Oral Hygiene Emerging as Key to Reducing Cognitive Decline

As a large swath of the United States population ages into its senior years, the specter of cognitive decline has become a perennial concern. With early detection seen as key in improving prognoses, there is growing consensus that oral disease might be the red flag that will lead to pre-emptive interventions.

Numerous studies are showing that when oral health suffers, diminished brain function may not be far behind. A recent Japanese study revealing a strong association between severe periodontitis and mild cognitive impairment (MCI) led the authors to conclude that periodontal diseases should be considered a risk factor for this type of brain disfunction.¹

Researchers examined 321 participants, accounting for variables such as education levels, age, and number of functional teeth. To gauge the relationship between gingival and brain health, they used an MCI screening test coupled with pocket-depth measurement.

Out of the study group, 123 participants had periodontitis, 41 of whom were diagnosed with MCI. In fact, 65.9% of participants with severe periodontitis developed MCI, while just 34.3% of those with healthy gingiva did.

GENETIC COMPONENT

A 2023 study screened approximately 40,000 middle-aged British adults without stroke or dementia for 105 genetic variants known to predispose people to poor oral health. The relationship between these risk factors and brain health was evaluated.²

Magnetic resonance imaging of participants’ brains revealed a higher burden of silent cerebrovascular disease among subjects with poor oral health. Additionally, those with overall genetically poor oral health had increased damage to the fine architecture of the brain. The researchers concluded that oral health may be a promising target for interventions focused on improving brain health.

TREASURE TROVE

Authors of a 2019 research review, focused on Alzheimer disease (AD), see the oral microbiome as a rich source of easily accessible biomarkers of AD, as well as a potential target for AD prevention. This could be beneficial in early identification and treatment of AD-susceptible individuals.⁴

The researchers in that study noted that antibodies for oral bacteria including Aggregatibacter actinomycetemcomitans, Tannerella forsythia, and Porphyromonas gingivalis, have been found to be higher in the serum of patients with AD compared to controls, suggesting a link between oral bacteria and AD. They wrote that simply chewing and brushing can leak bacteria and inflammatory markers into systemic circulation, particularly in those with periodontitis. Those with adequate immune responses may be able to eliminate the bacterial load. But those with compromised immune systems, including older adults, may lack the ability to clear it.

REFERENCES

1. Igase M, Igase K, Hino S, et al. Association of periodontitis with mild cognitive impairment in older adults. JAR Life. 2024;13:108-112.
2. Rivier C, Renedo D, de Havenon A, et al. Association of poor oral health with neuroimaging markers of white matter injury in middle-aged participants in the UK biobank. 2023;102:e208010.
3. American Stroke Association. Poor oral health may contribute to declines in brain health.
4. Orr ME, Reveles KR, Yeh CK, Young EH, Han X. Can oral health and oral-derived biospecimens predict progression of dementia? Oral Diseases. September 21, 2019.