Oral Infections Harm Health -- Prof. Greg Seymour

Professor Greg Seymour
Faculty of Dentistry
University of Otago

Oral infections harm general health

Poor oral health in adults may contribute to a host of other diseases including diabetes and cardiovascular disease and deserves greater attention, according to a leading New Zealand researcher.

The growing body of evidence pointing to the impact of oral health on systemic health is being put under the spotlight by the Dean of the University of Otago's Faculty of Dentistry, Professor Greg Seymour.

Guest speaker for the Colgate Lecture in Wellington tomorrow morning, Professor Seymour says recent studies link various infections to cardiovascular disease, diabetes and pre-term, low birth weight infants.

"The vast majority of those studies, in fact well over 90 per cent, show a positive relationship between periodontal disease and cardiovascular disease, including coronary heart disease, stroke and peripheral vascular disease." he says.

"A recent study in the New England Journal of Medicine showed that treating periodontal disease not only reduced the blood markers of cardiovascular disease, but also improved function of the endothelial cells lining the artery walls."

Over the past five years Prof Seymour has been involved in work trying to identify a possible biological mechanism to explain this intriguing relationship.

"One theory is that the infection itself can lead to the changes in the blood vessels, while another one is that the infection leads to inflammation and that inflammation can lead to changes in the blood vessels."

They are particularly interested in the first hypothesis and something called molecular mimicry, in which the immune response to the oral infection causes a cross-reaction in the arteries. Such a reaction can lead to inflammation in the arteries and that in turn can manifest as atherosclerosis.

Professor Seymour says they have found cells involved in this cross-reaction, in both the blood and arteries of patients with atherosclerosis, and also shown that they exist in the gums of people with periodontal disease.

They have also found a similar cross-reaction and an associated increase in atherosclerosis, in an animal model.

"So we've got very strong evidence that this is a plausible biological mechanism," he says.

"We have tried to put this together with how this relates to infection as a whole. This concept of molecular mimicry may be a mechanism by which the total burden of infection - including oral infection, respiratory infection, and gastrointestinal infection - can contribute to atherosclerosis and hence cardiovascular disease."

Professor Seymour says it is the responsibility of the dental profession to ensure that oral disease plays as little part as is possible.

"At least half of the people who get cardiovascular disease cannot be explained by the accepted risk factors of smoking, diabetes, obesity etc. So in that half, infection may be quite significant and in some of those oral infection may be significant."

There is also growing evidence that diabetes is more difficult to control in the presence of infection, including oral infection, he says.

Pre-term, low birth weight in babies has also been associated with infections of various sorts with strong evidence that the presence of periodontal disease in the mothers can contribute to pre-term, low birth weight infants.

A Chilean study, where they treated the periodontal disease of the mothers, showed that there was a reduction in the incidence of pre-term labour and hence low birth weight children.

"Again what we are saying is that oral disease may contribute and it is important to control oral disease in terms of controlling any other risk factors in the circumstances."

Professor Seymour says it all goes to show that oral health is important in the health of adults beyond just having good teeth so you are able to eat well and enjoy good nutrition.

"It also has more of a direct effect on the general health of adults and the concern that I have is that oral health in New Zealand is generally considered to be an issue for children and adolescents.

"What I think we are seeing now is that it is as important for the overall health of adults as are other factors. It is not just oral health of the elderly we are talking about. Diseases such as cardiovascular disease and diabetes don't just suddenly occur when you turn 55 or 60, they build up over the preceding decades."

ENDS

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