California Collaborative Consortium on Thirdhand Smoke
The California Collaborative Consortium on Thirdhand Smoke (THS Consortium) is a multiinstitutional, interdisciplinary, programmatic, and translational research effort. The Consortium aims to identify the potential health effects of exposure to THS residue from tobacco, vaping, and cannabis products in indoor environments, validate environmental indicators and biomarkers of exposure to THS, educate the public and relevant stakeholder groups (e.g. housing), and devise evidence-based policies to prevent such exposure. Funded by the California Tobacco-Related Disease Research Program (TRDRP), the central theme of the Phase 4 Funding Cycle (2023-2025) is leveraging THS research to inform and contribute to the California Tobacco Endgame Initiative which seeks to end the sale and use of all commercial tobacco products in the state by the year 2035.
The Consortium’s Pilot Research Awards aim to expand and promote the THS research priorities in relation to the Consortium’s central theme. This short-term funding supports pilot studies to inform the development of larger, peer-reviewed THS-focused research applications that can compete successfully for TRDRP or other funding.
The Collaborative Consortium on Thirdhand Smoke is pleased to announce that the 2024 Pilot Projects have been selected! Read the abstracts here.
2024 Pilot Research Awards
Carcinogens such as tobacco-specific nitrosamines (TSNAs) are emitted during smoking and can accumulate in indoor surface materials. They can readily undergo oxidative aging by common indoor oxidants such as ozone, potentially producing a large variety of byproducts that may exhibit different toxicities compared to the parent TSNAs. However, there is little information on the aging of TSNA present in thirdhand smoke (THS). Exposure models and health impact predictions are thus greatly limited by a poor understanding of their degradation chemistry and oxidation byproducts during THS oxidative aging on indoor surfaces.
The primary aim of this project is to bridge the above-mentioned knowledge gap by developing a new, “preparation-free” analytical technique with high sensitivity for TSNAs and investigating the ozone-induced aging of TSNAs on indoor surfaces and studying their degradation kinetics and the aging byproducts. This method using thermal desorption chemical ionization mass spectrometry can be a significant advancement compared to the current approach that involves labor-intensive sample extraction and derivatization prior to analysis. The results of this project will allow us to: (1) establish a quantitative understanding of the kinetics of THS carcinogen degradation in indoor environmental timescales; and (2) identify and quantify toxic byproducts from surface ozonolysis to which occupants are exposed. These critical results will be useful for estimating toxicant doses to which occupants can be exposed in THS contaminated homes, and for predicting the expected health impact associated with that exposure.
Mounting evidence has shown that tobacco smoke exposure during pregnancy has a detrimental effect on major health outcomes in children, including cognitive function. Reports on the harms of tobacco smoke exposure usually focus on active smoking or secondhand smoke exposure, but rarely examine thirdhand smoke (THS) exposure, the chemical residues that linger on surfaces and in dust after smoking. An accurate determination of exposure to tobacco smoke, particularly distinguishing THS from secondhand smoke exposure and active smoking in pregnant women, has significant public health implications. Self-reported data can be biased, which underscores the necessity of valid exposure assessments combining information from questionnaires and biomarkers, such as urinary cotinine. We propose a study with two objectives using resources from the ECHO program, a large collaborative project of 50,000 mother and child dyads from 69 cohort sites across the U.S. Benefiting from repeated collection of both urinary cotinine and self-reported smoke exposure throughout pregnancy in several cohorts, we will first determine cotinine cut-offs in each trimester to classify exposure to active, secondhand, THS, or no exposure, using self-identified tobacco exposure status as the reference. We will then apply the cotinine cut-offs to identify pregnant women with only THS in other ECHO cohorts, and further estimate the associations of urinary cotinine with child intelligence quotient in this unique population. Findings from the proposed research can be utilized to define smoking exposure in future studies targeting pregnant women, inform interventions to reduce THS exposure, and ultimately improve child cognitive development.
2023 Pilot Research Awards
Cotinine is a specific metabolite of nicotine and a gold standard marker of secondhand smoke (SHS) and thirdhand smoke (THS) in nonsmokers. In comparison to nicotine, cotinine is much easier to measure at low levels than nicotine, and more laboratories carry out cotinine analyses. Although cotinine is an analyte detected by many commercial laboratories in biological and environmental samples including surface wipes, there are no assessments on the cotinine levels recovered from human dermis using handwipes. As demonstrated in our previous silicone wristband study, in which the cotinine/nicotine ratio varied significantly between exposure levels, measuring nicotine in handwipes could potentially be used to differentiate exposure to SHS and THS. Also, there is a need to better understand the nicotine-cotinine metabolism and exposure ratios in relation to absorption-desorption of chemicals present in THS among young children. Therefore, we propose to investigate cotinine in handwipes as practical and accurate exposure assessment tool by levering samples that have been previously collected from children known to be exposed to SHS/THS. Our aims are to: 1) evaluate cotinine levels from handwipes in relation to children exposure to THS and SHS by using previously collected samples from 90 children (THS exposed = 30; SHS exposed = 30; control = 30); 2) assess the nicotine/cotinine exposure ratios from collected samples and compare cotinine in handwipes with salivary cotinine and handwipe nicotine levels; and 3) determine exposure cotinine cutoff values from handwipes that can be utilized in future studies and examine socio-demographic factors related to THS/SHS exposure.
Adverse birth outcomes are a critical global public health concern, with substantial health and financial impacts on mothers, babies, families and communities-at-large. Exposures to environmental pollutants are increasingly thought to contribute to pregnancy complications, adverse birth outcomes and/or developmental effects. For example, over the last half-century, there has been a large body of scientific evidence associating maternal both firsthand and secondhand smoke exposure with a multitude of pregnancy complications involving the placenta, adverse birth outcomes and developmental effects. Despite strong evidence linking firsthand and secondhand smoke exposure to offspring health effects, little is known about pregnancy health effects of maternal exposure to thirdhand smoke (THS), the chemical residues from secondhand smoke that accumulate on hard surfaces as dust-like particles and embed in soft surfaces over time. We plan to use two parallel in vitro models to investigate the toxic effects of thirdhand smoke collected from house dust samples on placenta using a placental cell line HTR-8/SVneo, and on fetal development using zebrafish. We will assess cell viability, cytotoxicity and proliferation in placental cells and embryonic survival, morphology (structural defects), and hatching success in zebrafish. In both models, mechanisms of toxicity will be assessed using fluorometric reporters of detoxification mechanisms and qPCR of important enzymes in xenobiotic response. Our research will provide crucial toxicological data for THS toxicity during pregnancy, which is currently unavailable. This data will be communicated with regulatory toxicologists and can be used to inform federal, state and local policies around smoking.