Ewa Cyranska-Chyrek1, Ewelina Szczepanek-Parulska2, Marek Ruchala2. 1. Department of Endocrinology, Metabolism and Internal Medicine, Poznan University of Medical Sciences, Poznan, Poland. mruchala@ump.edu.pl. 2. Department of Endocrinology, Metabolism and Internal Medicine, Poznan University of Medical Sciences, Poznan, Poland.