Sunlight exposure and sun sensitivity associated with disability progression in multiple sclerosis
MB D'hooghe marie.dhooghe@ms-centrum.be
National Centre For Multiple Sclerosis, Melsbroek, Belgium
P Haentjens
Center for Outcomes Research and Laboratory for Experimental Surgery, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel, Brussels, Belgium
G Nagels
National Centre For MS, Melsbroek/Service d’orthopédagogie Clinique, Faculty of Psychology and Education Sciences, University of Mons, Belgium
M Garmyn
Department of Dermatology, Universitaire Ziekenhuizen, Leuven, Belgium
J De Keyser
Dpt of Neurology UZ Brussel, Vrije Universiteit Brussel (VUB), Brussels, Belgium/Dpt of Neurology Uni. Med. Center Groningen, Groningen, The Netherlands
Abstract
Background: Sunlight and vitamin D have been inversely associated with the risk of multiple sclerosis (MS).
Objective: We investigated sunlight exposure and sun sensitivity in relation to disability progression in MS.
Methods: We conducted a survey among persons with MS, registered by the Flemish MS society, Belgium, and stratified data according to relapsing-onset and progressive-onset MS. We used Kaplan–Meier survival and Cox proportional hazard regression analyses with time to Expanded Disability Status Scale (EDSS) 6 as outcome measure. Hazard ratios for the time from onset and from birth were calculated for the potentially predictive variables, adjusting for age at onset, gender and immunomodulatory treatment.
Results: 704 (51.3%) of the 1372 respondents had reached EDSS 6. In relapsing-onset MS, respondents reporting equal or higher levels of sun exposure than persons of the same age in the last 10 years had a decreased risk of reaching EDSS 6. In progressive-onset MS, increased sun sensitivity was associated with an increased hazard of reaching EDSS 6.
Conclusion: The association of higher sun exposure with a better outcome in relapsing-onset MS may be explained by either a protective effect or reverse causality. Mechanisms underlying sun sensitivity might influence progression in progressive-onset MS.
MB D'hooghe marie.dhooghe@ms-centrum.be
National Centre For Multiple Sclerosis, Melsbroek, Belgium
P Haentjens
Center for Outcomes Research and Laboratory for Experimental Surgery, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel, Brussels, Belgium
G Nagels
National Centre For MS, Melsbroek/Service d’orthopédagogie Clinique, Faculty of Psychology and Education Sciences, University of Mons, Belgium
M Garmyn
Department of Dermatology, Universitaire Ziekenhuizen, Leuven, Belgium
J De Keyser
Dpt of Neurology UZ Brussel, Vrije Universiteit Brussel (VUB), Brussels, Belgium/Dpt of Neurology Uni. Med. Center Groningen, Groningen, The Netherlands
Abstract
Background: Sunlight and vitamin D have been inversely associated with the risk of multiple sclerosis (MS).
Objective: We investigated sunlight exposure and sun sensitivity in relation to disability progression in MS.
Methods: We conducted a survey among persons with MS, registered by the Flemish MS society, Belgium, and stratified data according to relapsing-onset and progressive-onset MS. We used Kaplan–Meier survival and Cox proportional hazard regression analyses with time to Expanded Disability Status Scale (EDSS) 6 as outcome measure. Hazard ratios for the time from onset and from birth were calculated for the potentially predictive variables, adjusting for age at onset, gender and immunomodulatory treatment.
Results: 704 (51.3%) of the 1372 respondents had reached EDSS 6. In relapsing-onset MS, respondents reporting equal or higher levels of sun exposure than persons of the same age in the last 10 years had a decreased risk of reaching EDSS 6. In progressive-onset MS, increased sun sensitivity was associated with an increased hazard of reaching EDSS 6.
Conclusion: The association of higher sun exposure with a better outcome in relapsing-onset MS may be explained by either a protective effect or reverse causality. Mechanisms underlying sun sensitivity might influence progression in progressive-onset MS.
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