[1] Med Univ Graz, Dept Internal Med, Div Endocrinol & Metab, A-8036 Graz, Austria
[2] Vrije Univ Amsterdam, Med Ctr, Dept Epidemiol & Biostat, Amsterdam, Netherlands
[3] Vrije Univ Amsterdam, Med Ctr, EMGO Inst Hlth & Care Res, Amsterdam, Netherlands
[4] Heidelberg Univ, Inst Publ Hlth Social & Prevent Med, Mannheim Med Fac, Mannheim, Germany
[5] Univ Ulm, Dept Internal Med, Div Endocrinol & Diabet, D-89069 Ulm, Germany
[6] Med Univ Graz, Clin Inst Med & Chem Lab Diagnost, A-8036 Graz, Austria
[7] Synlab Acad, Mannheim, Germany