Waterpipe smoking: the pressing need for risk communication

Abstract

Introduction:

Waterpipe (WP) smoking is an important public health problem that is rapidly evolving globally. Much of WP spread among youth is being perpetuated by a misperception of reduced harms compared to cigarettes. Increasing awareness about WP smoking harms through health warning labels (HWLs) represents a promising policy and regulatory strategy to curb WP smoking.

Areas covered:

Peer-reviewed publications indexed in PubMed and CINAHL were searched in March 2019. This review focuses on the current knowledge of WP smoking characteristics, its spread and patterns of use globally, and some of major WP-related health effects. This knowledge is utilized to advance a promising policy and regulatory avenue to curb WP smoking by increasing awareness of its potential harms through HWLs. It also addresses product configuration and unique features that influence the adaptation of HWLs for WP smoking.

Expert opinion:

HWLs are effective in communicating smoking-related risks to WP smokers in a way that affects their smoking behavior and experience as well as interest in quitting. Although based on limited data, the WP device appears to be a promising location for HWLs as it offers prolonged contact with smokers and those surrounding them.

1. Introduction

Tobacco use continues to be the leading preventable cause of morbidity and mortality worldwide [1]. While tobacco control efforts have succeeded in curbing cigarette smoking rates in developed countries, new and emerging tobacco products are threatening this success and continue to fuel the tobacco epidemic in the rest of the world. These include waterpipes (WP), and e-cigarettes, which have been shown to carry considerable risk and to potentiate cigarette smoking [2-4]. The WP (a.k.a hookah, shisha, narghile) in particular, is attracting an increasing number of youth worldwide that is in part driven by lack of knowledge about and misperception of its harms [5,6]. The assumed filtering of smoke by passing through the water, WP’s intermittent and social use patterns and its smooth and aromatic smoke all reinforce the feeling of product safety compared to cigarettes [7,8]. While evidence is pointing towards serious health risks associated with WP smoking, such misperception has not been countered in a systematic way. Peer-reviewed publications indexed in PubMed and CINAHL were searched in March 2019 for this review. Keywords included waterpipe, hookah, narghile, shisha as well as epidemiology, patterns, health effects and warning labels. Priority was given to studies relevant to this current review. In this review, we will provide a brief synopsis about this tobacco use method design, spread, and health risks, then move to discuss some of the promising strategies to communicating the risks of WP smoking to smokers and those around them.

1.1. The waterpipe

As used today, the WP consists of a head (where tobacco is placed), body, water base, and a hose that ends with a mouthpiece (Figure 1). Burning charcoal pieces are usually placed on top of a perforated aluminum foil that covers the tobacco-filled head, which allows the charcoal heated air to pass through the tobacco, while the holes in the bottom of the head allow the smoke to pass down through the WP stem. The lower part of the stem is immersed in water causing smoke to bubble through on its way via the hose and mouth tip to the smoker. The mouth tip is usually caped with a disposable mouthpiece for individual users [9].

Figure 1:

A typical waterpipe and its main components

As with cigarettes, the WP delivers a substantial amount of nicotine and has been shown to be associated with nicotine dependence [10,11]. The extent of nicotine generated from WP tobacco is likely affected by heating temperature, tobacco mixture used (including flavors, humectants, and additives), puffing patterns, as well as WP configuration and size [12,13]. WP tobacco is usually a combination of tobacco leafs, sweeteners, flavorings and humectants (e.g., glycerol). Data from many countries show that Maassel is the currently preferred form of tobacco for young WP smokers [14-18]. Maassel (Arabic for honeyed) is a sweetened and flavored tobacco mixture that is now mass produced and distributed globally under many brands and flavors, mainly through youth-oriented marketing such as the internet and social media [19,20].

Unlike cigarettes, the WP is a complex tobacco use method consisting of 3 main components; charcoal, device, and tobacco. They are also marketed by multiple loosely-related industries [14]. WPs and their components and accessories can be purchased from dedicated supply shops, and increasingly from internet vendors [21]. Many WP vendors market their products with unsubstantiated claims of reduced harm achieved through the use of accessories, such as filters, “natural” charcoal, and water additives [22]. Such marketing practices work to reinforce the perception of product safety compared to cigarettes [23,24].

