Francis Guillemin is epidemiologist and rheumatologist, professor of public health, Director of the APEMAC Research unit on Chronic diseases, perceived health and adaptation processes, of the University of Lorraine, Nancy, France. Alain Leplege, is professor at Paris Diderot University, France, specialized in health service research and outcome measurement, methodology and epistemology. Serge Briancon is epidemiologist, professor emeritus of public health, head of the School of Public Health (2001-2016) at Lorraine University, Nancy, France. Elisabeth Spitz is professor of health psychology at the University of Lorraine, Metz, France. Joel Coste is a rheumatologist, epidemiologist and historian of medicine, and professor at Paris Descartes University and Ecole Pratique des Hautes Etudes, France.