Gum Disease May Increase Cognitive Decline Risk in Alzheimer's

Those with the gum disease saw a 6-fold increase in cognitive decline over follow-up.
Those with the gum disease saw a 6-fold increase in cognitive decline over follow-up.

Periodontitis has been linked to an increased risk of cognitive decline in patients with Alzheimer's disease. The study was published in PloS ONE.

The same inflammation-causing antibodies seen in periodontitis have also been previously associated with rate of cognitive decline in Alzheimer's disease. In this study, researchers aimed to determine if periodontitis both increased dementia severity and cognitive decline, as well as increased an inflammatory state in Alzheimer's disease.

“A number of studies have shown that having few teeth, possibly as a consequence of earlier gum disease, is associated with a greater risk of developing dementia,” said study author Mark Ide, BDS, MSc, FDS, of King's College London. “We also believe, based on various research findings, that the presence of teeth with active gum disease results in higher body-wide levels of the sorts of inflammatory molecules which have also been associated with an elevated risk of other outcomes such as cognitive decline or cardiovascular disease. Research has suggested that effective gum treatment can reduce the levels of these molecules closer to that seen in a healthy state.”

The researchers conducted an observational study of 59 participants (mean age 77 years, 51% men) with mild to moderate Alzheimer's disease. Cognitive assessments, blood tests, and dental assessments were collected at baseline and at 6-month follow-up (n=52).

The baseline dental assessment indicated that 89% of participants had detectable plaque, with 37.3% fulfilling criteria for periodontitis. At baseline, mean Alzheimer's Disease Assessment Scale (ADAS-cog) score was 46.2 and mean standardized Mini-Mental State Examination (sMMSE) score was 20.4.

At 6-month follow-up, mean change was 2.9 for ADAS-cog and -1.4 for sMMSE. The presence of periodontitis at baseline was associated with a 6-fold increase in rate of cognitive decline over the follow-up period. This remained significant after adjusting for age, gender, and baseline ADAS-cog score.

There was no significant association between baseline serum PGingivalis antibody levels and rate of cognitive decline on the ADAS-cog or sMMSE score (Pearson -0.2; P= 0.1). However, the presence of periodontitis at baseline was associated with a drop in serum IL10 levels, while baseline serum PGingivalis antibody levels were associated with a drop in IL10 levels and increase in serum TNFα levels.

“These are very interesting results which build on previous work we have done that shows that chronic inflammatory conditions have a detrimental effect on disease progression in people with Alzheimer's disease,” said senior study author Professor Clive Holmes, of the University of Southampton.

“Our study was small and lasted for 6 months so further trials need to be carried out to develop these results. However, if there is a direct relationship between periodontitis and cognitive decline, as this current study suggests, then treatment of gum disease might be a possible treatment option for Alzheimer's.”

The study results need to be replicated in a larger cohort, but still lend themselves to furthering the idea that there is a significant connection between oral health and cognition.

Reference

Ide M, Harris M, Stevens A, et al. Periodontitis and Cognitive Decline in Alzheimer's Disease. PLoS ONE. 2016;11(3):e0151081.

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