Hand nicotine as an independent marker of thirdhand smoke pollution in children's environments

Evaluation of the Smoking Exposure Effects on Carcinogenesis Markers According to the Localization of Melanocytic Lesions

Melanoma is considered to be the most lethal skin cancer, and smoking is one of the most important public health issues, but its potential carcinogenic role in melanoma is still discussed. Our study aims to determine whether direct tobacco smoke exposure has an impact on melanocytic lesions regarding atypia and proliferation by analysing three markers of interest: DNA ploidy index, MCM6 and the α5-nicotinic acetylcholine receptor (CHRNA5). 90 patients with surgically removed melanocytic lesions were selected. Their smoking exposure data were collected. The expression of all three markers was analysed in lesions directly exposed to tobacco smoke and compared with lesions protected from exogen contact. No difference was found between lesions chronically exposed to smoke and those protected. In the smoker group, CHRNA5 expression (p = 0.25) and MCM6 expression (p = 0.24) were not statistically different depending on the location of lesions. There was also no difference in the DNA ploidy index (p = 0.3). Therefore, tobacco smoke does not seem to have an impact on CHRNA5 expression, proliferation and atypia markers in melanocytic lesions.

Analysis of Assessment Methods for Detecting Nicotine Residue and Its Impact on Humans: A Systematic Review

INTRODUCTION

Thirdhand smoke (THS) was first identified by Graham and colleagues in 1953, and nicotine was detected in household dust from smokers in 1991. Thirdhand smoke (THS) consists of toxic nicotine residues that persist on surfaces long after tobacco use, posing a significant public health concern. Individuals can be exposed to thirdhand smoke through skin contact or inhalation, particularly affecting children and infants who are most vulnerable to tobacco contaminants. This review aims to assess the effectiveness of different methods for measuring nicotine THS residues to evaluate their accuracy across various age groups.

METHODS

Relevant literature was sourced from databases including ProQuest (Ovid), Medline (Ovid), Embase (Ovid), Scopus, and the Cochrane Library. The timeframe for included studies ranged the last 25 years, from 1999 to 2024. Eligible participants consisted of human populations exposed to thirdhand smoke residue. For this review, the animal studies were excluded. There were no restrictions regarding age, sex, ethnicity, or nationality for participant selection. For data management and screening, the Covidence systematic tool was utilized. Data extraction was performed independently by two reviewers. This protocol was registered with PROSPERO (CRD42024574140).

RESULTS

A total of 394 studies were retrieved from 5 databases for the initial screening. A total of 67 studies included in full-text screening, and ultimately, 36 studies were selected for full review. The studies were classified into four categories based on assessment methods: (1) analysis of human secretions, including salivary or urinary tests; (2) cellular analysis utilizing cellulose substrates or paper-based materials; (3) environmental assessments, which examined outdoor surfaces, vehicles, residential spaces, and fabrics; and (4) epidemiological assessments, employing surveys or questionnaires. Non-invasive matrices such as saliva and urine were frequently utilized for biomarker analysis. The studies collectively investigated nicotine and its metabolites in human biological samples, environmental surface contamination, and thirdhand smoke (THS) exposure. They employed a diverse range of assessment tools including surveys, machine learning technique, and cellulose-based substrates.

CONCLUSIONS

This review identified various selective testing methods for detecting thirdhand smoke (THS) from nicotine. These assessment methods have advantages and disadvantages and underscores the need for further research. Improving these techniques for assessment of THS could significantly improve our understanding of the impact THS has on human health.

Trends in academic research on thirdhand smoke using bibliometric analysis

INTRODUCTION

This study used quantitative analysis to explore the current landscape of thirdhand smoke (THS) research by identifying gaps and emerging trends. Despite growing evidence of health risks associated with THS, research remains sparse, and no public policies address THS exposure. This analysis aimed to inform future studies and policies, in order to mitigate THS-related health risks.

METHODS

Using a bibliometric approach, our literature search identified 227 academic articles and reviews indexed in PubMed between 2009 and 2023. We used Biblioshiny, a bibliometrix R package, VOSviewer, and Excel to analyze the bibliographic data.

RESULTS

Since 2009, an average growth of 14.09% annually has been observed in THS-related publications. Additionally, we found that US institutions are major contributors to THS research. At the country level, studies conducted in the US, China, Spain, Italy, and South Korea are the most prevalent in the THS literature. Our findings indicate that THS research mainly focuses on human participants, health promotion, nicotiana/chemistry, air pollution/indoor analysis, tobacco smoke pollution, adolescent health, odorants/analysis, surface properties, carcinogens, and disease models/animals.

CONCLUSIONS

We analyzed THS research trends and identified the most impactful authors, journals, institutions, and countries. Considering the findings of this study, policymakers should continue policy development and implementation efforts to address THS exposure. The findings of this study can serve as basic reference material for scholars to guide future research directions regarding THS research.

