It has been known for some time that diabetics often suffer from gum disease. But now there is growing evidence that gum disease, or periodontitis, is also correlated with heart disease, stroke and pre-term births.
Periodontitis is severe inflammation of the gums caused by toxins secreted by a handful of anaerobic bacteria that live in the mouth. It leads to bleeding gums, the parting of the gums from the teeth (known as 'attachment loss'), and tooth decay, and it affects between 7 and 20% of adults.
At the American Association for the Advancement of Science annual conference in Anaheim, California, James Beck of the University of North Carolina announced that in a study of 4000 people between 45 and 64 years of age, severity of periodontal disease appeared to increase in direct proportion to arterial wall thickness (which is a good predictor of cardiac problems). And in a study of 320 men over 65, Walter Loesche of the University of Michigan found that those with fewer than 14 teeth were three times more likely to suffer coronary heart disease.
"This could be because periodontal disease causes a surge of bacteria and bacterial products in the blood stream," Beck speculates, "which is known to cause platelet aggregation, thrombus formation and atherogenesis [thickening of the artery walls]". Indeed 38-40% of atheromas, the deposits that can block blood vessels, contain
Periodontitis-infected gums are a toxic reservoir of inflammatory molecules, according to Stephen Offenbacher, also of the University of North Carolina at Chapel Hill. And these molecules are known to affect the placenta. Offenbacher has indeed found that hamsters with diseased gums have high rates of pre-term and low birthweight births. In another study of 124 human volunteers, he found that women with periodontitis have a seven-fold greater risk of having a pre-term, low birthweight baby (whereas alcohol or smoking increases the risk only three-fold).
The researchers believe that the effects on birthweight are most probably indirectly due to the inflammatory molecules that are released into the blood when the bacterial toxins set off the inflammatory process that destroys the connective tissue and muscle of the gums and the bone of the teeth.
These molecules include prostaglandins, which usually increase slowly throughout pregnancy and peak at the time of labour, when they induce uterine contractions and cervical dilation. An increase in prostaglandins as a result of periodontitis could make their levels peak too early. "It (periodontitis) may not be causal-we've not done any treatment studies yet," explained Offenbacher, "but the opportunity for intervention is compelling. Our evidence hints that 18% of all low birthweight could be attributable to periodontal disease. That's 45,000 births a year, at a cost of a billion dollars, in the US."