Second-hand smoke

Second-hand smoke and cardiovascular disease

Adults and children exposed to second-hand smoke (SHS, also known as environmental tobacco smoke) inhale many of the same toxic chemicals as smokers do. Second-hand smoke can cause or contribute to cardiovascular disease in people who have never smoked (Critselis et al., 2019; Khoramdad et al., 2020), and is specifically associated with ischemic heart diseases (IHD) (López et al., 2016; Fischer and Kraemer, 2015).

Estimates suggest that about 9% of all cases of CVD and over 2% of cardiovascular deaths in Europe are due to SHS; for some specific cardiovascular diseases, the proportion due to SHS is higher — e.g. around 3% of IHD deaths are due to SHS (GBD Collaborative Network, 2020; Zhang et al., 2020). Indeed, the effect of second-hand smoke on never-smokers might be much higher than that which their inhaled dose may suggest. For example, while the dose of cigarette smoke delivered to passive smokers is 1% of that delivered to active smokers, the relative risk (RR) of coronary artery disease for passive smokers could be close to 40% of the risk of active smokers (DiGiacomo et al., 2019). More generally, the risk of developing heart disease increases by up to 25-30% for non-smokers who breathe in second-hand smoke at home or at work (DHHS, 2014). People who already have heart disease are at especially high risk from the adverse effects of second-hand smoke and should be protected from even brief exposures. While we are still learning about the health (including cardiovascular) effects of second-hand aerosols from e-cigarettes and vaping, initial research already suggests health hazards stemming from second-hand exposure (Oriakhi, 2020; Islam et al., 2022).

Trends in exposure to second-hand smoke in Europe

On average, around 31% of the EU population is estimated to be exposed to second-hand tobacco smoke at home, at work, during leisure activities, in educational institutions or in public settings (Henderson et al., 2020). It is difficult to assess exposure to second-hand smoke across settings, age groups and European countries. A study by Ma et al. (2021) found a mixed picture in Europe in adolescents aged 12-16: from 1999 to 2018 their exposure increased, decreased or remained unchanged depending on the country. Another study covering 12 EU countries found very different levels of second-hand smoke outdoors (including around hospitals and schools): the presence of second-hand smoke was higher in countries with a higher prevalence of smoking and with less comprehensive tobacco control policies (Henderson et al., 2021). What is clear is that exposure can be significantly reduced by implementing total smoking bans in public places (Nogueira et al., 2022). A recent study in Germany (Burkhardt et al., 2023) credits smoking bans and regulations limiting SHS following European legislation with a decisive contribution to a significant decline in non-smokers’ exposure to SHS; the researchers measured an 82% decline in urinary cotinine (a biomarker related to exposure to tobacco smoke) in non-smokers from 1995 to 2019.

What the EU is doing about second-hand smoke

In parallel to adopting a body of regulations and action on tobacco control, advertising, promotion and sponsorship (DG SANTE, 2021), the EU issued a Council recommendation in 2009 on smoke-free environments and continuously supports Member States’ efforts in implementing the WHO Framework Convention on Tobacco Control. An update of this outdated recommendation is also expected for 2023. In addition, several EU Member States have banned smoking in public places, mainly indoors but in some cases also in outdoor areas (Henderson et al., 2021). Despite these efforts, a combination of insufficient regulation and/or weak enforcement in several countries means that significant proportions of the population may still be exposed to SHS (Nogueira et al., 2022).