Sunlight exposure exerts immunomodulatory effects to reduce multiple sclerosis severity
Authors: Ostkamp Patrick , Salmen Anke , Pignolet Béatrice , Görlich Dennis , Andlauer Till F. M. , Schulte-Mecklenbeck Andreas , Gonzalez-Escamilla Gabriel , Bucciarelli Florence , Gennero Isabelle , Breuer Johanna , Antony Gisela , Schneider-Hohendorf Tilman , Mykicki Nadine , Bayas Antonios , Then Bergh Florian , Bittner Stefan , Hartung Hans-Peter , Friese Manuel A. , Linker Ralf A. , Luessi Felix , Lehmann-Horn Klaus , Mühlau Mark , Paul Friedemann , Stangel Martin , Tackenberg Björn , Tumani Hayrettin , Warnke Clemens , Weber Frank , Wildemann Brigitte , Zettl Uwe K. , Ziemann Ulf , Müller-Myhsok Bertram , Kümpfel Tania , Klotz Luisa , Meuth Sven G. , Zipp Frauke , Hemmer Bernhard , Hohlfeld Reinhard , Brassat David , Gold Ralf , Gross Catharina C. , Lukas Carsten , Groppa Sergiu , Loser Karin , Wiendl Heinz , Schwab Nicholas ,   on behalf of the German Competence Network Multiple Sclerosis (KKNMS) and the BIONAT Network, Bayas Antonios , Rothacher Susanne , Starke Stephanie , Paul Friedemann , Bellmann-Strobl Judith , Behrens Janina , Dörr Jan-Markus , Gieß Rene , Kuchling Joseph , Rasche Ludwig , Gold Ralf , Chan Andrew , Ellrichmann Gisa , Fisse Anna Lena , Gahlen Anna , Grüter Thomas , Haghikia Aiden , Hoepner Robert , Koc Ümmügülsün , Lukas Carsten , Motte Jeremias , Pitarokoili Kalliopi , Salmen Anke , Schneider Ruth , Schöllhammer Joanna , Schroeder Christoph , Ambrosius Björn , Demir Seray , Warnke Clemens , Dehmel Thomas , Ingenhoven Kathleen , Linker Ralf , Lee De-Hyung , Lämmer Alexandra , Sauer Eva , Heesen Christoph , Stellmann Jan-Patrick , Stangel Martin , Boenig Lena , Gingele Stefan , Hümmert Martin , Schwenkenbecher Philipp , Skripuletz Thomas , Suehs Wolfram , Wildemann Brigitte , Korporal-Kuhnke Mirjam , Oßwald Hanna , Schwarz Alexander , Viehöver Andrea , Limmroth Volker , Gerbershagen Kathrin , Bergh Florian Then , Ettrich Barbara , Gray Steffi , Haars Sarah , Orthgieß Johannes , Schwanitz Nicole , Stoppe Muriel , Unterlauft Astrid , Paryjas Sandra , Bittner Stefan , Fleischer Vinzenz , Groppa Sergiu , Lüssi Felix , Piepgras Johannes , Uphaus Timo , Tackenberg Björn , Pütz Michael , Eienbröker Christian , Seipelt Maria , Hohlfeld Reinhard , Kümpfel Tania , Havla Joachim , Meinl Ingrid , Pellkofer Hannah , Schuh Elisabeth , Hemmer Bernhard , Aly Lilian , Berthele Achim , Pongratz Viola , Brinkhoff Kirsten , Buck Dorothea , Gasperi Christiane , Hermisson Mirjam , Hoshi Muna-Miriam , Kaminski Miriam , Klein Ana , Knier Benjamin , Kowarik Markus , Kronsbein Helena , Horn Klaus Lehmann , Mitsdörffer Meike , Pernpeintner Verena , Rothhammer Veit , Schweikert Andrea , Selter Rebecca , Mühlau Mark , Zimmer Claus , Kirschke Jan , Weber Frank , Staufer Heike , Knop Matthias , Nischwitz Sandra , Sämann Philipp , Wiendl Heinz , Meuth Sven , Klotz Luisa , Meyer zu Hörste Gerd , Krämer Julia , Schünemann Lena , Gross Catharina , Pfeuffer Steffen , Ruck Tobias , Belgriri Selma , Buchheister Alexander , Bünger Nora , Göbel Kerstin , Kirstein Lucienne , Melzer Nico , Simon Ole , Echterhoff Antje , Zettl Uwe , Winkelmann Alexander , Ziemann Ulf , Abdelhak Ahmed , Kowarik Markus , Krumbholz Markus , Paech Margarete , Ruschil Christoph , Stefanou Maria-Ioanna , Tünnerhoff Johannes , Zeltner Lena , Sheikh Hajera , Tumani Hayrettin , Fangerau Tanja , Lauda Florian , Rau Daniela , Taranu Daniela , Huss André , Brassat David , Pignolet Béatrice , Bucciarelli Florence , Scandella Lise , Lebrun-Frenay Christine , Debouverie Marc , Pittion-Vouyovitch Sophie , Brochet Bruno , Ruet Aurelie , Defer Gilles , Derache Nathalie , de Sèze Jérôme , Laplaud David , Wiertlewski Sandrine , Casez Oliver , Clavelou Pierre , Labauge Pierre , Pelletier Jean , Rico Audrey , Vukusic Sandra , Outteryck Olivier , Jean-Claude  , Ouallet Jean-Christophe , Hautecoeur Patrick , Tourbah Ayman , Castelnovo Giovanni , Berger Eric , Zéphir Hélène , Cabre Philippe , Camu William , Thouvenot Eric , Moreau Thibault , Fromont Agnès , Papeix Caroline , Lubetzki Catherine , Vermersch Patrick , Cohen Mikael , Rumbach Lucien 
Published: December 2020

SignificanceLow sunlight exposure and low vitamin D (vitD) levels are risk factors for the development of multiple sclerosis. However, there is still an ongoing debate, whether sunlight and vitD also modulate disease severity and worsening. Observational studies suggested vitD-dependent effects, but prospective supplementation studies have so far been inconclusive and reverse causality cannot be excluded as a source of bias. By using the sun-exposure measures vitD and latitude, we show correlations between vitD/latitude, vitD/disease severity, and latitude/disease severity in two multicentric cohorts. Although vitD cannot be proven as the causal factor, we provide evidence for clinically relevant effects of sunlight exposure. Furthermore, this study suggests sunlight-triggered pathways other than vitD could play additional and modulatory roles, as well.