highly significantP < 1.8 × 10 −6
Cluster 3 had multiple highly significant correlations (203, with an absolute value of rho ≥ 0.5 and P < 1.8 × 10 −6 ) including a group of proline-related metabolites (4-hydroxyproline, prolyl-hydroxyproline, and 4-hydroxyglutamate).