I've seen compulsive smokers (myself included) in developers, just as I seen them in almost every other profession.
I'm not sure how there's a correlation between developers and smoking, but I can surely confirm that sedentarism will harm you.<p>When I work at home, I just lose track of how many cigars I'm smoking until I see the ashtray and start crying inside.<p>My semi-conscious process goes like this:
I sit in front of the computer. I attempt to tackle bugs messing with my head.<p>If the problem is particularly difficult, I somehow figure out that I'm not smoking/flicking a cigar within my fingers and I light one up.
Later, I repeat this action for hours and hours.<p>Right now, for example, I've been up for a long time, trying to convert an x86 emulator to JS with the beautiful emscripten, to later run Windows 95 on top of it.
Just thinking about it makes me giggle, because it is proving to be a lot of fun!<p>The down side is that I'm an avid smoker and I will smoke quite a bunch of cigars in the process.<p>Also, there's a lot of weed among developers. Not sure how prevalent that is in the USA.