Periodontitis and Non-alcoholic Fatty Liver Disease, a population-based cohort investigation in the Study of Health in Pomerania

Background: Non-alcoholic fatty liver disease (NAFLD) affects 20%–30% of adults with risk factors like obesity and insulin resistance putatively acting through chronic low-grade inflammation. Because periodontitis elicits low-grade inflammation, we hypothesized that it could contribute to NAFLD occurrence. Objective: To investigate epidemiologic associations between periodontitis and the incidence of NAFLD among 2,623 participants of the Study of Health in Pomerania. Methods: Periodontitis at baseline was defined as the percentage of sites (0%, <30%, ≥30%) with (i) clinical attachment level (CAL) ≥3 mm; (ii) probing pocket depth (PD) ≥4 mm. Incident NAFLD was defined as a significant increase in liver echogenicity on ultrasound relative to the kidneys, with the diaphragm indistinct or the echogenic walls of the portal veins invisible. Results: After a median 7.7 years of follow-up, 605 incident NAFLD cases occurred at a rate of 32.5 cases per 1,000 person-years. Relative to participants without CAL ≥3 mm, NAFLD incidence was elevated slightly in participants with <30% of sites affected and moderately in participants with ≥30% of sites affected (multivariable-adjusted incidence rate ratio = 1.28, 95% CI, 0.84, 1.95 and 1.60, 95% CI, 1.05–2.43), respectively. A similar dose–response relationship was not observed for PD. Conclusion: History of periodontitis may be a risk factor for NAFLD.