Ethnic differences in mortality from ischemic heart disease: A study of migrant and native populations

Abstract

The population of Manitoba, by virtue of their various ethnic background, provide a good opportunity to investigate the extent to which the occurrence of ischemic heart disease (IHD) or its risk factors is determined by genetic or by environmental factors. Mortality from this disease has been measured and compared between ethnic groups of the immigrants and their descendants. Of a total of 6029 deaths from IHD in this province during 1960–1962, 3487 were foreign-born (outside Canada) and 2542 were Canadian-born. These along with 2880 deaths in 1961 from diseases other than cardiovascular (used as controls) were analyzed. The standardized mortality ratios from IHD and the relative risk (for some groups) were computed and compared between different ethnic groups and between the Canadian-born and the foreign-born subjects of the corresponding ethnic groups. A higher risk of mortality from IHD than the expected was found among the Jews, English, and Scottish; and a lower risk was found among the native Indians, Austrians, Germans and Ukrainians. In some groups a varying pattern of risk was found between the foreign-born and the Canadian-born subjects of the same ethnic background. The data suggest that both genetic and environmental factors operate in the development of IHD. However, some of the findings are consistent with the hypothesis that the environmental factors play a dominant role, and manipulations of these factors may therefore lead to successful prevention.