Another key “vector” that is unique to the WP is the WP venue, known as WP café, shisha café, hookah bar or lounge, etc. These venues are usually strategically located close to university campuses and youth-oriented areas and are engaged in the intensive promotion of WP smoking among youth. Evidence from the US shows the geographic concentration of these venues close to college and university campuses, and their relation to higher WP smoking among students of these colleges [9]. Evidence from the US as well shows that 50% of young WP smokers smoked their first WP in such venues and that 30% of current smokers usually smoke their WP in these venues [8,25]. Most of these establishments are not regulated in terms of clean indoor air laws, health warnings, or occupational safety, which allow them to continue spreading WP smoking and being harmful to their own staff and workers let alone customers [21,26,27].

Recently we proposed a WP-sensitive regulatory framework for the WP that takes into consideration its unique multi-component configuration, its youth-oriented marketing media, and the special place the WP café occupies in propagating WP smoking among youth [21]. Within this framework, we identified several goals and strategies that apply to each of the three main WP components. One of them, the application of health warning labels (HWLs) will be discussed in more details later in this review.

1.2. Waterpipe use patterns and spread

As an emerging global phenomenon, many surveillance efforts have started to closely monitor WP smoking among the general population. A recent review of WP epidemiological trends showed that the country-weighted regional prevalence estimates of WP use is highest among adults in the Eastern Mediterranean Region (EMR) and is similar among youth in the EMR and European regions [28]. For example, regular or occasional WP use among adults was 7.2% in the EMR, 3.8% in the Americas, and less than 1% in South East Asia, and the Western Pacific. Youth data revealed that past 30 days use was the highest in Europe at 10.6%, then the EMR at 10.3% and the Americas at 6.8% [28]. With respect to time-trends in WP use, studies reported increased use over time for past 30-day use, ranging from 0.3-1.0% per year among youth in the US to 2.9% per year among youth in Jordan [28]. Similar trends were reported for ever WP use trends. However, some countries reported a decrease in WP use, such as in Turkey (2.3% in 2008 to 0.8% in 2010) and Iraq (6.3% in 2008 and 4.8% in 2012) [28]. In the Western parts of the world, particularly in the US, WP use among young people has become a national public health problem. Data from the 2016 National Youth Tobacco Survey (NYTS), a nationally-representative school-based surveillance system, showed that 4.8% (95% CI 4.1-5.7%) of high school students (n=700,000) reported current (past 30 days) use of WP, with similar rates among male (4.5%) and female (5.1%) students [27]. Likewise, in the Monitoring the Future survey conducted in 2016, WP use among 12^th graders was 13.0% in the past year, with boys (15%) more likely to report WP use than girls (11%) [30]. Data from the Population Assessment of Tobacco and Health Study conducted between 2013-2014 of over 13,500 youth aged 12-17 years showed 7.5% (95% CI 6.8-8.2%) ever WP use and 1.7% past 30 days (current) use of WP [31]. Not surprising, ever and past 30-day use were higher among 15-17-year old (13.0% and 2.9%, respectively) than 12-14-year old (2.0% and 0.5%, respectively) [31]. In 2018, data from the NYTS showed that frequent WP use among high schoolers was 15.7%, and 26.2% among middle schoolers [32]. A similar picture was observed in Canada. Analyses of the 2010 Canadian Youth Smoking Survey data from over 30,000 9^th to 12^th graders showed that the prevalence of WP use was 10% [33]. Lastly, between 2013-2016, 1.7% (95% CI 1.5-2.1%) used WP at least monthly, and 9.9% (95% CI 9.2-10.7%) reported ever WP use among weighted national samples of 11-18 year olds in Great Britain [34].

1.3. WP-related health risks

Recent reviews have described in details the health effects of WP smoking to smokers and those exposed to WP smoking [10, 35-48]. Here we are going to briefly discuss the main domains of WP-related health risks as they pertain to developing communication messages to increase awareness of WP’s harmful potential. These are divided into 1- health risks; 2- addiction; 3- harm to others; 4- WP-specific harms; and 5- WP harms compared to cigarettes (details of evidence underlying these are presented in Table) [22].

Table.

Review of available evidence on the waterpipe harm and health effects

Author (s)a	Design	Title	Effects	OR (95% CI)b / P-valuec
Health Risks Associated with Waterpipe Smoking
Awan et al, 201736	Systematic review	Assessing the Effect of Waterpipe Smoking on Cancer Outcome: A Systematic Review of Current Evidence	Lung cancer Gastric Esophageal cancers	6.0 (1.78-20.26) 3.4 (1.7-7.1) 1.85 (1.41-2.44)
Waziry et al, 201737	Systematic review	The effects of waterpipe tobacco smoking on health outcomes: an updated systematic review and meta-analysis	Respiratory diseases Bronchitis Passive waterpipe smoking and wheeze Oral cancer Lung cancer Low birthweight Metabolic syndrome Cardiovascular disease	3.18 (1.25-8.08) 2.37 (1.49-3.77) 1.97 (1.28-3.04) 4.17 (2.53-6.89) 2.12 (1.32-3.42) 2.39 (1.32-4.32) 1.63 (1.25-2.45) 1.67 (1.25-2.24)
Montazeri et al, 201738	Systematic review	Waterpipe smoking and cancer: systematic review and meta-analysis	Lung cancer Oesophageal cancer	4.58 (2.61-8.03) 3.63 (1.39-9.44)
Mamtani et al, 201739	Meta-analysis	Cancer risk in waterpipe smokers: a meta-analysis	Head and neck cancer Esophageal cancer Lung cancer	2.97 (2.26-3.90) 1.84 (1.42–2.38) 2.22 (1.24–3.97)
Etemadi et al, 201740	Cohort Study	The association between waterpipe smoking and gastroesophageal reflux disease	Severe gastroesophageal reflux Frequent gastroesophageal reflux Severe and frequent gastroesophageal reflux	1.18 (1.04-1.35) 1.16 (1.02-1.32) 1.30 (1.08-1.56)
El-Zaatari et al, 201541	Review article	Health effects associated with waterpipe smoking	WP smoking acutely increase heart rate, blood pressure, impaired pulmonary function and carbon monoxide intoxication	P<.05
Munshi et al, 201542	Systematic review	Association between tobacco waterpipe smoking and head and neck conditions: A systematic review	Plaque index Gingival index Vertical bone defects Micronuclei (products of early events in the carcinogenic processes) Inflammation Candida Peroidontitis Dry socket Premalignant lesions Suspicious oral lesions Esophageal squamous cell carcinoma Attic retraction Edema in the vocal cords Lower habitual vocal pitch and voice	15.6 (P < .001) 2.9 (1.2-7.0) 2.9 (1.2-7.0) P < .001 P =.002 P =.002 RRd=5.1 (P < .001) P < .001 NA OR=4.42 (P< .01) NA P< .01 P= .012 P< .03
Sivapalan et al, 201444	Review article	Smoking water pipe is injurious to lungs	WP smoking negatively  affects the lung function	NA
Wu et al, 201345	Cohort Study	A prospective study of tobacco smoking and mortality in Bangladesh	WP smoking was associated with increased risk of death from any cause WPS was associated with increased risk of death from ischemic heart disease	1.35 (1.05-1.76) 1.96 (1.05-3.63)
Addiction
Auf R et al, 201259	Population-based cohort study	Assessment of tobacco dependence in waterpipe smokers in Egypt.	Waterpipe smokers exhibit some of the features of dependence previously described in cigarette smokers.	(P < 0.001) (P = 0.033)
