Why is the 'healthy immigrant effect' different between European countries?

BACKGROUND: Even if health status of immigrants constitutes an important public health issue, the literature provides contradictory results on the existence of a 'healthy migrant' effect in Europe. This study proposes to explore the heterogeneity of the health gap between migrants and natives across four European countries. DATA AND METHODS: Based on several harmonized national health interview surveys, the association between migratory status and self-assessed health was firstly explored separately in Belgium, France, Spain and Italy. To explore whether differences in health gap between countries reflect differences in health status of immigrants between host countries or whether they are because of differences in health status of natives between host countries, the association between the host country and health was secondly analysed separately among a pooled sample of immigrants and one of natives, controlling for socio-economic status and country of origin.
RESULTS: After controlling for socio-economic status, immigrants report a poorer health status than natives in France, Belgium and Spain, whereas they report a better health status than natives in Italy, among both women and men. A North-South gradient in immigrants' health status appears: their health status is better in Italy and in Spain than in France and Belgium. Conversely, health status of natives is poorer in Italy and in Belgium than in France and in Spain.
CONCLUSION: Differences in health gap reflect differences in health status of both natives and immigrants between host countries. This suggests differences in health selection at migration and in immigrants' integration between European countries.