Dobson et al. The month of birth effect in multiple sclerosis: systematic review, meta-analysis and effect of latitude. J Neurol Neurosurg Psychiatry doi:10.1136/jnnp-2012-303934
Background: Month of birth has previously been described as a risk factor for MS. This has been hypothesised to be related to maternal vitamin D levels during pregnancy, although conclusive evidence to support this is lacking. To date, no large studies of latitudinal variation in the month of birth effect have been performed to advance this hypothesis.
Methods: Previously published data on month of birth from 151 978 MS patients were compared to expected birth rates. A linear regression model was used to assess the relationship between latitude and observed:expected birth ratio of MS patients for each month.
Results: Analysis of all reported data demonstrated a significant excess of MS risk in those born in April (observed:expected 1.05, p=0.05) and reduction in risk in those born in October (0.95, p=0.04) and November (0.92 p=0.01). A conservative analysis of 78 488 patients revealed an excess MS risk in those born in April (1.07, p=0.002) and May (1.11, p=0.0006), and a reduced risk in those born in October (ratio 0.94, p=0.004) and November (0.88, p=0.0002). A significant relationship between latitude and observed:expected ratio was demonstrated in December, and borderline significant relationships in May and August.
Conclusions: Month of birth has a significant effect on subsequent MS risk. This is likely to be due to ultraviolet light exposure and maternal vitamin D levels, as demonstrated by the relationship between risk and latitude.
"If you are pregnant or planning to fall pregnant you need to make sure you are vitamin D replete. This may lower the chances of your child getting MS and other autoimmune diseases. My recommendation for pregnancy is 10,000U vD3 per day; this is double my recommendation of 5,000U per day for adults."
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Other related posts of interest on this blog:
27 Aug 2012
This month of birth effect is now being attributed to the effect of low vitamin D levels in the womb. The low vitamin D affects how the immature immune system develops. In other words if your mother was pregnant during winter, ...
21 Sep 2012
"The results of this study support the month-of-birth effect, but question the link to UV fluctuation. Unfortunately, this study cannot take into account cultural factors that affect UV exposure and vD, for example indoor vs. outdoor ...
03 Nov 2012
Investigating the month of birth effect in second generation MSers has not yet found anything interesting, Why not take it back another generation, so on and so forth? Posted by MouseDoctor at 07:00 · Email ThisBlogThis!
14 Jun 2011
The month of birth and risk of MS are associated, more so in familial cases, implying that there is some interactions between genes and environment that may be related to climate. Such interactions may act during gestation or ...
CoI: This work was done in our group.
Labels: month of birth, Vitamin D