^aCyprus International Institute for Environmental and Public Health, Cyprus University of Technology, Limassol, Cyprus

^bMRC Unit for Lifelong Health and Ageing, UCL, London, UK

^cMenzies Institute for Medical Research, University of Tasmania, Hobart, Tasmania, Australia

^dMedical Signal Analysis, Center for Health & Bioresources, AIT Austrian Institute of Technology GmbH, Vienna, Austria

^eDepartment of Medicine and Surgery, University of Perugia – Unit of Internal Medicine, Santa Maria Terni Hospital, Terni

^fInstitute of Clinical Physiology, CNR, Pisa, Italy

^gCardiology Department, Klinikum Wels-Grieskirchen, Wels, Austria

^h3rd Clinic of Internal Medicine, Papageorgiou GH, Aristotle University of Thessaloniki, Thessaloniki, Greece

Correspondence to Areti Triantafyllou, MD, MSc, PhD, Assistant Professor of Internal Medicine, 3rd Department of Internal Medicine, Aristotle University of Thessaloniki, Papageorgiou Hospital, Nea Efkarpia, Ring Road, 56429 Thessaloniki, Greece. E-mail: [email protected]