What were the findings of this study?
There is a lot of medical literature relating chronic bacterial infections to cardiovascular disease and stroke. We wanted to know if periodontal disease and tooth loss-which is partly a consequence of periodontal disease-were risk factors for ischemic stroke. We studied over 40,000 men, who were all health professionals, over the course of twelve years. We evaluated the periodontal disease and tooth loss and then followed them for twelve years to see how many of them developed stroke. And we found that men with 24 teeth or less had a 57% higher risk of stroke than men with 25 or more teeth. We also found a 33% increase risk of stroke associated with periodontal disease.
Isn't there a chance that people with fewer teeth or periodontal disease are more likely to have other risk factors that would naturally put them at risk for stroke?
There are many common risk factors for periodontal disease, tooth loss and ischemic stroke, such as smoking, socioeconomic status, diabetes, exercise, diet and smoking. It is important to be able to separate out these factors and to be able to see an association independent of these factors. This is why it is helpful to have a homogenous group of health professionals, with a more consistent, high spectrum of healthy behavior. They're likely to do more things to help their cardiovascular health and dental health. So there's less variation, and this helps control for some of the factors related to behavior, which we can measure as well as factors that we cannot measure.
So compared to other studies, we feel more confident in this kind of population than if it was a general population. But even within the group that we studied, there's still some variation. We try to control for it as best we can when analyzing the data and, by using this homogenous group, that gives an additional measure of control.
