After ten years of monitoring nearly 1,400 elderly people, researchers identified a particularly marked signal: bleeding gums. But there is no question of seeing it as a warning sign of Alzheimer’s.
What if brain health was also reflected in the mouth?
Seeing your gums bleed regularly is common. However, this little signal could be of interest well beyond the dental office.
In Japan, researchers at Kyushu University followed 1,396 people over the age of 60, free of dementia at the start of the study, for ten years. Their oral condition was assessed based on three criteria: the depth of the pockets between the teeth and the gums, the loss of attachment of the tissues that hold the teeth and the bleeding caused by the passage of a fine probe.
During follow-up, 267 participants developed dementiaincluding 194 Alzheimer’s disease and 51 vascular dementia. The results, published in the Journal of Clinical Periodontologyshow a particularly clear association with certain signs of periodontal disease.
Simple bleeding associated with 61% additional risk of Alzheimer’s
Participants with the most gingival bleeding had a 56% higher risk of dementia to that of people whose gums bled the least. For Alzheimer’s disease specifically, the risk was
61% higher.
The other indicators pointed in the same direction. The participants presenting the deepest periodontal pockets had a higher risk of dementia
72%while those with the greatest attachment loss had a higher risk of 59%.
The researchers took into account several factors that may influence dementia risk, including age, smoking, diabetes, blood pressure, physical activity and the number of remaining teeth.
For Michiko Furuta and her colleagues, “C“These results support a potential role of poor periodontal health in the development of dementia.”
The term “potential” is essential: this study is observational and does not show that gum problems cause Alzheimer’s.
Could chronic inflammation make the connection?
Why might the mouth have anything to do with the brain? One clue lies in inflammation. When periodontal disease sets in, the gums become inflamed and pockets can develop around the teeth. This local inflammation could contribute to a more general inflammation of the body.
Japanese researchers argue that “Persistent systemic inflammation can impair the blood-brain barrier, allow inflammatory mediators to enter brain tissue, and induce neuroinflammation and neuronal damage.”.
However, this hypothesis remains to be demonstrated in humans. Other work also suggests that certain bacteria in the mouth may have more direct effects on the brain, but these mechanisms are still being studied.
Warning: the link could also work the other way around
These results therefore do not mean that a person whose gums bleed is destined to develop dementia. In reality, another explanation is possible: early cognitive changes may themselves promote poor oral health. A person whose abilities are declining may have more difficulty brushing their teeth properly, making dental appointments, or maintaining regular hygiene.
A meta-analysis published in 2022 in the Journal of the American Geriatrics Societyrelating to 47 longitudinal studieshad already found an association between poor periodontal health and dementia, with a higher risk of approximately 21%. But its authors believed that the overall quality of the evidence was low and that reverse causality could not be ruled out.
The Japanese signal is therefore interesting, but it constitutes an additional piece of a puzzle that is still incomplete.
Gums that bleed regularly? Better to consult
There is therefore no question of panicking at the slightest bleeding, nor of considering brushing your teeth as a proven means of preventing Alzheimer’s.
On the other hand, gums that bleed regularly deserve a consultation with the dental surgeon. This person can look for gingivitis or periodontal disease and offer, if necessary, scaling and appropriate hygiene advice.
Because even if the link with dementia has yet to be confirmed, one thing is already certain: taking care of your gums protects your oral health. And researchers are now looking to find out if this simple gesture could also, in the longer term, help preserve brain health.