Association between periodontitis and NAFLD-related diseases: Results from the NHANES and Mendelian randomization study

Abstract

Background & Aim There are contradictory causal links between disorders associated to non-alcoholic fatty liver and periodontitis. The purpose of this research is to use Mendelian randomization (MR) to establish a causal association between periodontitis and non-alcoholic fatty liver disease (NAFLD), including the latter's development to liver fibrosis. Materials and Methods The study included 4,425 people from the National Health and Nutrition Examination Survey (NHANES) conducted in the United States between 2009 and 2014. The study employed two multivariable logistic regression models to evaluate the correlation between advanced fibrosis (AF) and periodontitis, as well as NAFLD. Model 1 did not involve any covariate adjustments; model 2 controlled for age, gender, and race; model 3 was additionally adjusted for Body Mass Index (BMI), education level, household income poverty ratio, smoking status, physical activity, and history of diabetes. Periodontitis (n:17,353 cases/28,210 controls) was used as the exposure, and NAFLD (n:2,275 cases/375,002 controls), fibrosis (n:146 cases/373,307 controls), cirrhosis (n:1,142 cases/373,307 controls) and fibrosis/cirrhosis (n:1,841 cases/366, 450 cases control) as outcomes and causality validation was performed. Sensitivity studies, such as heterogeneity tests, multiple validity tests, and exclusion analyses, were also carried out to guarantee the trustworthiness of the findings. Results In the observational study, there was no significant correlation between periodontitis and NAFLD (OR: 0.82, 95% CI: 0.64–1.95) or AF (OR: 1.06, 95% CI: 0.72–1.56). The MR analysis found no significant association between genetically predicted periodontitis and liver conditions in the IVW method (NAFLD: OR: 1.12, 95% CI: 0.98 − 1.27; fibrosis: OR: 0.84, 95% CI: 0.50 − 1.42; cirrhosis: OR:0.99, 95% CI: 0.82 − 1.19; fibrosis/cirrhosis: OR: 0.92, 95% CI: 0.83 − 1.26). There is consistency in sensitivity results. Conclusions According to cross-sectional research, there is no discernible link between NAFLD or liver fibrosis and periodontal disease, and the MR analysis does not support a causal relationship between them.