Assessment, detection, and validation of clinical associations of thirdhand smoke exposure (ADVOCATE) study protocol

BACKGROUND

Thirdhand smoke (THS) pollution is the residue of secondhand smoke (SHS) remaining in homes long after active smoking has ceased. This study is the first to characterize the clinical correlates of THS exposure (THSe) in children independent of secondhand smoke exposure (SHSe). The prevalence, sociodemographic characteristics, tobacco smoke exposure patterns, sources, clinical, and biomarker effects associated with THSe will be examined.

METHOD

Smoking and nonsmoking parents and their 0-11-year-olds (N = 1013) were recruited. Children were categorized into tobacco smoke exposure (TSE) groups via biochemical validation with salivary cotinine and hand nicotine: (1) no exposure group (NEG); (2) THSe-only group (TEG); and (3) Mixed SHSe and THSe group (MEG). At enrollment, 6-weeks, and 6-months, parental assessments and children's biological and home samples were obtained and analyzed for SHSe, THSe, THS pollution, inflammatory and oxidative stress markers.

RESULTS

The mean (SD) child age was 5.8 (3.4) years; 50.7% were female; and 97% were non-Hispanic (97.0%); 67.5% were White, 25.7% were Black, 6.8% were Other/unknown race. In total, 57.9%, 18.2%, and 21.9% were classified in the NEG, TEG, and MEG, respectively. Sample and data analyses are ongoing.

CONCLUSION

This project will provide unique insights into how THSe in the absence of SHSe affects the clinical, inflammatory, and oxidative responses in children.

IMPACT

This is the first prospective longitudinal study to examine the prevalence of thirdhand smoke exposure in children of nonsmokers. Unlike prior tobacco smoke exposure research, this study will examine the contribution of thirdhand smoke exposure to pediatric health outcomes. Results will provide unique insights into how thirdhand smoke exposure in the absence of secondhand smoke exposure affects the clinical, inflammatory, and oxidative responses in children of nonsmokers.

Policy-relevant differences between secondhand and thirdhand smoke: strengthening protections from involuntary exposure to tobacco smoke pollutants

Starting in the 1970s, individuals, businesses and the public have increasingly benefited from policies prohibiting smoking indoors, saving thousands of lives and billions of dollars in healthcare expenditures. Smokefree policies to protect against secondhand smoke exposure, however, do not fully protect the public from the persistent and toxic chemical residues from tobacco smoke (also known as thirdhand smoke) that linger in indoor environments for years after smoking stops. Nor do these policies address the economic costs that individuals, businesses and the public bear in their attempts to remediate this toxic residue. We discuss policy-relevant differences between secondhand smoke and thirdhand smoke exposure: persistent pollutant reservoirs, pollutant transport, routes of exposure, the time gap between initial cause and effect, and remediation and disposal. We examine four policy considerations to better protect the public from involuntary exposure to tobacco smoke pollutants from all sources. We call for (a) redefining smokefree as free of tobacco smoke pollutants from secondhand and thirdhand smoke; (b) eliminating exemptions to comprehensive smoking bans; (c) identifying indoor environments with significant thirdhand smoke reservoirs; and (d) remediating thirdhand smoke. We use the case of California as an example of how secondhand smoke-protective laws may be strengthened to encompass thirdhand smoke protections. The health risks and economic costs of thirdhand smoke require that smokefree policies, environmental protections, real estate and rental disclosure policies, tenant protections, and consumer protection laws be strengthened to ensure that the public is fully protected from and informed about the risks of thirdhand smoke exposure.

Effects of Environmental Tobacco Smoke on Oxidative Stress in Childhood: A Human Biomonitoring Study

Household smoking is one of the main sources of environmental tobacco smoke (ETS) exposure for children, a population considered to be at high risk for associated negative health outcomes. Several studies evidenced the occurrence of early effects related to ETS exposure, including the development of the oxidative stress process. The aim of this study was to evaluate the correlation between urinary levels of 8-oxo-7,8-dihydro-2-deoxyguanosine (8oxodGuo), a nucleic acid oxidation biomarker, and socio-demographic features and lifestyle factors in school children (aged 5-11 years). A cross-sectional study was conducted among 154 healthy children, residing in rural zones of central Italy. For each participant, one urine sample was analyzed by the HPLC-MS/MS technique to simultaneously quantify 8oxodGuo and cotinine (a biomarker of ETS exposure), while information on the children was collected using a questionnaire filled out by the parents. Urinary levels of 8oxodGuo was found to be significantly higher in children exposed to ETS compared to those not exposed (5.53 vs. 4.78 μg/L; p = 0.019). This result was confirmed by the significant association observed between urinary levels of cotinine and 8oxodGuo (r = 0.364, p < 0.0001). Additionally, children exposed to ETS with no smoking ban at home showed a further increased difference than those not exposed (6.35 μg/L vs. 4.78 μg/L; p = 0.008). Considering the great number of adverse effects on human health due to exposure to passive smoking, especially if this exposure begins early in life, it is essential to implement health promotion interventions in this area.

