Building the evidence base for waterpipe regulation and policy

N-Acetyltransferase Metabolism and DNA Damage Following Exposure to 4,4'-Oxydianiline in Human Bronchial Epithelial Cells

Waterpipe smoking is increasingly popular and understanding how chemicals found in hookah smoke may be harmful to human bronchial epithelial cells is of great importance. 4,4'-Oxydianiline (ODA), is an aromatic amine which is present at comparatively high levels in hookah smoke. The metabolism and the subsequent toxicity of ODA to human bronchial epithelial cells remains unknown. Given that ODA is an aromatic amine, we hypothesized that ODA is N-acetylated and induces DNA damage following exposure to immortalized human bronchial epithelial cells (BEP2D cells). We measured the N-acetylation of ODA to mono-acetyl-ODA and the N-acetylation of mono-acetyl-ODA to diacetyl-ODA by BEP2D cells following separation and quantitation by high performance liquid chromatography. For ODA, the apparent KM in cells was 12.4 ± 3.7µM with a Vmax of 0.69 ± 0.03 nmol/min/106 cells, while for mono-acetyl-ODA, the apparent KM was 111.2 ± 48.3µM with a Vmax of 17.8 ± 5.7 nmol/min/106 cells ODA exposure for 24h resulted in DNA damage to BEP2D cells following concentrations as low as 0.1µM as measured by yH2Ax protein expression These results demonstrate that ODA, the most prevalent aromatic amine identified in hookah smoke, is N-acetylated and induces DNA damage in human bronchial epithelial cells.

Waterpipe tobacco smoking (WTS) control policies: global analysis of available legislation and equity considerations

INTRODUCTION

The Framework Convention on Tobacco Control (FCTC) offers guidance on evidence-based policies to reduce tobacco consumption and its burden of disease. Recently, it has provided guidance for alternative tobacco products, such as the waterpipe. Waterpipe tobacco smoking (WTS) is prevalent worldwide and policies to address it need to take into consideration its specificities as a mode of smoking. In parallel, a growing body of literature points to the potential of evidence-based tobacco control policies to increase health inequities. This paper updates a previous global review of waterpipe tobacco policies and adds an equity lens to assess their impact on health inequities.

METHODS

We reviewed policies that address WTS in 90 countries, including 10 with state-owned tobacco companies; 47 were included in our final analysis. We relied primarily on the Tobacco-Free Kids organisation's Tobacco Control Laws website, providing access to tobacco control laws globally. We categorised country tobacco policies by the clarity with which they defined and addressed waterpipe tobacco in relation to nine FCTC articles. We used the PROGRESS (Place of residence, Race/ethnicity/culture/language, Occupation, Gender/sex, Religion, Education, Socioeconomic status and Social capital) framework for the equity analysis, by reviewing equity considerations referenced in the policies of each country and including prevalence data disaggregated by equity axis and country where available.

RESULTS

Our results revealed very limited attention to waterpipe policies overall, and to equity in such policies, and highlight the complexity of regulating WTS. We recommend that WTS policies and surveillance centre equity as a goal.

CONCLUSIONS

Our recommendations can inform global policies to reduce WTS and its health consequences equitably across population groups.

Hookah Smoke Mediates Cancer-Associated Epigenomic and Transcriptomic Signatures in Human Respiratory Epithelial Cells

Introduction

Although communal smoking of hookah by means of water pipes is perceived to be a safe alternative to cigarette smoking, the effects of hookah smoke in respiratory epithelia have not been well characterized. This study evaluated epigenomic and transcriptomic effects of hookah smoke relative to cigarette smoke in human respiratory epithelial cells.

Methods

Primary normal human small airway epithelial cells from three donors and cdk4 and hTERT-immortalized small airway epithelial cells and human bronchial epithelial cells were cultured for 5 days in normal media with or without cigarette smoke condensates (CSCs) or water pipe condensates (WPCs). Cell count, immunoblot, RNA sequencing, quantitative real-time reverse-transcriptase polymerase chain reaction, methylation-specific polymerase chain reaction, and quantitative chromatin immunoprecipitation techniques were used to compare effects of hookah and cigarette smoke on cell proliferation, global histone marks, gene expression, and promoter-related chromatin structure.

Results

CSC and WPC decreased global H4K16ac and H4K20me3 histone marks and mediated distinct and overlapping cancer-associated transcriptome signatures and pathway modulations that were cell line dependent and stratified across lung cancer cells in a histology-specific manner. Epiregulin encoding a master regulator of EGFR signaling that is overexpressed in lung cancers was up-regulated, whereas FILIP1L and ABI3BP encoding mediators of senescence that are repressed in lung cancers were down-regulated by CSC and WPC. Induction of epiregulin and repression of FILIP1L and ABI3BP by these condensates coincided with unique epigenetic alterations within the respective promoters.

Conclusions

These findings support translational studies to ascertain if hookah-mediated epigenomic and transcriptomic alterations in cultured respiratory epithelia are detectable and clinically relevant in hookah smokers.

Aquatic toxicity of waterpipe wastewater chemicals

INTRODUCTION

The recent increase in U.S. popularity and use prevalence of water pipe (WP) tobacco smoking raises concerns about the potential environmental impacts of WP waste disposal and the need for strategies to reduce such impacts. The U.S. Food and Drug Administration (FDA) is required to assess the environmental impacts of its tobacco regulatory actions per the U.S. National Environmental Policy Act (NEPA). The purpose of this study was to identify and quantify specific chemical constituents in WP wastewater and to determine their potential aquatic toxicity.

