Friday, 4 March 2016

Catching MS in Australia

Barnett MH, McLeod JG, Hammond SR, Kurtzke JF. Migration and multiple sclerosis in immigrants from United Kingdom and Ireland to Australia: a reassessment. III: risk of multiple sclerosis in UKI immigrants and Australian-born in Hobart, Tasmania.
J Neurol. 2016 Feb 25. [Epub ahead of print]


Our previous work suggested that migrants from the United Kingdom and Ireland (UKI) to Australia who left their home country at a young age had a longer interval between immigration and onset and likely acquired MS in Australia. In the present study, we reassessed Australian-born cases of MS identified in Hobart, Tasmania, a relatively high-risk zone, in our 1981 survey and compared these with cases of MS in UKI immigrants incident in Australia. The incidence of MS in Australian-born residents rose from 1.63 per 100,000 in 1941-1965 to 3.48 per 100,000 in 1966-1981. The bulk of UKI immigrants who developed MS in Australia migrated after the age of 15 years, and likely acquired their disease in the UKI. The mean interval from immigration to onset differed significantly (p < 0.01) between those migrating before (22 years) versus after (6 years) the age of 15, suggesting acquisition of MS in Australia in the former group. Identified environmental risk factors such as smoking, sunlight and exposure to Epstein-Barr virus do not fully account for the epidemiology of multiple sclerosis. The apparent introduction of MS into Hobart from the mid-1940s on could provide circumstantial support for the theory that MS is a transmissible disease.


The belief was that if you move from a low risk area to a high risk area of MS before the age of 15 develop the risk of where they go and those after the age of  15 take the risk from the birth area. 

So when Brits and Irish move to Tasmania which it has the highest risk of MS in Australia (it has been suggested because it is further from equator). In this study they looked at the risk of Australian born verses the Poms migrating in to the area. It was found that the incidence of MS increased from the 1940s at about 1.5 per 100,000 people to 3.5 per 100,000 people in the 1980s and of the migrants with MS they think that most acquired it there. The suggestion is that MS could be a transmissible disease. But What?

I wonder whether the virus is the humble Barbie as no Brits would have been near a BBQ until they moved to Oz. I bet no one had seen a Webber in the 1940s but by the 1980s every one has one or something like them.

In the UK BBQ use is now common place wonder if this is the reason why the second generation black immigrants to the UK get more MS than there parents.

A crazy idea...sure it is but is it any less crazy than some of the other plausible causes?

The only way to really find out is to modify the behaviour and see if it impacts on disease.

7 comments:

  1. These days I read this study on MS and a genetic investigation between the Ashkenazi Jews.
    Researchers have suggested that genetic factors contribute but seem to be the determining environmental factors for the onset of MS, from what I understand it seems that Ashkenazi have low presence of the allele pair HLA DRB 1*15:01.

    http://bmcmedgenet.biomedcentral.com/articles/10.1186/s12881-015-0201-2

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    1. Yes, but Cinara, it's crazy to think that you yourself live in the paradise exoticism of Brazil, yet you still developed MS. What gives? After all, you got plenty of sunshine, were never overweight, and probably originated from a more diverse gene pool than most UK residents.

      MS causation makes absolutely sense.

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    2. Yes, MS here seems to be well diversified. We see it reaching all races, but is more prevalent here really in people of European descent. My case is more "curious" even as I am Luso-Brazilian (my grandparents both paternal and maternal were Portuguese), I am very white but live in a town near the equator! (I live in Manaus, through the Amazon Forest).
      The climate is hot and humid equatorial, the sunlight is very strong, so gou generally can't spend 15 minutes outdoors.
      Low vitamin D dosage? Perhaps because at the time of the outbreak did not perform tests to assess how vitamin D was (in Brazil still has many neuros who doubt the effect of vitamin D on the immune system). Genes? Perhaps because as I said I am a direct descendant of the Portuguese, and the incidence of MS in Portugal appears to be high. But even with all that I am so far the only case of MS family and I had IM about 5 months before the first symptoms, I am a former athlete and continue to practice regular physical activity ... I even want to take an exam genetic just to satisfy their curiosity about it, but deep down I agree with Prof. G. and I think that an adult IM has a lot to say about ...

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  2. West Indians have been cooking and barbequeing outside for donkeys years.

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    1. Weast indians are no getting MS...that dreaded BBQ :-)

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  3. Despite the flaws in the commentary (prevalence vs incidence), I absolutely love the BBQ hypothesis. However, we (the authors) are hypothesizing that the Poms introduced MS to Australia, not the other way around. So unless the humble Aussie BBQ exudes protective aromas that diminish the risk of MS, methinks you Antipodeans are mistaken...

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    1. Or maybe the cause is the sneaky American bringing in a webber and thats the cause and looking a the british and Irish is a red herring:-)

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