Aboaziza E et al, 201560	Review article	Waterpipe tobacco smoking: what is the evidence that it supports nicotine/tobacco dependence?	WTS supports nicotine/tobacco dependence because it is associated with nicotine delivery Smokers experience withdrawal when they abstain from waterpipe, alter their behaviour with difficulty quitting	NA
Jacob et al, 201147	Clinical research	Nicotine, carbon monoxide, and carcinogen exposure after a single use of a water pipe.	The increase in plasma nicotine concentrations in WP smoking is comparable to cigarette smoking, The increase in CO levels is much higher than cigarette smoking.	NA
Harm to Others
Tamim et al, 200847	Retrospective cohort	Effect of waterpipe and cigarette smoking on newborn birthweight	Low birth weight	2.4 (1.2–5.0)
Nematollahi et al, 201834	Cohort Study	The effects of waterpipe smoking on birth weight: a population-based prospective cohort study in southern Iran	Low birth weight increased 2-fold in women who smoke water-pipe	2.09 (1.18-3.71)
Kassem et al, 201442	Cross-sectional	Children’s Exposure to Secondhand and Thirdhand Smoke Carcinogens and Toxicants in Homes of Hookah Smokers	Nicotine levels in indoor air in homes of daily WP smokers were significantly higher than in homes of non-smokers Uptake of nicotine and carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) in children living in weekly/monthly hookah smoker homes was significantly higher than in children living in non-smoker home	P<.05 P<.014
WP-specific Harm
CDCe, 201846	Report	Hookah smoke and Cancer	Even after it has passed through the water, the smoke produced by a WP contains high levels of toxic compounds, including carbon. Tobacco juices from hookahs irritate the mouth and increase the risk of developing oral cancers	NA
CDC, 201846	Report	Other Health Effects of Hookah Smoke	WP tobacco and smoke contain many toxic agents that can cause clogged arteries and heart disease	NA
CDC, 201846	Report	Hookah Smoking Compared with Cigarette Smoking	The WP smoking delivers nicotine The tobacco in WP is exposed to high heat from burning charcoal, and the smoke is at least as toxic as cigarette smoke WP smokers may absorb more of the toxic materials than cigarette smokers	NA
Ahmed et al, 201172	Prospective Cohort	Attitudes and practices of hookah smokers in the San Francisco Bay Area.	Majority of respondents considered hookah smoking to be harmful to their health (88%) yet 52% had no intention of quitting College student hookah smokers are highly educated and appear to have knowledge of the potential harmful effects of chronic hookah smoking, this does little to discourage them from smoking due to the social rewards of hookah smoking.	NA
Martin et al, 201373	Pilot Study	Mixed methods pilot study of sharing behaviors among waterpipe smokers of rural Lao PDR: implications for infectious disease transmission.	High prevalence of sharing behaviors that can potentially transmit infectious disease pathogens.	2.22 ( 0.96–5.17)
WP Harm Compared to Cigarettes
Cobb et al, 201010	Clinical research	Waterpipe Tobacco Smoking: An Emerging Health Crisis in the United States	Compared to a single cigarette (about 500 ml litter smoke), a single WP use episode (about 90,000 ml of smoke) is associated with 1.7 times the nicotine, 8.4 times the CO, and 36.0 times the tar.	NA

