Diligent Dental Flossing May Help Prevent Stroke
Abstract & Commentary
Source: Grau AJ, et al. Periodontal disease as a risk factor for ischemic stroke. Stroke. 2004;35:496-501.
Chronic inflammation is now a well-recognized cause of atherosclerotic vascular disease, including coronary artery disease and stroke. Asymptomatic individuals harboring the common bacterium Chlamydia pneumoniae have been shown to have an elevated incidence of plaque in both the coronary and carotid arteries. Elevations in C-reactive protein, a nonspecific marker of inflammation, have also been implicated as a stroke risk. Gingivitis and periodontitis have been previously associated with stroke, but these studies were limited by small sample sizes, limited dental data, and difficulties with confounding variables.
Grau and colleagues used a case-control methodology to analyze 303 patients hospitalized with an acute stroke and compared them to both community and other hospital controls. All study subjects underwent a complete clinical and radiographic dental examination. The primary outcome variable was the clinical attachment loss (CAL), a measure of periodontitis in which the "pocket" formed at the base of the tooth was probed. A particularly deep pocket (a CAL > 6 mm) was evidence of severe disease. Gingivitis was recorded based on gingival bleeding after a probe passing through the crevice between the teeth irritated the gums.
Grau et al found that severe periodontal disease was associated with a 4.3 times higher stroke risk. This finding also applied to gingivitis. Interestingly, the risk associated with periodontitis applied differently among stroke subtypes. The greatest association was with large artery atherosclerotic type, followed by cryptogenic type, and, to a lesser degree, cardioembolism. These data support the link between periodontitis and atherogenesis and also support the theory that periodontitis may create a prothrombotic state via a recurrent bacteremia and platelet activation.
In subgroup analysis, the risk of periodontitis applied to both first-ever and recurrent stroke. When the data were broken down by gender, the results were weaker and nonsignificant in women. When broken down by age, the results only applied to patients younger than 60.
These data provide further support that inflammation in general and periodontal disease more specifically are stroke risk factors. More importantly, these data identify a stroke risk factor that is clearly modifiable.
This study has weaknesses; in particular, there is no obvious explanation as to why there was such a prominent gender bias. Further analysis, especially in young people where there may be fewer confounding variables, is clearly needed. In the meantime, don’t forget to floss! Alan Z. Segal
Dr. Segal, Assistant Professor, Department of Neurology, Weill-Cornell Medical College, Attending Neurologist, New York Presbyterian Hospital is Assistant Editor of Neurology Alert.