Some reflections on the two studies examining Mexican immigrant health paradox:
1. I found interesting the idea of contrasting Mexican immigrants to those who remain in the country rather than with U.S.-born Hispanic population. If we are trying to test the hypothesis of health selection, then this contrast makes more sense, as (in causal framework) it's getting at the question "what the outcomes would be in those who migrated out of Mexico had they not migrated?" rather than "what the outcomes would be in foreign-born Hispanic populations if they were in fact born in the U.S?" I think the most interesting contrast would be between those Mexicans who recently immigrated to the U.S. and those with high likelihood of migrating, as I would expect these two groups to have more similarities and thus less potential confounding. Interestingly, we do not observe large differences in obesity between these two groups in males (Fig. 1), but we do observe it in females (Fig. 2).
2. When thinking about health selection I imagine that this should relate to some group having some predictors of good health or good health behaviors. Education is associated with healthy habits. But authors mention that migration likelihood was negatively associated with education attainment (p. 121). This was not the goal of this study, but I wonder how the population migrating out of Mexico is different from those who stay in Mexico in terms of health and healthy behaviors. Maybe Priz could comment on that?
3. In the study comparing infant mortality rates, authors mention how foreign-born and U.S.-born Hispanic populations fare better than non-Hispanic black populations and how this is unexpected given similar socioeconomic profiles. This is an interesting find in terms of the paradox, but I think it also highlights that the gap between these two populations may be due to other factors, like different experiences that they have with discrimination practices and systemic racism.