Periodontitis combined with smoking increases risk of the ulcerative colitis: A national cohort study

BACKGROUND: Periodontitis is a chronic inflammation of periodontal tissues. The effect of periodontitis on the development of inflammatory bowel disease (IBD) remains unclear. AIM: To assessed the risk of IBD among patients with periodontitis, and the risk factors for IBD related to periodontitis. METHODS: A nationwide population-based cohort study was performed using claims data from the Korean National Healthcare Insurance Service. In total, 9950548 individuals aged ≥ 20 years who underwent national health screening in 2009 were included. Newly diagnosed IBD [Crohn’s disease (CD), ulcerative colitis (UC)] using the International Classification of Disease 10(th) revision and rare intractable disease codes, was compared between the periodontitis and non-periodontitis groups until 2017. RESULTS: A total of 1092825 individuals (11.0%) had periodontitis. Periodontitis was significantly associated with older age, male gender, higher body mass index, quitting smoking, not drinking alcohol, and regular exercise. The mean age was 51.4 ± 12.9 years in the periodontitis group and 46.6 ± 14.2 years in the non-periodontitis group (P < 0.01), respectively. The mean body mass index was 23.9 ± 3.1 and 23.7 ± 3.2 in the periodontitis and non-periodontitis groups, respectively (P < 0.01). Men were 604307 (55.3%) and 4844383 (54.7%) in the periodontitis and non-periodontitis groups, respectively. The mean follow-up duration was 7.26 years. Individuals with periodontitis had a significantly higher risk of UC than those without periodontitis [adjusted hazard ratio: 1.091; 95% confidence interval (CI): 1.008-1.182], but not CD (adjusted hazard ratio: 0.879; 95% confidence interval: 0.731-1.057). The risks for UC were significant in the subgroups of age ≥ 65 years, male gender, alcohol drinker, current smoker, and reduced physical activity. Current smokers aged ≥ 65 years with periodontitis were at a 1.9-fold increased risk of UC than non-smokers aged ≥ 65 years without periodontitis. CONCLUSION: Periodontitis was significantly associated with the risk of developing UC, but not CD, particularly in current smokers aged ≥ 65 years.