Rise of waterpipe smoking

When we started investigating the waterpipe more than a decade ago,1 we knew that we were facing something that could have serious effects on global health. We did not know whether this was a passing fad or the full spectrum of risks the waterpipe poses to individuals and society.

Considerable strides in understanding the public health impact of waterpipe smoking have been made since. At the same time, our worst predictions of an escalating global epidemic have been vindicated.2 Data from the Global Tobacco Surveillance System, including over 100 countries and repeated surveys since 1999, are clear. Time trends among 13-15 year olds show that while cigarette smoking has been either stable or declining globally, waterpipe smoking is on the rise in many countries and is replacing cigarettes as the most popular method of tobacco use among Middle Eastern youth.2 3 As the epidemic progresses, the waterpipe’s spread among adults globally is increasingly documented.4

The waterpipe, also known as shisha, hookah, and narghile, is a centuries old method of tobacco use that has its roots in Eastern societies. In its most common form, charcoal heated air is passed through a tobacco mixture to produce smoke, which is bubbled through water before inhalation by the smoker (figure⇓). The mistaken belief that smoke is “filtered” as its passes through water accounts for the misperception of waterpipes as benign compared with cigarettes, although this has been convincingly refuted.5 What is unique about the waterpipe is that its use is usually social, practised in the company of friends and family, and often in a café or restaurant. Until recently, waterpipe smoking was on the decline, becoming confined to older men in the Middle East. All this changed in the early 1990s,6 when waterpipes’ popularity among youth took off, first in the Middle East, and soon globally.2

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How could a “cultural” habit become such a global phenomenon in record time? The answer lies in a “perfect storm” of developments. The introduction of flavoured, sweetened tobacco (maassel) in the Middle East during the early 1990s increased the waterpipe’s appeal to young people.2 7 Simultaneously, the burgeoning global economy and advancements in communication and social networking helped propel waterpipes onto the global stage.2 In Western societies, for example, where waterpipe venues may not be readily accessible, the internet and social media have an important role in spreading the habit among youth.2 8

Several barriers are slowing our understanding of the effect of the waterpipe epidemic. Firstly, not enough time has passed to capture several potentially important tobacco related effects that have long latencies, including cancer and cardiovascular disease. Secondly, research on the waterpipe is complicated by overly benchmarking on cigarettes, which can obscure some of the unique features of waterpipe use and exposures. Compared with cigarette smoking, waterpipe use is usually practised intermittently and in longer sessions that result in substantially greater intake of smoke.2 5 The amount and composition of tobacco mixture and charcoal used, as well as the shape and size of the waterpipe vary considerably and affect exposure to toxicants. Moreover, given waterpipes’ primarily intermittent use, cigarette based measures of use and dependence, such as current smoking (past month smoking), Fagerstrom test for nicotine dependence, and cessation (seven days’ abstinence), may not capture meaningful variations in waterpipe use. We therefore need waterpipe specific measures that take into account time spent smoking, its social dimension, as well as different levels of intermittent use.2 9 10

Notwithstanding these problems, research in the past decade has begun to generate a consistent picture of the health risks of waterpipe smoking.11 Studies clearly show waterpipe smokers’ exposure to nicotine, toxicants, and carcinogens associated with smoking-induced disease.5 11 10 In fact, exposure to some toxicants such as carbon monoxide and heavy metals is so high that unique health problems may result. For example, several cases of waterpipe users being admitted to emergency rooms with carbon monoxide poisoning have been reported, with carboxyhaemoglobin (COHb) levels much higher than have been observed in cigarette smokers (COHb≥30%).12 The popularity of waterpipe smoking among women in the Middle East makes such high carbon monoxide exposure of particular concern during pregnancy. While good quality studies of long term health effects of waterpipe smoking are only beginning, available evidence points to an association with some of the known risks of tobacco smoking such as lung cancer and cardiovascular disease.11 A new study found that lifetime waterpipe use was associated with a threefold, dose dependent increase in the odds of having severe coronary artery stenosis (≥70%) compared with non-smokers.13

What has not received enough focus is waterpipes’ potential to thwart cigarette cessation, potentiate initiation of cigarette smoking, and harm non-smokers.12 For example, a recent randomised clinical trial of the “Quit and Win” cessation programme found that college cigarette smokers who concurrently used waterpipes had lower short and long term tobacco abstinence rates.14 As the waterpipe is increasingly providing youth with their first experience of tobacco, those who become waterpipe dependent are likely to resort to the more accessible cigarettes to deal with their urges. A longitudinal study among Jordanian schoolchildren recently found a dose related increase in the risk of starting cigarette smoking according to the level of waterpipe use at baseline.15 Furthermore, non-smokers exposed to the waterpipe are at risk of toxic emissions including particulate matter, carcinogens, and carbon monoxide.16 Children exposed to waterpipe smoking at home have been shown to have higher levels of carcinogenic tobacco specific nitrosamines.17

Despite all these worrisome trends, waterpipe smoking is still exempt from, or flying under the radar of, most tobacco control policies.18 This needs to change. Major tobacco regulatory initiatives should include waterpipe specific policies, such as bans on flavouring, clean indoor air policies for waterpipe venues, age limits on smoking in café settings, and requiring large health warnings on waterpipes as well as the tobacco. Unlike a decade ago, we now know that waterpipe smoking is a well developed global public health epidemic in need of a clear and comprehensive regulatory approach. We have all the evidence we need for that, but only time will tell whether we have the will.