ORIGINAL RESEARCH
Secondary hyperparathyroidism associated with vitamin D deficiency in young highly trained athletes
1 Federal Research and Clinical Center for Children and Adolescents of the Federal Medical Biological Agency, Moscow, Russia
2 Endocrinology Research Centre, Moscow, Russia
3 Medical and Biological University of Innovation and Continuing Education of the Federal Medical Biophysical Center named after A. I. Burnazyan of the Federal Medical and Biological Agency of Russia
4 Russian University of Medicine of the Ministry of Health of the Russian Federation, Moscow, Russia
Correspondence should be addressed: Elena P. Isaeva
Moskvorechye, 20, 115409, Moscow, Russia; ur.liam@4747arod
Author contribution: Isaeva EP — developing the research protocol, data acquisition, processing and interpretation of the results, manuscript writing; Okorokov PL — data acquisition, critical interpretation of the results, manuscript writing; Zyabkin IV — approving the research protocol and the final version of the manuscript.
Compliance with the ethical standards: the study was approved by the Ethics Committee of the Gaaz Moscow Medical and Social Institute (protocol No. 4 dated 04 October 2021). The athletes’ parents/caregivers or legal representatives submitted the informed consent to participation in the study.