New research indicates that multiple sclerosis (MS) activity can increase during spring and summer months.
"Our results showed that the appearance of lesions on brain scans was two to three times higher in the months of March to August, compared to other months of the year," said study author Dominik Meier, of Brigham and Women's Hospital in Boston and a member of the American Academy of Neurology.
For the study, researchers compared MRI brain scans of 44 people taken from 1991 to 1993 to weather data from the same time period. Participants were between the ages of 25 and 52 with untreated MS.
Each person had eight weekly scans, then eight scans every other week followed by six monthly check-ups, for an average of 22 scans per person.
Weather information included daily temperature, solar radiation and precipitation measurements for the Boston area.
After one year, 310 new lesions were found in 31 people. Thirteen people had no new lesions during the study.
"Not only were more lesions found during the spring and summer seasons, our study also found that warmer temperatures and solar radiation were linked to disease activity," said Meier.
There was no link found between precipitation and lesions.
The research is published in the August 31, 2010, issue of Neurology(r), the medical journal of the American Academy of Neurology.