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Sun exposure across the life course significantly modulates early multiple sclerosis clinical course

Citation

Simpson Jr, S and Van Der Mei, I and Lucas, RM and Ponsonby, A-L and Broadley, S and Blizzard, L and Taylor, B, Ausimmune/AusLong Investigators Group, Sun exposure across the life course significantly modulates early multiple sclerosis clinical course, Frontiers in Neurology, 9, (FEB) Article 16. ISSN 1664-2295 (2018) [Refereed Article]


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Copyright Statement

Copyright 2018 Simpson, van der Mei, Lucas, Ponsonby, Broadley, Blizzard, Ausimmune/AusLong Investigators Group and Taylor. Licensed under Creative Commons Attribution 4.0 International (CC BY 4.0) https://creativecommons.org/licenses/by/4.0/

DOI: doi:10.3389/fneur.2018.00016

Abstract

Background: Low vitamin D and/or sun exposure have been associated with increased risk of multiple sclerosis (MS) onset. However, comparatively, few studies have prospectively examined associations between these factors and clinical course.

Objectives: To evaluate the association of sun exposure parameters and vitamin D levels with conversion to MS and relapse risk in a prospectively monitored cohort of 145 participants followed after a first demyelinating event up to 5-year review (AusLong Study).

Methods: Sun exposure prior to and after onset measured by annual questionnaire; ultraviolet radiation (UVR) "load" estimated by location of residence over the life course and ambient UVR levels. Serum 25-hydroxyvitamin D [25(OH)D] concentrations measured at baseline, 2/3-year, and 5-year review. MS conversion and relapse assessed by neurologist assessment and medical record review.

Results: Over two-thirds (69%) of those followed to 5-year review (100/145) converted to MS, with a total of 252 relapses. Higher pre-MS onset sun exposure was associated with reduced risk of MS conversion, with internal consistency between measures and dose-response relationships. Analogous associations were also seen with risk of relapse, albeit less strong. No consistent associations were observed between postonset sun exposure and clinical course, however. Notably, those who increased their sun exposure during follow-up had significantly reduced hazards of MS conversion and relapse. Serum 25(OH)D levels and vitamin D supplementation were not associated with conversion to MS or relapse hazard.

Conclusion: We found that preonset sun exposure was protective against subsequent conversion to MS and relapses. While consistent associations between postonset sun exposure or serum 25(OH)D level and clinical course were not evident, possibly masked by behavior change, those participants who markedly increased their sun exposure demonstrated a reduced MS conversion and relapse hazard, suggesting beneficial effects of sun exposure on clinical course.

Item Details

Item Type:Refereed Article
Keywords:CIS, behaviour change, first demyelinating event, multiple sclerosis, relapse, sun exposure, ultraviolet radiation, vitamin D
Research Division:Medical and Health Sciences
Research Group:Neurosciences
Research Field:Central Nervous System
Objective Division:Health
Objective Group:Clinical Health (Organs, Diseases and Abnormal Conditions)
Objective Field:Nervous System and Disorders
UTAS Author:Simpson Jr, S (Dr Steve Simpson JR)
UTAS Author:Van Der Mei, I (Associate Professor Ingrid van der Mei)
UTAS Author:Blizzard, L (Professor Leigh Blizzard)
UTAS Author:Taylor, B (Professor Bruce Taylor)
ID Code:126734
Year Published:2018
Web of Science® Times Cited:5
Deposited By:Menzies Institute for Medical Research
Deposited On:2018-06-21
Last Modified:2019-02-25
Downloads:80 View Download Statistics

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