Taking care of your gums by brushing,
flossing, and regular dental visits could help hold heart disease at bay.
Researchers at Columbia University's Mailman School of Public Health have shown
for the first time that as gum health improves, progression of atherosclerosis
slows to a clinically significant degree.
Findings appear online in the Journal
of the American Heart Association.
Artherosclerosis, or the narrowing of
arteries through the build-up of plaque, is a major risk factor for heart disease,
stroke, and death.
"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," says Moïse Desvarieux, MD, PhD, lead
author of the paper and associate professor of Epidemiology at the Mailman
The researchers followed 420 adults as part
of the Oral Infections and Vascular Disease Epidemiology Study (INVEST), a
randomly sampled prospective cohort of Northern Manhattan residents.
Participants were examined for periodontal infection.
Overall, 5 008 plaque samples were taken from
several teeth, beneath the gum, and analysed for 11 bacterial strains linked to
periodontal disease and seven control bacteria. Fluid around the gums was
sampled to assess levels of Interleukin-1ß, a marker of inflammation.
Atherosclerosis in both carotid arteries was measured using high-resolution
Over a median follow-up period of three
years, the researchers found that improvement in periodontal health – health of
the gum and a reduction in the proportion of specific bacteria linked to
periodontal disease correlated to a slower intima-medial thickness (IMT)
progression, and worsening periodontal infections paralleled the progression of
IMT. Results were adjusted for potential confounders such as body mass index,
cholesterol levels, diabetes, and smoking status.
There was a 0.1 mm difference in IMT change
over three years among study participants whose periodontal health was
deteriorating compared with those whose periodontal health was improving.
Previous research has shown that a .033 mm/year increase in carotid IMT
(equivalent to approximately 0.1 mm over three years) is associated with a
2.3-fold increased risk for coronary events.
"When it comes to atherosclerosis, a
tenth of a millimetre in the thickness of the carotid artery is a big deal.
Based on prior research, it appears to meet the threshold of clinical
significance," says Tatjana Rundek, MD, PhD, a co-author of the study and
professor at the University of Miami whose lab read the carotid ultrasounds.
Even subtle changes to periodontal status
had a dose-response relationship to carotid IMT. "Our results show a clear
relationship between what is happening in the mouth and thickening of the
carotid artery, even before the onset of full-fledged periodontal
disease," says co-author Panos N Papapanou, DDS, PhD, professor of Dental
Medicine at Columbia University's College of Dental Medicine, whose laboratory
assessed the bacterial profiles in the gums. "This suggests that incipient
periodontal disease should not be ignored."
Bacteria in the mouth may contribute to the
onset of atherosclerosis in a number of ways, scientists speculate. Animal
studies indicate that they may trigger immune response and high levels of
inflammatory markers, which may initiate or exacerbate the inflammatory aspect
The results build on previous findings. In
earlier cross-sectional results, Dr Desvarieux and colleagues had reported that
higher levels of disease-causing bacteria were associated with thicker IMT. The
current study takes the next step by looking at the cohort over time.
"Our results address a gap identified
in the AHA statement on periodontal disease and atherosclerosis, by providing
longitudinal data supporting this association," says study co-author Ralph
Sacco, MD, professor and chairman of Neurology at the University of Miami,
Miller School of Medicine and former president of the American Heart
Concludes Dr Desvarieux, "It is
critical that we continue to follow these patients to see if the relationship
between periodontal infections and atherosclerosis carries over to clinical
events like heart attack and stroke and test if modifying the periodontal flora
will slow the progression of atherosclerosis."