After further linear regression analysis, 41 metabolites (1 acylcarnitine, 3 lyso-PCs, 33 PCs and 4 amino acids) and 17 metabolites (3 acylcarnitine, 1 lyso-PCs, 10 PCs and 3 amino acids) were found to be associated with serum Hp levels (P < 0.05) in T2DM patients and non-DM subjects, respectively (see Additional file 1: Table S3). The gene discussed is HP; the disease is type 2 diabetes mellitus.