Emerging evidence from two studies links periodontal disease with heightened risk for cerebrovascular disease and stroke, suggesting a potential connection between oral and brain health.

While more research is needed to understand these relationships, the data suggest that “improving oral health may be an important part of stroke prevention efforts,” Souvik Sen, MD, MS, MPH, with University of South Carolina in Columbia, South Carolina, who worked on both studies, said in a statement.

Both studies were published online on October 22 in Neurology.

Gum Health, Brain Health?

In the Atherosclerosis Risk in Communities (ARIC) study, Sen and colleagues analyzed data from 1143 participants (mean age, 77 years) who underwent oral health assessments between 1996 and 1998 and brain MRI between 2011 and 2013. Of these, 800 had periodontal disease and 343 did not.

Participants with periodontal disease had significantly greater white matter hyperintensity (WMH) volume, a marker of cerebral small vessel disease, than those with good oral health (median WMH%, 2.83 vs 2.52; P = .012).

In multivariable analysis, those with periodontal disease had 56% higher odds of being in the highest quartile of WMH volume (adjusted odds ratio, 1.56).

There was no statistically significant association between periodontal disease and cerebral microbleeds or lacunar infarcts.

“This suggests that periodontal disease may contribute to cerebral small vessel disease pathology, particularly WMHs, through mechanisms involving systemic inflammation,” the investigators wrote.

In a parallel study, the same researchers categorized 5986 ARIC participants (mean age, 63 years) who had dental assessments between 1996 and 1998 into one of three groups: oral health (n = 1640), periodontal disease only (n = 3151), or periodontal disease with caries (n = 1195).

Incident ischemic stroke and major adverse cardiac events (MACEs) including ischemic stroke, myocardial infarction, and fatal coronary heart disease — were identified in ARIC records through 2019.

Over a 21-year median follow-up, the incidence of ischemic stroke was 4.1% in those with good oral health vs 6.9% in those with periodontal disease and 10.0% in those with periodontal disease and dental caries.

In fully adjusted models, periodontal disease with caries was associated with an increased risk for ischemic stroke (hazard ratio [HR], 1.86) and MACE (HR, 1.36). Elevated risk was noted for thrombotic (HR, 2.27) and cardioembolic (HR, 2.58) strokes.

Notably, regular dental care was associated with lower risk for periodontal disease and periodontal disease with caries (odds ratios, 0.71 and 0.19, respectively).

Brushing for Brain Health

In an accompanying editorial Leonardo Pantoni, MD, PhD, of the University of Milan, Milan, Italy, commented that the findings reinforce the established link between oral health and stroke risk and suggest that oral health may also play a role in the development of WMH, relationship that has not been studied as extensively.

He cautioned that epidemiologic observations like these can generate “pathogenetic hypotheses and are not suited to draw firm causal conclusions in this regard. For example, good oral health may also be associated with better lifestyle as well as adherence to vascular prevention and treatment strategies.”

Nonetheless, the findings suggest that “neurologists should consider incorporating lifestyle interventions such as oral health into stroke prevention strategies, as an adjunct to pharmacologic approaches,” Pantoni wrote.

Shaheen Lakhan, MD, PhD, neurologist and researcher in Miami, who wasn’t involved in the either study, agreed.

“For decades, neurologists have screened for hypertension, diabetes, and smoking, but almost never for oral health. Yet the inflammatory burden from gum disease can rival those classic risk factors. Integrating oral health into stroke prevention is a simple, powerful, and long-overlooked step toward true brain-body medicine,” Lakhan told Medscape Medical News.

Lakhan said when he practiced in Appalachia — often referred to as the “Stroke Belt,” he saw firsthand how unmet dental needs paralleled high stroke rates.

“These new findings give biological grounding to what many of us observed clinically: the mouth and brain share the same inflammatory highway,” Lakhan said.

“The mouth is the gateway to the brain. These studies show that gum disease doesn’t just reflect poor health, it may cause microvascular injury that raises stroke risk,” Lakhan said.

“Neurologists rarely ask about oral health, but we should. A toothbrush might be one of the simplest tools for brain protection,” he added.

The studies had no commercial funding. Sen and Lakhan had no relevant disclosures. Pantoni reported receiving consultancy fees from Medtronic, Amicus, and PIAM.