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Geographical variations in sex ratio trends over time in multiple sclerosis


Trojano, M and Lucchese, G and Graziano, G and Taylor, BV and Simpson JR, S and Lepore, V and Grand'Maison, F and Duquette, P and Izquierdo, G and Grammond, P and Amato, MP and Bergamaschi, R and Giuliani, G and Boz, C and Hupperts, R and Van Pesch, V and Lechner-Scott, J and Cristiano, E and Fiol, M and Oreja-Guevara, C and Saladino, ML and Verheul, F and Slee, M and Paolicelli, D and Tortorella, C and D'Onghia, M and Iaffaldano, P and Direnzo, V and Butzkueven, H, on behalf of the MSBase Study Group, the New Zealand MS Prevalence Study Group, Geographical variations in sex ratio trends over time in multiple sclerosis, PLoS ONE, 7, (10) Article e48078. ISSN 1932-6203 (2012) [Refereed Article]


Copyright Statement

Licensed under Creative Commons Attribution 3.0 Unported (CC BY 3.0)

DOI: doi:10.1371/journal.pone.0048078


Background: A female/male (F/M) ratio increase over time in multiple sclerosis (MS) patients was demonstrated in many countries around the world. So far, a direct comparison of sex ratio time-trends among MS populations from different geographical areas was not carried out.

Objective: In this paper we assessed and compared sex ratio trends, over a 60-year span, in MS populations belonging to different latitudinal areas.

Methods: Data of a cohort of 15,996 (F = 11,290; M = 4,706) definite MS with birth years ranging from 1930 to 1989 were extracted from the international MSBase registry and the New Zealand MS database. Gender ratios were calculated by six decades based on year of birth and were adjusted for the F/M born-alive ratio derived from the respective national registries of births.

Results: Adjusted sex ratios showed a significant increase from the first to the last decade in the whole MS sample (from 2.35 to 2.73; p=0.03) and in the subgroups belonging to the areas between 83 N and 45 N (from 1.93 to 4.55; p<0.0001) and between 45 N to 35 N (from 1.46 to 2.30; p<0.05) latitude, while a sex ratio stability over time was found in the subgroup from areas between 12° S and 55 S latitude. The sex ratio increase mainly affected relapsing-remitting (RR) MS.

Conclusions: Our results confirm a general sex ratio increase over time in RRMS and also demonstrate a latitudinal gradient of this increase. These findings add useful information for planning case-control studies aimed to explore sex-related factors responsible for MS development.

Item Details

Item Type:Refereed Article
Research Division:Biomedical and Clinical Sciences
Research Group:Neurosciences
Research Field:Central nervous system
Objective Division:Health
Objective Group:Clinical health
Objective Field:Clinical health not elsewhere classified
UTAS Author:Taylor, BV (Professor Bruce Taylor)
UTAS Author:Simpson JR, S (Dr Steve Simpson JR)
ID Code:82229
Year Published:2012
Web of Science® Times Cited:141
Deposited By:Menzies Institute for Medical Research
Deposited On:2013-01-22
Last Modified:2017-11-07
Downloads:311 View Download Statistics

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