Association between serum antibodies to oral microorganisms and nonalcoholic fatty liver disease in adults.

Background: Alterations in the bacteria, such as the periodontal bacteria, might be considered potential risk factors for nonalcoholic fatty liver disease (NAFLD). Most studies analyzing this association have focused mainly on a specific periodontal bacteria (Porphyromonas gingivalis) and have involved relatively small study populations (tens or hundreds of individuals). To address this gap, a sizable, nationally representative adult population was utilized to investigate the association between the incidence of NAFLD and high serum IgG antibodies for 19 periodontal bacteria.

Methods: To explore this association, data from the Third National Health and Nutrition Examination Survey (NHANES III)-which provides a cross-sectional representation of the noninstitutionalized U.S. population, encompassing 33,994 individuals-were analyzed. Participants aged 40 years and above with data on NAFLD-determined by the gold standard of ultrasound examination (USON)-as well as comprehensive records of serum IgG antibodies against periodontal bacteria, were included, resulting in a final analysis subset of 6,330 individuals.

Results: Using a cluster analysis based on the Socransky classification scheme for oral microorganisms, antibody titers for the 19 bacteria were grouped into four clusters-Red-Green, Orange-Blue, Yellow-Orange, and Orange-Red. When these clusters, as well as individual antibody relationships with NAFLD, were examined, the adjusted odds ratios (ORs) ranged from 0.958 [95% confidence interval (CI): 0.916, 1.003] to 1.021 [95% CI: 0.987, 1.055]. This indicated that no statistically significant associations were found (P > 0.05), underscoring the absence of a meaningful link.

Conclusions: In summary, it was discovered that there is currently no evidence to correlate serum antibodies to periodontal pathogens with NAFLD in the nationally representative NHANES III.

Clinical trial number: Not applicable.