1. Department of Restorative Dentistry, Periodontology, Endodontology, and Preventive and Pediatric Dentistry, Unit of Periodontology, University Medicine Greifswald, Greifswald, Germany
2. Institute of Clinical Chemistry and Laboratory Medicine, University Medicine Greifswald, Greifswald, Germany
3. Department of Periodontology, Johann Wolfgang Goethe-University Frankfurt, Frankfurt am Main, Germany
4. Department of Periodontology, Faculty of Medicine, Carl Gustav Carus, Technical University of Dresden, Dresden, Germany
5. Department of Periodontology, Witten/Herdecke University, Witten, Germany
6. Department of Periodontology and Synoptic Dentistry, Charité Centrum 3, Charité-Universitätsmedizin Berlin, Berlin, Germany
7. Section of Periodontology, Department of Conservative Dentistry, University Hospital Heidelberg, Heidelberg, Germany
8. Department of Periodontology, Justus-Liebig University Giessen, Giessen, Germany
9. Department of Periodontology, University Hospital Würzburg, Würzburg, Germany
10. Department of Psychoanalysis and Psychotherapy, Medical University of Vienna, Vienna, Austria
11. Department of Periodontology, University Hospital Münster, Münster, Germany
12. German Diabetes Center, Institute of Biometrics and Epidemiology, Düsseldorf, Germany
13. Institute of Biostatistics and Clinical Research, University of Münster, Münster, Germany