Over the past two decades, the number of international migrants has increased by approximately 150%, consequently, considerable attention has been spent for understanding of the unique health trend among immigrant populations, that is, healthy immigrant effect (HIE). While extant studies have primarily focused on uncovering the role of post-migration experience, less is known regarding the influence of the pre-migration experience. Drawing upon the eco-social theory in epidemiology, we tested the role of population-level wealth or poverty of pre-migration in immigrant health outcomes at post-migration. More specifically, this study examined whether the health status of immigrants from high GDP countries declines less sharply the longer they live in the receiving country compared to their counterparts from low GDP countries.
The present study used the Household, Income, and Labor Dynamics in Australia (HILDA) survey collected in 2016. Particularly, this study pooled a sample of adult immigrants whose birth country was not Australia and whose age at migration was greater than the age of 18 (N = 1,952). The dependent variable is immigrant health status assessing both mental and physical health dimensions. The length of stay in Australia and GDP per capita of the birth country are the primary independent variables. I controlled for gender, age, age at arrival, marital status, educational attainment, income, employment status, and English proficiency as covariates. The nested structure of the data, participants (N = 1,952) from countries (N = 96), the relationship between the GDP of a birth country and individual health outcomes were modeled using Hierarchical Linear Modeling (HLM).
The results showed that the positive association between the GDP per capita of the birth country and immigrant health is statistically significant covariates (β = .07, p <.01) after controlling for, indicating that the wealth of the birth country is positively related to immigrant health. Also, the cross-level interaction term between the length of stay (individual level) and the GDP per capita (country level) is significant (β = .42, p < .05) with moderate effect size, implying that immigrants from high GDP countries health decline less sharply the longer they live in the receiving country compared to their counterparts from low GDP countries.
Conclusions and Implications
Our findings illustrate that the deteriorating trend of immigrant health (HIE) is stronger among immigrants from low GDP countries compared to those from high GDP countries. These findings lend support to the importance of population-level pre-migration experiences in understanding immigrant health in addition to research focusing on current individual SES and post-migration experiences on immigrant health. This study suggests that, in addition to post-migration factors such as current SES in a receiving country and acculturation-related factors, researchers and policymakers working with immigrant health issues need to expand the research and policy scopes to include macro factors during the pre-migration phase.