Pilot Projects

California Collaborative Consortium on Thirdhand Smoke

Pilot Research Awards

Assessing Exposure to Thirdhand Smoke by Analyzing Cotinine in Handwipes

Nicolas Lopez Galvez, PhD, MPH, MA
San Diego State University

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.

Investigation of Toxic Effects of Thirdhand Smoke at the Placental-Embryonic Interface

Elana Elkin, PhD, MPH
San Diego State University

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.

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.

Download the 2023 Call for applications here.

Applications for 2023 are closed.