Association between Periodontal Disease and Cognitive Impairment in Adults

Background

Periodontitis is an increasingly common severe oral disease which until recently was believed to be confined to the oral cavity. However, increasing numbers of studies are showing an association between periodontal disease and systemic disorders caused by the initiation of the inflammatory response and pro-inflammatory cytokines. The association of cardiovascular disease and periodontal disease has now been widely accepted and well-established; however, this systematic review intended to highlight a link between periodontitis and neuroinflammatory disorders such as Alzheimer’s, Parkinson’s and amyotrophic lateral sclerosis (ALS).

Methods

This systematic review included a literature search using the following platforms: PubMed, Web of Science, and Cumulative Index to Nursing and Allied Health Literature (CINAHL) between the date of inception up to September 2021. Using the typical PICO framework (population, intervention, comparator, and outcome) the review searched for subjects ≥18 years (population) who suffer from periodontitis (intervention) at increased risk for cognitive impairment (outcome) compared with adults without periodontitis (comparator). The selection criteria produced six cohort studies, three cross-sectional studies, and two case-control studies to analyse. 

Results

Evaluation of the 11 studies found that patients with ≥8 years of chronic periodontitis have a higher associated risk of developing dementia and experience cognitive decline. Periodontal parameters assessed during a detailed periodontal charting such as attachment loss, pocket depth, bleeding on probing, and alveolar bone are correlated with cognitive impairment. The pathology behind the association is unclear; although, studies showed levels of inflammatory markers such as epidermal growth factor, interleukin 8 and monocyte chemoattractant protein-1 were reduced whilst interleukin 1-β was found to be over-expressed in patients suffering from cognitive decline with pre-existing severe periodontitis.

Conclusion

This systematic review found a link between exposure of chronic severe periodontitis and cognitive decline. This is especially important in the ageing population with both neuroinflammatory disorders and chronic periodontitis affecting increasing numbers of the older population. A paucity of research into the pathophysiology of the association indicates that further research in this field is warranted.

Research Summary Written By: Raman Dehil, University of Manchester – BDS3