Healthy migrant effect in the Swedish context: a register-based, longitudinal cohort study.

Objectives Studies have found a 'healthy-migrant effect' (HME) among arriving migrants, that is, a better health status compared with others in the home country, but also in comparison with the population in the host country. The aims were to investigate whether the HME hypothesis is applicable to the Swedish context, that is, if health outcomes differed between a group of mainly labour migrants (Western migrants) and a group of mainly refugee/ family reunion migrants (non-Western migrants) compared with the native Swedish population, and if there were any correlations between labour market attachment (LMA) and these health outcomes. Design Register-based, longitudinal cohort study. Participants The cohort was defined on 31 December 1990 and consisted of all migrants aged 18-47 years who arrived in Sweden in 1985-1990 (n=74 954) and a reference population of native Swedes (n=1 405 047) in the same age span. They were followed for three consecutive 6-year periods (1991-1996, 1997-2002 and 2003-2008) and were assessed for five measures of health: hospitalisation for cardiovascular and psychiatric disorders, mortality, disability pension, and sick leave. Results Western migrants had, compared with native Swedes, lower or equal HRs for all health measures during all time periods, while non-Western migrants displayed higher or equal HRs for all health measures, except for mortality, during all time periods. Age, educational level, occupation and LMA explained part of the difference between migrants and native Swedes. High LMA was associated with higher HRs for cardiovascular disorders among Western migrants, higher HRs of psychiatric disorders among non-Western migrants and higher HRs of mortality among both migrant groups compared with native Swedes. Conclusions There were indications of a HME among Western migrants, while less proof of a HME among non-Western migrants. Stratification for LMA and different migrant categories showed some interesting differences, and measurements of the HME may be inconclusive if not stratified by migrant category or other relevant variables.