MS Increasingly a Woman's Disease
Steady Rise in Rates of Multiple Sclerosis Seen in Women
April 26, 2007 -- Women with multiple sclerosis (MS) now appear to outnumber men with the disease by a ratio of four to one in the U.S., new research shows.
The review of data from a voluntary MS registry suggests a steady increase in MS rates among women over time, while rates among men appear to have remained stable.
In 1940, twice as many women as men in the U.S. had multiple sclerosis. By 2000, four out of five cases were occurring among women, University of Alabama professor of biostatistics Gary Cutter, PhD, tells WebMD.
That represents an increase in the ratio of women to men of nearly 50% per decade, and it mirrors recent findings from other countries with more comprehensive MS registries, including Canada, Norway, and Denmark.
It is not clear why MS rates seem to be increasing only among women, but the observation could help researchers searching for the cause or causes of the disease, Cutter says.
Some believe that environmental or viral influences early in life trigger the disease in people who are genetically predisposed toward getting it. Though there are many theories about what these triggers are, there is no proof that any of them cause MS.
MS is a disease that affects the brain and spinal cord. Experts believe that it is due to an abnormal response of the immune system attacking the myelin sheath that surrounds nerve fibers. Myelin is needed for sending nerve signals such as those that control movement. The National Multiple Sclerosis Society estimates that 400,000 Americans have MS.