Low Sun Exposure Increases Multiple Sclerosis Risk Both Directly and Indirectly
J Neurol, 2019 Dec 17, PMID: 31844981 DOI: 10.1007/s00415-019-09677-3
Anna Karin Hedström 1, Tomas Olsson 2, Ingrid Kockum 2, Jan Hillert 2, Lars Alfredsson 3 4
Items in both categories MS and UV are listed here:
- Mutiple Sclerosis half as likely in children spending 30 to 60 minutes per day in the sun – Dec 2021
- Sun reduces risk of Multiple Sclerosis via both Vitamin D and another way – Dec 2019
- UV helped EAE mice (MS) designed to not respond to Vitamin D – Oct 2019
- Multiple Sclerosis 2X more likely if low winter UV – June 2018
- Multiple Sclerosis half as likely if get plenty of sunshine (not a news item) – March 2018
- Clinically Isolated Syndrome progresses to Multiple Sclerosis, unless UVB treatments – RCT Dec 2017
- Vitamin D and Sun conference – Germany June 2017
- Multiple Sclerosis suppressed by an Ultraviolet wavelength not associated with Vitamin D (mice) – Nov 2016
- Multiple Sclerosis helped by UV – possibly via cytokines, etc. – Oct 2015
- Hypothesis – Multiple Sclerosis risk increases with low UV, viral infections, and antibiotics in childhood – March 2015
- How UVB reduces autoimmune diseases such as Multiple Sclerosis – April 2014
- UV decreases Multiple Sclerosis via cis-urocanic acid (and via vitamin D) – June 2013
- MS prevention by UV is 2X better than prevention by vitamin D levels – Jan 2012
- There is more in UV than vitamin D which suppresses MS in mice – April 2010
- UV produces more than vitamin D – Aug 2011
- Lack of UV 20X more associated with MS than any other variable – Dec 2010
- Hypothesis - more in sunshine than vitamin D to reduce MS – Feb 2010
- MS UV and Vitamin D – 2009
- Lack of UV increased offspring MS - April 2010
- Mouse MS: UVB but not Vitamin D reduced incidence - April 2010
Download the PDF from VitaminDWiki
Objective: We aimed to study (1) to what extent the influence of low sun exposure on multiple sclerosis (MS) risk is mediated by low vitamin D levels; (2) whether low sun exposure or vitamin D deficiency act synergistically with HLA-DRB1*15:01 and absence of HLA-A*02:01.
Methods: We used two population-based case-control studies (7069 cases, 6632 matched controls). Subjects with different HLA alleles, sun exposure habits and vitamin D status were compared regarding MS risk, by calculating odds ratios (OR) with 95% confidence intervals (CI) employing logistic regression. Mediation analysis was used to identify the potential mediation effect of vitamin D on the relationship between low sun exposure and MS risk.
Results: Low sun exposure increased MS risk directly as well as indirectly, by affecting vitamin D status. The direct effect, expressed as OR, was 1.26 (95% CI 1.04-1.45) and the indirect effect, mediated by vitamin D deficiency, was 1.10 (95% CI 1.02-1.23). Of the total effect, nearly 30% was mediated by vitamin D deficiency. There was a significant interaction between low sun exposure and vitamin D deficiency (attributable proportion due to interaction 0.3, 95% CI 0.04-0.5) accounting for about 12% of the total effect. Further, both factors interacted with HLA-DRB1*15:01 to increase MS risk.
Interpretation: Our findings indicate that low sun exposure acts both directly on MS risk as well as indirectly, by leading to low vitamin D levels. The protective effect of sun exposure thus seems to involve both vitamin D and non-vitamin D pathways, which is of relevance for prevention, in particular for those with a genetic susceptibility to MS.