Proper care of teeth and gums may offer benefits beyond oral health, including improving brain health, new research suggests.
In a large observational study of middle-aged adults without stroke or dementia, poor oral health was strongly associated with multiple neuroimaging markers of white matter injury.
"Because the neuroimaging markers evaluated in this study precede and are established risk factors of stroke and dementia, our results suggest that oral health, an easily modifiable process, may be a promising target for very early interventions focused on improving brain health," wrote the authors, led by Cyprien Rivier, MD, MS, with the Department of Neurology, Yale University School of Medicine, New Haven, Connecticut.
The study was published online on December 20, 2023, in Neurology.
Research data came from 40,175 adults (mean age, 55 years; 53% women) with no history of stroke or dementia who enrolled in the UK Biobank from 2006 to 2010 and had brain MRI between 2014 and 2016.
Altogether, 5470 (14%) participants had poor oral health, defined as the presence of dentures or loose teeth. Those with poor (vs optimal) oral health were older, more likely to be male, and had higher prevalence of hypertension, hypercholesterolemia, diabetes, overweight/obesity, and current or past smoking history.
In a multivariable model, poor oral health was associated with a 9% increase in white matter hyperintensity (WMH) volume (P < .001), a well-established marker of clinically silent cerebrovascular disease.
Poor oral health was also associated with a 10% change in aggregate fractional anisotropy (FA) score (P < .001) and a 5% change in aggregate mean diffusivity (MD) score (P < .001), two diffusion tensor imaging metrics that accurately represent white matter disintegrity.
Genetic analyses using Mendelian randomization confirmed these associations. Individuals who were genetically prone to poor oral health had a 30% increase in WMH volume (P < .001), 43% change in aggregate FA score (P < .001), and 10% change in aggregate MD score (P < .01), the researchers reported.
These findings, they noted, add to prior epidemiologic evidence for an association between poor oral health and a higher risk for clinical outcomes related to brain health, including cognitive decline.
'Huge Dividends'
The authors of an accompanying editorial praised the authors for looking at the consequences of poor oral health in a "new and powerful way by using as their outcome MRI-defined white matter injury, which is associated with, but antedates by many years, cognitive decline and stroke."
"The fact that these imaging changes are seen in asymptomatic persons offers the hope that if the association is causal, interventions to improve oral health could pay huge dividends in subsequent brain health," wrote Steven Kittner, MD, MPH, and Breana Taylor, MD, with the Department of Neurology, University of Maryland School of Medicine in Baltimore.
"The mechanisms mediating the relationship between the oral health genetic risk score and white matter injury are likely to be complex, but the authors have taken an important step forward in addressing a hypothesis of immense public health importance," they added.
Data from the World Health Organization suggested that oral diseases, which are largely preventable, affect nearly 3.5 billion people globally, with three out of four people affected in middle-income countries.
Funding for the study was provided in part by grants from the National Institutes of Health, the American Heart Association, and the Neurocritical Care Society Research Fellowship. The authors and editorialists disclosed no relevant conflicts of interest.