Geographical Variations in Sex Ratio Trends over Time in Multiple Sclerosis

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Author(s)
Trojano, Maria
Lucchese, Guglielmo
Graziano, Giusi
Taylor, Bruce V
Simpson, Steve
Lepore, Vito
Grand'Maison, Francois
Duquette, Pierre
Izquierdo, Guillermo
Grammond, Pierre
Amato, Maria Pia
Bergamaschi, Roberto
Giuliani, Giorgio
Boz, Cavit
Hupperts, Raymond
Van Pesch, Vincent
Lechner-Scott, Jeannette
Cristiano, Edgardo
Fiol, Marcela
Oreja-Guevara, Celia
Laura Saladino, Maria
Verheul, Freek
Slee, Mark
Paolicelli, Damiano
Tortorella, Carla
D'Onghia, Mariangela
Iaffaldano, Pietro
Direnzo, Vita
Butzkueven, Helmut
Griffith University Author(s)
Year published
2012
Metadata
Show full item recordAbstract
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 ...
View more >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 83ࠎ and 45ࠎ (from 1.93 to 4.55; p<0.0001) and between 45ࠎ to 35ࠎ (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 12ࠓ and 55ࠓ 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.
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View more >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 83ࠎ and 45ࠎ (from 1.93 to 4.55; p<0.0001) and between 45ࠎ to 35ࠎ (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 12ࠓ and 55ࠓ 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.
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Journal Title
PLoS ONE
Volume
7
Issue
10
Copyright Statement
© 2012 Trojano et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits
unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Subject
Medical and Health Sciences not elsewhere classified