Saturday, 24 November 2012

Vitamin D as a protective factor in multiple sclerosis

Salzer et al. Vitamin D as a protective factor in multiple sclerosis. Neurology. 2012 Nov 20;79(21):2140-5. doi:10.1212/WNL. 0b013e3182752ea8.

OBJECTIVE: To examine the association between 25-hydroxyvitamin D (25[OH]D) levels and the risk of multiple sclerosis (MS) in blood samples collected prospectively and during gestation.

METHODS: In this nested case-control study, 2 population-based biobanks with 291,500 samples from 164,000 persons collected since 1975 in the northern half of Sweden were used. We identified prospectively collected blood samples from MS cases (n = 192, controls matched 2:1) and gestational samples from pregnant mothers where the offspring had later developed MS (n = 37, control mothers matched 5:1). 25(OH)D levels were measured using an ELISA, and the risk of MS was analyzed using matched logistic regression.

RESULTS: Levels of 25(OH)D ≥75 (vs. <75) nmol/L in prospectively collected blood samples were associated with a decreased risk of MS (odds ratio [OR] 0.39, 95% confidence interval [CI] 0.16-0.98). No decrease in MS risk was found in the offspring exposed to gestational 25(OH)D levels ≥75 (vs <75) nmol/L (OR 1.8, 95% CI 0.53-5.8). The prevalence of 25(OH)D levels ≥75 nmol/L in female controls decreased gradually during 1976-2005 (p trend = 0.005).

CONCLUSION: This study supports the presence of an association between high 25(OH)D levels during the years preceding disease onset and a decreased risk of MS. In the very limited material with samples drawn in early pregnancy, where month-of-birth effects were controlled for, we found no association between gestational 25(OH)D levels and MS risk in the offspring. Decreasing 25(OH)D levels in the population may contribute to explain the increasing MS incidence that is suggested from epidemiologic studies.



This study shows what can be done using routinely collected data and samples stored in Scandinavia. The authors looked at blood samples stored before MS onset in patients and compared to matched controls, individuals who went on to develop MS had lower levels of vitamin D, showing that vitamin D deficiency is a risk factor for MS.

This study confirms a landmark previous study, and these are the only two studies to assess vitamin D levels prior to disease onset. Measuring vitamin D levels post onset does not really address whether low vitamin D levels cause MS or a consequence of the inflammatory processes that are going on in MS (known as reverse causality). There is still the potential for reverse causality for both of the pre-onset studies as it is not known when the disease actually starts, it may be many years before clinical signs become apparent.
An additional aspect of this study was to look at vitamin D levels in pregnant mums who had children who went on to develop MS. However, this study found no association between pregnancy vitamin D levels and offspring risk of MS. This may be because they only had samples from 37 mothers, or that they only had vitamin D levels available in the first trimester or that there is actually no effect of vitamin D during pregnancy. This needs further work.

6 comments:

  1. I realized something interesting whilst using VitD supplements, which was reproducible but not measureable:

    I started to take 2000 IU VitD every day. On day 7 I have felt a pain on the right side in my inner ellbow. I guess it was the Median Nerve. It was a pain similar to someone stitching you with a needle.

    The pain started 2 days later on the left side too. I then stopped to take the 2000 IU supplements. It took 2 days before the pain went away.

    So I waited for a week before I started over with VitD. The same thing happend again.
    I tried the same procedure 5 times and it was reproducible.

    So I stopped to take 2000 IU and switched to 400 IU.
    With 400 IU there was no pain. I can take 400 IU every day without any problems.

    Is there any explanation for this or is this just an odd case of coincidence?

    I have Relapsing Progressive MS.

    Thanks.

    Info: the statement above is only valid for me, my genes, my form of MS...you get the point.. :D

    ReplyDelete
  2. I will let G answer this I have no idea, 5 times and 5 reproducible effects it does not sound like chance

    ReplyDelete
  3. AnonymousSaturday, November 24, 2012 9:54:00 PM Do you get the same effect if you expose your skin to the midday sun (UVB)? If you don't respond in the same way then it is something else in the tablets. The sun would create much more D than is in the tablets. Otherwise magnesium deficiency?

    ReplyDelete
    Replies
    1. I have to check this, if it gets sunnier.
      Good idea!

      I doubt a Magnesium deficit as the cause.
      I have normal levels of Magnesium. The same for Potassium.
      Both get checked every 3rd month when I am at the hospital for my infusions.

      These are just normal VitD3 tablets. No Calcium or any other additives.
      Only the usual soya bean oil, Gelatin and Glycerol

      Delete
    2. If you're in the UK you will have to wait till summer. This time of year the sun is too low in the horizon for the skin to make Vit D, doesn't matter if day is sunny.

      Delete
  4. exposing skin to mid day sun

    Yes but in the UK November-April there is not enough strength in the sun.

    A few minutes can give about 15,000 units.

    Prof G or Ram can give details.

    ReplyDelete

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