Myocardial infarction associated with recency of immigration to Ontario.
BACKGROUND
New immigrants to North America exhibit lower rates of obesity and hypertension than their native-born counterparts. Whether this is reflected by a lower relative risk of acute myocardial infarction (AMI) is not known.


OBJECTIVE
To determine the risk of AMI among new immigrants compared to long-term residents, and, among those who develop AMI, their short- and long-term mortality rate.


METHODS
Population-based, matched, retrospective cohort study.


METHODS
Entire province of Ontario, the most populated province in Canada, from 1 April 1995 to 31 March 2007.


METHODS
A total of 965,829 new immigrants were matched to 3,272,393 long-term residents by year of birth, sex and geographic location.


METHODS
The main study outcome was hospitalization with a most responsible diagnosis of AMI. Secondary study outcomes among those who sustained an AMI were in-hospital, 30-day and 1-year mortality.


RESULTS
The mean age of the participants at study entry was approximately 34 years. The incidence rate of AMI was 4.14 per 10,000 person-years among new immigrants and 6.61 per 10,000 person-years among long-term residents. After adjusting for age, income quintile, urban vs. rural residence, history of hypertension, diabetes mellitus and smoking and number of health insurance claims, the hazard ratio for AMI was 0.66 [95% confidence interval (CI): 0.63-0.69].


CONCLUSIONS
New immigrants appear to be at lower risk of AMI than long-term residents. This finding does not appear to be explained by the availability of health-care services or income level.
Saposnik
G
G
Department of Medicine, St Michael's Hospital, University of Toronto, Toronto, Ontario, Canada. saposnikg@smh.toronto.on.ca
Redelmeier
D A
DA
Lu
H
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Fuller-Thomson
E
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Lonn
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Ray
J G
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D000293:Adolescent; D000328:Adult; D015331:Cohort Studies; D054242:Emigrants and Immigrants / Q000706:statistics & numerical data*; D005260:Female; D017052:Hospital Mortality; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000453:epidemiology* / Q000401:mortality; D009864:Ontario / Q000453:epidemiology; D012189:Retrospective Studies; D018570:Risk Assessment; D055815:Young Adult