1. Department of Periodontology, University of Bern, Freiburgstrasse 7, 3010 Bern, Switzerland
2. Institute of Social and Preventive Medicine, University of Bern, Finkenhubelweg 11, 3012 Bern, Switzerland
3. Centre for Aging Sciences (Ce.S.I.), G. d’Annunzio University Foundation, Palazzina SEBI 3° livello, Campus Universitario Chieti Scalo, 66100 Chieti Scalo, Italia
4. CTU Bern, Department of Clinical Research, University of Bern, Finkenhubelweg 11, 3012 Bern, Switzerland