Periodontitis May Accelerate Hippocampal Atrophy in Older Adults

The degree of periodontitis and tooth loss may be associated with hippocampal atrophy, according to study findings published in the journal Neurology.

Although the majority of dementia cases have no known determinant, tooth loss and periodontitis have recently been suggested as potential risk factors for Alzheimer disease (AD) and related dementia. With the highly prevalent nature of dental disease worldwide, researchers conducted a longitudinal study on the relationship between baseline number of teeth and degree of periodontitis to hippocampal volume change rate in a population of older adults.

Participants of the Ohasama Study, a prospective cohort study on hypertension and cardiovascular disease, were selected to participate. A total of 172 men and women (average age, 67) who had at least 2 brain magnetic resonance imaging (MRI) scans taken 4 years apart and had undergone an oral examination by dentists were included in the study. Individuals with edentulism and/or suspected cognitive decline at baseline were excluded. Participants also completed the Mini-Mental State Examination (MMSE) and Zung Self-Rating Depression Scale.

At baseline, dentists evaluated each patient for the number of teeth present, and periodontal probing depth (PD), which is used as a marker to reflect the degree of periodontitis of the oral cavity.

MRI scans of the left and right hippocampus were conducted at baseline and follow-up to assess volumetric changes. Each participant was followed for an average of 4.0 years.

Multiple regression analyses revealed that the number of teeth present, mean PD, and their interaction were significantly associated with the annual percent change of left hippocampal volume (R²=0.26, adjusted R²=0.24).

Individuals with low-level periodontitis (mean PD -1 SD) had a faster rate of left hippocampal atrophy as their number of teeth decreased (mean PD=2.05mm, P =.026).

Individuals with a high level of periodontitis (mean PD +1 SD), on the other hand, had a higher rate of left hippocampal atrophy as their number of teeth increased (mean PD=4.50 mm, P <.001).

Furthermore, the number of teeth present and mean PD were significantly associated with annual MMSE score changes (B=0.042; 95% CI, 0.007-0.077; P =.018), reflecting associated cognitive decline.

The researchers concluded, “This finding indicates that periodontitis may have a greater association with left hippocampal atrophy than the association exhibited by age. Furthermore, in cases of mild periodontitis, fewer teeth may be associated with a subsequent decline in cognitive function.”

There were several limitations in this study, including data being extracted from a voluntary survey conducted in only 1 region of Japan and the fact that the researchers did not take into account the changes in the number of teeth or periodontitis status from baseline to follow-up, which could be a confounding factor.

Disclosures: Several study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see original source for full list of disclosures.