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]