Correlates of arterial stiffness in an ageing population: Role of asymmetric dimethylarginine

A number of previous investigators have demonstrated that arterial augmentation index (AIx), a measure of apparent arterial stiffness, reflects in part vascular endothelial function, and that AIx is modulated by nitric oxide (NO) responses. We evaluated AIx in a population of 253 ageing subjects (mean age 63.4+/-6 (standard deviation, SD) years) and its relationship to (i) plasma levels of asymmetric dimethylarginine (ADMA), a marker and mediator of vascular endothelial dysfunction and (ii) the ratio of ADMA to its non-metabolised enantiomer symmetric dimethylarginine (SDMA), an inverse index of ADMA metabolic clearance. Evaluation was performed by univariate followed by multivariate analyses. On multivariate analyses, both ADMA (beta=0.16, p=0.01) and ADMA:SDMA (beta=0.21, p