Global youth vaping and respiratory health: epidemiology, interventions, and policies.

E-cigarette usage (also known as e-cigarettes or vaping products) has increasingly been recognized as a global public health problem. One challenge in particular involves their marketing to minors (teenagers and children) and the rising prevalence of use in this population. E-cigarettes unnecessarily expose minors to health risks, these include respiratory health problems, such as exacerbations of asthma, bronchitis, and respiratory-tract irritation. Nicotine, commonly found in e-cigarettes, is also associated with cognitive impairment and neurodevelopmental problems. E-cigarettes are also risk factors for downstream substance use, including cigarettes and cannabis initiation (the gateway hypothesis), which compounds health risks in dual users. Current public health preventative and intervention studies are limited, and there is a clear need for more interventions that may prevent usage and assist with cessation in this vulnerable population. Physician education and screening uptake should also be enhanced. Stricter public health policy and protection measures are also needed on a global scale to limit e-cigarette exposure in minors.

Introduction

The use of electronic cigarettes (also known as e-cigarettes, e-cigs, or vaping products) has increasingly been recognized as a global public health problem[1]. Vaping consists of inhaling a smoke-free aerosol through a mouthpiece, which is produced through the heating of a liquid such as glycol or glycerin in an electronic device[2,3]. Most e-cigarettes have the shape of a pen, but others are more discrete-looking such as JUUL, which resembles a USB drive and is popular among teenagers[4]. Common terminology for e-cigarettes is summarized in Table 1. E-cigarettes have often been used by smokers as a harm-reduction intervention aimed to assist with cigarette-smoking cessation[5]. A meta-analysis found that e-cigarette users (who received free e-cigarettes in trials) were 1.5 times more likely to quit smoking than the control group[6]. Thus, they may play a role in smoking cessation in adult smokers and the benefits of use may outweigh the risks from a public health-harm reduction perspective as they are a safer alternative[7]. However, e-cigarettes are increasingly initiated by teenagers, some of whom have never previously smoked[8] and who are exposed to unnecessary health risks associated with e-cigarette use, making them a public health issue[9].

Table 1

Common electronic cigarette related terms[2–4,37,124,125].

Term	Meaning
Electronic cigarettes	A battery operated device, which heats a liquid, commonly containing glycerol, glycol, nicotine, flavorings, and other additives, producing an aerosol, which the user inhales with the mouthpiece. The cartridge is either refillable or disposable.
E-cigarettes/E-cigs	Short terminology for electronic cigarettes
Vape pens	Another term for e-cigarettes that are shaped like or resemble pens
Pods	Another term for e-cigarettes
Vape products	A term which broadly includes all forms of electronic cigarettes made by different manufacturers including nicotine free e- cigarettes and ones with nicotine along with other chemical additives
Vaping	The act of (verb) using electronic cigarettes/ vape products by inhalation of the smoke free aerosol that is generated from the device
Juice	The liquid that is added to electronic cigarettes, which is heated for inhalation by the user. It can include nicotine, cannabis oil, flavorings, and other chemical additives.
JUUL	A discrete looking electronic cigarette device which resembles a USB drive and has a high content of nicotine
EVALI	Electronic Cigarette of Vaping Related Lung Injury resulting from the inhalation of vitamin E acetate and cannabis using electronic cigarettes

Some of the reported reasons for e-cigarette use in teenagers and young adults include their flavoring[10,11], discreteness[12], easy accessibility[10], desire to experiment[10], perceptions that they are safer[10], and advertising as well as marketing that directly targets young people[13]. Research on flavoring found that sweet flavors (e.g., fruity or candy flavored) were more often selected by teenagers over tobacco or minty flavored (conventional) e-cigarettes[14].

Here, we review of the epidemiology of e-cigarette use in teenagers and young adults and associated health risks, theoretical mechanisms, and management, including prevention as well as interventions and policies. The overarching aim is to provide an in-depth overview of e-cigarette usage in teenagers and young adults from a public health perspective and to provide insight into emerging trends as well as opportunities for health promotion.

Methods

A review of PubMed (Medline) and Google Scholar was undertaken in September 2021. We broadly included all up-to-date studies that were related to teenage-vaping epidemiology, mechanisms, and global policies published in the English language. Primary studies that were not undertaken in teenager ages 13–18 or young-adult ages 19–24 were excluded. Systematic reviews and meta-analyses were only included if they were related to global policies or epidemiological updated findings related to our study population or highly applicable to it. Studies on youth perceptions of e-cigarettes were only included if the papers addressed policy.

We used broad search terms that included word variations for “e-cigarettes” or “vaping”, “teenagers”, “respiratory health effects”, and “vaping policies”. MESH terminology and free text was used in the search. A medical librarian assisted with the search strategy. Manual hand and primary government-database searches were also undertaken. The details of the Medline search-strategy example are summarized in Table 2.

Table 2

PubMed/Medline search strategy.

