The waterpipe (also known as gouza, narghile, hubble-bubble, hookah or shisha, depending on the local tradition) has been used for smoking tobacco for centuries in the Eastern Mediterranean Region. Formerly associated almost exclusively with older males, usually of lower socioeconomic level, waterpipe smoking is now spreading to other segments of society in the region, particularly young men and women, and those from higher socioeconomic levels. Recent surveys from Lebanon, Saudi Arabia and Egypt, as documented in this monograph, have begun to study the characteristics, knowledge, beliefs and attitudes of waterpipe users. This literature review reveals that surprisingly little information is actually available on the level of human exposure to the harmful constituents of the tobacco smoke from these devices, and even less is known of its impact on public health. 1. Many differences are apparent when comparing waterpipe to cigarette smoking. In general, compared to cigarette smoking, waterpipe smoking is characterized by less frequent exposure (one to four sessions per day) but with a much more intense exposure per session which varies between 15 and 90 minutes. The uptake of tobacco nicotine is equivalent to 2–12 cigarettes per portion of tobacco used (hagar). A regular user of waterpipes usually smokes several hagar per session and on average smokes 2–3 sessions per day. This translates into an intake of nicotine equivalent to more than one pack of cigarettes per session for most waterpipe smokers. However, it is known that waterpipe smoking produces more smoke than cigarette smoking, and it has been estimated that smoke exposure could be as much as 100–200 cigarettes per session. Therefore the types and magnitudes of health hazards of waterpipe smoking are likely to be different from those of cigarette smoking, and there is a need to standardize exposure measurements for the proper assessment of health hazards related to this particular kind of tobacco exposure. 2. In addition, the temperature of burning tobacco in waterpipes is much lower than that in cigarettes, and the force needed to pull air through the high resistance of the water pathway permits the smoke to be inhaled very deeply into the lungs. Therefore the sites and patterns of cell injury in the oral and respiratory tracts are likely to be different from those due to cigarette smoking. This area requires further toxicological and pathological investigation and needs expanded research support. Indeed, the entire field of the health effects of waterpipe smoking is ripe for new and comprehensive research, including interdisciplinary approaches to the major questions raised in this review. 3. The prevalence of overall smoking among adult males in Egypt was estimated from a national survey in 2002 focusing on hypertension, obesity and diabetes prevalence to be 47% (34% cigarettes only, 10% waterpipes only, 3% mixed), while smoking prevalence among adult females was less than 1%. 4. Remarkably, this survey of 6950 adults revealed a significantly greater prevalence of abdominal obesity among waterpipe smokers compared to nonsmokers. The data further suggest that tobaccorelated mortality and smoking prevalence are both increasing in Egypt, with a prominent decline in the younger cohort in the mean age of regular smoking initiation. If such trends continue, Egypt and other nations in the Region with similar patterns will experience longer lifetime duration of smoking among these young smokers, and consequently increases in the burden of smoking-related diseases. 5. A more recent national survey in Egypt carried out by the Egyptian Smoking Prevention Research Institute (ESPRI) in 2005 in 25 of the 27 governorates of Egypt revealed that, among males 18 years and older, 13.6% (95% confidence interval 10.3%–17.8%) in rural areas reported current use of the waterpipe, compared to 10.5% (95% confidence interval 7.0%–15.4%) in urban areas. These figures translate to approximately two million current waterpipe smokers in Egypt, confirming anecdotal and popular press reports of the rise in popularity of waterpipe smoking. 6. A detailed survey of waterpipe smoking in the rural areas of the Nile Delta, carried out by ESPRI in 2003–2004 in nine randomly selected villages (each with 10 000–20 000 residents) revealed that waterpipe smoking was inversely related to ducational level, and that most users believed that it is less hazardous than smoking cigarettes. The survey found that more than 70% of male waterpipe smokers smoked in the presence of their children and wives at home, which calls attention to the unfortunate fact of indoor environmental tobacco smoke exposure. 7. Current smoking behavioural practices among females in Egypt are not well known, due to their reluctance to report their tobacco habits when interviewed at home in the presence of family members. A survey of 196 female university student patrons of cafés in Cairo that served waterpipes was carried out by the ESPRI team in order to obtain a better picture of current smoking behaviour among females where the women felt comfortable discussing smoking. It revealed that 27% reported smoking cigarettes exclusively, while 38% smoked tobacco using waterpipes exclusively, and 32% used both types of tobacco moking method. 8. Most of the female waterpipe smokers had the perception of the waterpipe as fashionable, and believed that waterpipes are less harmful than cigarettes. 9. There is little research on waterpipe smoking and health; for example, waterpipe smoking is a source of heavy metal exposure to consumers, and evidence suggests that waterpipes concentrate these metals in the water chamber of the device. More work needs to be done in this area. 10. Biological markers of tobacco harm, such as carbon monoxide poisoning, have been scarcely studied in waterpipe users, and many questions remain to be explored in detail. 11. Special health concerns that distinguish waterpipe smoking from cigarette smoking include the possibility that waterpipe users are prone to infections due to the habit of sharing waterpipes without changing the mouthpiece. 12. Maternal and child health effects from exposure to second-hand waterpipe smoke at home are almost entirely unknown at present. 13. No reliable dependency scale for waterpipe tobacco smoking has been developed and validated, which is hindering efforts to understand the psychological and physiological aspects of waterpipe smoking behaviour. 14. As an example of biomarker-based research strategies that are needed to evaluate possible genotoxic actions of substances in the waterpipe tobacco smoke, ESPRI conducted a study of micronuclei in oral mucosa cells (small DNA structures separated from the main nucleus of the basal epithelial layers and exfoliated into the oral cavity). It was found that the mean micronuclei level was significantly higher (more than twofold) among the waterpipe smokers compared to never smokers. Validation and standardization of such tests will permit the quantification of waterpipe tobacco–related exposure levels and early biological effects.
