A systematic review of existing medical literature on multiple sclerosis (MS) could shed light on MS causes and predictors for disease progression, and on lifestyle changes — ranging from vitamin D intake to weight loss — that might reduce a person’s risk. The report, “Factors associated with onset, relapses or progression in multiple sclerosis: A systematic review,“ appeared in the journal NeuroToxicology.

Led by Kyla A. McKay of the Division of Neurology, Faculty of Medicine, Djavad Mowafaghian Centre for Brain Health at University of British Columbia, Vancouver, the researchers reviewed existing medical literature to uncover potential MS risk factors. Studies included those published between 1960 to 2012. The investigators used a total of six databases, and focused on those risk factors that can be modified by lifestyle changes or treatment. They identified 15 systematic reviews and 169 original articles.

Overall, the scientists uncovered several factors that could lead to MS onset and progression. These included Epstein-Barr virus exposure, smoking, low serum vitamin D levels, and adolescent obesity. MS relapse increased with low sunlight exposure, low serum vitamin D levels, upper respiratory infections, and stress. Interestingly, relapses dropped during pregnancy, for unclear reasons. Cigarette smoking also increased long-term MS-associated disability.

Investigators noted that obesity may be the most important factor uncovered by their study. “Emerging research with the greatest potential to impact public health was the suggestion that obesity during adolescence may increase the risk of MS; if confirmed, this would be of major significance,” they wrote.

Clearly, reducing obesity rates should be a major health priority for several reasons, including the impact on the onset of MS. The study also indicated several other lifestyle factors that can be modified to reduce MS risk or severity, including exposure to sunlight, increased vitamin D intake, smoking cessation, and stress reduction. Further studies that prospectively assess these factors, and their impact on MS progression and relapse, are warranted.

MS is an autoimmune disease characterized by inflammation. Immune cells attack the body’s own myelin, an insulating substance that helps nerve cells to conduct impulses. MS is the most common cause of neurological disability in young adults. There is increasing evidence that neuron death and loss of the axons that extend from neurons also occurs in MS, due to inflammation. MS causes several symptoms, including sensory problems, cognitive deficits, emotional issues, pain, fatigue, balance problems, walking difficulties, and bladder problems.