Based on the dependent and independent variables, an electronic anonymous questionnaire available in English, French and Spanish was compiled (FluidSurveys™). In addition, the following descriptive variables were retrieved: age, stature, body mass, duration of professional sports career, years since retirement, nature of retirement (voluntarily or not), current occupation and number of working hours per week. Information about the study was emailed to potential participants by their respective association involved in the study. The invitation procedures were blinded to the responsible researchers for reasons of privacy and confidentiality of the former elite athletes. The participants were asked to give their informed consent and to complete the online questionnaire within 2 weeks while reminders were sent after 2 and 4 weeks. The questionnaire took about 20 min to complete. Ethical approval of the study was provided by the board of St. Marianna University School of Medicine (2014/04/16; Kawasaki, Japan), the Faculty of Health Sciences Human Research Ethics Committee of the University of Cape Town (642/2014, 843/2014; Cape Town, South Africa) and the Medical Ethics Review Committee of the Academic Medical Center (W15_060#15.0072, W15_171#15.0207; Amsterdam, The Netherlands). The present study was conducted in accordance with the 2013 Declaration of Helsinki and its later amendments or comparable ethical standards.