title: Fast multiple sclerosis progression in North Africans: Both genetics and environment matter.
abstract: OBJECTIVE
  To compare multiple sclerosis (MS) disability progression among North Africans (NAs) living in France (NAF) and in Tunisia (NAT) and Caucasian patients born and living in France (CF).
  
  
  METHODS
  Patients with MS admitted to the day hospital in the Neurology Department at Pitié-Salpêtrière Hospital (France) and Razi Hospital (Tunisia) were questioned on their place of birth and the place of birth of their parents. To compare delay to outcomes, log-rank tests were used. Univariate and multivariate Cox models were used to determine factors influencing time to Expanded Disability Status Scale (EDSS) 6.
  
  
  RESULTS
  We consecutively included 462 patients: 171 CF, 151 NAT, and 140 NAF. Sex ratio, disease forms, and delay from disease onset to diagnosis were similar between the groups. NAF differed from other groups, with a shorter median time to reach EDSS 3, 4, and 6, and a more frequent incomplete recovery after first relapse (p< 0.0001). Furthermore, the NA second-generation group showed the youngest median age at onset (26.5 ± 8.8 years,p= 0.001), the shortest median time to EDSS 6 in relapsing-remitting patients, and an increased mean number of relapses during the first 5 years of the disease (6.1 ± 3.7,p= 0.01) compared to CF. The Cox proportional hazard models demonstrate that (1) NA ethnicity is a significant predictor of fast progression even when adjusting for major covariates and (2) treatment did not influence the models.
  
