Commentary: The waterpipe—a global epidemic or a passing fad

Six years ago, we published in Tobacco Control the first comprehensive review about the waterpipe (also known as shisha, hookah, arghile and narghile) in response to what seemed to be a burgeoning global epidemic.1 In the most common form of waterpipe used nowadays, charcoal-heated air passes through a perforated aluminum foil separating the charcoal from the flavoured tobacco (a.k.a. Maassel) to become a smoke that cools as it bubbles through the water before inhalation by the smoker. Although waterpipe smoking is a centuries-old tobacco use method, it was for the most part confined to older men in Middle Eastern societies. We do not have detailed epidemiological estimates of the spread of waterpipe smoking before the 1990s, but the absence of such data is suggestive of limited popularity. All this changed in the early 1990s, when, beginning in the Middle East, waterpipe smoking conquered the world’s youth in record time. Prevalence rates of current (past month) waterpipe smoking can range from 6 to 34% among Middle Eastern adolescents, 5 to 17% among American adolescents and from 10 to 20% among American university students.1–3 Similar patterns have been reported from Europe, Canada and Australia. But perhaps the most compelling evidence about the waterpipe’s growing impact on youth’s tobacco use globally comes from a recent report of the Global Tobacco Youth Survey (GYTS), looking at time trends (1999–2008) of tobacco use of over half a million youth ageing 13–15 years, and involving 209 surveys in 95 countries and five areas.3 This global surveillance effort shows that whereas cigarette smoking is showing either stable or declining trend globally, other forms of tobacco use are showing a rising trend, mainly as a result of waterpipe smoking. We noted in our review that available evidence about the long-term health effects of waterpipe smoking suffer from methodological limitations;1 a view that was re-reiterated a year later in the first advisory on waterpipe smoking published by the World Health Organization.4 In this issue of the IJE, Akl et al.5 provide the first comprehensive evaluation of the evidence concerning the health effects of waterpipe smoking. In their systematic review, Akl et al.5 applied the Cochrane Collaboration methodology to compile 24 studies that were judged eligible for the analysis. They found that waterpipe smoking more than doubles the risk of lung cancer [odds ratio (OR) = 2.12; 95% confidence interval (95% CI) 1.32–3.42], respiratory illness (OR = 2.3; 95% CI 1.1–5.1) and low birth weight (OR = 2.12; 95% 1.08–4.18). Waterpipe smoking, however, was not significantly associated with bladder cancer (OR = 0.8; 95% CI 0.2–4.0), nasopharyngeal cancer (OR = 0.49; 95% CI 0.2–1.23), oesophageal cancer (OR = 1.85; 95% CI 0.95–3.58), oral dysplasia (OR = 8.33; 95% CI 0.78–9.47) or infertility (OR = 2.5; 95% CI 1.0–6.3), but the wide confidence intervals do not rule out such associations.5 In terms of the quality of the reviewed studies, Akl et al.5 note that most suffer from inadequate assessment of exposure and/or outcome, control of confounding or lack of power to detect the studied associations. They rightly note that the status of evidence considering the health effects of waterpipe smoking can reflect also the novelty of the waterpipe epidemic, compared with the known latency between smoking initiation and the development of serious smoking-related morbidity and mortality. As Akl et al.5 join in calling for better studies, the quality of currently available evidence led them to be uncertain whether to recommend a rigorous public health response early on in the waterpipe epidemic or a wait-and-see approach. I do not share that uncertainty, as I firmly believe that the spread of waterpipe smoking among the world’s youth represents, already, a global public health crisis. This conviction is based on several reasons. First, waterpipe smoke contains many of the same toxicants as cigarette smoke, including those that cause cardiovascular disease [e.g. carbon monoxide (CO)], lung disease (e.g. volatile aldehydes), cancer (e.g. polycyclic aromatic hydrocarbons) and dependence (i.e. nicotine).6 Secondly, waterpipe smoking is an efficient means of delivering toxicants to the smoker. For example, recent research reveals that, relative to a single cigarette, a single waterpipe session exposes the smoker to 3–9 times the CO and 1.7 times the nicotine.7 Thirdly, waterpipe smoking is associated with features of dependence, such as drug-seeking behaviour, inability to quit despite repeated attempts and abstinence-induced withdrawal that is suppressed by subsequent waterpipe use.8 Fourthly, sharing the waterpipe, a popular practice among youth world wide can be associated with infectious disease risks, such as tuberculosis.9 Fifthly, waterpipe smoking-related emissions can harm non-smokers. For example, a recent study showed that waterpipe smoking generates high levels of toxicants/carcinogens (e.g. volatile organic compounds, polycyclic aromatic hydrocarbons, metals, CO, as well as particulate matter) in the surrounding air, putting non-smokers at risk.10 And finally, evidence suggests that waterpipe smoking can undermine tobacco control, as it can be used as a replacement for cigarettes among quitters or serves as a gateway to cigarette initiation.11 This body of evidence on the serious public health potential of waterpipe smoking is faced, until now, with a scarcity of evidence-based solutions to curtail waterpipe smoking. Interventions are needed to prevent initiation among youth, stop their progression to nicotine dependence and treat dependent waterpipe users. As dependence in waterpipe smokers is likely influenced by its unique features (e.g. non-portability, intermittent use, potent sensory cues, prolonged smoking sessions and frequent social use), knowledge of the anatomy of dependence in waterpipe smokers is instrumental for the development of such interventions. For now, we can start moving on the policy front, as most current tobacco control policies are unclear about the waterpipe or in fact can contribute to its spread by exempting waterpipe venues, e.g. from clean indoor air laws (as it is the situation in many parts of the USA).12 Policies on package descriptors can influence waterpipe smoking, in particular, as many waterpipe users are driven by a misperception of its reduced harm and addictiveness. Such perception can be re-enforced by deceptive descriptors that appear frequently on waterpipe tobacco packages (e.g. ‘0% tar, 0.05% nicotine’ and ‘light’).2,11,13 Limiting minors’ access to the waterpipe can also be an important front for policy interventions, given the broad social acceptability and tolerance towards waterpipe smoking by minors compared with cigarettes. Considering the story with other ‘local or cultural’ tobacco products that did not develop significantly beyond their defined geo-ethnic boundaries (e.g. cigar, pipe, bidi, kretek and snus), the patterns of spread of waterpipe smoking represent a true global epidemic in a way that we have not witnessed, perhaps since the beginning of the cigarette pandemic. This global spread combined with the waterpipe’s potential to hook young people on nicotine, and to harm smokers and non-smokers alike, should become a wake-up call for an urgent public health response. The GYTS was an eye-opener to the dramatic changes in youth’s tobacco use patterns world wide; changes that will likely determine the tobacco control landscape of the future.