One-Third of Non-Smoking U.S. Adults Underestimate Their Exposure to Secondhand Smoke

A study compared blood cotinine measurements of non-smoking adults with their reports of second-hand smoke exposure. It showed that non-smokers were significantly more exposed to second-hand smoke than they reported, with this trend being more pronounced in certain subgroups. Alerting non-smokers about their exposure and adopting protective measures in public spaces could help reduce this risk.

Preventing second-hand smoke is a major public health issue. Worldwide, 1.3 million people die from second-hand smoke each year and there is no safe level of exposure to tobacco smoke.[1]. Awareness and knowledge of the risks associated with passive smoking are, however, unequally distributed in society, as shown by a study published by the University of Florida.

Large underestimation of exposure to passive smoking

Using data from the National Health and Examination Survey from 2013 to 2020, the researchers compared blood cotinine measurements—a metabolite that indicates nicotine exposure—with their reports of exposure to secondhand smoke among 13,503 nonsmoking U.S. adults.[2]. Cotinine was found in the serum of 51.2 % of these non-smoking adults, with 22 % of the non-smoking adults reporting exposure to second-hand smoke, and 34.6 % of them underreporting their exposure. Underreporters of second-hand smoke exposure were those who reported no exposure to tobacco products, although they had detectable cotinine levels.

Among nonsmokers with positive serum cotinine, 67.6 % reported no exposure to tobacco smoke. This trend was more common among men, African Americans, and other minorities (Asian American, Native American, Pacific Islander), and those without cardiovascular risk. Those reporting exposure to tobacco smoke had significantly higher median cotinine levels than those reporting no exposure.

Alert and protect against the risks associated with tobacco smoke

The high sensitivity of tests detecting cotinine makes it possible to establish that a significant proportion of non-smokers who declare that they are not exposed to tobacco smoke would still be. Without deciding on the subject, the researchers put forward several hypotheses regarding these declarations. The presence of cotinine could come from exposure – sometimes distant or delayed – to tobacco smoke in public spaces, without the people affected realizing it. It is also possible that people who are aware of being exposed to passive smoking have not declared it, for fear of being discriminated against.

The authors believe that these results encourage greater overall vigilance regarding exposure to passive smoking. They consider that it is imperative, through awareness campaigns and targeted interventions, to make non-smokers aware of the health risks (cardiovascular, respiratory, cancer) to which tobacco smoke exposes them. They also recommend increasing the number of measurements of exposure to tobacco smoke or aerosols from electronic cigarettes in open public spaces. They suggest subsequently adapting public policies for protection against passive smoking, in light of the data collected.

On this subject, the Stopping Tobacco Organisations and Products (STOP) organisation recently published an article on its blog recalling that these policies of protection against passive smoking do not in any way harm the development of trade and tourism.[3]Companies themselves have everything to gain (productivity, work stoppages, etc.) from enforcing these regulations in their establishments.

Keywords: non-smokers, passive smoking, tobacco smoke, cotinine.

M.F.

[1] Tobacco, Key facts, WHO, published July 31, 2023, accessed September 26, 2023.

[2] Wang R, Hall J, Salloum R, Kates F, Cogle C, Bruijnzeel A, Hong YR, LeLaurin J, Prevalence of Underreported Nicotine Exposure Among US Nonsmoking Adults: A Comparison of Self-Reported Exposure and Serum Cotinine Levels From NHANES 2013–2020, Nicotine & Tobacco Research, ntad165, Published online: 30 August 2023, https://doi.org/10.1093/ntr/ntad165

[3] Smoke-Free Policies Help—Not Hurt—Business and Economies, STOP, published September 25, 2023, accessed September 26, 2023.

National Committee Against Smoking |