As we get older, many of us fear that we’ll develop some form of dementia, especially if we’ve seen the condition affect our grandparents or other loved ones. But dementia isn’t a normal part of aging and it doesn’t affect everyone once they get older, the Centers for Disease Control and Prevention (CDC) notes. There’s no surefire way to know if you’ll be one of the millions of adults to develop dementia, but there are risk factors you should be aware of. And new research has found that your oral health is one of the most important things to consider. Read on to find out what dementia risk factor you can spot just by looking in your mouth.
A new meta-analysis published July 8 in the Journal of the American Medical Directors Association examined the link between tooth loss, cognitive impairment, and dementia. The researchers analyzed 14 studies that included more than 34,000 participants and nearly 5,000 cases of cognitive impairment or dementia. According to the study, the risk of both cognitive impairment and dementia was increased in participants who had more tooth loss. The researchers found that the risk of being diagnosed with dementia was increased by 28 percent for adults with tooth loss, while the risk of developing cognitive impairment was 48 percent higher.
“Given the staggering number of people diagnosed with Alzheimer’s disease and dementia each year, and the opportunity to improve oral health across the lifespan, it’s important to gain a deeper understanding of the connection between poor oral health and cognitive decline,” Bei Wu, PhD, the study’s senior author and dean’s professor in Global Health at NYU Rory Meyers College of Nursing, said in a statement.
The researchers also found that the risk of cognitive impairment increases with every tooth lost, which they call a “dose-response” association. According to the study, each additional missing tooth was associated with a 1.4 percent increased risk of cognitive impairment and a 1.1 percent higher risk of being diagnosed with dementia. Participants with no teeth at all had a 54 percent higher risk of cognitive impairment and a 40 percent higher risk of being diagnosed with dementia—further cementing the increased risk associated with each tooth lost.
“This ‘dose-response’ relationship between the number of missing teeth and risk of diminished cognitive function substantially strengthens the evidence linking tooth loss to cognitive impairment, and provides some evidence that tooth loss may predict cognitive decline,” Xiang Qi, a doctoral condition from NYU Meyers, said in a statement.
According to the study, the association between tooth loss and cognitive decline was not significant among those who had dentures, however. The researchers found that adults missing teeth were more likely to develop cognitive impairment if they did not have dentures compared to those who had dentures. This may suggest that “timely prosthodontic treatment with dentures may reduce the progression of cognitive decline related to tooth loss,” the researchers explained in the study. For one thing, dentures help correct the problems that missing teeth lead to with chewing, which has been associated with nutritional deficiencies and changes in the brain.
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This is not the first study to link tooth loss with cognitive decline. Previous studies have touched on the association between tooth loss, gum disease, and dementia. According to the Mayo Clinic, tooth loss can be caused by untreated gum disease, which may be the starting point for cognitive decline. A large-scale study from 2020 published in the Journal of Alzheimer’s Disease suggests that the risk comes from Porphyromonas gingivalis, an oral bacteria that most commonly causes gum disease. The researchers for this study found that the antibodies produced to fight off this bacteria and gum disease may be associated with the development of one form of dementia, Alzheimer’s disease.
Both gum disease and tooth loss are a prevalent issue in the U.S., especially among older adults. According to the latest data from the CDC, more than 47 percent of adults 30 years or older have some form of periodontal disease. But it increases to more than 70 percent when looking at adults 65 years and older. In terms of tooth loss, the CDC reports that 26 percent of adults 65 years and older have eight or fewer teeth, while 1 in 6 of these adults have lost all of their teeth. According to the agency, “older adults who are poor, have less than a high school education, or are current cigarette smokers are more than three times as likely to have lost all their teeth.”