Plasma concentrations of advanced glycation end-products and colorectal cancer risk in the EPIC study.

Advanced glycation end-products (AGEs) are a heterogeneous group of compounds formed by the non-enzymatic reaction between amino-acids and reducing sugars, or dicarbonyls as intermediate compounds. Experimental studies suggest that AGEs may promote colorectal cancer, but prospective epidemiologic studies are inconclusive. We conducted a case-control study nested within a large European cohort. Plasma concentrations of three protein-bound AGEs: N ε-(carboxy-methyl)lysine (CML), N ε-(carboxy-ethyl)lysine (CEL) and N δ-(5-hydro-5-methyl-4-imidazolon-2-yl)-ornithine (MG-H1) were measured by ultra-performance liquid chromatography tandem mass-spectrometry in baseline samples collected from 1,378 incident primary colorectal cancer cases and 1,378 matched controls. Multivariable-adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were computed using conditional logistic regression for colorectal cancer risk associated with CML, CEL, MG-H1, total AGEs, and [CEL+MG-H1: CML] and [CEL:MG-H1] ratios. Inverse colorectal cancer risk associations were observed for CML (OR comparing highest to lowest quintile, ORQ5vs.Q1=0.40, 95%CI:0.27-0.59), MG-H1 (ORQ5vs.Q1=0.73, 95%CI:0.53 - 1.00) and total AGEs (OR Q5vs.Q1=0.52, 95%CI:0.37 - 0.73) whereas no association was observed for CEL. A higher [CEL+MG-H1: CML] ratio was associated with colorectal cancer risk (ORQ5vs.Q1=1.91, 95%CI:1.31-2.79). The associations observed did not differ by sex, or by tumour anatomical subsite. Although individual AGEs concentrations appear to be inversely associated with colorectal cancer risk, a higher ratio of methylglyoxal-derived AGEs versus those derived from glyoxal (calculated by [CEL+MG-H1: CML] ratio) showed a strong positive risk association. Further insight on the metabolism of AGEs and their dicarbonyls precursors, and their roles in colorectal cancer development is needed.