Periodontal Inflammation in Relation to Cognitive Function in an Older Adult Danish Population

Abstract

Inflammation plays a significant role in Alzheimer's disease (AD) pathogenesis. Studies have shown that systemic, peripheral infections affect AD patients. Cognitive dysfunction is a consistent finding in AD and periodontal disease is a chronic, peripheral infection often resulting in tooth loss. We hypothesized that older adults with periodontal inflammation (PI) or many missing teeth would show impaired cognition compared to subjects without PI or with few missing teeth, and among subjects with PI, those with many missing teeth would show impaired cognition compared to those with few missing teeth. The effect of PI/tooth loss on cognitive function [measured by Digit Symbol (DST) and Block Design (BDT) tests] was assessed in 70-year old Danish subjects. We found: 1) subjects with PI obtained lower mean DST scores compared to subjects without PI (p < 0.05); 2) subjects with many missing teeth had lower mean DST and BDT scores compared to subjects with few missing teeth (p < 0.05); 3) the association of PI with DST and BDT scores was dependant on the number of missing teeth (interaction: p = 0.03 and p = 0.06); and 4) education and previous cognitive scores (age 50) were important covariates. Subjects with PI had significantly lower adjusted mean DST scores compared to subjects without PI. However for adjusted BDT, the significance held only for subjects with few missing teeth. No difference in the adjusted DST and BDT scores was seen between subjects with many missing teeth compared to those with few missing teeth. These results support the hypothesis that PI may affect cognition.

Potential biomarkers relating pathological proteins, neuroinflammatory factors and free radicals in PD patients with cognitive impairment: a cross-sectional study

“…Epidemiological data indicate a slightly inverse relationship between TNF-α level and cognitive function in the 50 to 60-year old of healthy subjects [28]. Chronic inflammatory disease exerts detrimental effects on cognitive function for persons with chronic periodontal inflammation [29]. High IL-1 level in hippocampus impairs learning ability [30].…”

Tooth loss, periodontal disease, and cognitive decline in the Atherosclerosis Risk in Communities (ARIC) study

“…Since most studies have been cross-sectional and conducted primarily in older adults (4,8,9,12–18), the possibility exists that poor nutritional status resulting from tooth loss may negatively affect cognitive ability (18,19). Cognitive dysfunction may lead to poorer self-care, thereby worsening oral health status (20).…”

“…Whereas many studies report associations of fewer teeth and complete tooth loss with poorer cognitive function (3,5,14,22–24), evidence regarding the association between actual periodontal disease and cognitive ability is mixed (3,6–8,14,15). Furthermore, periodontal disease exposure in earlier studies has been assessed with measures, such as the community periodontal index (CPI), which are based on clinical signs that do not provide much information about the underlying biology of periodontal disease (7).…”

Periodontal systemic associations: review of the evidence

“…A further recent European study of 152 dentate 70-year-old subjects in Denmark found that those with periodontal inflammation had lower scores in tests of cognitive function (Kamer et al 2012). Periodontal inflammation was equated with pocketing 4 mm affecting 10% of the remaining teeth and so did not meet the threshold set in the current review for periodontitis.…”