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Sex ratio of multiple sclerosis and clinical phenotype
Author(s) -
Ramagopalan S. V.,
Byrnes J. K.,
Orton S.M.,
Dyment D. A.,
Guimond C.,
Yee I. M.,
Ebers G. C.,
Sadovnick A. D.
Publication year - 2010
Publication title -
european journal of neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.881
H-Index - 124
eISSN - 1468-1331
pISSN - 1351-5101
DOI - 10.1111/j.1468-1331.2009.02850.x
Subject(s) - multiple sclerosis , medicine , sex ratio , rank correlation , spearman's rank correlation coefficient , correlation , population , clinically isolated syndrome , immunology , statistics , geometry , mathematics , environmental health , machine learning , computer science
Background and purpose: In a longitudinal population‐based dataset of patients with multiple sclerosis (MS), we have previously observed a substantial increase in the female to male sex ratio in Canada over the last 50 years. Here, we aimed to determine whether this change in sex ratio is related to the clinical course of MS.
Methods: We calculated sex ratios by birth year in 11 868 patients with relapsing–remitting (RR) MS and 2825 patients with primary progressive (PP) MS identified as part of the Canadian Collaborative Project on the Genetic Susceptibility to MS.
Results: Year of birth was a significant predictor for sex ratio in RR MS ( P < 0.0001, χ 2 = 21.2; Spearman’s rank correlation r = 0.67), but not for PP MS ( P = 0.44, χ 2 = 0.6; Spearman’s rank correlation r = 0.11).
Conclusions: An increase in the number of female RR MS patients over time accounts for the increasing sex ratio of MS. This has implications for pathogenesis, for assessment of clinical trial results and for disease prevention. The factors underlying the selective increase in MS in females need to be uncovered.