# Distinguishing Exposure to Secondhand and Thirdhand Tobacco Smoke and Electronic Cigarettes among U.S. Children based on Multiple Biomarker Profiles

> **NIH NIH R21** · UNIVERSITY OF CINCINNATI · 2020 · $266,573

## Abstract

PROJECT SUMMARY
 Thirdhand smoke (THS) is a distinct public health hazard resulting from aged secondhand smoke (SHS)
left behind from active smoking that absorbs into surfaces, dust, and furnishings. Multiple harmful toxicants
are in THS including nicotine that reacts with ambient oxidants (e.g., nitrous acid) to create carcinogenic
tobacco-specific nitrosamines and tobacco-nonspecific toxicants such as polycyclic aromatic hydrocarbons and
volatile organic compounds. Electronic cigarette (EC) aerosol exposure is a source of tobacco-specific
toxicants despite not generating by-products from combustion. Children are most vulnerable to THS and EC
aerosol exposure and its related effects. SHS and THS differ in composition and can be assessed with
biomarkers in biological samples of children with varying tobacco smoke exposure (TSE) levels, which is the
cumulative exposure to SHS and THS. Methods to distinguish THS from SHS in nonsmokers are limited to
assessing self-report, THS-related main metabolites and NNAL-to-cotinine ratios. Currently, there are no gold
standard TSE biomarkers to differentiate exposure to THS from exposure to SHS or exposure to ECs from
combustible tobacco products. Our research and others indicates child TSE results in negative health
outcomes and EC aerosol exposure is linked with asthma symptoms. It is crucial to examine existing tobacco-
specific and nonspecific biomarkers to assess children’s exposure to diverse tobacco/nicotine products and
heterogeneous pollutants. This will provide insight on TSE classification in children and disentangle related
health effects. Thus, we propose to conduct an innovative secondary analysis of National Health and Nutrition
Examination Survey (NHANES) 2013-2016 data. This project will be the first to examine the prevalence,
contributions, and health risks of exposure to SHS and THS among children presumed to be unexposed to any
tobacco smoke and among children exposed to EC aerosol only. We will examine multiple biomarkers since
proportions in SHS, THS, and likely EC aerosol, differ. NHANES data will be analyzed to distinguish child TSE
groups: 1) Mixed SHS and THS group (MEG): lives with nonsmokers or smokers of combustible products only,
reported SHS; 2) Predominant THS group (TEG): lives with nonsmokers or smokers, no reported SHS; 3)
Predominant EC group (ECG): lives with EC only users, reported EC aerosol exposure; and 4) No/minimal
TSE group (NEG): lives with nonsmokers, no reported SHS. First, we will compare tobacco-specific biomarker
data with interview data to validate self-report and distinguish children into TSE groups. Then, we will use
classification algorithms to identify a set of tobacco-specific and nonspecific biomarkers and ratios that best
differentiates between TSE groups. Lastly, associations between TSE groups and demographics, and clinical
and healthcare utilization patterns will be examined. The potential for generating results to inform the
FDA-CTP is substantial ...

## Key facts

- **NIH application ID:** 10033879
- **Project number:** 1R21ES032161-01
- **Recipient organization:** UNIVERSITY OF CINCINNATI
- **Principal Investigator:** Ashley L Merianos
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $266,573
- **Award type:** 1
- **Project period:** 2020-09-01 → 2022-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10033879

## Citation

> US National Institutes of Health, RePORTER application 10033879, Distinguishing Exposure to Secondhand and Thirdhand Tobacco Smoke and Electronic Cigarettes among U.S. Children based on Multiple Biomarker Profiles (1R21ES032161-01). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10033879. Licensed CC0.

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