[1] Imperial Coll London, Dept Primary Care & Publ Hlth, London, England
[2] Univ Federico II Naples, Dept Publ Hlth, Naples, Italy
[3] Univ Federico II Naples, CIRMIS Interdept Ctr Res Healthcare Management &, Naples, Italy
[4] Univ Manitoba, Dept Internal Med, Max Rady Coll Med, Rady Fac Hlth Sci, Winnipeg, MB, Canada
[5] Univ Manitoba, Dept Community Hlth Sci, Max Rady Coll Med, Rady Fac Hlth Sci, Winnipeg, MB, Canada
[6] UCL, Queen Sq Multiple Sclerosis Ctr, Dept Neuroinflammat, UCL Queen Sq Inst Neurol,Fac Brain Sci, London, England
[7] Univ Coll London Hosp, Biomed Res Ctr, Natl Inst Hlth Res, London, England