Influence of periodontal disease on risk of dementia: a systematic literature review and a meta-analysis

This is an accepted manuscript of an article published by Springer in European Journal of Epidemiology on 12/06/2020, available online: https://doi.org/10.1007/s10654-020-00648-x The accepted version of the publication may differ from the final published version.Periodontal disease (PD) is common and increases cardiovascular diseases. However, it is unclear whether PD is associated with increased risk of dementia. We carried out a systematic review and meta-analysis to investigate the influence of PD on dementia. We projected the number of dementia cases to be saved by reducing PD prevalence in the world. We searched cohort and case–control studies reporting the association of PD with all dementia (or any specific type of dementia) through PubMed, MEDLINE, PsycINFO, SocINDEX, CINHAL, and CNKI until 7th November 2018. Five cohorts and seven case–control studies were identified for review. We pooled eligible data to calculate relative risk (RR) of dementia in relation to PD and computed the number of dementia cases saved through reducing PD prevalence. Of 12 studies, six were undertaken in Asia, four in Europe and two in America. Eleven studies showed a positive association between PD and the risk of dementia, of which 10 were significant, and one reported a non-significant inverse association. Overall their quality was good. Pooled RR of dementia in relation to PD from all high quality studies was 1.38 (95%CI 1.01–1.90); in the five cohorts was 1.18 (1.06–1.31) and in the two case–control studies 2.25 (1.48–3.42). A 50% reduction in the current prevalence of 20% of PD in the population could save 850,000 (630,000–1,420,000) patients with dementia in the world. PD could increase the risk of incident dementia. Preventing and treating PD could contribute to controlling the global epidemic of dementia.Professor Ruoling Chen and Dr Jie Tang thank an EU Grant from Horizon 2020 MSCA – DEMAIRPO #799247. Dr Kaarin Anstey is funded by NHMRC Fellowship #1102694. Dr Wu is the recipient of BBSRC [BB/P004695/1] and NIA [1R01AG049321-01A1] Grant for aging research. Dr Yuyou Yao, Associate Professor of Anhui Medical University, China is a visiting scholar at the Faculty of Education, Health and Wellbeing, University of Wolverhampton to support this study and has made valuable comments on the manuscript.Published versio