Tooth loss is a risk factor for cognitive impairment and dementia—and with each tooth lost, the risk of cognitive decline grows, according to a new analysis led by US researchers.
However, this risk was not significant among older adults with dentures, suggesting that timely treatment with dentures may protect against cognitive decline.
Prior studies show a connection between tooth loss and diminished cognitive function, with researchers offering a range of possible explanations for this link. For one, missing teeth can lead to difficulty chewing, which may contribute to nutritional deficiencies or promote changes in the brain. A growing body of research also points to a connection between gum disease—a leading cause of tooth loss—and cognitive decline. In addition, tooth loss may reflect lifelong socioeconomic disadvantages that are also risk factors for cognitive decline.
A team at NYU Rory Meyers College of Nursing conducted a meta-analysis using longitudinal studies of tooth loss and cognitive impairment—and published their findings in the Journal of Post-Acute and Long-Term Care Medicine. The 14 studies included in their analysis involved a total of 34,074 adults and 4689 cases of people with diminished cognitive function.
The researchers found that adults with more tooth loss had a 1.48 times higher risk of developing cognitive impairment and 1.28 times higher risk of being diagnosed with dementia, even after controlling for other factors.
However, a further analysis revealed that the association between tooth loss and cognitive impairment was not significant when participants had dentures.
The researchers also conducted an analysis using a subset of eight studies to determine if a greater number of missing teeth was linked to a higher risk for cognitive decline. Their findings confirmed this relationship: each additional missing tooth was associated with a 1.4 per cent increased risk of cognitive impairment and 1.1 per cent increased risk of being diagnosed with dementia.
“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,” study author Xiang Qi said.