Response to: 'Concerns about report suggesting glucosamine and chondroitin protect against cartilage loss' by Felson. Issue 8 (1st April 2015) - Martel-Pelletier, Johanne; Roubille, Camille; Abram, François; Hochberg, Marc; Dorais, Marc; Delorme, Philippe; Raynauld, Jean-Pierre; Pelletier, Jean-Pierre