Ro and Fleischer is an excellent study uses the dynamic trends of obesity prevalence in Mexico to explain the healthy migrant effect and examine the change of health selection. I wonder how generalizable these findings are to the other countries (e.g., other countries in Latin America and Asia) or health conditions other than obesity. Does the health selection always increase with worsening health conditions? And it is also interesting to see that the effect of the health selection does not last for a long time or past to the next generation. The long-term immigrants had higher prevalence of obesity compared to the recent immigrants in 2012. And the US-born Mexican had higher prevalence of obesity compared to recent immigrants in both years.
In Hummer et al., the authors eliminated the impact of out-migration by using the age-specific infant mortality rate. I am curious that if the lower IMR of infants born to Mexican immigrants can be explained by immigration selectivity, why there is no such effect among the non-Hispanic Black immigrants?