Examining the environmental risk factors of progressive-onset and relapsing-onset multiple sclerosis: recruitment challenges, potential bias, and statistical strategies

- Li, Ying; Saul, Alice; Eichau, Sara; Onofrj, Marco; Ozakbas, Serkan; Horakova, Dana; Havrdova, Eva Kubala; Grand'Maison, Francois; Alroughani, Raed; Gerlach, Oliver; Amato, Maria Pia; Altintas, Ayse; Taylor, Bruce; Girard, M; Duquette, P; Blanco, Y; Ramo-Tello, C; Laureys, G; Kalincik, T; Khoury, SJ; Shaygannejad, V; Etemadifar, M; Singhal, B; Ponsonby, Anne-Louise; Mrabet, S; Foschi, M; Habek, M; John, N; Hughes, S; McCombe, P; Ampapa, R; van der Walt, A; Butzkueven, H; de Gans, K; Simpson-Yap, Steve; McGuigan, C; Oreja-Guevara, C; Sa, MJ; Petersen, T; Al-Harbi, T; Sempere, AP; Van Wijmeersch, B; Grigoriadis, N; Prevost, J; Gray, O; Blizzard, Leigh; Castillo-Trivino, T; Macdonell, R; Lugaresi, A; Sajedi, SA; van der Mei, I; Broadley, Simon; Lechner-Scott, Jeannette; Karabudak, Rana; Patti, Francesco