Mental health articles

What is the “HealthyMigrant Effect”?
Firstly, the question has to be resolved whether the
observed mortality advantage of migrants is real or
due to bias. One possible explanation is the “salmon
bias”. Its underlying claim is that gravely ill migrants
tend to return to their countries of origin. This leads
to a numerator-denominator (numerator-denominator
bias) mismatch and thus to an underestimation of mortality.
Study designs that are based on repeated crosssectional
analyses are prone to this type of bias. For example, a considerably lower all-cause mortality was
observed among male Turkish migrants in Germany than among German men (Razum et al. 1998). In a longitudinal design, however, their peers in the Netherlands had a higher mortality than Dutch men. Still, this observation cannot be generalized.Moreover, cohort studies which could rule out return migration confirmed that there are real and sometimes quite large mortality advantages of migrants. More studies based on individual follow-up are needed to analyze the size and direction of observed mortality differentials.
The data sets used for many of the studies listed above have an additional limitation: the association between socioeconomic indicators such as unemployment on the one hand, and health outcomes on the other, is merely ecological ( ecological association). Thus it remains unclear whether migrants with a low socioeconomic status have a higher or lower mortality than those of high socioeconomic status, and how social mobility of migrants affects their mortality. Only measurements at individual level can help to further clarify the determinants of trends in disparity. They should be complemented by measurements of community attributes such as the extent of discrimination. Clearly, present studies examine only selected aspects of the association between migration and health.

Tags: Health