Fig. 3

OTUs are differentially abundant in the microbiota from the combined Danish-Indian group of T2D patients after controlling for confounding factors. Relative abundances of differentially abundant OTUs are shown in log scale. Among T2D patients, metformin-treated individuals are represented by filled circles and metformin-naive individuals are represented by hollow circles. Danish and Indians’ samples are included in the analysis (also see Additional file 2: Figure S11 for separate visualizations for the countries). These four OTUs are consistently identified from six different analyses where country and metformin were always adjusted for, while each additional factor (BMI, age, gender, usage of sulfonyl urea, statins, and proton pump inhibitors) was adjusted for one by one. NG, normoglycemic controls (n = 275); T2D, type 2 diabetes (n = 298)