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


Taylor, BV and Lucas, RM and Dear, K and Kilpatrick, TJ and Pender, MP and van der Mei, IAF and Chapman, C and Coulthard, A and Dwyer, T and McMichael, AJ and Valery, PC and Williams, D and Ponsonby, AL, Latitudinal variation in incidence and type of first central nervous system demyelinating events, Multiple Sclerosis, 16, (4) pp. 398-405. ISSN 1352-4585 (2010) [Refereed Article]

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Copyright 2010, SAGE Publications.

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DOI: doi:10.1177/1352458509359724


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 (1859 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) 7.3711.78, 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 9.6819.94, p < 0.001); female 8.13% (95% CI 5.6910.62, p < 0.001)); and also by the presenting FDE type: optic neuritis 11.39% (95% CI 7.1515.80, p < 0.001); brainstem/cerebellar syndrome 9.47% (95% CI 5.1813.93, p < 0.001); and spinal cord syndrome 5.36% (95% CI 1.789.06, 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.

Item Details

Item Type:Refereed Article
Keywords:Multiple sclerosis, incidence, first demyelinating event, latitude
Research Division:Biomedical and Clinical Sciences
Research Group:Neurosciences
Research Field:Central nervous system
Objective Division:Health
Objective Group:Public health (excl. specific population health)
Objective Field:Preventive medicine
UTAS Author:Taylor, BV (Professor Bruce Taylor)
UTAS Author:van der Mei, IAF (Professor Ingrid van der Mei)
ID Code:65869
Year Published:2010
Web of Science® Times Cited:72
Deposited By:Menzies Institute for Medical Research
Deposited On:2010-12-08
Last Modified:2011-05-02
Downloads:2 View Download Statistics

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