Contamination of surfaces in children's homes with nicotine and the potent carcinogenic tobacco-specific nitrosamine NNK

BACKGROUND

Tobacco smoke exposure (TSE) through secondhand and thirdhand smoke is a modifiable risk factor that contributes to childhood morbidity. Limited research has assessed surface TSE pollution in children's environments as a potential source of thirdhand smoke exposure, and none have examined levels of the tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) on surfaces.

OBJECTIVE

This study measured surface NNK and nicotine in children's homes and associations with sociodemographics and parent-reported TSE behaviors. We assessed correlations of surface NNK and nicotine with dust NNK, dust nicotine, and child cotinine.

METHODS

Home surface wipe NNK and nicotine data from 84 children who lived with smokers were analyzed. Tobit and simple linear regression analyses were conducted to assess associations of surface NNK and nicotine with child characteristics. Spearman's (ρ) correlations assessed the strength of associations between environmental markers and child cotinine.

RESULTS

Nearly half (48.8%) of children's home surfaces had detectable NNK and 100% had detectable nicotine. The respective geometric means (GMs) of surface NNK and nicotine loadings were 14.0 ng/m2 and 16.4 µg/m2. Surface NNK positively correlated with surface nicotine (ρ = 0.54, p < 0.001) and dust NNK (ρ = 0.30, p = 0.020). Surface nicotine positively correlated with dust NNK (ρ = 0.42, p < 0.001) and dust nicotine (ρ = 0.24, p = 0.041). Children with household incomes ≤$15,000 had higher surface NNK levels (GM = 18.7 ng/m2, p = 0.017) compared to children with household incomes >$15,000 (GM = 7.1 ng/m2). Children with no home smoking bans had higher surface NNK (GM = 18.1 ng/m2, p = 0.020) and surface nicotine (GM = 17.7 µg/m2, p = 0.019) levels compared to children with smoking bans (GM = 7.5 ng/m2, 4.8 µg/m2, respectively).

IMPACT

Although nicotine on surfaces is an established marker of thirdhand smoke pollution, other thirdhand smoke contaminants have not been measured on surfaces in the homes of children living with smokers. We provide evidence that the potent carcinogenic tobacco-specific nitrosamine NNK was detectable on surfaces in nearly half of children's homes, and nicotine was detectable on all surfaces. Surface NNK was positively correlated with surface nicotine and dust NNK. Detectable surface NNK levels were found in homes with indoor smoking bans, indicating the role of NNK as a persistent thirdhand smoke pollutant accumulating on surfaces as well as in dust.

Changes and stability of hand nicotine levels in children of smokers: Associations with urinary biomarkers, reported child tobacco smoke exposure, and home smoking bans

BACKGROUND

Exposure to thirdhand smoke (THS) residue takes place through inhalation, ingestion, and dermal transfer. Hand nicotine levels have been proposed to measure THS pollution in the environment of children, but little is known about its variability and stability over time and correlates of change.

OBJECTIVES

The goal was to determine the stability of hand nicotine in comparison to urinary biomarkers and to explore factors that influence changes in hand nicotine.

METHODS

Data were collected from 0 to 11-year-old children (Mean age = 5.9) who lived with ≥1 tobacco smokers (N = 129). At a 6-week interval, we collected repeated measures of hand nicotine, four urinary biomarkers (cotinine, trans-3'-hydroxycotinine, nicotelline N-oxides, and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol), and parent-reported child tobacco smoke exposure (TSE). Dependent sample t-tests, correlations, and multivariable regression analyses were conducted to examine the changes in child TSE.

RESULTS

Hand nicotine levels (r = 0.63, p < 0.001) showed similar correlations between repeated measures to urinary biomarkers (r = 0.58-0.71; p < 0.001). Different from urinary biomarkers, mean hand nicotine levels increased over time (t(113) = 3.37, p < 0.001) being significantly higher in children from homes without smoking bans at Time 2 (p = 0.016) compared to Time 1 (p = 0.003). Changes in hand nicotine correlated with changes in cotinine and trans-3'-hydroxycotinine (r = 0.30 and r = 0.19, respectively, p < 0.05). Children with home smoking bans at Time 1 and 2 showed significantly lower hand nicotine levels compared to children without home smoking bans.

DISCUSSION

Findings indicate that hand nicotine levels provide additional insights into children's exposure to tobacco smoke pollutants than reported child TSE and urinary biomarkers. Changes in hand nicotine levels show that consistent home smoking bans in homes of children of smokers can lower THS exposure. Hand nicotine levels may be influenced by the environmental settings in which they are collected.