Canadian Immigrants See Multiple Sclerosis Risk Increase the Longer They Live There

The cause of multiple sclerosis, an autoimmune disorder impacting the nervous system, isn’t well understood. Genetics, infectious agents, and environmental factors seem to all play a role, but researchers aren’t sure how. Even geography appears to play a role, with populations living north of the equator being at greater risk. This risk increases the further north one goes. Reduced exposure to UVB radiation has been proposed as an explanation, but this theory is far from proven.

Does Canada Cause MS?

According to a story from Science Direct, a recent study of Canadian immigrants found that their risk of multiple sclerosis increases with the proportion of their lifespan spent living there. This study looked at data from 1.5 million people that emigrated to the country between 1985 and 2003. These individuals had health insurance for a minimum of two years without a multiple sclerosis diagnosis. The group was monitored through 2016.

A total of 934 people were diagnosed with the disease during the study window. On average, the immigrant population had spent 20% of their lives in Canada. The researchers found that people that had spent 70% of their lives in the country had a risk of multiple sclerosis that was 38% higher in comparison to people that had spent 20% of their lives there. This result accounted for other contributing factors as well, such as age, sex, or the presence of other health problems.

The study didn’t prove that living in Canada for a longer portion of one’s life necessarily causes the disease, but merely that there is an association. The team theorized that environmental factors, changes to diet, smoking, social determinants of health, and changes to the gut microbiome could contribute to the findings.

About Multiple Sclerosis

Multiple sclerosis is a neurological disease which is characterized by damage to the myelin sheath, a fatty, insulating, protective covering that surrounds nerve cells and allows them to communicate effectively. Although a precise cause has not been determined, multiple sclerosis is considered an autoimmune disease, in which a certain trigger, such as an infection, may cause the immune system to mistakenly attack healthy tissue. Smoking and certain genetic variants are also considered risk factors for the disease. Symptoms include blurred vision, double vision, blindness in one eye, numbness, abnormal sensations, pain, muscle weakness, muscle spasms, difficulty speaking and swallowing, mood instability, depression, loss of coordination, and fatigue. There are a number of treatments available for the disease, but no cure. Life expectancy for patients is slightly reduced. To learn more about multiple sclerosis, click here.

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