October 15, 2020
Immigrants and multiple sclerosis in Canada
Several recent studies examined risk factors for MS in immigrants in Ontario. These studies looked at MS incidence, mortality rates, and access to health services to understand differences in immigrant populations as compared to long-term residents.
To understand risk factors for MS in immigrant populations in Canada, Dr. Dalia Rotstein and colleagues conducted a retrospective study that analyzed the Permanent Resident Database of Immigration, Refugees and Citizenship Canada (IRCC) database and health administrative data from Ontario. Immigrants, defined as those arriving in Canada since 1985, were compared to long-term residents, individuals born in Ontario or whose date of residence was before 1985. The following results summarize several recent studies.
- Overall, immigrants had a markedly lower risk of MS as compared to long-term residents.
- The greatest risk was seen in immigrants from the Middle East, followed by those from Western nations, with those from East Asia having the lowest risk.
- Migrating at a younger age is associated with higher risk of developing MS, although environmental exposures into adulthood contribute to MS risk.
- Immigrants with MS had a lower mortality than longer-term residents with MS, which may be due to a ‘healthy immigrant’ effect where recent immigrants are in better health than longer-term residents.
- While mortality was lower overall, in the first year after MS onset immigrants have a higher risk of death. The cause of death warrants further investigation as they may be preventable.
- Before, during and the year after MS diagnosis, immigrants with MS had favourable access to health services.
- Immigrants with MS had greater rates of neurology outpatient care and lower use of emergency department services.
- In the year of MS diagnosis, immigrants had higher rates of hospitalizations as compared to long-term residents, which may be due to severity of symptoms.
There are a number of risk factors for MS, including genetics, sunlight exposure, vitamin D deficiency (read more here), obesity, and North American diet (lower in fish and high in saturated fat). A better understanding of risk factors for different populations can be used to improve health outcomes for people living with MS and support strategies that mitigate disparities in at-risk populations.
For more detailed information, refer to scientific publications: