Are there differences in all-cause and coronary heart disease mortality between immigrants in Sweden and in their country of birth? A follow-up study of total populations

BACKGROUND Mortality from cardiovascular diseases is higher among immigrants than native Swedes. It is not clear whether the high mortality persists from the country of birth or is a result of migration. The purpose of the present study was to analyse whether all-cause and coronary heart disease mortality differ between immigrants in Sweden and in the country of birth. METHODS Two cohorts including the total population from Swedish national registers and WHO were defined. All-cause and CHD mortality are presented as age-adjusted incidence rates and incidence density ratios (IDR) in eight immigrant groups in Sweden and in their country of birth. The data were analysed using Poisson regression. RESULTS The all-cause mortality risk was lower among seven of eight male immigrant groups (IDR 0.39-0.97) and among six of eight female immigrant groups (IDR 0.42-0.81) than in their country of birth. The CHD mortality risk was significantly lower in male immigrants from Norway (IDR = 0.84), Finland (IDR = 0.91), Germany (IDR = 0.84) and Hungary (IDR = 0.59) and among female immigrants from Germany (IDR = 0.66) and Hungary (IDR = 0.54) than in their country of birth. In contrast, there was a significantly higher CHD mortality risk in male immigrants from Southern Europe (IDR = 1.23) than in their country of birth. CONCLUSION The all-cause mortality risk was lower in the majority of immigrant groups in Sweden than in their country of birth. The differences in CHD mortality risks were more complex. For countries with high CHD mortality, such as Finland and Hungary, the risk was lower among immigrants in Sweden than in their country of birth. For low-risk countries in South Europe, the risk was higher in immigrants in Sweden than in South Europe.