So what is the explanation?
They analyzed data through 2009. Lets look at the factors the study discusses -
The transfat ban was approved in 2006 and effective in July of 2008. Hardly enough time to have an effect on the death rate.
Less than 0.6% of New Yorkers commute by bicycle as of 2009. The number was even lower in the early part of the decade. That's too small a number to have a meaningful effect.
The NY Times tells us that we're fatter than ever. So much for the effect of calorie counts and anti-fat subway posters.
Yes, the smoking rate in NY dropped from 22% in 2002 to 14% in 2009. But the *national* smoking rate dropped from 29% to 19% during that same period. Before Bloomberg the Great became mayor we already were ahead of the nation by 7%. It's by no means clear how much Bloomberg's efforts drove the recent decline and how much other factors played a part.
That people who live in large, cosmopolitan urban areas tend to be wealthier and have better lifestyle habits than people who live in other places? And murder rates have collapsed?