A new study has confirmed what many had suspected — a seasonal pattern in subclinical disease activity in patients with multiple sclerosis (MS).
“Our results showed that the appearance of lesions on brain scans was 2 to 3 times higher in the months of March to August, compared to other months of the year,” lead investigator Dominik Meier, PhD, from Brigham and Women’s Hospital in Boston, Massachusetts, said in a news release.
Researchers found the new T2 activity on weighted magnetic resonance imaging correlated strongly with regional climate data. Their results appear in the August 31 issue of Neurology.
The study involved 44 MS patients. Each person had 8 weekly scans, then 8 scans every other week followed by monthly checkups. After 1 year, investigators identified 310 new lesions. In all, 31 patients developed new lesions and 13 had none.
“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,” Dr. Meier said.
“This is an important study because it analyzes records from the early 1990’s, before medications for relapsing multiple sclerosis were approved so medicines likely could not affect the outcome,” Anne Cross, MD, from the Washington University School of Medicine in St. Louis, Missouri, added in the news release. “A study like this probably won’t be able to be repeated.”
Dr. Cross is the author of an accompanying editorial. Along with coauthor Becky Jo Parks, MD, also at Washington University, she writes this study “lends further support for an environmental effect on MS activity.”
Relapsing and progressive MS exhibited different seasonal patterns, the investigators found, with peak prevalence shifting toward spring for progressive disease.