[1] Univ Heidelberg, German Ctr Res Ageing, Dept Epidemiol, D-69115 Heidelberg, Germany
[2] Univ Ulm, Dept Epidemiol, D-89069 Ulm, Germany
[3] Harvard Univ, Sch Publ Hlth, Dept Biostat, Boston, MA 02115 USA
[4] Harvard Univ, Sch Publ Hlth, Dept Epidemiol, Boston, MA 02115 USA
[5] Univ Bielefeld, Dept Epidemiol & Stat Med, D-4800 Bielefeld, Germany
[6] SAP AG, Walldorf, Germany