Li, Ying; Saul, Alice; Taylor, Bruce; Ponsonby, Anne-Louise; Simpson-Yap, Steve; Blizzard, Leigh; Broadley, Simon; Lechner-Scott, Jeannette; Lucas, Robyn; Dear, Keith; Ponsonby, Anne-Louise; Dwyer, Terry; van der Mei, Ingrid; Blizzard, Leigh; Simpson-Yap, Steve; Taylor, Bruce; Broadley, Simon; Kilpatrick, Trevor; Williams, David; Lechner-Scott, Jeanette; Shaw, Cameron; Chapman, Caron; Coulthard, Alan; Pender, Michael; Valery, Patricia; Karabudak, Rana; Patti, Francesco; Eichau, Sara; Onofrj, Marco; Ozakbas, Serkan; Horakova, Dana; Kubala Havrdova, Eva; Grand’Maison, Francois; Alroughani, Raed; Gerlach, Oliver; Amato, Maria Pia; Altintas, Ayse; Girard, Marc; Duquette, Pierre; Blanco, Yolanda; Ramo-Tello, Cristina; Laureys, Guy; Kalincik, Tomas; Khoury, Samia J.; Shaygannejad, Vahid; Etemadifar, Masoud; Singhal, Bhim; Mrabet, Saloua; Foschi, Matteo; Habek, Mario; John, Nevin; Hughes, Stella; McCombe, Pamela; Ampapa, Radek; van der Walt, Anneke; Butzkueven, Helmut; de Gans, Koen; McGuigan, Chris; Oreja-Guevara, Celia; Sa, Maria Jose; Petersen, Thor; Al-Harbi, Talal; Sempere, Angel Perez; Van Wijmeersch, Bart; Grigoriadis, Nikolaos; Prevost, Julie; Gray, Orla; Castillo-Triviño, Tamara; Macdonell, Richard; Lugaresi, Alessandra; Sajedi, Seyed Aidin; van der Mei, Ingrid: Examining the environmental risk factors of progressive-onset and relapsing-onset multiple sclerosis: recruitment challenges, potential bias, and statistical strategies