Saturday, 3 January 2015

Puberty in females enhances the risk of MS.

Ahn JJ, O'Mahony J, Moshkova M, Hanwell HE, Singh H, Zhang MA, Marrie RA, Bar-Or A, Sadovnick DA, Dunn SE, Banwell BL.
Puberty in females enhances the risk of an outcome of multiple sclerosis in children and the development of central nervous system autoimmunity in mice. Mult Scler. 2014. pii: 1352458514551453. [Epub ahead of print]

BACKGROUND:For reasons that remain unclear, three times more women develop multiple sclerosis (MS) than men. This preponderance among women is evident only after 12 years of age, implicating pubertal factors in the risk of MS.
OBJECTIVE:To investigate the influence of female puberty on central nervous system (CNS) autoimmunity.
METHODS: We examined the relationship between age of menarche on MS outcomes in 116 female children (< 16 years old) whom presented with incident 'acquired demyelinating syndromes' (ADS) and were followed prospectively in the national Canadian Paediatric Demyelinating Disease Study, from 2004-2013. Furthermore, we directly investigated the effects of puberty on susceptibility to experimental autoimmune encephalomyelitis (EAE) in two groups of female mice that differed only in their pubertal status.
RESULTS: In the ADS children, a later age of menarche was associated with a decreased risk of subsequent MS diagnosis. This relationship persisted, after accounting for patient age at ADS presentation and the presence of ≥1 T2 lesions on brain magnetic resonance imaging (MRI), with a hazard ratio (HR) of 0.64; and additional factors that associate with MS outcomes in ADS children, including low vitamin D levels. Furthermore, we found female mice that had transitioned through puberty were more susceptible to EAE than age-matched, pre-pubertal mice.
CONCLUSION: Puberty in females enhances CNS autoimmune mechanisms that lead to MS in humans and EAE in mice.
Yet more evidence that sex hormones influence autoimmunity

7 comments:

  1. Hi MD, while I've no doubt sex hormones play a role, my symptoms always get worse just before my periods. Butk I'm puzzled by the early age of puberty link. Wile there are many examples of this getting -rapidly- earlier in the last 20 years, with older generations this is rarely the same. I did not reach puberty/menarche until 15.7 years, most of my classmates were around the same time or a year earlier at most. It was still shocking (in that girly middle class hushed shocked way - i realise you may not know what I mean there) to hear of girls who began there periods at a younger age! This is no different to the average age in the early part of 19th century, in fact in the US it was slightly lower at this time. There has, been a gradual decline over the last 200 years as nutrition has improved (unlike the more rapid decline in last 20 odd years or so influenced more by a rise in childhood obesity and more estrogen in the environment through discarded birth control etc. Or is this study taking an extra extra long view? I don't see how this would be possible beyond the last 200, possibly 300 years. If you go back further, then the median ages were far younger. Also as menarche age varies considerably between cultures, I wonder how they found the median on this. By the way I find your pink womb image a bit gruesome at this time of morning :)

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    1. In the 1900s MS sex ratio was about 1:1 and now nearer to 3:1, The age of puberty has been dropping in that time. In this cohort those people with a demyelinating event who were not t puberty were less likely to present with MS subsequently

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    2. Very interesting, can you point me to this research, because I'm intrigued at how this could be known with any real certainty at the beginning of 19century. I'm not disputing it but nor am I totally convinced. I feel it it is possible that the earlier menarche begins could be part of the changes in ratio with female/male MS but there seems too many other variables. In countries, such as Sweden who have looked at this, the ratio has stabilised at times during the 20 century and were similar at times to the early 19century. I agree that age of puberty has dropped dramatically in last 30 years and this could easily be another risk factor. As I'm fully convinced sex hormones play a role in MS but how much of a risk factor? If we go back further, it seems that puberty was reached around age 12 in 12th century, obviously it would not be possible to find data concerning MS then but did that means girls were at greater risk or did MS not exist then? Given puberty started at 15.7 years for me, which was the average for 19th century and similarly for other women of my age with MS, on a personal level, I find this intriguing.

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    3. But there are enough exceptions, girls who had a demyelinating event before puberty and went on to get MS before menarche

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  2. Which hormone is it bad to have too much of then... Oestrogen or Testosterone?

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    1. yes...it is all context dependent.
      However both Oestrogen and Testosterone can be good too
      http://www.ncbi.nlm.nih.gov/pubmed/22209870

      The biology is not simple

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    2. Nope, it isn't, I've been looking into this for few years, one also has to look at a whole host of other hormones, such as lutenizing hormone as well as role of the pituitary gland, FSH etc etc, bloody complicated. Dr Sabina Luchetti has done much work on this.

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