Study finds presence of additional environmental risk factors affect the etiology of multiple sclerosis.
Attaining a high level of education could lower a person's risk for multiple sclerosis (MS), a Norwegian study reported.
"In this large population-based study we observed that a higher level of education was associated with lower MS risk that could not be fully explained by currently established risk factors including smoking, vitamin D and infectious mononucleosis. This strongly suggests the presence of additional environmental risk factors in the etiology of MS,” the study published in the January issue of Multiple Sclerosis Journal said.
The statistically significant association between education level and risk showed that participants with higher levels of education had a roughly 50 percent less chance of having MS than those with less education (OR 0.53, 95% CI), the study reported.
After adjusting for key environmental factors (infectious mononucleosis, smoking, outdoor activity, cod liver oil and fatty fish consumption and body mass index), the association between education level and risk was essentially the same. The researchers said that “may imply that education could be a marker for unknown exposures that are important for the etiology of the disease.”
Past studies have found that both higher and lower levels of education increase the risk, Kjetil Bjornevik from the Department of Global Health and Primary Care at the University of Bergen and her colleagues explained. “Although there may be some geographical differences in how SES [socioeconomic status] affects MS risk, some of the conflicting results may also be explained by methodological factors, such as a lack of adjustment for known risk factors,” they added.
The prevalence of MS in Norway is one of the highest in the world, according to the study, which was based on a Norwegian population sample. Participants 18 years old and up who had been diagnosed in the last 10 years were selected from the Norweigan MS registry and the biobank at Haukeland University Hospital in Bergen.
An anonymous questionnaire was mailed to 1368 eligible participants and 4728 age and sex matched controls. It asked for self-reports on education levels and exposures to the risk factors included in the study. The response rate for participants was 69.7% and36.3% for controls.
Education levels were defined as elementary school (7 years or less), middle school (9 to 10 years), high school (11 to 13 years) and college (14 years or more).