1. Endothelial function will be assessed by 24h urinary microalbumin excretion and digital pulse wave amplitude hyperemic response (photoplethysmography,PPG). To determine amplitude changes of the digital pulse, the response of the PPG pulse wave amplitude to hyperemia will be calculated from the hyperemic fingertip as ratio of post-deflation PPG pulse to baseline amplitude (PAht/PAh0, PA=pulse amplitude, h=hyperemic finger, t=time interval, 0=baseline). To obtain this ratio, we will divide the PAht/PAh0 ratio by the corresponding ratio at the control hand (PAct/PAc0, c=control finger)[Kuznetsova et al.].