^aArticles are listed in order based on most recent.

^bOR: Odds Ratio; CI: Confidence Interval; NA: Not Applicable.

^cNote: P-values are for waterpipe smokers compared with nonsmokers/or cigarette smokers.

^dRR: Relative Risk.

^eCDC: Center for Diseases Prevention and Control.

1.3.1. Health risks associated with WP smoking

Although the novelty of WP epidemic precludes having robust evidence of its long-term health effects, current evidence is suggestive of serious health risk associated with WP smoking. For example, systematic reviews found a significant association of WP smoking with lung and oral cancer, and premalignant lesions [36,37]. WP smoking also was associated significantly with cardiovascular disease (CVD), respiratory diseases (e.g., chronic obstructive pulmonary disease, bronchitis), periodontal disease, candida and skin disease [37,41,42,49]. Two recent studies showed that WP smoking is associated with increased risk of coronary artery disease, and coronary artery calcium deposition, a known early marker of CVD [50,51]. Carbon monoxide (CO) is perhaps the signature exposure of WP smoking, as levels of CO associated with WP smoking are several folds higher than with cigarette smoking [9]. Most of the CO emitted in WP smoking seems to come from the burning charcoal, because replacing charcoal with an electric heater decreases CO emissions by 90% [52]. In a laboratory study, CO increased by 24 ppm after 45 min of WP smoking and 3 ppm after smoking a single cigarette [53]. At comparable peak plasma nicotine levels, a single session of WP use is associated with 3-times greater blood carboxyhemoglobin levels compared to single cigarette [53]. Other than its obvious negative effect on the cardiovascular and respiratory systems, exposure to high levels of CO in WP smoke could lead to acute poisoning, [54] with several cases of CO poisoning related to WP smoking been documented in young, otherwise healthy adults have been reported in the literature [55-58].

1.3.2. Addiction

The fact that WP smoking delivers nicotine, the same highly addictive drug found in other tobacco products, is well established [59,60]. The increase in plasma nicotine concentrations in WP smoking is comparable to cigarette smoking. For example, a meta-analysis of studies of nicotine exposure associated with WP smoking from four countries indicates that on average, daily use of WP smoking a 24 h urinary cotinine level of 0.783 mg/ml, which is equivalent to smoking 10 cigarettes per day [61]. Moreover, exclusive WP smokers show the classical signs of nicotine dependence such as craving, withdrawal, and inability to quit despite known harms [11]. Longitudinal studies of adolescent WP smokers shows that they experience symptoms of nicotine dependence earlier and at a lower frequency of use compared to cigarettes [62]. However, as a tobacco use method with a strong social dimension, the social context of WP smoking affects the way nicotine dependence is manifested in WP smokers. For example, in a cohort of adolescents, WP smokers in Lebanon reporting difficulty refraining from smoking WP while in a restaurant was the strongest predictor of progression of nicotine dependence among WP smokers [61].

1.3.3. Harm to nonsmokers

WP smoking is a social activity with a strong potential of exposing nonsmokers to secondhand smoke. Significant particulate matter (PM)_2.5 concentrations have been recorded in WP cafes/venues, where WP smoking takes place (349 μg/m³) [63-67]. While PM levels associated with WP smoke will vary according to the number of individuals smoking, venue size and ventilation, high PM_2.5 concentrations (e.g., 287μg/m³) way above the Environmental Protection Agency air quality limits (35 μg/m³) have been repeatedly reported [9]. WP smoke contains other potentially hazardous constituents such as CO, nicotine, tobacco-specific nitrosamines, and polycyclic aromatic hydrocarbons (PAHs). Higher levels of ambient CO were observed inside WP cafés/restaurants (7.3±2.4 mg/m³) located in London, UK relative to levels measured outside these venues (0.9±0.7 μg/m³) [68]. The home environments of daily WP smokers also show higher levels of air nicotine and surface nicotine (i.e., third-hand smoke) compared to nonsmoking homes [43]. Such air levels translate into higher exposure to nicotine, tobacco-specific carcinogenic nitrosamine (NNAL, 4-methylnitrosamino-1-3-pyridyl-1-butanol), and acrolein (3-HPMA, hydrolyzed polymaleic anhydride) among children living in daily WP smoking homes compared to nonsmoking homes [43]. Two studies from Lebanon showed that occupational or home exposure to WP smoke are associated with negative respiratory symptoms (e.g., wheezing, chronic cough) [69,70]. Finally, babies born to women who smoked WP every day while pregnant weigh at least 3.5 ounces less than babies born to non-smokers [48]. Babies born to WP smokers are also at increased risk for respiratory diseases [71].

WP-specific harm: Unlike cigarettes, components other than the tobacco-generated smoke can be the source of harm in WP smoking. For example, the charcoal used to heat the tobacco can raise health risks by producing high levels of CO, metals and cancer-causing chemicals, even after the smoke has passed through the water in the WP [46]. In fact, several studies have shown that WP’s burning charcoal is the main source of most of PAH, and CO, both are major risks for cancer and CVD. Infections as well can be passed to other smokers by sharing a WP, or due to lack of proper cleaning and sanitation procedures or guidelines for repeatedly used WPs in the café setting [21,72,73].

