Many thanks for your post and your link to the US research. It's striking how similar the findings and conclusions are:
"The substantial increase in the female to male sex ratio in Canada seems to result from a disproportional increase in incidence of multiple sclerosis in women. This rapid change must have environmental origins even if it is associated with a gene-environment interaction, and implies that a large proportion of multiple sclerosis cases may be preventable in situ".
When I sat next to Professor Ebers (one of the authors) in May he tried to explain this gene-environment to me. I got lost in the technicl stuff. But I had thought that you needed genetic susceptibility and then a trigger e.g. a virus kicked off the disease process. I think his view was that the environmental factor had an effect on the genes. But don't quote me - I didn't pass basic biology at school.
"Such marked changes in geography, sex, and race in such a short interval strongly imply a primary environmental factor in the cause or precipitation of this disease".
When I attended the MS / EBV seminar in May, a researcher from Denmark said the incidence of MS was increasing, but only among women.
Earlier this year there was another piece of research from Canada which showed that immigrants without a northern European ancestry were also being diagnosed with MS - which sort of shot down the Viking ancestry theory. So it may be that the genetic susceptility is more common than originally thought (and more widespread than just those with northern European ancestry).
If strikes me that the researchers need to focus on the increasing incidence of MS in women if they are to identify the environmental factor. I tried to identify social changes over the last 30 years which have impacted upon women (sort of contrasting the position with my mother who married in the early 1960s) - more having careers & family, more experiencing divorces / break-ups, drinking more alcohol, smoking more, more sexual partners, less time outside (due to work / home), more using the contraceptive pill, more going to University - this is all very generalised, but there have been substantial changes compared with the 1950s / 1960s. Unfortunately, whichever change I pick e.g. the pill, I could come up with a woman with MS where this did not fit e.g. my nun with MS example.
But standing back, I looked at what Sharon said about stress. All these changes have resulted, on the whole, in additional stress (I guess increases in mental health illnesses e.g. depression might show an increase as well). So maybe, this is the common factor - perhaps stress leads to chemical changes in the brain which then disrupts the normal functioning of the immune system. For example, viruses are present in the CNS but are kept under control by immune system surveillance. Once disrupted, the cascade of events which are seen in MS might follow. Or the chemical changes cause damage to the CNS which then results in the immune system mopping up the debris. Unless the researchers come up with something better, I'd say that stress could be the common denominator. Not sure how we deal with it.
PS I see that Jimmylegs is having boyfriend problems. I'll put a word in for you if you want Dignan. But you know I'm not one to meddle in the private lives of users of this website. Failing that, Scoobyjude might be a backup if Jimmylegs isn't interested.