Living in the North Raises MS Risk

(Ivanhoe Newswire) -- Where you were born and live may increase your risk for multiple sclerosis.

Researchers from the Keck School of Medicine at the University of Southern California in Los Angeles followed more than 700 pairs of twins diagnosed with MS. They discovered people born in the North tended to have an MS onset earlier than those who were born farther south. Also, the number of identical twins diagnosed with MS from the North was nearly twice as high as those born elsewhere -- 18.6 percent compared to 9.5 percent.

Northern locations for this study include Canada and states above 42 degrees north of the equator, specifically Alaska, Oregon, Washington, Idaho, Montana, Nebraska, North Dakota, South Dakota, Wyoming, Michigan, Minnesota, Wisconsin, Connecticut, Maine, Massachusetts, New Hampshire, New York, Rhode Island, and Vermont.

The study also reveals that identical twins were far more likely to get the disease than fraternal twins.

The researchers say this could mean there is an environmental and genetic interplay that raises one's risk for MS.

Researchers hypothesize living in the North could give a person less opportunity for early exposure to the sun, thereby having an environmental deficit in protection, or, for unknown reasons, an increased susceptibility to a virus.

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SOURCE: Annals of Neurology, 2006;60:56-64