First thing you guys should consider is cigarettes are condemned totally out of proportion to the risk and that is a result of tobacco research being politically motivated junk science. If any of you are up to reading a bit I suggest that you take a look at a critical examination of the famed and often cited Surgeon General reports on smoking which can be found here: http://www.lcolby.com/b-chap7.htm
In terms of relative risk cigarette use entails less health risk then being a professional welder, a male homosexual, being obese or being poor. As the text points out, do to lack of adequate statistical controls the Surgeon General report may in fact be a better study of the risks of being poor then an appraisal of the risks of tobacco use. I would also recommend that you guys check out a book called “For Your Own Good” by Jacob Sullum which covers all sorts of aspects regarding public policy towards smoking.
As to narghile use I am of the opinion that no studies have been done that deserve to be taken seriously for the following reasons:
1) Coals not intended for narghile use are employed in such tests creating very high CO levels.
2) The tobacco is combusted fully in such tests which is only meaningful if one was to consider tombac instead of moassel or jurak use.
3) The cleanliness of the narghile, hose, bowl and mouth piece are never addressed.
4) Adequate controls for socioeconomic status and genetic variances are not taken into account.
5) Analysis of smoke content in terms of the flavourings, glycerin, type of sugar, tobacco & dyes used are not addressed.
6) All the studies use smoking machines which do not behave like real smokers
7) All the studies are underwritten by openly anti-tobacco groups like the WHO.
8) No attention is given to the issues of narghile height and volumetric capacity nor hose size.
9) No attention is given to actually smoking technique (ex does one inhale or not and if so, how often)
In the end I feel it reasonable to say that narghile use is basically an unknown risk but likely a substantial one which is less then cigarettes (which is exaggerated) provided you don’t regularly smoke tombac.