Smoking and Periodontitis Can Play a Synergistic Role in the Development of Psoriasis: A Nationwide Cohort Study

Background: Periodontitis is a chronic inflammatory disorder involving the periodontium. The precise nature of the association between periodontitis and psoriasis has not been determined. Objective: This nationwide population-based study investigated the relationship between periodontitis and the risk of psoriasis. Methods: A health screening database, which is a sub-dataset of the Korean National Health Insurance System database, was used in this study. Subjects with (n = 1,063,004) and without (n = 8,655,587) periodontitis who underwent health examinations from January to December 2009 were followed for 9 years. Results: In multivariable analysis, compared to the non-periodontitis group, periodontitis patients had a significantly higher risk of developing psoriasis (hazard ratio 1.116, 95% confidence interval 1.101-1.13). Non-smokers with periodontitis had an 11% increase in risk of psoriasis and smokers with periodontitis had a 26.5% increase in risk of psoriasis compared to non-smokers without periodontitis. Conclusion: Our study highlights periodontitis as a potential independent risk factor for psoriasis, increasing awareness of the synergistic role of smoking and periodontitis in the pathogenesis of psoriasis.