that narrows arteries, is a major risk factor for heart disease, stroke and death. Co-authors Tatjana Rundek, M.D., Ph.D., professor of neurology and public health sciences, and Ralph Sacco, M.D., M.S., professor and chair of neurology and Olemberg Family Chair in Neurological Disorders, provided ultrasound core laboratory support and interpretation of the carotid ultrasounds for the study, which was led by the Columbia University Mailman School of Public Health.
The researchers followed 420 adults as part of the Oral Infections and Vascular Disease Epidemiology Study (INVEST), a randomly sampled prospective cohort from the Northern Manhattan study. Participants were examined for periodontal disease, specifically looking for inflammation markers. Atherosclerosis was measured in both carotid arteries using high-resolution ultrasound. Over a three-year period, researchers found that improvement in periodontal health, the health of the gums, and a reduction in the proportion of specific bacteria linked to periodontal disease correlated to a slower carotid intima-medial thickness (IMT) progression.
Researchers found there was a 0.1 mm difference in IMT change over three years in patients who experienced deteriorating periodontal health, compared with those whose gum health was improving. Previous research has shown that a 0.1 mm increase in that time span is associated with a 2.3-fold increased risk for coronary events.
“When it comes to atherosclerosis, a tenth of a millimeter in the thickness of the carotid artery is a big deal. Based on prior research, it appears to meet the threshold of clinical significance,” said Rundek.
“These results are important because atherosclerosis progressed in parallel with both clinical periodontal disease and the bacterial profiles in the gums. This is the most direct evidence yet that modifying the periodontal bacterial profile could play a role in preventing or slowing both diseases,” said Moise Desvarieux, M.D., Ph.D., lead author of the paper and associate professor of epidemiology at the Mailman School.
Scientists speculate that bacteria in the mouth may contribute to the onset of atherosclerosis in several ways. Animal studies indicate they may trigger immune response and high levels of inflammatory markers, which could exacerbate the inflammatory aspect of atherosclerosis. In earlier studies, higher levels of disease-causing bacteria were associated with thicker IMT. This study takes the next step.
“Our results address a gap identified in the AHA statement on periodontal disease and atherosclerosis, by providing longitudinal data supporting this association,” said Sacco. Scientists plan to follow these patients to see if the relationship between periodontal infections and atherosclerosis carries over to clinical events like heart attack and stroke. Further, they plan to test if modifying the periodontal flora will slow the progression of atherosclerosis.
Additional co-authors are Panos N. Papapanou, D.D.S., Ph.D., and Ryan T. Demmer, Ph.D., M.P.H., from Columbia’s Mailman School, and David R. Jacobs, Jr., Ph.D., from the University of Minnesota and the University of Oslo.
The study was funded by grants from the National Institute of Dental Research and the National Institute of Neurological Disorders and Stroke.
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