Cardiovascular Consequences of Childhood Secondhand Tobacco Smoke Exposure: Prevailing Evidence, Burden, and Racial and Socioeconomic Disparities: A Scientific Statement From the American Heart Association

Abstract

Background Although public health programs have led to a substantial decrease in the prevalence of tobacco smoking, the adverse health effects of tobacco smoking is by no means a thing of the past. In the U.S, four out of 10 school aged children and 1 out of 3 adolescents are involuntarily exposed to second-hand tobacco smoke (SHS) with children of minority ethnic backgrounds and those living in low socioeconomic status households being disproportionately affected (68% and 43% respectively). Children are particularly vulnerable with little control over home and social environment and lack the understanding, agency, and ability to avoid SHS exposure on their own volition; they also have physiological or behavioral characteristics that render them especially susceptible to effects of SHS. Side stream smoke (the smoke burned directly off the end of the cigarette), a major component of SHS, contains a higher concentration of some toxins than mainstream smoke (inhaled by the smoker directly), making SHS potentially more dangerous than direct smoking. Compelling animal and human evidence shows that SHS exposure during childhood is detrimental to arterial function and structure resulting in premature atherosclerosis and its cardiovascular consequences. Childhood SHS exposure is also related to impaired cardiac autonomic function and changes in heart rate variability. In addition, childhood SHS exposure is associated with clustering of cardiometabolic risk factors such as obesity, dyslipidemia, and insulin resistance. Individualized interventions to reduce childhood exposure to SHS are shown to be at least modestly effective, so are broader based policy initiatives such as community smoking bans and increased taxation. Purpose The purpose of this statement is to summarize the available evidence on the cardiovascular health consequences of childhood SHS exposure which will support ongoing efforts to reduce and eliminate SHS exposure in this vulnerable population. This statement reviews relevant data from epidemiologic studies; laboratory based experiments, and controlled behavioral trials, concerning SHS and cardiovascular disease risk in children. Information regarding the effects of SHS exposure on the cardiovascular system in animal and pediatric studies, including vascular disruption and platelet activation, oxidation and inflammation, endothelial dysfunction, increased vascular stiffness, changes in vascular structure, and autonomic dysfunction are examined. Conclusion The epidemiological, observational and experimental evidence accumulated to date, demonstrates the detrimental long-term cardiovascular consequences of SHS exposure in children. Implications Increased awareness of these adverse effects will facilitate the development of targeted individual, family-centered and community public health interventions to reduce and ideally eliminate SHS exposure in the vulnerable pediatric population. This evidence calls for a robust public health policy that embraces “zero tolerance” to childhood SHS exposure.

Tobacco, e-cigarettes, and child health

“…The evidence for the negative impact of childhood tobacco smoke exposure on cardiovascular health has been summarized in a scientific statement from the American Heart Association [35**]. A study in a Finnish population demonstrates how biomarkers of tobacco smoke exposure, specifically cotinine, are valuable tools in providing strong evidence of linkage between childhood exposure to tobacco smoke and increased risk of cardiovascular disease [36**].…”

“…The reason for the difference is that some of the parents protected their children from tobacco smoke exposure as demonstrated by negligible urinary cotinine levels in these children. Tobacco smoke chemicals proposed to responsible for the adverse cardiovascular effects of environmental tobacco smoke include nicotine, acrolein, crotonaldehyde, cadmium, lead and particulate matter [35**]. …”

A Review of the Field on Children’s Exposure to Environmental Contaminants: A Risk Assessment Approach

“…The adverse respiratory and carcinogenic effects of second-hand and, increasingly, third-hand smoke continues to concern public health officials as an avoidable environmental exposure indoors for children (both pre- and postnatal exposures) that lead to lung cancer, motor impairment, hearing and vision problems, cardiovascular consequences, and learning disabilities [37,38,39]. Disparities in exposures continue to exist, where children from minority backgrounds and those in low socio-economic groups experience higher exposures to second-hand tobacco smoke not only in the United but in other countries [39,40].…”

“…Disparities in exposures continue to exist, where children from minority backgrounds and those in low socio-economic groups experience higher exposures to second-hand tobacco smoke not only in the United but in other countries [39,40]. Children’s exposures to tobacco smoke and other contaminants that occur in multi-unit apartment buildings also pose particular challenges to control outside of established smoke-free policies in the United States [41].…”

Role of NADPH oxidase-2 and oxidative stress in children exposed to passive smoking

“…Children exposed to passive smoking have a higher risk to develop cardiovascular events in adulthood1; oxidative stress generated by cigarette smoke increases cardiovascular events through endothelial dysfunction, increased intimal-medial thickening (IMT) and platelet activation 1…”