The association between plasma levels of 20 amino acids and risk of diabetes

Objective To investigate the association between the plasma levels of 20 amino acids and the risk of diabetes in middle-aged and elderly population. Methods This study was a part of the Chinese multi-provincial cohort study conducted in communities of Shougang. In 2007 and 2012, the population was investigated for diabetes and other risk factors. Blood samples collected from 475 people were tested for various amino acid levels by liquid chromatography-tandem mass spectrometry. A multivariate logistic regression analysis was used to analyze the association between plasma amino acid levels and diabetes risk. Results The age of the selected population at baseline was (58.7±6.3) years, and the blood glucose level at baseline was (5.68±1.34) mmol/L. Among them, 56 (11.79%) subjects were diabetes. Multivariate logistic regression analyses showed that after adjusting for age, gender, body mass index, systolic blood pressure and dyslipidemia, individuals with plasma branched-chain amino acid (valine, leucine and isoleucine) and cysteine in the highest tertile levels were at high risk of diabetes with the ORs of 3.61 (95% CI 1.48-8.80), 3.27 (95% CI 1.34-7.99), 2.46 (95% CI 1.04-5.84) and 2.09 (95% CI 1.02-4.27), respectively. After 5 years′ followed up, 5.73% (24/419) subjects developed diabetes. Compared with those in the lowest tertile, individuals with plasma branched-chain amino acid (total concentration), phenylalanine, and tyrosine levels at baseline in the highest tertile had 3.69 times, 3.61 times and 4.14 times higher risk to develop new diabetes, respectively. In contrast, individuals with plasma glycine level in the highest tertile had only 76% (OR 0.24, 95% CI 0.06-0.91) risk for the development of diabetes compared with those with plasma glycine level in the lowest tertile. Conclusions The increase in plasma branched-chain amino acid and cysteine levels is significantly associated with an increase in incident diabetes. Subjects with higher levels of branched-chain amino acids and aromatic amino acids (phenylalanine, tyrosine) had a significantly higher risk of developing new-onset diabetes, while those with higher glycine levels had a significantly lower risk of developing diabetes in 5 years. Key words: Amino acids; Diabetes mellitus; Blood glucose