1.3.4. WP harm compared with cigarettes

Generally, the scope of harmful substances found in WP smoke is similar to that found in the smoke of cigarettes [74]. However, WP smoke constituents differ from cigarettes due to the specific configuration of WP, its use pattern of prolonged intermittent sessions (averaging an hour), and its multi-component nature such as the use of charcoal to heat the tobacco at lower temperature (450 °C) compared to the combustion in cigarettes (900 °C) [12]. Yet, under smoking machine protocols developed on the basis of Middle Eastern smoking patterns, [13] a single WP smoking session generates on average 70 times higher levels of tar and 11-fold higher levels of CO than cigarettes. Even when normalized per mg nicotine in the tobacco, the CO yield of WP smoke is about 3-fold higher than cigarettes [12]. On average, an hour-long WP smoking session involves approximately 200 puffs, while smoking one cigarette involves 10–13 puffs on average [10]. Therefore, the amount of smoke inhaled during a typical hookah session is about 90_000_mL, compared with 500–600_mL inhaled when smoking a cigarette [22].

2. Communicating risks of WP smoking

WP spread among youth has been in part driven by the lack of awareness of its harmful nature, which is reinforced by different marketing claims made by WP related-vendors and sellers [24]. Therefore, communicating WP health risks to smokers and bystanders represent a priority for public health efforts aimed at limiting WP spread and its related morbidity and mortality [10,14,21]. One of the effective strategies to communicate the health risks of tobacco use has been the use of HWLs. HWLs communicate evidence-based risk information that can correct misperceptions of a safe product and have been a principal strategy for reducing tobacco use globally [75-78]. For cigarettes, HWLs have been shown to contribute to raising awareness about smoking harmful effect, prevent initiation and encourage smoking cessation [79]. Similarly, exploratory studies conducted among WP smokers and non-smokers in Egypt suggested that pictorial HWLs could deter experimentation with WP and promote cessation [80,81]. Research also showed that inserting pictorial HWLs on WP motivates WP smokers to consider quitting, reduce their consumption, forgo a smoke and attempt to quit WP [82].

Recognizing the importance of HWLs for WP control, several national and international public health bodies recommended using HWLs as a promising policy and regulatory strategy for WP smoking. For example, the Word Health Organization (WHO) have prioritized HWLs as an effective strategy to address WP spread globally [76]. In the US, beginning in 2018, the Food and Drug Administration (FDA) required that WP tobacco packages have a textual HWL: “WARNING: This product contains nicotine. Nicotine is an addictive chemical” [83].

Implementing HWLs for the WP, however, is not an easy task due to the substantial differences from cigarettes alluded to earlier. For example, while the cigarette pack is an optimal position for cigarettes HWLs given its standard size, display prominence and exposure potential, the WP tobacco pack is less standard and is not as prominent in terms of visibility to smokers and non-smokers alike. For example, in the popular WP café setting the WP is served pre-prepared, where the smokers and those accompanying them are not in contact with the tobacco packet where HWLs usually are. Moreover, other components of the WP such as the charcoal, device, and accessories are important contributors to WP health risks and need to carry HWLs as well [22]. Recognizing the special configuration and context of WP use, the WHO has released a report recently recommending placing HWLs on the WP device, especially in the WP cafés settings [84]. Funded by the US National Institutes of Health (NIH), our team started 2 years ago a research project aiming at developing and testing WP-specific HWLs. Here, we will discuss some of the work conducted to date.

