Association of plasma amino acids and the risk of developing diabetes in a rural Chinese population: a nested case-control study

Abstract

Objective To investigate the association of plasma amino acids and the risk of developing of type 2 diabetes mellitus (T2DM) and their prediction ability of T2DM in a rural Chinese population. Methods A nested case-control study was carried out in the Handan Eye Study conducted from 2006 to 2013. During follow-up, 209 individuals developed diabetes, and 394 individuals matched for age and gender were identified as controls. Relationship of metabolic biomarkers to incident T2DM was assessed by conditional logistic regression. Results After adjusted for age, sex, body mass index (BMI), waist circumference, and family history of diabetes, the plasma concentrations of tyrosine, leucine, valine, alanine and glycine were significantly associated with incident T2DM, and the odds ratios (OR) [95% confidence interval(CI)] were 4.56 (1.77-11.73), 5.73 (1.80-18.25), 6.73 (2.02-22.34), 5.89 (2.26-15.36) and 0.39 (0.17-0.89), respectively (Model 2, all P<0.05). After further adjustment of fasting plasma glucose and triglyceride, only tyrosine and the combination of four-amino acids were still significantly associated with incident rate of T2DM, and the OR (95%CI) were 3.36 (1.10-10.29) and 1.11 (1.02-1.22), respectively (Model 3, both P<0.05). None of these amino acids significantly improved the C-statistics and net reclassification improvement. Only the four-amino acids combination significantly improved the integrated discrimination improvement, but the net changes were not remarkable. Conclusions Levels of branched-chain and aromatic amino acids, alanine and glycine, particularly tyrosine, are significantly associated with incident T2DM. However, none of these amino acids significantly improves T2DM risk prediction. Key words: Diabetes mellitus, type 2; Biological markers; Amino acids; Rural population