Fig. 1

PCA score plots, PLS-DA score plots, and PLS-DA model permutation test derived from metabolomics profiles comparing the POI and control groups. A PCA score plot with QC samples in positive polarity mode. B PCA score plot with QC samples in negative polarity mode. C PLS-DA score plot in positive polarity mode. D PLS-DA score plot in negative polarity mode. E PLS-DA model permutation test in positive polarity mode. F PLS-DA model permutation test in negative polarity mode