# Prevalence and Clinical Correlates of Thirdhand Smoke Exposure in a Pediatric Patient Population

> **NIH NIH R01** · CINCINNATI CHILDRENS HOSP MED CTR · 2021 · $569,648

## Abstract

PROJECT SUMMARY
 Thirdhand smoke (THS) is the persistent toxic residue of tobacco smoke pollutants that attaches to
surfaces, remains in dust, and becomes embedded in environments where secondhand smoke (SHS) has
been released into the air. Even when parents are diligent in attempting to shield their children from tobacco
smoke, exposure to SHS (SHSe) and THS (THSe) still occurs. Residue from previously smoked tobacco at
home or in a car creates a pervasive reservoir of tobacco smoke pollutants that are within reach of a child's
hand such as on carpets, furniture, clothes, and toys, and breathed in dust. Homes of smokers become
reservoirs of these pollutants that persist for years, become more toxic with age, and are later reemitted into
the gas phase, or react with common ambient oxidants and other environmental compounds to yield secondary
pollutants such as carcinogenic tobacco-specific nitrosamines. The clinical effects of THSe are unknown
because prior research has examined children exposed to both SHS and THS. Studies exclusively focusing on
THSe are needed. Thus, we have conducted in-vitro, animal, and pilot pediatric studies that demonstrate that
THSe is associated with high levels of inflammatory cytokines, respiratory illnesses, and oxidative stress
including DNA damage, in mice. We have found even in the presence of smoking bans, children still have high
levels of THS pollution on their hands and that nonsmokers' homes have high THS pollution levels. However,
in the absence of large-scale, rigorous human studies, conclusions about the clinical effects of THSe cannot be
made. Thus, we propose an innovative prospective longitudinal cohort study that will move the field forward
and away from the laboratory to a pediatric clinical setting as the first pediatric study to use biochemical
validation to identify children exposed to THS-only over time. We will screen 1000 children from the pediatric
emergency department, a setting which cares for children with varying tobacco smoke exposure (TSE) levels
and illnesses. Using strict screening and chemical analysis techniques, we will identify and compare children
that comprise three distinct TSE groups: 1) THSe only group: live with nonsmokers, no reported SHSe,
confirmed negative/low levels of SHSe, elevated levels of THSe; 2) Mixed SHSe+THSe group: live with
smokers, reported SHSe, confirmed moderate/high levels of SHSe, high levels of THSe; and 3) No TSE group:
live with nonsmokers, no reported SHSe, confirmed negative levels of SHSe and THSe. The prevalence and
levels of THSe, demographics, and exposure and illness patterns of these groups will be compared over time.
Next, we will disentangle which environmental sources contribute to THSe levels and the association between
THSe and inflammatory (i.e., cytokines) and oxidative (i.e., DNA, lipid, protein oxidation) biomarkers and TSE-
related clinical illnesses. Results will provide unique insights into how THSe and sources of tobacco smoke
pol...

## Key facts

- **NIH application ID:** 10227009
- **Project number:** 5R01ES030743-03
- **Recipient organization:** CINCINNATI CHILDRENS HOSP MED CTR
- **Principal Investigator:** E. Melinda Mahabee-Gittens
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $569,648
- **Award type:** 5
- **Project period:** 2019-08-15 → 2024-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10227009

## Citation

> US National Institutes of Health, RePORTER application 10227009, Prevalence and Clinical Correlates of Thirdhand Smoke Exposure in a Pediatric Patient Population (5R01ES030743-03). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10227009. Licensed CC0.

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