New York City's Upsurge in Life Expectancy

Over the period 1990–2010, the increase in life expectancy for males in New York City was 6.0 years greater than for males in the United States. The female relative gain was 3.9 years. Male relative gains were larger because of extremely rapid reductions in mortality from HIV/AIDS and homicide, declines that reflect effective municipal policies and programs. Declines in drug- and alcohol-related deaths also played a significant role in New York City's advance, but every major cause of death contributed to its relative improvement. By 2010, New York City had a life expectancy that was 1.9 years greater than that of the US. This difference is attributable to the high representation of immigrants in New York's population. Immigrants to New York City, and to the United States, have life expectancies that are among the highest in the world. The fact that 38 percent of New York's population consists of immigrants, compared to only 14 percent in the United States, accounts for New York's exceptional standing in life expectancy in 2010. In fact, US-born New Yorkers have a life expectancy below that of the United States itself.

That is from this paper by Samuel H. Preston & Irma T. Elo.