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 .
The Hawthorne Effect: a randomised, controlled trial
Background The ' Hawthorne Effect ' may be an important factor affecting the generalisability of clinical research to routine practice , but has been little studied . Hawthorne Effects have been reported in previous clinical trials in dementia but to our knowledge , no attempt has been made to quantify them . Our aim was to compare minimal follow-up to intensive follow-up in participants in a placebo controlled trial of Ginkgo biloba for treating mild-moderate dementia . Methods Participants in a dementia trial were r and omised to intensive follow-up ( with comprehensive assessment visits at baseline and two , four and six months post r and omisation ) or minimal follow-up ( with an abbreviated assessment at baseline and a full assessment at six months ) . Our primary outcomes were cognitive functioning ( ADAS-Cog ) and participant and carer-rated quality of life ( QOL-AD ) . Results We recruited 176 participants , mainly through general practice s. The main analysis was based on Intention to treat ( ITT ) , with available data . In the ANCOVA model with baseline score as a co-variate , follow-up group had a significant effect on outcome at six months on the ADAS-Cog score ( n = 140 ; mean difference = -2.018 ; 95%CI -3.914 , -0.121 ; p = 0.037 favouring the intensive follow-up group ) , and on participant-rated quality of life score ( n = 142 ; mean difference = -1.382 ; 95%CI -2.642 , -0.122 ; p = 0.032 favouring minimal follow-up group ) . There was no significant difference on carer quality of life . Conclusion We found that more intensive follow-up of individuals in a placebo-controlled clinical trial of Ginkgo biloba for treating mild-moderate dementia result ed in a better outcome than minimal follow-up , as measured by their cognitive functioning . Trial registration Current controlled trials : IS RCT
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 .