title: Periodontitis and risk of psoriasis: a systematic review and meta-analysis.
abstract: BACKGROUND
  The association between periodontitis and systemic diseases has been increasingly recognized. However, the data on the association between periodontitis and psoriasis are still limited.
  
  
  OBJECTIVE
  To summarize all available data on the association between periodontitis and the risk of psoriasis.
  
  
  METHODS
  Two investigators independently searched published studies indexed in MEDLINE and EMBASE databases from inception to July 2016 using a search strategy that included terms for psoriasis and periodontitis. Studies were included if the following criteria were met: (i) case-control or cohort study comparing the risk of psoriasis in subjects with and without periodontitis; (ii) subjects without periodontitis were used as comparators in cohort studies while participants without psoriasis were used as controls in case-control studies; and (iii) effect estimates and 95% confidence intervals (CI) were provided. Point estimates and standard errors from each study were extracted and combined together using the generic inverse variance technique described by DerSimonian and Laird.
  
  
  RESULTS
  Two cohort studies and three case-control studies met the inclusion criteria and were included in the meta-analysis. The pooled risk ratio of psoriasis in patients with periodontitis versus comparators was 1.55 (95% CI, 1.35-1.77). The statistical heterogeneity was insignificant with an I2of 18%. Subgroup analysis according to study design revealed a significantly higher risk among patients with periodontitis with a pooled RR of 1.50 (95% CI, 1.37-1.64) for cohort studies and a pooled RR of 2.33 (95% CI, 1.51-3.60) for case-control studies.
  
  
  CONCLUSIONS
  Patients with periodontitis have a significantly elevated risk of psoriasis.
authors.affiliation: Division of Rheumatology, Department of Internal Medicine, Mayo Clinic College of Medicine, Rochester, MN, USA.
authors.forename: P
authors.initials: P
authors.lastname: Ungprasert
authors.affiliation: Department of Internal Medicine, Bassett Medical Center, Cooperstown, NY, USA.
authors.forename: K
authors.initials: K
authors.lastname: Wijarnpreecha
authors.affiliation: Department of Dermatology, Mayo Clinic College of Medicine, Rochester, MN, USA.
authors.forename: D A
authors.initials: DA
authors.lastname: Wetter
mesh_terms: D016022:Case-Control Studies; D015331:Cohort Studies; D006801:Humans; D010518:Periodontitis / Q000150:complications*; D011565:Psoriasis / Q000150:complications*; D012307:Risk Factors