title: Risk of periodontitis in patients with psoriasis and psoriatic arthritis.
abstract: BACKGROUND
  Psoriasis and periodontitis are chronic inflammatory disorders with overlapping inflammatory pathways, but data on risk of periodontitis in psoriasis are scarce and a possible pathogenic link is poorly understood.
  
  
  OBJECTIVE
  We investigated the association between psoriasis and periodontitis in a nationwide cohort study.
  
  
  METHODS
  All Danish individuals aged ≥18 years between 1 January 1997 and 31 December 2011 (n = 5,470,428), including 54 210 and 6988 patients with mild and severe psoriasis, and 6428 with psoriatic arthritis, were linked through administrative registers. Incidence rate ratios (IRRs) were estimated by Poisson regression.
  
  
  RESULTS
  Incidence rates of periodontitis per 10 000 person-years were 3.07 (3.03-3.12), 5.89 (1.07-6.84), 8.27 (5.50-12.45) and 11.12 (7.87-15.73) for the reference population, mild psoriasis, severe psoriasis and psoriatic arthritis respectively. Adjusted IRRs were (1.66; 1.43-1.94) for mild psoriasis, (2.24; 1.46-3.44) for severe psoriasis and (3.48; 2.46-4.92) for psoriatic arthritis. Similar results were found when a case-control design was applied.
  
  
  CONCLUSIONS
  We found a significant psoriasis-associated increased risk of periodontitis, which was highest in patients with severe psoriasis and psoriatic arthritis.
authors.affiliation: Department of Dermatology and Allergy, Herlev and Gentofte Hospital, University of Copenhagen, Hellerup, Denmark.|Department of Cardiology, Herlev and Gentofte Hospital, University of Copenhagen, Hellerup, Denmark.
authors.forename: A
authors.initials: A
authors.lastname: Egeberg
authors.affiliation: Unit of Dermatology and Venereology, Karolinska Institutet, Stockholm, Sweden.
authors.forename: L
authors.initials: L
authors.lastname: Mallbris
authors.affiliation: Department of Cardiology, Herlev and Gentofte Hospital, University of Copenhagen, Hellerup, Denmark.|The Danish Heart Foundation, Copenhagen, Denmark.|The National Institute of Public Health, University of Southern Denmark, Copenhagen, Denmark.
authors.forename: G
authors.initials: G
authors.lastname: Gislason
authors.affiliation: Department of Cardiology, Herlev and Gentofte Hospital, University of Copenhagen, Hellerup, Denmark.
authors.forename: P R
authors.initials: PR
authors.lastname: Hansen
authors.affiliation: Psoriasis-Center at the Dept. of Dermatology, University Medical Center Schleswig-Holstein, Campus Kiel, Germany.
authors.forename: U
authors.initials: U
authors.lastname: Mrowietz
mesh_terms: D000293:Adolescent; D000328:Adult; D015535:Arthritis, Psoriatic / Q000150:complications*; D003718:Denmark; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010518:Periodontitis / Q000150:complications*; D011565:Psoriasis / Q000150:complications*; D055815:Young Adult