E-Cigarettes: The New Threat to Public Health

TON - March 2017, Vol 10, No 2

Vienna, Austria—In the 1970s, the tobacco industry marketed “light” cigarettes in an attempt to make smokers switch to a product they believed to be less harmful. It is now widely known that light cigarettes are no safer than regular cigarettes and were only marketed in an attempt to undermine smokers’ wishes to quit smoking. According to Charlotta Pisinger, PhD, MPH, Assistant Professor, Research Centre for Prevention and Health, Capital Region, Denmark, the tobacco industry is now using the same tactic with electronic cigarettes (e-cigarettes).

E-cigarettes are a nicotine delivery system that allows users, or vapers, to achieve the same level of nicotine in their blood as smokers of conventional cigarettes, which means that e-cigarettes can be just as addictive as conventional cigarettes. In addition to nicotine and added flavors that contain water, alcohol, and various chemical additives, an e-cigarette contains >90% vapor-producing agents composed of propylene glycol and/or glycerin. In recent years, aggressive marketing on the part of the tobacco industry has led to an explosive increase in the sales of e-cigarettes. Globally, the market is still largely unregulated, but the relative “safety” of e-cigarettes is often emphasized in advertising, said Dr Pisinger at the International Association for the Study of Lung Cancer 17th World Conference on Lung Cancer.

E-Cigarettes and Health

There is a paucity of data surrounding the health risks associated with the use of e-cigarettes, but one of the major methodologic challenges in this new field of research is that there is no standard e-cigarette. In addition, most studies compare vaping to smoking, but an e-cigarette is a completely different product. Risk depends on the brand and batch, the flavor, the heating of the e-cigarette, the vaporizer, how dirty or worn the e-cigarette is, method of vaping, and factors still unknown. Consumers often do not know what they are buying because of misleading or missing information on product ingredients, and no studies of long-term effects exist, “so there’s a little bit of fortune-telling in it,” said Dr Pisinger.

In a systematic review of 175 studies examining the health effects of e-cigarettes published by the World Health Organization, >33% of the studies had a conflict of interest.

“In general, studies with severe conflicts of interest have findings indicating no or little harm on health—but the tobacco industry has been publishing studies, and, historically, we know we can’t trust them,” she said.

Some studies from the systematic review identified harmful substances in the fluid and vapor, including carcinogenic tobacco-specific nitrosamines, carcinogenic carbonyls, and harmful metals, among others. These substances are known to be associated with lung cancer and asthma attacks, but in most of these studies, the concentrations in e-cigarette vapor were much lower than those found in conventional cigarettes, although results varied widely.

In several studies, toxicants and potentially carcinogenic substances were found in study, subjects’ urine and breath, so users are clearly absorbing what is found in the vapor. More than 500 brands of e-cigarettes are currently on the market, and most are highly customizable, allowing vapers to choose and blend their own flavors, of which there are >8000 options. Although many flavors are approved as safe for oral intake and ingestion, the safety of their inhalation is not the same, nor is it addressed. For example, the food sweetener diacetyl, which is used in e-cigarettes, caused airway obstructions in workers who inhaled it in popcorn factories. This is one factor that does not apply to conventional cigarettes, but increases the relative toxicity of e-cigarettes.

Human experimental studies of the pulmonary system have found that particle doses in e-cigarette users’ lungs were on par with concentrations found in the lungs of conventional cigarette smokers. Additional findings include significant inhibition of cough reflex sensitivity and significant airway obstruction, particularly among patients with asthma and chronic obstructive pulmonary disease. Experimental sessions on lung function have found decreases in lung function to be the same within 1 hour of smoking or vaping.

“These effects remind us of those seen with smoking, only less pronounced,” Dr Pisinger said.

A large epidemiologic study of >45,000 Chinese students found that e-cigarette use was significantly associated with self-reported respiratory symptoms, physician diagnosis of asthma, and absence from school as a re­sult of severe asthma symptoms, and chronic symptoms of cough, phlegm, or bronchitis.

But Aren’t They Safer Than Cigarettes?

Many people assume that switching from conventional cigarettes to e-cigarettes is healthier, and some studies have shown improvements in respiratory function when smokers switch to e-cigarettes. However, this rationale for harm reduction applies only if the smoker actually abstains from smoking cigarettes. In reality, 8 of 10 vapers also smoke, as evidenced in studies done worldwide.

“The reality is they don’t exchange a harmful product for a less harmful one; they just add on an extra product and end up with dual use,” Dr Pisinger reported.

Still, many assume that dual use would be accompanied by a decrease in cigarette consumption, and therefore would be an improvement on cigarette smoking alone. On the contrary, large epidemiologic studies have shown that reducing a smoker’s daily intake of cigarettes by ≥50% is not associated with a reduction in all-cause mortality, or incidence of cardiovascular disease, or smoking-related cancer, or cancer mortality. Two studies did show a small reduction in lung cancer risk when cigarette consumption was reduced by ≥50%, but substantial reductions have not been reported in dual users.

“Smokers won’t see a health benefit by using both cigarettes and e-cigarettes,” she said.

Regarding the use of e-cigarettes as a smoking cessation tool, 18 longitudinal studies showed that the use of e-cigarettes is associated with a 25% lower probability of becoming smoke-free.

“So this seems to be undermining smoking cessation in real life,” she added.

According to Dr Pisinger, no firm conclusions can be drawn on the safety of e-cigarettes, but there is an increasing body of evidence indicating harm.

“I see this as a win-win for the tobacco industry. We’re just adding on to the products already used by smokers,” she concluded.—MB

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