Figure 2.

Metabolite contributions to serum sample variation in principal component analysis. The red line depicts the average amount of variability each metabolite contributes to overall variability captured in the PCA model. Metabolites with bars taller than the red line contributed more than the average, while metabolites with bars shorter than the red line contributed less. Metabolite contributions were calculated using the factoexta package, and are proportional to the sum of square of the loadings weighted by the eigenvalues.