Multiple sclerosis is an autoimmune disease. The family of autoimmune diseases include such diseases as lupus, rheumatoid arthritis, Crohn’s disease, type 1 diabetes, and ulcerative colitis. Unfortunately, someone with one autoimmune disease has an increased risk of also developing a second disease in this category. For example, there is a trend for someone with multiple sclerosis to be at risk for the inflammatory bowel disease of Crohn’s disease (and vice versa).
This elevated risk of several autoimmune diseases occurring in certain individuals continues to be researched. For example, recently birth cohort patterns were studied to better understand this issue. One important finding from this study was that the risk of an autoimmune disease may not only be accounted for by internal risk factors (e.g., genetics), but external factors can also be at play.
It appears that exposure to certain environmental risk factors during an early period in life can increase the risk of both Crohn’s disease and multiple sclerosis. These risk factors might be similar or even be the same factors influencing both of these diseases. Although more remains to be understood on this issue, what is currently known is that autoimmune diseases overall are more likely in those consuming a typical Western diet which is higher in salt and saturated fats (the type of fat found in animal foods, such as red meat), as well as those with certain bacterial and viral infections early in life or exposed to certain medications (e.g., procainamide or hydrolyzine).
While these connections between autoimmune diseases continues to be uncovered, one important take-away in the meantime for patients who have one autoimmune disease is this: be aware of the increased risk of developing an additional autoimmune disease. Symptoms of a second autoimmune disease should be discussed with a health care provider.
Sonnenberg A, Ajdacic-Gross V. Similar birth-cohort patterns in Crohn’s disease and multiple sclerosis. Mult Scler 2018;24(2):140-149. doi:10.1177/1352458517691620.