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 intake and incidence of multiple sclerosis
Background : A protective effect of vitamin D on risk of multiple sclerosis ( MS ) has been proposed , but no prospect i ve studies have addressed this hypothesis . Methods : Dietary vitamin D intake was examined directly in relation to risk of MS in two large cohorts of women : the Nurses ’ Health Study ( NHS ; 92,253 women followed from 1980 to 2000 ) and Nurses ’ Health Study II ( NHS II ; 95,310 women followed from 1991 to 2001 ) .  Diet was assessed at baseline and up date d every 4 years thereafter . During the follow-up , 173 cases of MS with onset of symptoms after baseline were confirmed . Results : The pooled age-adjusted relative risk ( RR ) comparing women in the highest quintile of  total vitamin D intake at baseline with those in the lowest was 0.67 ( 95 % CI = 0.40 to 1.12 ; p for trend = 0.03 ) . Intake of vitamin D from supplements was also inversely associated with risk of MS ; the RR comparing women with intake of ≥400 IU/day with women with no supplemental vitamin D intake was 0.59 ( 95 % CI = 0.38 to 0.91 ; p for trend = 0.006 ) . No association was found between vitamin D from food and MS incidence . Conclusion : These results support a protective effect of vitamin D intake on risk of developing MS
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 .