Study author Robyn Lucas of Australian National University in Canberra says the multi-site study involved 216 people ages 18-59 who had a first event with symptoms of the type seen in MS. They were matched with 395 people with no symptoms of possible MS who were similar ages of the same sex and from the same areas of Australia.
The study subjects reported how much sun they were exposed to during different periods of their lives. Vitamin D levels -- from sun exposure, diet and supplement use -- were measured by blood tests, Lucas says.
"Previous studies have found similar results, but this is the first study to look at people who have just had the first symptoms of MS and haven't even been diagnosed with the disease yet," Lucas says in a statement. "Other studies have looked at people who already have MS -- then it's hard to know whether having the disease led them to change their habits in the sun or in their diet."
The study, published in Neurology, found people with most evidence of skin damage from sun exposure were 60 percent less likely to develop a first MS event than those with the least damage, and those with the highest levels of vitamin D also were less likely to be diagnosed with MS than people with the lowest levels.