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, pregnancy, breastfeeding, and postpartum multiple sclerosis relapses.
OBJECTIVE To determine whether low levels of 25-hydroxyvitamin D ( 25[OH]D ) contribute to the increased risk of postpartum multiple sclerosis ( MS ) relapses . DESIGN Prospect i ve cohort study . SETTING Out patients identified through membership records of Kaiser Permanente Northern California or Stanford University outpatient neurology clinics . PATIENTS Twenty-eight pregnant women with MS . INTERVENTIONS We prospect ively followed up patients through the postpartum year and assessed exposures and symptoms through structured interviews .  Total serum 25(OH)D levels were measured using the DiaSorin Liaison Assay during the third trimester and 2 , 4 , and 6 months after giving birth . The data were analyzed using longitudinal multivariable methods . MAIN OUTCOME MEASURES Levels of 25(OH)D and relapse rate . RESULTS Fourteen ( 50 % ) women breastfed exclusively , and 12 women ( 43 % ) relapsed within 6 months after giving birth . During pregnancy , the average 25(OH)D levels were 25.4 ng/mL ( range , 13.7 - 42.6 ) and were affected only by season ( P=.009 ) . In contrast , in the postpartum period , 25(OH)D levels were significantly affected by breastfeeding and relapse status . Levels of 25(OH)D remained low in the exclusive breastfeeding group , yet rose significantly in the nonexclusive breastfeeding group regardless of season ( P=.007 , unadjusted ; P=.02 , adjusted for season ) . By 4 and 6 months after childbirth , 25(OH)D levels were , on average , 5 ng/mL lower in the women who breastfed exclusively compared with the nonbreastfeeding group ( P=.001 ) . CONCLUSIONS Pregnancy and exclusive breastfeeding are strongly associated with low 25(OH)D levels  in women with MS . However , these lower vitamin D levels were not associated with an increased risk of postpartum MS relapses . These data suggest that low vitamin D in isolation is not an important risk factor for postpartum MS relapses
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 .