"Recent immigrants to Canada and the U.S. face many stressors as they adapt to changes in their diet, jobs, housing and relationships which may adversely affect stroke risk," said study author Gustavo Saposnik, MD, MSc, with St. Michael's Hospital, the University of Toronto and a member of the American Academy of Neurology. "Other studies have shown that compared to people born in those countries, recent immigrants to Canada and the U.S. may have lower rates of diseases such as high blood pressure. On the other hand, the lower prevalence of hypertension and other risk factors such as diabetes and smoking among new immigrants may decrease their vascular risk. We evaluated which of these two competing factors (psychosocial stress associated to the new environment vs. health immigrant effect) prevail."

There are several theories why immigrants may be healthier than long-term residents: Those willing to undergo the stress of immigration are usually in good health prior to immigrating; the medical examination required of all potential immigrants screens out unhealthy candidates; and immigrants who experience poor health may return to their home country for support.

"More research to determine whether the risk of stroke in immigrants 'normalizes' to the level seen in longer-term residents may help shed light on undiscovered risk factors for stroke," said Bradley S. Jacobs, MD, MS, of Wright State University Boonshoft School of Medicine in Dayton, Ohio, who wrote an editorial accompanying the study.

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