RESULTS / DISCUSSION Both cross-sectional and longitudinal studies have fairly consistently demonstrated a strong positive correlation between  vitamin D deficiency and subsequent relapse and /or disability in patients with MS .
As well , there appears to be a negative correlation between vitamin D levels and inflammatory markers in MS patients , suggesting that vitamin D modifies serum cytokines to a more anti-inflammatory profile .
However , the criteria of temporality , dose-response , and experimental evidence are yet to be adequately met , although there is preliminary evidence from longitudinal studies and r and omized clinical trials ( RCTs ) of supplementation that vitamin D can attenuate the autoimmune response in patients , and potentially reduce relapse rates and burden of disease .
Ultimately , the current evidence does not permit inference of a causal relationship between vitamin D deficiency and disease activity in MS .
INTRODUCTION Given that vitamin D has a role in immunomodulation , and its levels appear to correlate with the development of Multiple Sclerosis ( MS ) , it is conceivable that vitamin D may also influence disease activity in MS patients .
In this regard , we conducted a systematic review investigating the evidence for : ( 1 ) the role of vitamin D in disease activity in MS , and ( 2 ) the therapeutic supplementation of vitamin D in MS .
Vitamin D levels in Hispanics with multiple sclerosis
Vitamin D has been associated with multiple sclerosis ( MS ) and several markers of disease state in whites . There are limited reports of vitamin D ’s influence in MS in ethnic groups , such as in Hispanics . In this study , we compared vitamin D levels in  Hispanics and whites with MS and tried to determine whether season or increasing disability influence hypovitaminosis D in Hispanics with MS .  Serum 25-hydroxyvitamin D [ 25(OH)D ] levels and clinical characteristics were compared in a cross-sectional sample of Hispanics ( n = 80 ) and whites ( n = 80 ) with MS recruited from the University of Southern California . Serum 25(OH)D levels were significantly lower in Hispanics than whites with MS ( mean and st and ard deviation 25.1 ± 9.4 and 37.3 ± 19.8 ng/ml , respectively ; p < 0.001 ) . Hispanics were significantly more likely than whites to be  vitamin D insufficient ( ≤30 ng/ml ; 70 vs. 41 % , respectively ; p < 0.001 ) and deficient ( ≤20 ng/ml ; 40 vs. 14 % , respectively , p < 0.001 ) . In Hispanics , serum 25(OH)D levels were not influenced by season ( p = 0.8 ) or higher physical disability ( EDSS ≥6 , p = 0.7 ) . We found that the relationship between vitamin D and MS differs by Hispanic ethnicity . Hypovitaminosis D was significantly more common among Hispanics than among whites with MS , and the majority of Hispanics were vitamin D insufficient . Interestingly , there was no association between vitamin D levels and season or increasing disability in the Hispanics . Our findings imply that factors influencing vitamin D levels and possibly vitamin D  requirements may vary by ethnicity in patients with MS . These results should be confirmed in larger , prospect i ve multi-ethnic cohort studies
RESULTS / DISCUSSION Both cross-sectional and longitudinal studies have fairly consistently demonstrated a strong positive correlation between  vitamin D deficiency and subsequent relapse and /or disability in patients with MS .
As well , there appears to be a negative correlation between vitamin D levels and inflammatory markers in MS patients , suggesting that vitamin D modifies serum cytokines to a more anti-inflammatory profile .
However , the criteria of temporality , dose-response , and experimental evidence are yet to be adequately met , although there is preliminary evidence from longitudinal studies and r and omized clinical trials ( RCTs ) of supplementation that vitamin D can attenuate the autoimmune response in patients , and potentially reduce relapse rates and burden of disease .
Ultimately , the current evidence does not permit inference of a causal relationship between vitamin D deficiency and disease activity in MS .
INTRODUCTION Given that vitamin D has a role in immunomodulation , and its levels appear to correlate with the development of Multiple Sclerosis ( MS ) , it is conceivable that vitamin D may also influence disease activity in MS patients .
In this regard , we conducted a systematic review investigating the evidence for : ( 1 ) the role of vitamin D in disease activity in MS , and ( 2 ) the therapeutic supplementation of vitamin D in MS .