(NaturalNews) For decades, scientists have noticed something odd about the condition known as multiple sclerosis (MS). This chronic disease of the brain and spinal cord is less likely to occur in people who live in warmer climates than those dwelling in colder places. Now a study published in the February 8, 2011, issue of Neurology, the medical journal of the American Academy of Neurology, provides a compelling reason why this is true. People who spend more time outside in the sun and those with higher vitamin D levels are far less likely to ever develop MS than those with inadequate sun exposure and low levels of vitamin D.
MS, which frequently involves flare-ups of symptoms that are recurring, often starts with a first episode of the disease marked by neurological symptoms that last anywhere from a few days to many weeks. The new research, conducted by scientists at the Australian National University in Canberra, is the first study to look at people have experienced the very first symptoms of MS before they were officially diagnosed with the disease.
"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," study author Robyn Lucas, PhD, said in a statement to the media.
The multi-site study included 216 research subjects between the ages of 18 and 59 who had a first episode of symptoms that indicated MS. This group of study participants was matched with 395 people with no symptoms of possible MS who were of similar ages, of the same sex and lived in the same locations in Australia. All the participants reported how much sun exposure they'd had at different times in their lives. The scientists also documented the amount of skin damage participants had from sun exposure and the amount of melanin in their skin. Blood tests were used to measure vitamin D levels (from sun exposure, diet and supplement use) in each research subject, too.
The results showed that people with the most evidence of skin damage from sun exposure were 60 percent less likely to develop the first symptoms of MS than the people with the least damage. In addition, those with the highest levels of vitamin D also were less likely to have a diagnosed first MS event than people with the lowest levels.
The Australian study also confirmed previous studies that have shown that MS is more common in latitudes further away from the equator. "Added together, the differences in sun exposure, vitamin D levels and skin type accounted for a 32 percent increase in a diagnosed first event from the low to the high latitude regions of Australia," Dr. Lucas stated.
He pointed out that the effects of sun exposure and vitamin D acted independently of each other when it came to the risk of initial MS symptoms. "Further research should evaluate both sun exposure and vitamin D for the prevention of MS," Dr. Lucas concluded in the press statement.