Received: 1 April 2021
Accepted: 13 August 2021
First Online: 21 August 2021
: The study was approved by the local Committee on Bioethics of the School of Public Health of Al-Farabi Kazakh National University. Every participant signed an informed consent to participate. All methods were carried out in accordance with relevant guidelines and regulations.
: Not applicable.
: The authors declare that they have no competing interests.