  
  CONCLUSIONS
  Our study further supports severity of MS in NAs and unravels the particular severity in NAs living in France, mainly for the second generation.
authors.affiliation: From the Department of Neurology (Y.S., E.M., C.L., C.P.) and Biostatistics Unit (S.T.d.M.), Pitié-Salpêtrière Hospital, Assistance Publique-Hôpitaux de Paris, France; Department of Neurology (Y.S., I.K., R.G.), UR12SP21, Razi Hospital; Faculty of Medicine of Tunis (Y.S., I.K., R.G.), University Tunis Elmanar, Tunisia; UMR_S1136 (S.T.d.M.) and UMR_S 1127 (C.L.), UPMC Univ Paris 06, Sorbonne Universités; and INSERM UMR_S 1136 (S.T.d.M.), Institut Pierre Louis d'Epidémiologie et de Santé Publique, Paris, France. Youssef.sidhom@gmail.com.
authors.forename: Youssef
authors.initials: Y
authors.lastname: Sidhom
authors.affiliation: From the Department of Neurology (Y.S., E.M., C.L., C.P.) and Biostatistics Unit (S.T.d.M.), Pitié-Salpêtrière Hospital, Assistance Publique-Hôpitaux de Paris, France; Department of Neurology (Y.S., I.K., R.G.), UR12SP21, Razi Hospital; Faculty of Medicine of Tunis (Y.S., I.K., R.G.), University Tunis Elmanar, Tunisia; UMR_S1136 (S.T.d.M.) and UMR_S 1127 (C.L.), UPMC Univ Paris 06, Sorbonne Universités; and INSERM UMR_S 1136 (S.T.d.M.), Institut Pierre Louis d'Epidémiologie et de Santé Publique, Paris, France.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Maillart
authors.affiliation: From the Department of Neurology (Y.S., E.M., C.L., C.P.) and Biostatistics Unit (S.T.d.M.), Pitié-Salpêtrière Hospital, Assistance Publique-Hôpitaux de Paris, France; Department of Neurology (Y.S., I.K., R.G.), UR12SP21, Razi Hospital; Faculty of Medicine of Tunis (Y.S., I.K., R.G.), University Tunis Elmanar, Tunisia; UMR_S1136 (S.T.d.M.) and UMR_S 1127 (C.L.), UPMC Univ Paris 06, Sorbonne Universités; and INSERM UMR_S 1136 (S.T.d.M.), Institut Pierre Louis d'Epidémiologie et de Santé Publique, Paris, France.
authors.forename: Sophie
authors.initials: S
authors.lastname: Tezenas du Montcel
authors.affiliation: From the Department of Neurology (Y.S., E.M., C.L., C.P.) and Biostatistics Unit (S.T.d.M.), Pitié-Salpêtrière Hospital, Assistance Publique-Hôpitaux de Paris, France; Department of Neurology (Y.S., I.K., R.G.), UR12SP21, Razi Hospital; Faculty of Medicine of Tunis (Y.S., I.K., R.G.), University Tunis Elmanar, Tunisia; UMR_S1136 (S.T.d.M.) and UMR_S 1127 (C.L.), UPMC Univ Paris 06, Sorbonne Universités; and INSERM UMR_S 1136 (S.T.d.M.), Institut Pierre Louis d'Epidémiologie et de Santé Publique, Paris, France.
authors.forename: Imen
authors.initials: I
authors.lastname: Kacem
authors.affiliation: From the Department of Neurology (Y.S., E.M., C.L., C.P.) and Biostatistics Unit (S.T.d.M.), Pitié-Salpêtrière Hospital, Assistance Publique-Hôpitaux de Paris, France; Department of Neurology (Y.S., I.K., R.G.), UR12SP21, Razi Hospital; Faculty of Medicine of Tunis (Y.S., I.K., R.G.), University Tunis Elmanar, Tunisia; UMR_S1136 (S.T.d.M.) and UMR_S 1127 (C.L.), UPMC Univ Paris 06, Sorbonne Universités; and INSERM UMR_S 1136 (S.T.d.M.), Institut Pierre Louis d'Epidémiologie et de Santé Publique, Paris, France.
authors.forename: Catherine
authors.initials: C
authors.lastname: Lubetzki
authors.affiliation: From the Department of Neurology (Y.S., E.M., C.L., C.P.) and Biostatistics Unit (S.T.d.M.), Pitié-Salpêtrière Hospital, Assistance Publique-Hôpitaux de Paris, France; Department of Neurology (Y.S., I.K., R.G.), UR12SP21, Razi Hospital; Faculty of Medicine of Tunis (Y.S., I.K., R.G.), University Tunis Elmanar, Tunisia; UMR_S1136 (S.T.d.M.) and UMR_S 1127 (C.L.), UPMC Univ Paris 06, Sorbonne Universités; and INSERM UMR_S 1136 (S.T.d.M.), Institut Pierre Louis d'Epidémiologie et de Santé Publique, Paris, France.
authors.forename: Riadh
authors.initials: R
authors.lastname: Gouider
authors.affiliation: From the Department of Neurology (Y.S., E.M., C.L., C.P.) and Biostatistics Unit (S.T.d.M.), Pitié-Salpêtrière Hospital, Assistance Publique-Hôpitaux de Paris, France; Department of Neurology (Y.S., I.K., R.G.), UR12SP21, Razi Hospital; Faculty of Medicine of Tunis (Y.S., I.K., R.G.), University Tunis Elmanar, Tunisia; UMR_S1136 (S.T.d.M.) and UMR_S 1127 (C.L.), UPMC Univ Paris 06, Sorbonne Universités; and INSERM UMR_S 1136 (S.T.d.M.), Institut Pierre Louis d'Epidémiologie et de Santé Publique, Paris, France.
authors.forename: Caroline
authors.initials: C
authors.lastname: Papeix
mesh_terms: D000328:Adult; D000368:Aged; D051401:Aquaporin 4 / Q000276:immunology; D004185:Disability Evaluation; D004777:Environment; D005260:Female; D005602:France / Q000453:epidemiology; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D053208:Kaplan-Meier Estimate; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D020528:Multiple Sclerosis, Chronic Progressive / Q000097:blood / Q000453:epidemiology* / Q000235:genetics*; D016016:Proportional Hazards Models; D014416:Tunisia / Q000453:epidemiology; D044465:White People
chemical_list: C496030:AQP4 protein, human; D051401:Aquaporin 4; D007074:Immunoglobulin G