Necessity of Research on Thirdhand Smoke for Maternal and Child Health

ABSTRACT

The causal relationship between cigarette smoking during pregnancy and adverse maternal and child health outcomes, such as preterm birth, low birth weight, and sudden infant death syndrome are well known. In addition, cigarette compounds are neurotoxic even at extremely low levels. Thirdhand smoke (THS) is the contamination that persists after secondhand tobacco smoke has been emitted into air. It refers to the tobacco-related gases and particles that become embedded in materials such as carpets, walls, furniture, blankets, and toys. THS is not strictly smoke but chemicals that adhere to surfaces from which they can be released back into the air, undergo chemical transformations, and/or accumulate. The concept of THS is a relatively new phenomenon in the environmental and public health field. Currently, the hazards of THS are not as well documented as the hazards of secondhand smoke. Furthermore, its health effects and biological effects are largely unknown. This review summarizes recent research progress in reproductive toxicology studies that use animal models and in vitro systems, studies of environmental contamination by THS, human exposure studies, and priorities for further research. Future research must be conducted to facilitate hazard identification, and exposure and risk assessment to address its health effect on susceptible populations, such as pregnant women and children. In addition, policies and laws concerning tobacco smoke will need to be reviewed and possibly revised with the role of THS considered as an indispensable component of a broader tobacco control strategy in maternal and child health.