2.1. Developing WP-specific HWLs

Our approach to developing WP HWLs involved developing a battery of potential HWLs corresponding to five main themes identified from the literature (health risks, addiction, harm to nonsmokers, WP-specific harm and WP harm compared with cigarettes), and then conduct an international Delphi study among a panel of tobacco control experts to improve the design of the developed HWLs and select the top ranked HWLs in terms of their effectiveness potential for further development and testing. Given ample evidence about the advantage of pictorial (text + image) over text-only HWLs, [85-89] we opted to focus on the potentially most effective pictorial HWLs. Best practice recommendations for HWLs development include three main steps: (1) developing the content (or text) by identifying the themes (e.g, health risk, addiction), (2) selecting the image that makes the information vivid and relevant (e.g., the picture is clear and easy to understand, it has immediate impact, it arouses emotion and interest, it leads to interest or curiosity in the explanatory text) and (3) constructing the HWL (text + image) to decide on the general presentation style [85]. This process has led to the development of 28 prototypes of pictorial HWLs for the WP by our team to be included in the Delphi study (Figure 2) [22].

Figure 2:

The final set of labels that was selected based on experts’ agreement in an international three rounds Delphi study

In the Delphi study [22], a three-round survey was conducted among international tobacco control experts to reach consensus on a set of the most potentially effective HWLs for each theme. Briefly, the first round involved rating of HWLs prototypes on different dimensions (attention, relevance, communication) and were asked to provide feedback on the way to improve them. In round 2 participants were asked to rate the revised HWLs in each theme were ordered in terms of importance based on the feedback from round 1, and in round 3 they were shown the labels ordered according to the results of the second round total against their own ranking and were asked to reconsider their ranking. This study led to a consensus on the 13 most important WP-specific HWLs that were related to oral and heart disease, WP’s harmful effects on newborn children and the amount of smoke inhaled from WP compared to cigarettes (Figure 2).

2.2. Testing WP-specific HWLs

As we were developing the WP-specific HWLs we picked two promising prototypes and wanted to provide a proof of concept testing of the effectiveness of placing HWLs on the device itself as it offered the larger space and most protracted contact with the smokers and those around them (Figure 3) [90]. This study examined the effect of pictorial HWLs on the WP device on smokers' experience, puffing behavior, harm perception and exposure to respiratory toxicants. Thirty WP smokers completed two 45-min ad libitum smoking sessions (WP without HWL vs. WP with HWL) in a crossover design study. Exhaled carbon monoxide (CO) was measured before and after each smoking session. Puff topography was recorded throughout the smoking session, and participants completed survey questionnaires assessing their smoking experiences and harm perception [90]. Significant differences were observed in CO levels between the two study conditions, with lower levels of CO boost recorded following smoking the WP fitted with HWL (16 ppm) compared with WP without the HWL (22.7 ppm). Participants also demonstrated less intensive puffing behavior (e.g., less and shallower puffs), and less satisfaction in the HWL condition compared to usual smoking (no HWL) (p values <0.05). By contrast, WP harm perception was significantly higher among participants in the HWL condition compared to no HWL. This pilot study shows that placing HWLs on the WP device is effective in reducing WP smoker's positive experiences, puffing parameters and exposure to exhaled CO. HWLs also led to more appreciation of WP harmful effects, making them a promising policy/regulatory approach to address the spread of WP smoking among young adults in the USA.

Figure 3:

Testing WP-specific HWLs

3. Conclusions

WP tobacco smoking is becoming a global tobacco use problem among young people. Several factors contribute to the spread of WP smoking including the sweetened and flavored WP tobacco, youth-oriented promotion through the internet and social media, the proliferation of WP cafés especially around college campuses, and misperceptions regarding its harm compared to cigarettes. In fact, WP smoking involves the inhalation of huge amount of smoke, toxicants, is addictive and is associated with known tobacco-related diseases. Compared to a single cigarette, a WP session exposes smokers to significantly higher levels of PAHs, cardiorespiratory toxicants such as volatile organic compounds, and heavy metals such as cadmium and lead that can injure the blood vessels and the brain.

Information about WP harmful and addictive nature needs to be communicated to WP smokers and nonsmokers to correct misperceptions related to its harm. HWLs are effective in communicating tobacco-related harms in a way that has been shown to reduce smoking and increase quitting. Adapting HWLs to communicate WP-related risks, however, requires an understanding of its configuration, components, marketing, and its social context. Our team has suggested a regulatory framework that identifies targets for policy and regulation for each of these domains involved in the perpetuation of this tobacco use method.

