Author contribution: Eliseeva YuV — academic advising, study concept and design, writing an article, approval of a manuscript for publication; Ratushnaya NSh — collection, data acquisition and processing, analysis and interpretation of results, writing an article; Dubrovina EA — collection, data acquisition and processing, result analysis and interpretation, writing an article.

Compliance with ethical standards: the trial was approved by the Local Ethics Committee of V. I. Razumovsky Saratov State Medical University (protocol No. 5 as of 02.03.2021). Voluntary informed consent was obtained from every trial participant and signed by all those examined by healthcare professionals. The trial corresponded to the requirements of biomedical ethics. No participant was exposed to danger.