Have you ever wondered how your new environment might affect your health? A groundbreaking study from the University of Toronto has shed light on an important health issue for immigrants in Canada, particularly those from Africa. The research suggests that the longer immigrants live in Canada, the higher their risk of developing multiple sclerosis (MS).
Understanding the Study
The study, led by Dr. Dalia Rotstein, analyzed health data from over 1.5 million immigrants who arrived in Ontario between 1985 and 2003. Participants were followed for an average of 13 years, revealing a concerning trend: immigrants who spent a greater proportion of their lives in Canada had a higher risk of developing MS. Specifically, the study found that immigrants who had spent 70% of their lives in Canada were 38% more likely to develop MS compared to those who had spent only 20% of their lives in the country.
Study Methodology
The researchers used health administrative data and immigration records from Ontario to analyze MS risk among the immigrants. They applied a validated algorithm to identify incident MS cases and used multivariable proportional hazard models, adjusting for demographics and comorbidities, to evaluate the association between the proportion of life spent in Canada and the incidence of MS. The study included immigrants from various regions, including Western countries, South Asia, East Asia, Africa, the Caribbean, Latin America, and the Middle East.
The researchers found that 934 immigrants out of the 1.5 million analyzed were diagnosed with MS during the follow-up period¹. They used statistical tests to compare rates of MS based on the proportion of each individual’s life spent living in Canada. For example, a 20-year-old who immigrated at age 1 would have spent 95% of their life in Canada, whereas a 20-year-old who immigrated at age 19 would have spent only 5%.
Why Does This Happen?
Several factors might contribute to this increased risk. Environmental and lifestyle changes, such as lower sun exposure and reduced vitamin D levels in Canada, are believed to play a significant role. While the study shows an association, it does not prove causation, meaning more research is needed to fully understand these dynamics.
The Healthy Immigrant Effect
Initially, immigrants tend to have a lower risk of MS compared to long-term residents, a phenomenon known as the “healthy immigrant effect.” Healthier individuals are often more likely to migrate. However, over time, as immigrants adapt to the Canadian environment and lifestyle, their risk of MS increases. The study found that 934 immigrants out of the 1.5 million analyzed were diagnosed with MS during the follow-up period.
What Can Be Done?
Understanding these risk factors is important for developing strategies to prevent MS, especially among immigrant populations. Awareness and proactive health measures, such as ensuring adequate vitamin D intake, can be vital steps in mitigating this risk.
Way Forward
This study highlights the importance of considering environmental and lifestyle factors in our health, especially for immigrants adapting to new countries. By raising awareness and supporting further research, we can work towards better prevention strategies and improved health outcomes for all.
