Evidence suggests that chronic infectious diseases, including periodontitis and gingivitis, can lead to atherosclerosis, which is a risk factor for stroke and coronary heart disease (CHD). The mechanism proposed for the association is through direct invasion as microorganisms from the oral cavity have been found in the carotid artery plaques and thrombectomy samples from patients who experienced stroke.1
It is thought that direct invasion occurs when microorganisms enter the bloodstream during chewing or oral hygiene practices via compromised tooth-supporting structures, such as the periodontal ligament and the alveolar bone. This leads to transient bacteremia, and the resulting pro-inflammatory immune response is responsible for plaque rupture, platelet aggregation, thrombus formation, and thromboembolism, all of which can lead to stroke.1
While periodontal disease has been implicated as a probable risk factor for stroke occurrence, whether oral diseases can modify stroke through the role of inflammation remains unclear.1
A systematic review and meta-analysis aimed to “determine the association between the most common inflammatory conditions of the oral cavity – periodontitis and gingivitis – and stroke of various types.”1
The Study
The systematic review and meta-analysis included a total of 19 studies. Of those 19 studies, 13 were on the association of periodontitis with various stroke types, and six were on the association between gingivitis and stroke. The total number of participants in the studies evaluated was 35,937, with all participants over the age of 17.1
The primary outcome assessed was the association between periodontitis or gingivitis and stroke of various types, including ischemic stroke, hemorrhagic stroke, and transient ischemic attacks (TIAs).1
Secondary outcomes included tooth loss, bleeding on probing, probing depth, plaque index, and gingival recession.1
The Results
There was a significant association between periodontitis and stroke among the participants in the studies included in this review. There was also a significant association between gingivitis and stroke.1
Of the six studies that explored the association between gingival inflammation and the incidence of stroke, two found no association. The other four found that high levels of gingival inflammation were associated with stroke, concluding that gingivitis was a risk factor for various types of stroke.1
Most of the studies reviewed found that increased probing depths and tooth loss were independent risk factors for stroke. One study concluded that stroke was significantly associated with gingival inflammation and calculus index. Another study found that C-reactive protein and interleukin 6 (IL-6) were higher in patients with a cardiovascular risk.1
However, there were limitations regarding the quality of several studies included in this review, impeding results and conclusions.1 Limitations included misclassification bias, selection bias, small sample size, lack of data, and concerns regarding data validity.1
The quality assessment for the cohort studies included found there was a lack of information on some risk factors such as body mass index (BMI), smoking history, and history of other inflammatory diseases.1
Significant heterogeneity or diverse criteria for evaluating periodontal status among participants limited the generalization of the studies included, ultimately meaning the association was not robust.1
Additionally, several studies included in this review had concerns about methodology, including the quality of measurements and blinding. This could lead to an overestimation or even an underestimation of the association between periodontitis and stroke.1
A few of the studies included enrolled individuals with neurological diseases such as degenerative disease, myasthenia gravis, and Wilson’s disease. This is concerning regarding selection bias.1
Previous systematic reviews and meta-analyses have struggled to clearly identify an association between dental diseases and stroke due to poor-quality studies. One such review found a lack of uniform definitions and periodontal diagnosis measures. This complicated the interpretation of the data and results, as some included studies indicated a moderate association between periodontal disease and stroke, while others showed no association at all.1
Due to the poor quality of the studies on this topic, the authors have suggested future studies with better methodology to confirm the association between periodontitis, gingivitis, and stroke.1
The authors suggest prospective cohort studies to validate the findings of this systematic review and meta-analysis. They go on to give specific considerations for future studies. Such as a follow-up of at least ten years or more to ascertain a definite association between dental conditions and stroke. Studies should include patients with chronic periodontitis and gingivitis who have no other systemic illnesses or inflammatory diseases.1
Conclusion
Within the limitations of the studies included in this systematic review and meta-analysis, it was determined that there was a significant association between stroke and periodontal disease in case-control, cohort, and cross-sectional studies.1
Nonetheless, with the concerns regarding potential bias and the methodology of many of the included studies, further well-designed research is necessary to identify an association between periodontitis and gingivitis and stroke of various types.1
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Reference
- Dewan, M., Pandit, A.K., Goyal, L. Association of Periodontitis and Gingivitis with Stroke: A Systematic Review and Meta-Analysis. Dent Med Probl. 2024; 61(3): 407-415. https://dmp.umw.edu.pl/pdf/2024/61/3/407.pdf
