A person’s risk of cognitive decline grows with each tooth lost, says a new study published in JAMDA: The Journal of Post-Acute and Long-Term Care Medicine by researchers led by New York University.
According to the Centers of Disease Control and Prevention (CDC), around 1 in 6 people aged 65 and above have lost all of their teeth. Previous studies have also shown a link between tooth loss and reduced cognitive function.
The reasons for the link remain largely unknown, however, some have theorized that difficulty chewing may lead to nutritional deficiencies which may affect the brain. A growing body of evidence also suggests a link between cognitive decline and gum disease, a leading cause of tooth loss.
To understand the link better, researchers conducted a meta-analysis using 14 longitudinal studies of tooth loss and cognitive impairment. Altogether, their research included data from 34,074 adults and 4,689 cases of people with reduced cognitive function.
In the end, the researchers found that adults with more tooth loss were 1.48 times more likely to develop cognitive decline and 1.28 times more likely of receiving a dementia diagnosis. These results remained after controlling for other factors.
They also found that 23.8% of adults with missing teeth had cognitive impairment compared to 16.9% of those with dentures. After factoring in the use of dentures, the researcher found that there was no significant link between tooth loss and cognitive impairment when participants wore dentures.
The researchers later conducted further analysis on whether the number of missing teeth affected one’s likelihood of cognitive impairment. In doing so, they found that each additional missing tooth was equivalent to a 1.4% increase in risk for cognitive impairment, and a 1.1% higher chance of being diagnosed with dementia.
"Our findings underscore the importance of maintaining good oral health and its role in helping to preserve cognitive function," says Bei Wu, senior author of the study.