Author contribution: Gumenyuk LN — study idea and design; Bordyugov MD, Sarchuk EV — data collection, analysis and interpretation; Knyazeva SV, Zastavsky VA — statistical data processing; Kritskaya DV, Saytibragimova SE, Kurtvelieva AI — article authoring.

Compliance with ethical standards: the study was approved by the Ethics Committee of the Medical Academy named after S. I. Georgievsky of Vernadsky Crimean Federal University (Minutes № 10 of October 16, 2021); it was planned and conducted in compliance with the Declaration of Helsinki. All participants of the study signed the voluntary informed consent form.