[1] Heinrich Heine Univ Dusseldorf, Leibniz Ctr Diabet Res, German Diabet Ctr, Inst Clin Diabetol, D-40225 Dusseldorf, Germany
[2] German Ctr Diabet Res, Munich, Germany
[3] Heinrich Heine Univ, Fac Med, Div Cardiol Pulmonol & Vasc Med, Dusseldorf, Germany
[4] Heinrich Heine Univ, Fac Med, Div Endocrinol & Diabetol, Dusseldorf, Germany