METHODS

Using a modified Beirut smoking regimen, five different WP charcoal brands (n = 70) and ten WP tobacco brands (n = 35) were smoked separately using a WP smoking machine in which smoke was passed through the WP base water. We analyzed and quantified specific chemical constituents in the WP bowl wastewater through standardized U.S. Environmental Protection Agency's (EPA) Hazardous Waste Test Methods. We then characterized the ecological hazard for acute and chronic aquatic toxicity posed by the specific chemicals through compilations of Globally Harmonized System of Classification and Labelling of Chemicals (GHS) and hazardous concentration values (concentration affecting 50% of the species).

RESULTS

Among the list of 31 specific chemicals analyzed, we detected 22 and 11 chemicals in wastewater from WP tobacco and WP charcoal smoking, respectively. Nearly half of the 22 WP wastewater chemicals were classified as "very toxic" or "toxic" for acute and chronic aquatic toxicity per GHS classification. The most hazardous compounds with acute and chronic toxicity in aquatic organisms include acrolein, acrylonitrile, and metals (cadmium, lead, chromium, nickel, cobalt) found in both WP tobacco and charcoal wastewater, and N-nitrosonornicotine, nicotine, crotonaldehyde and selenium were additionally found in WP tobacco wastewater. All the identified chemicals are considered harmful or potentially harmful constituents in tobacco products and tobacco smoke per FDA's list, and seventeen of them represent hazardous waste per EPA's list.

CONCLUSION

Our study expands the identification and quantifies several WP wastewater chemical constituents. It characterizes the ecological hazard of these chemicals and identifies chemicals of concern, aiding our evaluation of the environmental impacts of WP waste products. Our results add to the existing evidence that WP wastewater is a source of toxins that could affect water quality and aquatic organisms, and bioaccumulate in the environment if disposed of into public sewers, on the ground, or in an onsite septic system. These findings highlight the importance of concerted efforts to raise awareness of appropriate WP waste disposal practices in both retail and residential settings, and applicable regulatory compliance requirements for WP retailer establishments, thereby limiting hazards from WP wastewater.

Hookah venue employees' knowledge and perceptions of hookah tobacco smoking

BACKGROUND

Recent years showed sharp proliferation of hookah bars worldwide with scarcity of workplace safety regulations. Hookah server employees are at high risk for elevated harm. This study reported hookah smoke exposure, assessed acute problems and evaluated factors related to knowledge of hookah-smoking harm and toxicity among high-risk hookah servers.

METHODS

A mixed methods design was employed. A self-reported questionnaire was distributed online, and semistructured in-depth interviews were used. Hookah server employees were recruited using snowball sampling, with 52 participants included in quantitative analyses and 10 participating in semistructured interviews.

RESULTS

Hookah server employees took a median 389 hookah puffs per workday compared with 169-170 per session for customers. Servers were limited in knowledge of potential hookah harms and smoke toxicant exposure. Almost all believed that hookah water bowls filtered out toxicants. Smoking with family members (p=0.012) was associated with lower knowledge scores for hookah harms and exposure. Hookah server employees reported carbon monoxide-poisoning symptoms of dizziness, headaches and fainting during work but believed their bodies would adapt. Home remedies were taken to alleviate symptoms. Work environment and salary attracted hookah server employees to their position and none considered quitting for reasons of harm.

CONCLUSION

Findings demonstrate need for workplace policies and regulations to protect hookah server employees and provide targets for educational interventions for high-risk hookah server employees.

Quantification of Flavorants and Nicotine in Waterpipe Tobacco and Mainstream Smoke and Comparison to E-cigarette Aerosol

INTRODUCTION

Waterpipe use remains popular among youth with the availability of flavored shisha tobacco being one of the main drivers of waterpipe use. Although waterpipe mainstream toxicant emissions are well understood, less is known about the carryover of flavorants such as vanillin, benzaldehyde, and eugenol. In this study, flavored waterpipe tobacco was analyzed for flavorants and nicotine, and subsequent carryover to mainstream smoke.

METHODS

Flavorants vanillin, benzaldehyde, and eugenol, and nicotine were quantified in vanilla-, cherry-, and cinnamon-flavored shisha tobacco by gas chromatography/flame ionization detector and subsequently in waterpipe mainstream smoke generated by a smoking machine. The setup allowed for sampling before and after the water-filtration step.

RESULTS

Flavorant and nicotine content in smoke was reduced 3- to 10-fold and 1.4- to 3.1-fold, respectively, due to water filtration. Per-puff content of filtered waterpipe mainstream smoke ranged from 13 to 46 µg/puff for nicotine and from 6 to 55 µg/puff for flavorants.

CONCLUSIONS

Although water filtration reduced flavor and nicotine content in waterpipe mainstream smoke, the detected flavorant concentrations were similar or higher to those previously reported in e-cigarette aerosol. Therefore, users could be drawn to waterpipes due to similar flavor appeal as popular e-cigarette products. Absolute nicotine content of waterpipe smoke was lower than in e-cigarette aerosol, but the differential use patterns of waterpipe (>100 puffs/session) and e-cigarette (mostly <10 puffs/session, multiple session throughout the day) probably result in higher flavorant and nicotine exposure during a waterpipe session. Strategies to reduce youth introduction and exposure to nicotine via waterpipe use may consider similar flavor restrictions as those for e-cigarettes.

IMPLICATIONS

Although waterpipe mainstream smoke is well characterized for toxicants content, little is known about carryover of molecules relevant for appeal and addiction: flavorants and nicotine. This study shows that flavorant content of waterpipe mainstream smoke is comparable or higher than e-cigarette aerosol flavorant content. Regulatory action to address tobacco use behaviors targeting the availability of flavors should also include other tobacco products such as flavored shisha tobacco.