An interesting (and well-known) artifact is that Asians in the US have highest life expectancies in the world. In addition to possibly having good genetics for this purpose, they avoid the anomalous adverse factors in US life expectancies (vehicular accidents and homicide) while taking advantage of the fact that the US generally has the best average medical outcomes in the world for the diseases that tend to kill older populations.

From a life expectancy standpoint, Asian Americans have the perfect intersection of genetics, avoidance of injury, and medical outcomes. Given the size of disparities in life expectancy, shifts in demographics alone would be sufficient to explain some of the increase in life expectancy.