Tooth loss and bleeding gums might be a sign of declining thinking skills
among the middle-aged, a new study contends.
"We were interested to see if people with poor dental health had
relatively poorer cognitive function, which is a technical term for how well
people do with memory and with managing words and numbers," said study
co-author Gary Slade, a professor in the department of dental ecology at the
University of North Carolina at Chapel Hill.
"What we found was that for every extra tooth that a person had lost or
had removed, cognitive function went down a bit," Slade said. "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
"The same was true when we looked at patients with severe gum
disease," he said.
Slade and his colleagues reported their findings in the December issue of The
Journal of the American Dental Association.
To explore a potential connection between oral health and mental health, the
authors analysed data gathered between 1996 and 1998 that included tests of
memory and thinking skills, as well as tooth and gum examinations, conducted
among nearly 6 000 men and women. All the participants were between the ages of
45 and 64.
Roughly 13% of the participants had no natural teeth, the researchers said.
Among those with teeth, one-fifth had less than 20 remaining (a typical adult
has 32, including wisdom teeth). More than 12% had serious bleeding issues and
deep gum pockets.
The researchers found that scores on memory and thinking tests including
word recall, word fluency and skill with numbers were lower by every measure
among those with no teeth when compared to those who had teeth.
The researchers also found that having fewer teeth and serious gum bleeding
were associated with worse scores on the tests, compared to those with more
teeth and better gum health.
Which condition developed first? The answer is murky, the researchers said.
"It could be that poor dental health reflects a poor diet, and that the
lack of so-called 'brain foods' rich in antioxidants might then contribute to
cognitive decline," Slade said. "It could also be that poor oral
health might lead to the avoidance of certain foods, thereby contributing to
"It could also be that dental disease, especially gum disease, gives
rise to inflammation not only in the gums but throughout the circulatory
system, ultimately affecting cognition," he said.
"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
Catherine Roe, an assistant professor of neurology at the Washington University
School of Medicine, in St Louis, said the findings were "fascinating".
"Oral health isn't a widely talked about risk factor for cognition
issues, and from this study we can only tell there's an association between the
two, not that it's causal," Roe said.
"But the idea of a relationship between the two is certainly a very
interesting possibility," she said. "It could be that systemic
inflammation might have an overall effect on both dental health and cognition,
as they discuss in the paper.
"There might be a genetic link between the two diseases, with a certain
gene promoting both oral health issues and cognition problems," Roe said.
"Or, of course, it could simply be that if you've got cognitive problems
you just aren't taking very good care of your teeth.
"The thing to do is to continue to follow these people, who are now in
their 50s and 60s, which is actually very early to develop dementia or
Alzheimer's disease," she said. "It would be good to see to what
extent the people who have teeth problems today but are cognitively normal
right now go on to develop cognitive issues."
For more on dental care, visit the US
National Institutes of Health.