We have also started, with support from NIH, a research project aimed at developing and testing HWLs for the WP. This effort has already produced 13 candidate HWLs to be used for further development and adaptation to different local contexts as well as for testing. We have also identified the WP device as the most promising location for such HWLs given its large surface and the extended contact it offers to smokers and nonsmokers alike. We also started testing some of the HWLs on the device in a clinical lab model and found them very promising in terms of reducing WP’s pleasurable experiences, craving, puffing patterns and exposure to harmful substances such as CO. There is also a strong indication, based on limited data, of the value WP HWLs in encouraging smokers to quit.

4. Expert opinion

The spread of WP smoking among youth has been fueled by a misperception of their reduced harm compared to traditional cigarettes. While evidence point to the contrary, there has been no systematic efforts to counter this misperception and increase youth’s awareness about the harmful effects of WP smoking. HWLs are effective in communicating smoking-related risks to WP smokers in a way that reflects on their smoking behavior and experience as well as interests in quitting. However, WP’s unique configuration and the contribution of different components (tobacco, charcoal, device) to its risk profile necessitate special adaptation to how we usually apply HWLs for tobacco products. We believe that given that WP smokers have the most extended contact with the WP device itself during prolonged WP smoking sessions that usually average an hour, they provide the most promise in terms of effectiveness on smokers’ experiences and awareness of the risks of WP smoking. Our pilot lab data [87], provide a proof-of-concept for the effectiveness of the use of pictorial HWLs on the WP device for raising awareness and changing the perception and experiences of WP smokers. Future studies can look at how smoking WP in groups, which is common in WP venues (cafés), may be affected by HWLs and whether they can change the social atmosphere of smoking WP in groups, and prompt discussions of its negative health effects.

The regulatory and policy implications of these results are strong and support the consideration of placing pictorial HWLs on WP devices in addition to the tobacco packaging. Policies considering the implementation of HWLs in the popular WP café setting moreover, are usually under the jurisdiction of local legislators, and thus can be easier to achieve and enforce than national regulations. As many of these venues serve food and beverages in addition to WP, it seems adequate to have the ingredients of WP, and its smoking risks disclosed on the menu in resemblance to other items served (e.g., peanuts warning for those with food allergy). Risks to staff working in these venues can be also covered by labor and workforce protection laws. Given the strong evidence of exposure to toxicants for those working in WP venues [67], such protection and relevant precautions, and compensations should be included in licensing and hiring requirements and procedures of staff for these venues. Such work can also benefit from the success story of flight attendants legal battle to be compensated and protected from secondhand smoke, which led together with other initiatives to the banning of smoking on all flights in 1990 [91].

Future research can address the impact of implementing WP HWLs on smokers’ perceptions, intention to quit, and quitting, as well as WP use uptake at the population level. It can also assess how such policies can influence the exposure of nonsmokers, including workers in the WP hospitality sector, to WP secondhand smoke. Such steps would need to be complemented with closing the loopholes that allow WP smoking in public indoor spaces, an area where occupational safety, business licensing, and local legislation can play prominent roles. This review will hopefully stimulate and further encourage research and policy initiatives aimed at curtailing WP smoking and protecting young people through communication of its harmful and addictive properties.

Article highlights.

• Waterpipe (WP) has become a global public health phenomenon attracting an increasing number of youth who are not fully aware of its risks to their and others’ health.

• WP smoking is addictive, its smoke contains much of the same toxicants found in cigarette smoking and carries similar risks to those associated with cigarette smoking such as lung cancer, respiratory and cardiovascular disease.

• Health warning labels (HWLs) are effective in communicating smoking-related risks to correct misperceptions about WP harms. Developing WP-specific HWLs is a promising policy to curb WP smoking, but its implementation needs to take into consideration WP configuration, components, marketing, and its social context.