Previous studies suggested that
chronic periodontitis may be a risk factor for
psoriasis. However, no study has confirmed this relationship for all stages of
periodontal disease (
gingivitis and
periodontitis). This nationwide population-based retrospective cohort study aimed to investigate whether
periodontal disease is an independent risk factor for the development of subsequent
psoriasis. Patients aged ≥ 20 years who underwent both medical and oral checkups from the National Health Screening Program between 2002 and 2007 were selected from a customized database provided by the National Health Insurance Service (NHIS). Then, patients with
periodontal disease (n = 3,682,468) and without
periodontal disease (control, n = 3,637,128) according to
oral examination results were identified. We tracked each patient for subsequent
psoriasis diagnosis until the end of 2018 using NHIS database. The incidence rates of
psoriasis per 1000 person-years were 0.36 and 0.34 in the
periodontal disease group and control groups, respectively. After adjusting for potential cofactors, no significant increase in risk (adjusted hazard ratio, 0.994; 95% confidence interval, 0.974-1.015) was observed. Similar results were observed when analyzing the risk of
psoriasis in patients who required scaling or periodontal surgery. In conclusion,
periodontal disease is not an independent risk factor of
psoriasis.