Association of oral frailty and gut microbiota with hypertension: cross-sectional results in the Shika study

Although recent studies have reported the association between toxins produced by certain gut microbiota and elevated blood pressure, the relationship between oral frailty (OF) and gut microbiota has rarely been investigated. The purpose of this study was to epidemiologically investigate the relationship between the combination of OF and specific gut microbiota on hypertension in the residents of Shika Town, Ishikawa Prefecture, Japan. A total of 322 residents aged ⩾ 50 years in Shika Town agreed to participate and met the criteria. The OF was evaluated difficulty in chewing and swallowing, oral dryness, number of remaining teeth, and frequency of tooth brushing. Blood pressure was measured using an automatic digital blood pressure meter. Next-generation sequencing was used to analyze the gut microbiota. A two-way analysis of covariance revealed a significant interaction between the two OF groups and the two hypertension groups on Megamonas. The binomial logistic regression analysis stratified by OF revealed a positive correlation between Megamonas and hypertension (OR 1.317; P = 0.023). This cross-sectional epidemiological study of the local residents revealed that the abundance of Megamonas in the OF group was significantly higher in the hypertension group than in the normotension group; however, no such relationship was observed in the non-OF group.