Latitudinal variation in incidence and type of first central nervous system demyelinating events

Taylor, Bruce V., Lucas, Robyn M., Dear, Keith, Kilpatrick, Trevor J., Pender, Michael P., van der Mei, Ingrid A. F., Chapman, Caron, Coulthard, Alan, Dwyer, Terence, McMichael, Anthony J., Valery, Patricia C., Williams, David and Ponsonby, Anne-Louise (2010) Latitudinal variation in incidence and type of first central nervous system demyelinating events. Multiple Sclerosis, 16 4: 398-405. doi:10.1177/1352458509359724


Author Taylor, Bruce V.
Lucas, Robyn M.
Dear, Keith
Kilpatrick, Trevor J.
Pender, Michael P.
van der Mei, Ingrid A. F.
Chapman, Caron
Coulthard, Alan
Dwyer, Terence
McMichael, Anthony J.
Valery, Patricia C.
Williams, David
Ponsonby, Anne-Louise
Title Latitudinal variation in incidence and type of first central nervous system demyelinating events
Journal name Multiple Sclerosis   Check publisher's open access policy
ISSN 1352-4585
1477-0970
Publication date 2010-04-01
Year available 2010
Sub-type Article (original research)
DOI 10.1177/1352458509359724
Open Access Status DOI
Volume 16
Issue 4
Start page 398
End page 405
Total pages 8
Editor Alan J. Thompson
Place of publication Biggleswade, U.K.
Publisher Sage Publications
Language eng
Subject 2808 Neurology
2728 Clinical Neurology
Abstract Increasing prevalence and variable geographic patterns of occurrence of multiple sclerosis suggest an environmental role in causation. There are few descriptive, population-level, data on whether such variability applies to first demyelinating events (FDEs). We recruited 216 adults (18-59 years), with a FDE between 1 November 2003 and 31 December 2006 in a multi-center incident case-control study in four locations on the south-eastern and eastern seaboard of Australia, spanning latitudes 27 degrees south to 43 degrees south. Population denominators were obtained from the Australian Bureau of Statistics censuses of 2001 and 2006. Age and sex adjusted FDE incidence rates increased by 9.55% (95% confidence interval (CI) 7.37-11.78, p<0.001) per higher degree of latitude. The incidence rate gradient per higher degree of latitude varied by gender (male: 14.69% (95% CI 9.68-19.94, p<0.001); female 8.13% (95% CI 5.69-10.62, p<0.001)); and also by the presenting FDE type: optic neuritis 11.39% (95% CI 7.15-15.80, p<0.001); brainstem/cerebellar syndrome 9.47% (95% CI 5.18-13.93, p<0.001); and spinal cord syndrome 5.36% (95% CI 1.78-9.06, p = 0.003). Differences in incidence rate gradients were statistically significant between males and females (p = 0.02) and between optic neuritis and spinal cord syndrome (p = 0.04). The male to female ratio varied from 1 : 6.7 at 27 degrees south to 1 : 2.5 at 43 degrees south. The study establishes a positive latitudinal gradient of FDE incidence in Australia. The latitude-related factor(s) influences FDE incidence variably according to subtype and gender, with the strongest influence on optic neuritis presentations and for males. These descriptive case analyses show intriguing patterns that could be important for understanding the etiology of multiple sclerosis.
Formatted abstract
Increasing prevalence and variable geographic patterns of occurrence of multiple sclerosis suggest an environmental role in causation. There are few descriptive, population-level, data on whether such variability applies to first demyelinating events (FDEs). We recruited 216 adults (18—59 years), with a FDE between 1 November 2003 and 31 December 2006 in a multi-center incident case-control study in four locations on the south-eastern and eastern seaboard of Australia, spanning latitudes 27° south to 43° south. Population denominators were obtained from the Australian Bureau of Statistics censuses of 2001 and 2006. Age and sex adjusted FDE incidence rates increased by 9.55% (95% confidence interval (CI) 7.37—11.78, p < 0.001) per higher degree of latitude. The incidence rate gradient per higher degree of latitude varied by gender (male: 14.69% (95% CI 9.68—19.94, p < 0.001); female 8.13% (95% CI 5.69—10.62, p < 0.001)); and also by the presenting FDE type: optic neuritis 11.39% (95% CI 7.15—15.80, p < 0.001); brainstem/cerebellar syndrome 9.47% (95% CI 5.18—13.93, p < 0.001); and spinal cord syndrome 5.36% (95% CI 1.78—9.06, p = 0.003). Differences in incidence rate gradients were statistically significant between males and females (p = 0.02) and between optic neuritis and spinal cord syndrome (p = 0.04). The male to female ratio varied from 1 : 6.7 at 27° south to 1 : 2.5 at 43° south. The study establishes a positive latitudinal gradient of FDE incidence in Australia. The latitude-related factor(s) influences FDE incidence variably according to subtype and gender, with the strongest influence on optic neuritis presentations and for males. These descriptive case analyses show intriguing patterns that could be important for understanding the etiology of multiple sclerosis.
© The Author(s) 2010
Keyword Multiple sclerosis
Incidence
First demyelinating event
Latitude
Clinically isolated syndromes
Environmental risk-factors
Multiple-sclerosis
Optic neuritis
Follow-up
Natural-history
MS
Multicenter
Diagnosis
Gradient
Q-Index Code C1
Q-Index Status Confirmed Code
Grant ID RG 3364A1/2
316901
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2011 Collection
School of Medicine Publications
 
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Created: Sun, 25 Apr 2010, 10:01:57 EST