Topic	Keywords
Population	“adolescent”[MeSH Terms] OR “adolescen*”[All Fields] OR “youth”[tiab] OR “youths”[tiab] OR “teen”[tiab] OR pubescen*[tiab] OR puberty[tiab] OR minor[tiab] OR minors[tiab] OR underage*[tiab] OR “under age*”[tiab] OR “young adult”[mesh] OR young adult*[tiab] OR “high school*”[tiab] OR student*[tiab] AND
Intervention	(“Counseling”[Mesh] OR counsel*[tiab]) OR (((reduc*[ti] OR decreas*[ti]) AND (use[tiab] OR utilization[tiab]))) OR (“harm reduction*”[tiab] OR “Mass Screening”[Mesh] OR “screen*”[tiab] OR “routine testing”[tiab] OR experiment*[tiab] OR intervention*[tiab] OR study[tiab] OR studies[tiab] OR trial*[tiab] OR RCT[tiab] OR random*[tiab] OR “secondary prevention”[mesh] OR “tertiary prevention”[mesh] OR quit*[tiab] OR stop[ti] OR stopped[ti] OR stopping[ti] OR stops[ti]) OR (“Health campaign*”[tiab] OR “education campaign*”[tiab] OR “educational campaign*”[tiab] OR “media campaign*”[tiab]) OR (((Public health[ti] OR regulat*[ti]) AND (effect*[tiab] OR impact*[tiab] OR strateg*[tiab] OR campaign*[tiab] OR policy[tiab] OR policies[tiab] OR program*[tiab]))) OR (Taper*[tiab] OR “Behavioral support*”[tiab] OR “behavioral support*”[tiab] OR “Behavioral therap*”[tiab] OR “Behavioral therap*”[tiab] OR manag*[ti] OR control*[ti]) OR (((“flavoring agents”[mesh] OR flavor*[tiab] OR flavor*[tiab]) AND (restrict*[tiab] OR limit*[tiab] OR decreas*[tiab]))) OR (“reduced risk”[tiab] OR “risk reduction”[tiab] OR “vaping cessation”[tiab] OR “cessation therap*” OR “cessation treatment*”[tiab]) OR ((increas*[tiab] AND price[tiab])) OR (“smoke free law”[tiab] OR “smoke free laws”[tiab] OR “population health standard*”[tiab] OR “warning label*”[tiab] OR tax[tiab] OR taxation[tiab] OR taxed[tiab] OR taxes[tiab] OR taxing[tiab] OR tax[tiab] OR taxation[tiab] OR taxed[tiab] OR taxes[tiab] OR taxing[tiab] OR “Commerce”[Mesh]) OR (((“Flavoring Agents”[Mesh] OR flavor*[tiab] OR flavor*[tiab]) AND (restricted[tiab] OR restriction[tiab] OR limit*[tiab] OR decreas*[tiab]) OR (increas*[tiab] AND price[tiab]))) OR (((reduc*[tiab] OR decreas*[tiab]) AND (use[tiab] OR utilization[tiab]))) OR (“Government Regulation”[Mesh] OR “Public Policy”[Mesh] OR “legislation and jurisprudence”[MeSH Subheading]) OR (“prevention and control”[sh] OR “public health”[mesh:noexp] OR “consumer product safety”[mesh] OR “public health practice”[mesh]) AND
Outcome	“adverse effects” OR “Lung injury” OR “EVALI” OR “toxicity”[Subheading] OR “poisoning” OR “irritation” OR “inflammation” OR “pneumonia” OR “allergy” OR intoxication OR “respiratory effect” OR “cardiovascular” OR “health effect*” OR “case report*” OR “adverse effects”[Subheading] OR “lung injury”[MeSH Terms] OR “poisoning”[MeSH Terms] OR “poisoning”[Subheading] OR “poisons”[MeSH Terms] OR “poisons”[All Fields] OR “irritants”[MeSH Terms] OR “inflammation”[MeSH Terms] OR “pneumonia”[MeSH Terms] OR “hypersensitivity”[MeSH Terms] OR “allergy and immunology”[MeSH Terms] OR “cardiovascular system”[MeSH Terms] OR casereports[Filter] Combined into one large search string

After screening 2481 titles against the inclusion and exclusion criteria, followed by abstract screening and full-text retrieval, 113 studies were included in the final review. Figure 1 illustrates the search process (PRISMA flow chart)[15].

Fig. 1

Prisma flow chart.

Table 3

E-Cigarettes Potential Harms and Benefits[6,7,35,37,46–48,51,62,63,72].

Exposure	Potential benefits	Potential risks
E-Cigarettes	• May assist with smoking cessation • Potential harm reduction intervention for cigarette smokers as a form of nicotine replacement (also mimics smoking hand to mouth behaviors) • Safer alternative than smoking cigarettes • Less toxic chemicals and in lower doses than in conventional cigarettes	• Exposure of e-cigarettes to minors (children and teenagers) and previous nonsmokers • Potential gateway to smoking and initiation of other substances in teenagers • Dual smoking and e-cigarette use compounds public health risks • May increase the risk of respiratory health problems • May increase the risk deficits in cognition, brain development, effort-reward imbalances in the brain in children and teenagers • Long-term effects on health are unknown