2006-11-01 01:10:26 MST
TORONTO -- Researchers have discovered women with multiple sclerosis inexplicably outnumber men by a ratio of more than three-to-one.
The researchers have also found the gender ratio, rather than being stable, has been rising for at least 50 years.
It jumped from about 1.9 women for every man for those born in the 1930s, to 3.2 women for every man for those born around 1980.
The rise has made multiple sclerosis an overwhelmingly female disease.
A paper on the new findings appears in the November edition of the journal Lancet Neurology.
Researchers who conducted the study of Canadian MS data speculate something new has arisen in the environment in the past half-century to make women far more likely to develop the disease.
"What is going on here is something presumably that is preventable," said George Ebers, the Oxford professor who authored the study.
