In particular this Australian study, and this Danish one show that even with the risks of cycling in traffic, you're still better off in terms of longevity.
Of course, longevity is good for the economy in terms of productivity but also increases the duration of your carbon footprint* so there may well be environmental penalties from cycling as well.
*In case you're wondering, yes, I have used this link before, and there was some interesting discussion last time around.