I found a research article about adverse effects of Water Pipe / Nargile / Hookah smoking:
http://pediatrics.aappublications.org/cgi/content/full/116/1/e113 Just what I was looking for... some statistical evidence of significantly adverse effects of sheesha...
Nicotine: higher content than in cigarettes
Tar: higher
Carbon monoxide: higher
Heavy metals: yep, they're there
dixi