Immigrant obesity and unhealthy assimilation: alternative estimates of convergence or divergence, 1995-2005.

We re-examine the pace of rising obesity among Hispanic immigrants and the effects associated with longer duration in the US, or what is referred to as unhealthy assimilation, the convergence of immigrant health to a less healthy native-born standard. Consistent with previous research, we find that across all race-ethnic groups, immigrants tend to be less obese than native-born persons. Second, obesity is clearly on the rise, with obesity rates increasing for both immigrant and native-born populations between 1995 and 2005. However, our findings are that immigrant obesity rises more slowly than for native-born Hispanics in the same age cohort. The significance is that immigrants do not converge to obesity prevalence of the native-born as commonly assumed and, in fact, the differential is wider in 2005 than it was in 1995. The analysis, which is based on the National Health Interview Survey tracks the obesity rates of different cohort populations observed in repeated cross-sections (1995 and 2005), as both immigrants and the native-born grow older and additionally, as immigrants reside in the U.S. longer. More specifically, for immigrants, our study distinguishes the effects of length of U.S. residence (observed at a single point in time) and increasing duration of residence (observed over time). Of crucial importance, we contrast the changes over time for native and foreign-born residents passing through the same age range from 1995 to 2005. Misconclusions of previous research stem from 1) assuming that any change for immigrants equates to assimilation, without regard to native-born change, and 2) an unbalanced analysis that fails to track in parallel the growing obesity of both immigrant and native-born cohorts.