1. Second Propedeutic Department of Internal Medicine, Aristotelian University, Hippocration Hospital, Thessaloniki, Greece
2. Department of Internal Medicine, University of Crete, Heraklion, Greece
3. First Propedeutic Department of Internal Medicine, Aristotelian University, AHEPA Hospital, Thessaloniki, Greece
4. Endocrinology Clinic, Hippocration Hospital, Thessaloniki, Greece
5. Department of Clinical Biochemistry, UCL Medical School, University College London, Royal Free Campus, London, UK