nutrients Article MS Sunshine Study: Sun Exposure But Not Vitamin D Is Associated with Multiple Sclerosis Risk in Blacks and Hispanics Annette Langer-Gould 1, *, Robyn Lucas 2 ID , Anny H. Xiang 3 , Lie H. Chen 3 , Jun Wu 3 , Edlin Gonzalez 3 , Samantha Haraszti 3,4 , Jessica B. Smith 3 , Hong Quach 5 and Lisa F. Barcellos 5 1 Los Angeles Medical Center, Department of Neurology, Southern California Permanente Medical Group, 100 S Los Robles, Pasadena, CA 91101, USA 2 College of Medicine, Biology & Environment, Australian National University, Canberra, ACT 2000, Australia; robyn.lucas@anu.edu.au 3 Department of Research & Evaluation, Kaiser Permanente Southern California, 100 S. Los Robles Avenue, Pasadena, CA 91101, USA; anny.h.xiang@kp.org (A.H.X.); lie.h.chen@kp.org (L.H.C.); jun.x.wu@kp.org (J.W.); edlin.g.gonzales@kp.org (E.G.); samanthaha@pcom.edu (S.H.); Jessica.b.smith@kp.org (J.B.S.) 4 Philadelphia College of Osteopathic Medicine, 4170 City Avenue, Philadelphia, PA 19131, USA 5 QB3 Genetic Epidemiology and Genomics Lab, School of Public Health, University of California Berkeley, 209 Hildebrand Hall, Berkeley, CA 94720-7356, USA; hquach@berkeley.edu (H.Q.); lbarcellos@berkeley.edu (L.F.B.) * Correspondence: Annette.M.Langer-Gould@kp.org; Tel.: +1-626-564-3992; Fax: +1-626-564-3403 Received: 9 January 2018; Accepted: 23 February 2018; Published: 27 February 2018 Abstract: Multiple sclerosis (MS) incidence and serum 25-hydroxyvitamin D (25OHD) levels vary by race/ethnicity. We examined the consistency of beneficial effects of 25OHD and/or sun exposure for MS risk across multiple racial/ethnic groups. We recruited incident MS cases and controls (blacks 116 cases/131 controls; Hispanics 183/197; whites 247/267) from the membership of Kaiser Permanente Southern California into the MS Sunshine Study to simultaneously examine sun exposure and 25OHD, accounting for genetic ancestry and other factors. Higher lifetime ultraviolet radiation exposure (a rigorous measure of sun exposure) was associated with a lower risk of MS independent of serum 25OHD levels in blacks (adjusted OR = 0.53, 95% CI = 0.31–0.83; p = 0.007) and whites (OR = 0.68, 95% CI = 0.48–0.94; p = 0.020) with a similar magnitude of effect that did not reach statistical significance in Hispanics (OR = 0.66, 95% CI = 0.42–1.04; p = 0.071). Higher serum 25OHD levels were associated with a lower risk of MS only in whites. No association was found in Hispanics or blacks regardless of how 25OHD was modeled. Lifetime sun exposure appears to reduce the risk of MS regardless of race/ethnicity. In contrast, serum 25OHD levels are not associated with MS risk in blacks or Hispanics. Our findings challenge the biological plausibility of vitamin D deficiency as causal for MS and call into question the targeting of specific serum 25OHD levels to achieve health benefits, particularly in blacks and Hispanics. Keywords: multiple sclerosis; vitamin D; sun exposure; blacks; Hispanics 1. Introduction Evidence from animal models and observational studies [1–3] in white populations shows that higher levels of serum 25-hydroxyvitamin D (25OHD) are associated with reduced risk of multiple sclerosis (MS). Some consider that causality has been established and vitamin D supplementation to prevent MS is widely supported [4]. Nutrients 2018, 10, 268; doi:10.3390/nu10030268 www.mdpi.com/journal/nutrients