TY - JOUR AU - Kowalec, K; McKay, K A; Patten, S B TI - Comorbidity increases the risk of relapse in multiple sclerosis; a prospective study JO - Neurology VL - 89 PY - 2017 DO - 10.1212/WNL.0000000000004716 SP - 2455 EP - 2461 N1 - et al. ER -