1 Institute of Medical Sociology and Rehabilitation Science, Charité-Universitätsmedizin Berlin, Berlin, Germany. Electronic address: paul.gellert@charite.de.
2 Institute of Medical Sociology and Rehabilitation Science, Charité-Universitätsmedizin Berlin, Berlin, Germany.
3 WIdO-AOK Research Institute, Berlin, Germany.
4 Deparment of Endocrinology, Diabetes and Metabolism, Charité-Universitätsmedizin Berlin, Berlin, Germany.