Supplementary Material for: Association between Obesity and periodontitis in US Adults: NHANES 2011–2014

Introduction: It is controversial whether obesity and periodontitis are related. A representative U.S. population was examined for the relationship between obesity and periodontitis. Methods: In the National Health and Nutrition Examination Survey (NHANES) 2011-2014, participants (n = 6662)aged 30 or older and underwent periodontal examinations were chosen for analysis. An assessment of obesity was based on body mass index (BMI) and waist circumference (WC). Estimates of obesity and periodontal disease were made using univariate and multivariate logistic regression models. Results: According to an adjusted odds ratio (OR) for periodontitis,BMI (OR=1.01, 95%CI: 1.01~1.02) and WC (OR=1.01, 95%CI: 1~1.01) were significantly associated with periodontitis, respectively. After adjusting for confounding factors, the OR for patients with high WC with periodontitis was 1.18 (1.04~1.33) compared to normal WC. BMI and WC subgroups showed no significant interaction (P for interaction > 0.05), except for the age interaction in BMI. Among young adults aged 30 to 44, obesity was significantly associated with periodontitis in subgroups, the adjusted OR for having periodontal disease were 1.02 (1~1.03) and 1.01 (1~1.02) for subjects with BMI, and WC, respectively. When all covariates were adjusted, BMI ≥ 30 kg/m2 was statistically significantly associated with prevalence of periodontal disease among people aged 30 to 44 (P <0.001). Conclusions: BMI and WC are significantly associated with periodontitis, even after adjusting for many variables, and were equally significant in obese (BMI≥30 kg/m2 ) young people (30 to 44 years).