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Monthly ambient sunlight, infections and relapse rates in multiple sclerosis

Citation

Tremlett, H and Van der Mei, IAF and Pittas, F and Blizzard, CL and Paley, GA and Mesaros, D and Wood-Baker, R and Nunez, M and Dwyer, T and Taylor, BVM and Ponsonby, AL, Monthly ambient sunlight, infections and relapse rates in multiple sclerosis, Neuroepidemiology, 31, (4) pp. 271-279. ISSN 0251-5350 (2008) [Refereed Article]

DOI: doi:10.1159/000166602

Abstract

Background: Monthly variation in multiple sclerosis (MS) relapses has been found. The relationship between seasonal environmental factors, infections, serum vitamin D [25(OH)D] and MS relapses is undetermined. Methods: We prospectively followed a population-based cohort of relapsing-remitting (RR) MS patients in Southern Tasmania for a mean 2.3 years (January 2002-April 2005). Associations between monthly ambient environmental factors, estimated serum 25(OH)D, upper respiratory tract (URT) infections and relapse rates were examined using weighted Pearson's correlation and linear regression. Results: Of 199 definite MS patients, 142 had RRMS. The lowest relapse rate of 0.5 per 1,000 days (95% CI: 0.2-1.3) occurred in February (mid-late summer) versus the March-January RR of 1.1 per 1,000 days (95% CI: 0.9-1.3; p = 0.018, weighted regression). Monthly relapse rates correlated with: (1) prior erythemal ultraviolet radiation (EUV): lagged 1.5 months, r = -0.32, p = 0.046; (2) URT infection rate: no lag, r = 0.39, p = 0.014; (3) 25(OH)D: no lag, r = -0.31, p = 0.057. The association between URT infections and relapses was reduced after adjustment for monthly EUV. Conclusions: Relapse rates were inversely associated with EUV and serum 25(OH)D levels and positively associated with URT infections. The demonstrated lag between EUV but not 25(OH)D and relapse rates is consistent with a role for EUV-generated 25(OH)D in the alteration of relapse rates. Future work on the association between URT infections and relapses should be considered in the context of ultraviolet radiation and vitamin D. Copyright © 2008 S. Karger AG.

Item Details

Item Type:Refereed Article
Research Division:Medical and Health Sciences
Research Group:Public Health and Health Services
Research Field:Epidemiology
Objective Division:Health
Objective Group:Clinical Health (Organs, Diseases and Abnormal Conditions)
Objective Field:Nervous System and Disorders
Author:Van der Mei, IAF (Associate Professor Ingrid van der Mei)
Author:Pittas, F (Dr Fotini Pittas)
Author:Blizzard, CL (Associate Professor Leigh Blizzard)
Author:Paley, GA (Ms Glenys Paley)
Author:Mesaros, D (Dr Desiree Meszaros)
Author:Wood-Baker, R (Professor Richard Wood-Baker)
Author:Nunez, M (Dr Manuel Nunez)
Author:Dwyer, T (Professor Terry Dwyer)
Author:Taylor, BVM (Professor Bruce Taylor)
Author:Ponsonby, AL (Professor Anne Ponsonby)
ID Code:53802
Year Published:2008
Web of Science® Times Cited:92
Deposited By:Menzies Institute for Medical Research
Deposited On:2009-01-09
Last Modified:2009-05-02
Downloads:0

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