Although the prevalence of cigarette smoking has decreased by more than half since 1965, an estimated 17.8% of Americans still smoke.1 Of the 7 million deaths caused by tobacco use each year, approximately 890,000 are attributed to secondhand smoke exposure in nonsmokers.2 In addition, emerging evidence points to yet another source of tobacco-related harm: thirdhand smoke.
“Thirdhand smoke remains on surfaces and in dust for a long time after smoking happens, reacts with oxidants and other compounds to form secondary pollutants, and is re-emitted as a gas and/or resuspended when particles are disturbed and go back into the air where they can be inhaled,” according to a review published in 2017 in the Journal of Clinical Outcomes Management.2
Exposure can occur through ingestion, inhalation, or dermal absorption. Compared with secondhand smoke, which can be removed by ventilation, thirdhand smoke “exposure can take place during much longer time frames…and [its] components are difficult to remove from carpets, furniture, and surfaces, including walls,” wrote the authors of a 2016 paper published in Public Health Reports.1
Although the term was coined in 2006 by researchers from the Clinical Effort Against Secondhand Smoke Exposure (CEASE) program at Massachusetts General Hospital in Boston, the concept of thirdhand smoke was originally introduced in 1953, when rodent studies conducted at the Washington School of Medicine in St. Louis first demonstrated the carcinogenic effects of the residue from tobacco smoke.2 An increasing body of research supports the harmful effects of thirdhand smoke, especially in children.
To explore the evidence and clinical implications pertaining to thirdhand smoke, Pulmonology Advisor spoke with Jeremy Drehmer, MPH, CPH, clinical research program/project manager of CEASE projects at the Center for Child and Adolescent Health Research and Policy at Massachusetts General Hospital, and coauthor of the 2017 review, as well as 3 authors of the 2016 paper: Thomas F. Northrup, PhD, associate professor of family and community medicine at McGovern Medical School at the University of Texas Health Science Center in Houston; Melbourne F. Hovell, PhD, MPH, director of the Center for Behavioral Epidemiology and Community Health and Distinguished Professor of Public Health at San Diego State University; and Georg E. Matt, PhD, professor and chair in the department of psychology at San Diego State University.
Pulmonology Advisor: What are some of the strongest research findings thus far regarding the effects of thirdhand smoke?
Mr Drehmer: Children live in homes contaminated with thirdhand smoke and concentrations of thirdhand smoke exposure in children have been found to be disproportionately higher than in adults.2 Findings also demonstrate that thirdhand smoke contains chemicals that cause DNA damage and carcinogens that increase the risk [for] cancer in exposed children. In animal studies, thirdhand smoke has been linked to many common pediatric conditions, including low birth weight, asthma, prediabetes and metabolic syndrome, and hyperactivity.
Dr Northrup: Some of the most important studies that attempt to isolate the health-related harms from thirdhand smoke exposure have demonstrated DNA damage and hindered wound healing, using in vitro methods, and impaired respiratory development in an animal model.1 [In addition], research has demonstrated the extreme difficulty making public spaces, such as nonsmoking hotel rooms, rental cars, and neonatal intensive care units, and homes vacated by individuals who smoke, completely free of thirdhand smoke, raising public health concerns.1