According to new research published in the Journal of the
American Geriatrics Society, there may be a link between oral health and
the progression of cognitive decline.
"Clinical evidence suggests that the frequency of oral
health problems increases significantly in cognitively impaired older people,
particularly those with dementia,” said lead researcher Bei Wu, PhD, of Duke
University's School of Nursing in Durham, North Carolina in the US.
"In addition, many of the factors associated with poor
oral health — such as poor nutrition and systemic diseases like diabetes and
cardiovascular disease — are also associated with poor cognitive function,” he
added.
The researchers caution, however, that more studies are
needed.
Findings came from the first systematic review of studies
focused on oral health and cognition. These two important areas of research are
important because in a growing older adult population, some 36% of people over
age 70 are already living with some degree of cognitive decline. Researchers
believe that a common inflammatory pathway may hold the key to a link between
oral hygiene and cognitive impairment, if such a link exists.
Poor oral health has been blamed for heart disease, due to
the spread of bacteria and oral health problems may be aggravated by diabetes
and HIV/AIDS due to reduction of body’s resistance to infection.
Alzheimer's Association estimates around 5.4 million people
in the US have Alzheimer's disease - the most common form of dementia.
To look for a link between oral health and cognitive status,
Dr. Wu and her colleagues combed through 56 studies published between January1993 and March 2013 that examined the relationship between oral
health and change in cognitive health or dementia incidence. They analyzed relevant
cross-sectional (data collected at one specific point in time) and longitudinal
(data collected over an extended period of time).
Some of the studies analyzed found that dental health
measures, such as the number of teeth, the number of cavities, and the presence
of gum disease, were linked to an increased risk of cognitive decline or
dementia. Which is interesting considering a 2013 study found gum disease
bacteria in the brains of Alzheimer’s disease patients — but this study in no
way proved that gum disease causes Alzheimer’s disease. It just acknowledged an
association.
However, researchers involved with the current review also
noted that the findings based on the number of teeth or cavities are
conflicting, and limited studies suggested that the dental conditions such as
gingivitis are associated with cognitive decline. Similarly, the team didn’t
regularly find that cognitive decline was associated with greater loss of teeth
or number of decayed teeth. However, it is likely that "methodological
limitations play a major role in explaining the inconsistent findings," they
wrote.
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"There is not enough evidence to date to conclude that
a causal association exists between cognitive function and oral health. For
future research, we recommend that investigators gather data from larger and
more population representative samples, use standard cognitive assessments and
oral health measures, and use more sophisticated data analyses," Dr. Wu
said.
