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This could go a long way to explaining why MS incidence is rising among women faster than men:


Age of puberty and the risk of multiple sclerosis: a population based study.

Eur J Neurol. 2008 Dec 23.
Ramagopalan SV, Valdar W, Criscuoli M, Deluca GC, Dyment DA, Orton SM, Yee IM, Ebers GC, Sadovnick AD; for the Canadian Collaborative Study Group*.
Wellcome Trust Centre for Human Genetics, and Department of Clinical Neurology, University of Oxford, Oxford, UK.

Background and purpose
Genetic and environmental factors have important roles in multiple sclerosis (MS) susceptibility. Given a potential role for sex hormones in MS, we have investigated whether or not the age of puberty influences the risk of developing MS in a population-based cohort.

Methods
We identified 5493 MS index cases and 1759 spousal controls with age of puberty information from the Canadian Collaborative Project on Genetic Susceptibility to MS. Age of puberty was compared between index cases and controls, and any effect of age of puberty on the age of onset of MS was also investigated.

Results
There were no significant differences between male index cases and controls with respect to age of puberty, P = 0.70. However, a significant difference was observed between female index cases and female controls, with average age of puberty being 12.4 and 12.6 years respectively, P = 0.00017, providing a relative risk decrease of 0.9 per year increase of age of puberty. There was no effect of the age of puberty on the age of MS onset in either sex.

Conclusions
Earlier age at menarche increases the risk of MS in women. Whether this association is a surrogate for a disease causative factor or directly involved in MS disease aetiology needs to be uncovered.

http://www.ncbi.nlm.nih.gov/pubmed/19170744

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Dignan

Thanks for posting this. You wrote:

This could go a long way to explaining why MS incidence is rising among women faster than men

How so from your perspective?

The abstract concluded:

Earlier age at menarche increases the risk of MS in women

My personal bias continues to be that "stress" (via higher levels of the stress hormone cortisol) may be one of the reasons why MS incidence is rising faster among women than men. Here's some interesting research which found the cortisol level at awakening (CAR) was associated with menarche.

Diurnal patterns of salivary cortisol across the adolescent period in healthy females

This effect for the CAR was associated with the onset of menarche alone, unlike cortisol levels over the remainder of the day.

Here's some other info on the topic.

Role of Environmental Factors in the Timing of Puberty

Hypotheses to explain the proposed recent population-level changes in puberty timing from the mid-1900s to the present time are controversial.

One prominent hypothesis is that exposure to endocrine-disrupting chemicals (EDCs) cause an earlier age of puberty.10,20,21

EDCs are a class of chemicals that interfere with steroid hormone activity via a variety of modes of action, at a number of levels, and puberty timing has been identified as a sensitive marker of response to EDC exposure.

Lynda Carol--heads up for this quote from the same article:

In addition to the EDC hypothesis, other hypotheses include increasing obesity11,28,29 and increasing hyperinsulinemia and insulin resistance,30 but all of these hypotheses remain controversial.

At least I've identified two of my risk factors, being a woman and early menarche.

Take care all

Sharon