According to a study that used MRI scans to detect MS related brain lesions, new legions occurred two to three more times more often during spring and summer, when compared to MRIs taken during the cooler times of the year.

"We found significantly increased levels of disease activity, as defined by new T2 lesion occurrence, during the spring and summer seasons," the study authors wrote in the Aug. 31 issue of Neurology.

The study used 939 brain scans from 44 patients with MS in the Boston area. No treatment was received by the volunteers at the time of the study. The study’s duration was two years.

According to the results, after one year, 31 people had 310 new brain lesions. Also, from March to August, the occurrence of new lesions was  greater ( two to three times higher) than when compared to winter months.

"The environment has, for many decades, been implicated in MS, especially in the development of the disease. Now, here's another piece of evidence," Dr. Anne Cross said.

"The big question, of course, is if spring and summer are the times these new lesions appear, what are some of the possibilities behind this?" Nicholas LaRocca added.

"The other intriguing issue is that while new lesions are likely to appear in the spring and summer, that doesn't mean a causal agent is operating at that time. It could be something going on prior to those seasons that takes a longer time to manifest. In the fall and winter, there is less exposure to ultraviolet light, so there's less vitamin D. Also, in the fall and winter, there is greater exposure to viral infections. Or, maybe it's dietary. People may eat different things in different seasons," furthermore LaRocca added.

He also stated that during warmer months it is highly recommended for people with MS to avoid heat, because it can exacerbate their symptoms, and that it is very helpful to "develop strategies to cope with the warm weather”. “Make sure you have air conditioning and try to avoid significant activity during the warmer parts of the day" LaRocca concluded.