Involvement of Megasphaera in the oral microbiome and dyslipidemia onset: evidence from a community-based study in Japan.

Dyslipidemia is a major risk factor for cardiovascular diseases and is influenced by genetic and environmental factors, including diet. Emerging research suggests a link between the gut microbiome and metabolic disorders. While the connection between the gut microbiota and dyslipidemia is well documented, the specific relationship between oral bacteria and dyslipidemia has not been thoroughly investigated. This study aimed to identify oral bacterial species associated with dyslipidemia in a community-based Japanese population. We conducted a metagenomic analysis on tongue coating samples from 763 participants in the Iwaki Health Promotion Project, which were collected during health checkups in 2017 and 2019. Dyslipidemia was diagnosed using standard lipid level criteria. The oral microbiome was analyzed via 16S rDNA amplicon sequencing. Statistical analyses included multiple regression and β diversity assessments. Our analysis revealed that the abundances of several bacterial genera, including Veillonella, Atopobium, Stomatobaculum, Tanneralla, and Megasphaera, are significantly associated with dyslipidemia. A higher relative abundance of Megasphaera was specifically observed in individuals with dyslipidemia. Moreover, Megasphaera abundance was closely associated with the onset of dyslipidemia (P = 0.038, odds ratio: 1.005, 95% confidence interval: 1.000-1.009), suggesting its role in metabolic regulation. This study revealed a significant association between the abundance of specific oral bacteria and dyslipidemia, suggesting the potential of using the oral microbiota as a biomarker for the early detection and management of dyslipidemia. Future research should explore the mechanisms through which oral bacteria influence lipid metabolism and the potential for microbioma-based therapies.