A common belief among users is that the smoke is significantly less dangerous than that from cigarettes.The water moisture induced by the hookah makes the smoke less irritating and may give a false sense of security and reduce concerns about true health effects. Doctors at institutions including the Mayo Clinic have stated that use of hookah is equally detrimental to a person's health as smoking cigarettes,and a study by the World Health Organization also confirmed these findings.
Each hookah session typically lasts more than 40 minutes, and consists of 50 to 200 inhalations that each range from 0.15 to 0.50 liters of smoke. Reports by the World Health Organization and the American Cancer Society have shown that, in a one-hour hookah session, users consume about 100 to 200 times the smoke and about 70% more nicotine than they would in one cigarette.
A 2005 study found that water pipe smokers were five times more likely than non-smokers to show signs of gum disease. People who smoked water pipes had five times the risk of lung cancer as non-smokers.
The water used to filter the smoke does not work efficiently to remove all the harmful chemicals.
A study on hookah smoking and cancer in Pakistan was published in 2008. Its objective was "to find serum CEA levels in ever/exclusive hookah smokers, i.e. those who smoked only hookah (no cigarettes, bidis, etc.), prepared between 1 and 4 times a day with a quantity of up to 120 g (the average bowl in holds 30g) of a tobacco-molasses mixture each (i.e. the tobacco weight equivalent of up to 60 cigarettes of 1 g each) and consumed in 1 to 8 sessions". Carcinoembryonic antigen (CEA) is a marker found in several forms of cancer. Levels in exclusive hookah smokers were lower compared to cigarette smokers although the difference was not statistically significant between a hookah smoker and a non-smoker. Also the study concluded that heavy hookah smoking (2–4 daily preparations; 3–8 sessions a day ; 2 hrs to 6 hours) substantially raises CEA levels.
