Research shows that exposure to passive vaping is very low compared to passive smoking

Children exposed to indoor vaping absorb less than a seventh as much nicotine as children exposed to indoor smoking, but more than those exposed to neither, according to a new study led by UCL researchers.

The study, published in JAMA network opened looked at blood tests and survey data for 1,777 children ages three to 11 in the United States.

The researchers said second-hand exposure to harmful substances in e-cigarettes would likely be much lower because e-cigarettes deliver similar amounts of nicotine as tobacco but contain only a fraction of the toxic and carcinogenic substances.

The researchers looked at nicotine absorption in children, but said the findings would likely be similar in adults.

Lead author Dr. Harry Tattan-Birch, from the UCL Institute of Epidemiology & Health Care, said: “Our research shows that, using real-world data rather than an artificial laboratory environment, nicotine absorption is much lower than from second-hand vapor. than by passive smoking.

“Nicotine itself poses limited risk, but it shows what the highest possible exposure can be from secondhand vaping. Exposure to harmful non-nicotine substances present in vapor is likely to be significantly lower.”

Senior author Professor Lion Shahab, from the UCL Institute of Epidemiology & Health Care, said: “This paper suggests that concerns about secondhand vaping may be somewhat exaggerated, with secondhand exposure to toxicants likely to be very low.

“The findings confirm the risks of smoking indoors near children, which should be avoided at all costs. However, because second-hand vaping still exposes children to more harmful substances than not vaping or smoking at all, it is best to avoid vaping indoors. also around children.”

The study used data from a nationally representative sample of children in the US collected between 2017 and 2020 as part of the annual US National Health and Nutrition Examination Survey (NHANES).

Blood tests detecting the concentration of cotinine were used to assess how much nicotine the children had absorbed. Cotinine is a chemical that the body produces after exposure to nicotine. The survey responses revealed whether the children had been exposed to smoking or vaping indoors in the past week.

The researchers focused on data from children because, unlike adults, children were unlikely to have vaped or smoked themselves, meaning higher nicotine absorption was only due to secondhand vaping or smoke. However, two children were excluded from the analysis because they had a cotinine concentration that indicated they had directly vaped or smoked. Children exposed to both indoor smoking and vaping were also excluded from the analysis.

The team found that children exposed to indoor vaping absorbed 84% less nicotine than children exposed to indoor smoking, while children exposed to neither absorbed 97% less.

The lower levels of nicotine among those exposed to secondhand vaping were consistent with previous laboratory studies showing that people retained 99% of the nicotine they produced while vaping. With tobacco cigarettes, smoke is generated both by the smokers’ exhalation and by the lit end of the cigarette. However, e-cigarettes do not generate aerosol except when vapers exhale.

The researchers said their findings had implications for whether vaping should be allowed indoors, providing further evidence that the impact of vaping on the health of bystanders will be far less than that of smoking.

However, the researchers said there are other factors to consider when assessing whether indoor spaces should be made vapor-free. Particularly if vaping occurs frequently indoors, this can normalize the behavior, encouraging people to start vaping and making it harder for them to quit.

Previous research from the same team found that adults in England were much more likely to vape indoors than smoke: 9 in 10 vapers were found to vape indoors, while only half of smokers smoked indoors.