Having poor oral health — as shown by periodontal (gum) disease, tooth loss, and other conditions affecting the mouth — is linked to a higher risk for dementia, according to a new analysis published in the Journal of the American Geriatrics Society.
People with diabetes are at higher risk for both gum disease and dementia — both of which may be linked to elevated blood glucose levels. But the relationship between diabetes and oral health appears to run in both directions. On the one hand, poor glucose control is linked to tooth loss, and one in four people with diabetes has gum disease. But taking care of your teeth and mouth may actually help your blood glucose control — extra attention to oral health has been shown to help control type 2 diabetes, and regularly brushing your teeth may even help prevent diabetes.
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Some researchers have tried to explain the connection between oral health and diabetes by noting that poor oral health may contribute to inflammation throughout the body, which can affect a person’s diabetes risk and blood glucose control. So it’s natural that scientists might wonder if inflammation related to poor oral health could also contribute to dementia. For the latest study, researchers tried to answer this question by reviewing past studies on cognitive decline and dementia (advanced cognitive impairment).
Oral health conditions linked to cognitive decline
After looking through thousands of studies, the researchers found 47 in total — 24 on cognitive decline and 23 on dementia — that could be included in their review because they had relevant data on oral health. They compared rates of certain oral health conditions — namely gum disease, tooth loss, deep periodontal pockets, and alveolar bone loss (next to the upper teeth) — with cognitive outcomes, and found that these oral health conditions were linked to a 23% higher risk for cognitive decline and a 21% higher risk for dementia.
Tooth loss, specifically, was found to increase the risk for cognitive decline by 23% and dementia by 13%. When the researchers looked at the data in more detail, they found that partial tooth loss — meaning loss of some teeth — was linked to a 50% higher risk for cognitive decline, while complete tooth loss (loss of all teeth) was linked to a 23% higher risk for dementia.
The researchers noted that at least some of the link between poor oral health and cognitive decline or dementia could be explained by so-called reverse causality — meaning that people with worse cognitive health might neglect their oral health, rather than poor oral health causing cognitive decline or dementia. The design of the available studies made it difficult to determine how much this was the case, so the researchers cautioned that they couldn’t draw firm conclusions about the connection between oral health and cognitive health. “Further well-designed studies involving standardized periodontal and cognitive health assessment and addressing reverse causality are highly warranted,” they wrote.
Want to learn more about oral health for diabetes? Read “Diabetes and Oral Health: What’s Their Relationship?” “Disease, Treatment, and Oral Health,” and “Choosing Dental Care.”
