"What we found was that for every extra tooth that a person had lost or had removed, cognitive function went down a bit,? said Slade. "People who had none of their teeth had poorer cognitive function than people who did have teeth, and people with fewer teeth had poorer cognition than those with more? the same was true when we looked at patients with severe gum disease."
Researchers looked at data gathered between 1996 and 1998 on 6000 men and women between the ages of 45 and 64. Data included tests of memory and thinking skills, as well as tooth and gum examinations, and led to some surprising findings:
- Approximately 13% of the participants had no natural teeth.
- Among those with teeth, one-fifth had less than 20 remaining.
- More than 12% of participants had serious bleeding issues and deep gum pockets.
- Scores on memory and thinking tests were lower by every measure among those with no teeth when compared to those who had teeth.
But why might having fewer teeth and serious gum bleeding cause worse scores on the tests, compared to those with more teeth and better gum health?
According to Slade, poor dental health could reflect or even lead to a poor diet, which might then contribute to cognitive decline. Alternatively, dental disease, especially gum disease, could give rise to inflammation not only in the gums but throughout the circulatory system, ultimately affecting cognition.
"If we want to focus on what might actually be contributing to cognitive decline and how to screen for that, then perhaps [poor] dental health should be thought of as yet another indication of both poor overall health and poor cognition," Slade said. "It's certainly a factor to be aware of."
The findings will be reported in the December issue of The Journal of the American Dental Association.