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Effects of Thirdhand Smoke Exposure on the Microbiome of Young Children

Institution: San Diego State University Research Foundation
Investigator(s): Georg Matt, Ph.D.
Award Cycle: 2017 (Cycle 26) Grant #: 26IP-0047 Award: $361,180
Subject Area: Environmental Exposure/Toxicology
Award Type: High Impact Pilot Award

Initial Award Abstract

The human body contains a large number of microorganisms such as bacteria that perform critical functions and help regulate the immune system. Disruptions to these microorganisms, called the human microbiome, can increase the risk of chronic and infectious disease. Tobacco smoke contains many chemical compounds that are known to interfere with the growth of microorganisms, and research has shown that smokers have different microbiomes in their mouth, nose, lung, and gut than nonsmokers. Smokers are also known to be more likely to suffer from bacterial and viral infections and are at higher risk for various cancers, lung and heart disease. Recent research has shown that tobacco smoke pollutants collect and remain in house dust and on surfaces months after tobacco has been smoked and can be found in homes and cars of smokers with smoking bans. Known as thirdhand smoke (THS), many of these long-lasting pollutants also have strong antimicrobial properties. Our own research has shown that THS pollutants are found at high concentrations on the hands of children and nonsmoking adults living with smokers. THS pollutants can also be found on nonsmokers who move into homes previously occupied by smokers. Young children are particularly at risk of exposure to THS and also are the most susceptible to adverse health effects. This is because their immune system and organs are not yet fully developed, they frequently put hands and other objects in their mouths, and they are in close physical contact with caretakers who may carry THS pollutants on their hands and clothes. This pilot study will examine if THS in dust and on surfaces in the homes of smokers changes children’s microbiomes in ways that may weaken their immune systems. Specifically, we will compare young children of smokers and nonsmokers to determine if (1) homes of smokers show higher levels of THS pollutants, (2) children of smokers show higher levels of THS on their hands and in their bodies, and (3) the microbial organisms in the mouth, nose, ear, and on the skin of the children of smokers differ in ways that may affect the regulation of their immune system. To examine these questions, we have put together a research team with expertise in THS pollution and exposure, the human microbiome, and child health. We will use research methods that we developed in our previous research on THS. We plan to recruit 20 THS exposed children (<= 2 years) who live with smokers who have strict indoor smoking bans. We will also recruit 10 children who are not exposed to secondhand smoke (SHS) and who live with never smokers who have strict indoor smoking bans. We will visit homes to conduct personal interviews with parents and to examine house dust and surfaces for THS. We will wipe the children’s skin, nose, mouth, and ear to collect to determine the types of microbes that are present. We will wipe the children’s dominant hand to determine if they carry nicotine on their skin. We will collect urine samples from the children to examine if they have absorbed THS. We will analyze the data to determine if the smokers’ homes are polluted with THS and if children of smokers are exposed to THS on their hands and in their bodies. We will examine the samples collected from their mouth, nose, ear, and skin to determine if THS may have changed the number of different types of microbes. Findings from this study will help better understand how young children are exposed to tobacco smoke even if their parents do not smoke in their presence. We will learn if exposure to THS affects the microbial organisms in the children’s mouth, ear, nose, and on their skin. This in turn can help better understand how changes in the microbiome may affect the immune system. If successful, findings from this study will draw attention to the role of THS in the homes of smokers and how to better protect all children from THS exposure and the harmful long-term effects of tobacco smoke.