WHO publishes synthesis on the links between smoking and asthma

The World Health Organization (WHO) has published a new synthesis of the state of knowledge[1] on the relationship between smoking and asthma. This highlights the harmful effects of smoking on the onset and severity of asthma. WHO stresses the need for comprehensive measures to combat active and passive smoking, with support for people seeking to quit smoking.

Asthma is a major global public health problem, affecting approximately 262 million people and causing 455,000 deaths each year. Asthma is the most common chronic disease in children and adolescents, affecting approximately one in ten children/adolescents worldwide. It is an inflammation of the airways that causes the bronchial tubes to narrow due to contraction of their muscles, making breathing more difficult, especially during attacks.

This document provides information and awareness-raising for health professionals directly concerned by the problem of asthma, in particular pulmonologists, allergists and pediatricians, as well as those involved in the fight against smoking and the prevention of its harmful effects on health.

Active smoking promotes the onset of asthma and worsens its severity

Smoking is a risk factor for developing asthma, and, for the same smoking rate, this risk is greater in women than in men.

In asthmatics, smoking aggravates their disease in several ways: attacks are more frequent and more severe, and their sensitivity to inhaled treatments, particularly corticosteroids, is altered; in the long term, the progression to chronic bronchitis, with deterioration of respiratory function and respiratory failure, or even possible death, is more rapid.

Finally, smoking exposes you to the medium-term risk of developing chronic obstructive pulmonary disease (COPD) and/or lung cancer.

Exposure to environmental passive smoking promotes the occurrence of asthma in children and worsens its severity in children and adults

Exposure to secondary and tertiary passive smoking increases the frequency of asthma in children and worsens its severity in children and adults with more frequent and severe attacks, and a reduction in the effectiveness of inhaled treatments. This toxicity of environmental passive smoking is all the more significant when exposure takes place in a confined environment such as a vehicle or apartment.

Exposure to fetal secondhand smoke increases the risk of asthma in the unborn child

Smoking during pregnancy is associated with smaller lungs and a higher incidence of asthma in children and adolescents exposed in utero. Similarly, exposure of a non-smoking woman to environmental secondhand smoke during pregnancy puts her unborn child at higher risk of developing asthma.

Links between asthma and e-cigarette use

Several cross-sectional and longitudinal studies[2]-[3] reported respiratory symptoms, such as chronic cough, wheezing, shortness of breath, and asthma in adolescents and young adults who use e-cigarettes. They show that e-cigarette use is associated with an increased prevalence of asthma symptoms, and that this prevalence is even higher among vapers who smoke tobacco at the same time.[4].

Preventive support targeted at pregnant women and parents

Since in utero exposure to passive smoking is particularly harmful to the respiratory system of unborn children, and young asthmatic children are particularly vulnerable to second-hand and third-hand environmental smoke, it is imperative for WHO to target parents who smoke and support them in helping them quit smoking.

The importance of quitting smoking on asthma

WHO says it is essential that all people with asthma who smoke receive personalised advice and support to quit smoking, with emphasis on the short- and long-term benefits of quitting which lead to improved lung function with reduced airway inflammation and hyper-responsiveness, resulting in better asthma control, and improved quality and life expectancy.

WHO recommendation for healthy environments without exposure to passive smoking

WHO recommends, as a public policy, the implementation of smoking ban measures with the expansion of smoke-free spaces, both in indoor public places, workplaces and public transport, because the implementation of such measures is associated with an almost immediate reduction in levels of pollution due to second-hand smoke and a marked improvement in the respiratory health of populations.

©Generation Without Tobacco

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[1] WHO tobacco knowledge summaries: Tobacco and asthma, WHO, published July 30, 2024, accessed July 31, 2024

[2] National Academies of Sciences, Engineering, and Medicine; Health and Medicine Division; Board on Population Health and Public Health Practice; Committee on the Review of the Health Effects of Electronic Nicotine Delivery Systems. Eaton DL, Kwan LY, Stratton K, editors. Public health consequences of e-cigarettes. Washington (DC): National Academies Press; 2018. (https://doi.org/10.17226/24952).

[3] Schweitzer RJ, Wills TA, Tam E, Pagano I, Choi K. E-cigarette use and asthma in a multiethnic sample of adolescents. Prev Med. 2017;105:226-31. (https://doi.org/10.1016/j.ypmed.2017.09.023).

[4] Asfar T, Jebai R, Li W, Oluwole OJ, Ferdous T, Gautam P et al. Risk and safety profile of electronic nicotine delivery systems (ENDS): an umbrella review to inform ENDS health communication strategies. Tob Control. 2024;33:373-82. (http://orcid.org/0000-0003-0472-3807)