Funding for this research was provided by:
Russian Foundation for Basic Research (grant 06-04-48400)
Received: 24 May 2019
Revised: 17 April 2020
Accepted: 29 May 2020
First Online: 5 June 2020
Compliance with ethical standards
: Authors have no conflict of interest to declare.
: Data collection protocol #2003–2014 was approved by the Committee of Bioethics of Lomonosov Moscow State University.