title: Is Periodontal Disease Associated with Alzheimer's Disease? A Systematic Review with Meta-Analysis.
abstract: BACKGROUND
  In the last decade, several observational studies have suggested that there exists an association between periodontal disease (PD) and Alzheimer's disease (AD). The aim of this systematic review was to investigate whether or not this link exists.
  
  
  CONCLUSIONS
  The Preferred Reporting Items for Systematic Reviews and Meta-Analysis guideline for systematic review was used and registered at PROSPERO (CRD42016035377). The search strategy included using electronic databases and by hand searching articles published up to January 2016. MEDLINE via PubMed, EMBASE and Web of Science were searched by 2 independent reviewers. Observational studies including patients meeting criteria for both AD and PD were eligible to be included in the analysis. Quality assessment of selected studies was performed by the Newcastle-Ottawa Scale. From a total of 550 titles and abstracts, 5 studies were included (2 cross-sectional, 2 case-control and one cohort study) in the review. A fixed effects meta-analysis showed that the presence of PD is associated with the presence of AD (OR 1.69, 95% CI 1.21-2.35). When only severe forms of PD were evaluated, a significant association was also observed (OR 2.98, 95% CI 1.58-5.62). Key Messages: In the present review, a significant association was observed between PD and AD. Further studies should be carried out in order to investigate the direction of the association and factors that may confound it.
authors.affiliation: Department of Periodontology, School of Dentistry, University of Santiago de Compostela, Santiago de Compostela, Spain.
authors.forename: Yago
authors.initials: Y
authors.lastname: Leira
authors.forename: Clara
authors.initials: C
authors.lastname: Domínguez
authors.forename: Juan
authors.initials: J
authors.lastname: Seoane
authors.forename: Juan
authors.initials: J
authors.lastname: Seoane-Romero
authors.forename: Juan Manuel
authors.initials: JM
authors.lastname: Pías-Peleteiro
authors.forename: Bahi
authors.initials: B
authors.lastname: Takkouche
authors.forename: Juan
authors.initials: J
authors.lastname: Blanco
authors.forename: José Manuel
authors.initials: JM
authors.lastname: Aldrey
mesh_terms: D000544:Alzheimer Disease / Q000150:complications / Q000453:epidemiology*; D006801:Humans; D010510:Periodontal Diseases / Q000150:complications / Q000453:epidemiology*
keywords: Alzheimer’s disease; Dementia; Meta-analysis; Periodontal disease; Periodontitis; Review