Is there a link between gum disease and Alzheimer's disease?
In a 2020 analysis led by the National Institute on Aging, (NIA), scientists suggest that bacteria that cause gum disease are also associated with the development of Alzheimer's disease and related dementias, especially vascular dementia. The results were reported in the Journal of Alzheimer's disease.
A 2016 study performed jointly by the University of Southampton and Kings College London also reported a link between gum disease and greater rates of cognitive decline in individuals with early stages of Alzheimer's disease.
Professor Clive Holmes, senior author from the University of Southampton, stated at its conclusion, "These are very interesting results which build on previous work we have done that shows that chronic inflammatory conditions have a detrimental effect on disease progression in people with Alzheimer's disease. Our study was small and lasted for six months so further trials need to be carried out to develop these results. However, if there is a direct relationship between periodontitis and cognitive decline, as this study suggests, then treatment of gum disease might be a possible treatment option for risk of Alzheimer's."
Periodontitis, or gum disease, is common in older individuals and is likely more common in Alzheimer's disease because of the reduced ability to take care of oral hygiene as the disease progresses. The increased levels of antibodies to periodontal bacteria are associated with increased levels of inflammatory molecules elsewhere in the body, which in turn has been linked to greater rates of cognitive decline in Alzheimer's disease. In the Southampton study, researchers set out to determine whether periodontitis is associated with increased disease severity and/or with subsequent escalation of cognitive decline in individuals developing the disease.
Porphyromonas gingivalis is the most common culprit of gum disease. Studies suggest that plaques of beta-amyloid protein, a major hallmark of Alzheimer's disease, may be produced as a response to this infection.
The NIA analysis revealed that older adults with signs of gum disease and mouth infections at baseline were more likely to develop Alzheimer's during the study period. Among those 65 years or older, both Alzheimer's diagnoses and deaths were associated with antibodies against the oral bacterium P. gingivalis, which can cluster with other bacteria such as Campylobacter rectus and Prevotella melaninogenica to further increase those risks.
Researchers note that the Southampton study should be replicated with a larger cohort, as the precise means by which gum disease may be linked to cognitive decline are not fully transparent and other factors may play a part in cognitive decline alongside oral health.
Gum disease is an infection caused by bacteria that get under the gum tissue. Toxins from bacteria and the body's response to infection can begin to destroy the gums and bones that support the teeth.
According to the National Health and Nutrition Examination Survey, an estimated 42% of U.S. adults aged 30 years or older have periodontitis, with about 7.8% of those adults having severe periodontitis. The American Dental Association recommends the practice of good oral hygiene daily, including brushing properly at least twice a day, using toothpaste, flossing, eating a healthy diet that limits sugary beverages and snacks, and visiting a dentist regularly for prevention and treatment of oral disease. Treatment for periodontitis includes professional cleaning, gum grafting, laser gum surgery and root planing.