Fast multiple sclerosis progression in North Africans: Both genetics and environment matter

Neurology. 2017 Mar 28;88(13):1218-1225. doi: 10.1212/WNL.0000000000003762. Epub 2017 Feb 24.

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.

Conclusion: Our study further supports severity of MS in NAs and unravels the particular severity in NAs living in France, mainly for the second generation.

Publication types

  • Multicenter Study
  • Observational Study

MeSH terms

  • Adult
  • Aged
  • Aquaporin 4 / immunology
  • Disability Evaluation
  • Environment*
  • Female
  • France / epidemiology
  • Humans
  • Immunoglobulin G / blood
  • Kaplan-Meier Estimate
  • Longitudinal Studies
  • Male
  • Middle Aged
  • Multiple Sclerosis, Chronic Progressive / blood
  • Multiple Sclerosis, Chronic Progressive / epidemiology*
  • Multiple Sclerosis, Chronic Progressive / genetics*
  • Proportional Hazards Models
  • Tunisia / epidemiology
  • White People

Substances

  • AQP4 protein, human
  • Aquaporin 4
  • Immunoglobulin G