TUESDAY, Dec. 10, 2013 (HealthDay News) -- 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
"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 more."
"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
The Journal of the American Dental Association.
To explore a potential connection between oral health and mental
health, the authors analyzed 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 percent 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 percent had serious bleeding issues and deep gum
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
"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 cognitive decline."
"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 of."
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
For more on dental care, visit the
U.S. National Institutes of Health.