Footnotes

• Contributors PP: drafting/revising the manuscript, study concept, and acquisition, analysis and interpretation of the data. PMB: drafting/revising the manuscript, study concept, and acquisition and interpretation of the data. SK: drafting/revising the manuscript, and acquisition and interpretation of the data. MDS: drafting/revising the manuscript, and acquisition and interpretation of the data. AM: analysis and interpretation of the data. PJP: drafting/revising the manuscript, and interpretation of the data. MAR: drafting/revising the manuscript, study concept, interpretation of the data and study supervisor. MF: drafting/revising the manuscript, study concept, interpretation of the data and study supervisor. JJGG: drafting/revising the manuscript, study concept, interpretation of the data and study supervisor. LEJ: drafting/revising the manuscript, study concept, acquisition and interpretation of the data and study supervisor.

• Funding We thank the VU University MS Centre and the Dutch MS Research Society for their financial support (grant 14-358e MS).

• Competing interests PP received speakers honoraria from Biogen Idec, Novartis, Merck-Serono and ExceMED. PMB received research support from the Dutch MS Foundation, grant number 19-1049. SK, MDS, AM and PJP have nothing to disclose. MAR received speakers honoraria from Biogen Idec, Novartis, Genzyme, Teva, Merck Serono, Roche, Celgene and Bayer and receives research support from the Italian Ministry of Health, MS Society of Canada and Fondazione Italiana Sclerosi Multipla. MF is Editor-in-Chief of the Journal of Neurology; received compensation for consulting services and/or speaking activities from Bayer, Biogen Idec, Merck-Serono, Novartis, Roche, Sanofi Genzyme, Takeda, and Teva Pharmaceutical Industries; and receives research support from Biogen Idec, Merck-Serono, Novartis, Roche, Teva Pharmaceutical Industries, Italian Ministry of Health, Fondazione Italiana Sclerosi Multipla, and ARiSLA (Fondazione Italiana di Ricerca per la SLA). JJGG reports grants from Biogen, grants from Novartis, grants from Sanofi Genzyme and he is Editor for Europe of Multiple Sclerosis Journal. LEJ reports grants from Alzheimer’s Association and Michael J Fox foundation.

• Provenance and peer review Not commissioned; externally peer reviewed.

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