Competing interests: AT: received honoraria/support for travel for consultancy from Eisai, Hoffman La Roche, and Excemed. He received support for travel from the International Progressive MS Alliance, as chair of their Scientific Steering Committee and the National MS Society (USA) as member of their Research Programs Advisory Committee. He receives an honorarium from SAGE Publishers as Editor-in-Chief of Multiple Sclerosis Journal, and a free subscription from Elsevier as a board member for the Lancet Neurology. JP: support for scientific meetings and honorariums for advisory work from Merck Serono, ABIDE, Biogen Idec, Novartis, Alexion, MedImmune, Teva, Chugai Pharma and Bayer Schering, and unrestricted grants from Merck Serono, Novartis, Biogen Idec and Bayer Schering; funded to run a highly specialised service for neuromyelitis optica and congenital myasthenia; grants from the MS Society; GMSI, NIHR and Guthy-Jackson Foundation for research studies. JJC: speaker’s honoraria and consulting fees from Biogen, Novartis, Merck, Bayer, Teva, Genzyme and Roche; research grant from Biogen; President-Elect, Portuguese MS Study Group; scientific council member, MS Patient’s Association (’Todos com a Esclerose Múltipla'). KS: speaking honoraria from, and/or served in an advisory role for, Biogen, Merck, Novartis, Roche and Teva; supported for attendance of meetings by Genzyme, Merck and Novartis; PI of trials sponsored by Novartis, Roche, Teva and Medday; involved in trials sponsored by Biogen, Genzyme, BIAL, Cytokinetics and Canbex; research grant support from Novartis and Biogen. RG: support for scientific meetings and courses and honorariums for advisory work from Biogen Idec, Novartis, Bayer Schering, Merck Serono and Teva; this does not relate to the theme of presentation on the interaction of vascular comorbidities in multiple sclerosis. DASC: attended a company-sponsored event (Sanofi-Genzyme) for which he will be reimbursed modest travel costs and paid an honorarium; acts as a paid scientific advisor to the Lundbeck Foundation (Denmark).