Abstract: Objective To investigate the relationship between periodontal disease (PD) and risk of rheumatoid arthritis (RA) by performing a metaanalysis.Methods Such databases as PubMed,EMbase,CBM,CNKI,and WanFang databases were searched from their inception to May 20th,2014 to collect casecontrol studies about the PD and risk of RA,and the relevant references of the included literature were also retrieved.Two reviewers independently screened the literature according to the inclusion and exclusion criteria,extracted the data,and assessed the methodological quality.Then metaanalysis was conducted using CMA v2 software.Results Eventually nine casecontrol studies were included,2 in Chinese literature,7 articles in English literature,including RA group 465 cases and 421 cases of normal control group.The metaanalysis showed that exposure to PD could obviously increase incidence of rheumatoid arthritis 2.81 times (OR=2.81,95% CI 1.41 to 5.60,P=0.003),and sensitivity analysis showed the results were robust.There was no publication bias existing.Conclusions PD is an independent and significant factor to AR.Further studies according to the degrees of PD and the clinical subtypes of rheumatoid arthritis should be carried out.

Key words: periodontal disease, rheumatoid arthritis, Metaanalysis, casecontrol study, risk factor