Fig. 5

A The effect of clinical indicators and demographic variables on the microbial a-diversity of the tongue, with red representing positive correlations and blue representing negative correlations.” + ” indicates p < 0.05,” +  + ” indicates p < 0.001. B Contributions of clinical and demographic variables to the differences in relative abundances of key distinguishing bacterial species for four tongue coatings based on Spearman correlation coefficients and best multiple regression model. Color bar shows correlation values, where red color indicates positive association, blue color negative association, and only significant correlations were shown.” + ” indicates p < 0.05,” +  + ” indicates p < 0.001