1 Department of Chronic Disease Epidemiology, Yale School of Public Health, 60 College Street, New Haven, Connecticut 06511, USA. Electronic address: yetsa.tuakli-wosornu@yale.edu.
2 Institute of Sports and Exercise Medicine, International Olympic Committee Research Centre-South Africa, FIFA Medical Center of Excellence, Division of Orthopaedic Surgery, Faculty of Medicine and Health Sciences, University of Stellenbosch, PO Box 19063, Francie Van Zijl Drive, Rylaan, Tygerberg 7505, South Africa. Electronic address: ewderman@iafrica.com.