Investigating the dynamics of migration and health in Australia: a longitudinal study

There have been few longitudinal studies investigating the immigrant health and changes in their health with longer residency in the host country. Additionally, the pathways and mechanisms by which transition of health over time occurs are poorly understood, limiting the ability to implement policies that will result in improved health for all, including immigrants. We assessed differences in health outcomes among foreign-born people from English speaking countries and non-English speaking countries relative to native-born Australians over a 10-year period using a large representative longitudinal dataset. We also explored English language proficiency, socio-economic factors and health behaviour factors as possible mechanisms through which health outcomes change over time post-migration. Conventional multilevel mixed and hybrid regression models were used to evaluate health outcomes in 9558 native-born and 3067 foreign-born people from the Household, Income and Labour Dynamics in Australia survey. There were clear differences in physical health, mental health and self-assessed health between foreign-born subgroups in comparison with native-born Australians. Foreign-born people from English speaking countries typically had a health advantage relative to native-born people, and foreign-born people from non-English speaking countries had a health disadvantage with respect to native-born people for all health outcomes. There was no evidence that these differences changed by duration of residence except for self-assessed health amongst foreign-born people from non-English speaking countries when duration of residence exceeded 20 years. English language proficiency mediated the relationship between duration of residence and health for foreign-born people from non-English speaking countries.