Risk of premature stroke in recent immigrants (PRESARIO): population-based matched cohort study.
BACKGROUND
New immigrants to North America, most of whom are under age 50 years, exhibit fewer risk factors for cardiovascular disease than their native-born counterparts, yet the stress of resettlement may conceivably place them at higher risk of stroke. We determined the risk of acute stroke associated with recency of immigration.


METHODS
We completed a population-based matched cohort study in Ontario, the largest province in Canada, from April 1, 1995, to March 31, 2007. Overall, 965,829 new immigrants were matched to 3,272,393 long-term residents by year of birth, sex, and location. New immigrants were identified as new recipients of universally available public health insurance, and long-term residents were those insured for 5 years or longer.


RESULTS
The mean age of the participants at study entry was about 34 years and the total number of observed strokes was 6,216 after a median duration of follow-up of about 6 years. The incidence rate of acute stroke was 1.69 per 10,000 person-years among new immigrants and 2.56 per 10,000 person-years among long-term residents (crude hazard ratio [HR] 0.66, 95% confidence interval [CI] 0.62-0.71). After adjusting for age, income quintile, urban vs rural residence, history of hypertension, diabetes mellitus and smoking, and number of health insurance claims, the HR for stroke was 0.69 (95% CI 0.64-0.74). Similar risk estimates were seen for both ischemic and hemorrhagic stroke subtypes.


CONCLUSIONS
New immigrants appear to be at lower risk of premature acute stroke than long-term residents. This finding does not appear to be explained by the availability of health care services or income level.
Division of Neurology, Department of Medicine, St. Michael's Hospital, University of Toronto, 55 Queen St E, Toronto, Ontario, M5C 1R6, Canada. saposnikg@smh.toronto.on.ca
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Saposnik
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Redelmeier
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Lonn
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Fuller-Thomson
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Ray
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D015331:Cohort Studies; D018672:Community Health Planning; D016001:Confidence Intervals; D016208:Databases, Factual / Q000706:statistics & numerical data; D004641:Emigration and Immigration; D005260:Female; D006801:Humans; D008297:Male; D009864:Ontario / Q000453:epidemiology; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D020521:Stroke / Q000453:epidemiology* / Q000517:prevention & control; D013997:Time Factors; D055815:Young Adult