MS Sunshine Study: Sun Exposure But Not Vitamin D Is Associated with Multiple Sclerosis Risk in Blacks and Hispanics

• Published in: Nutrients Vol. 10; no. 3; p. 268
• Main Authors: Langer-Gould, Annette, Lucas, Robyn, Xiang, Anny H, Chen, Lie H, Wu, Jun, Gonzalez, Edlin, Haraszti, Samantha, Smith, Jessica B, Quach, Hong, Barcellos, Lisa F
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 27-02-2018; MDPI
• Subjects: 25-Hydroxyvitamin D; Adult; Alleles; Black or African American; Black People; blacks; Body Mass Index; California - epidemiology; Case-Control Studies; Dietary Supplements; Ethnic factors; Ethnicity; Exposure; Female; Genotyping Techniques; Hispanic or Latino; Hispanic people; Hispanics; Histocompatibility Antigens Class II - genetics; Histocompatibility Antigens Class II - metabolism; Humans; Incidence; Male; Middle Aged; Minority & ethnic groups; Multiple sclerosis; Multiple Sclerosis - blood; Multiple Sclerosis - ethnology; Polymorphism, Single Nucleotide; Radiation effects; Radiation measurement; Risk; Risk Factors; Risk reduction; Sun; sun exposure; Sunlight; Ultraviolet radiation; Ultraviolet Rays; Vitamin D; Vitamin D - administration & dosage; Vitamin D - blood; Vitamin D Deficiency - complications; Vitamin D Deficiency - ethnology; Vitamin deficiency; White People; Young Adult; California; sun exposure; multiple sclerosis; vitamin D; Hispanics; blacks
• DOI: 10.3390/nu10030268
• EISSN: 2072-6643

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;
= 0.007) and whites (OR = 0.68, 95% CI = 0.48-0.94;
= 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;
= 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.