Assessing secondhand smoke using biological markers

Association between menopausal age and smoking status defined using urinary cotinine or tobacco-specific nitrosamine metabolite 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol: The Korea National Health and Nutrition Examination Survey 2016-2018

This study aimed to establish the optimal cut-off values for urinary cotinine and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL)to determine smoking status in Korean women over 20 years of age and to assess the correlation of these biomarkers with reproductive health, particularly menopausal age, in postmenopausal women. Utilizing data from the 7th edition of the Korea National Health and Nutrition Examination Survey (2016-2018), researchers included postmenopausal women aged 40-60 years who were within 5 years of menopause. Self-reported smoking status was aligned with biomarkers levels to calculate optimal cut-off values, classifying a total of 503 postmenopausal women into four groups: never smokers (cotinine <0.738 ng/mL, NNAL <1.595 pg/mL), secondhand smokers (SHSrs; cotinine 0.738-37.7 ng/mL, NNAL 1.595-12.35 pg/mL), light current smokers (cotinine 37.7-837 ng/mL, NNAL 12.35-91.55 pg/mg), and heavy current smokers (cotinine >837 ng/mL, NNAL >91.55 pg/mL). Differences in menopausal age were analyzed using Kaplan-Meier curves and log-rank tests. The results indicated significant differences in menopausal age between never smokers and heavy smokers (51.4 ± 3.9 vs. 49.6 ± 3.0 years, p = 0.001) as well as SHSrs and heavy smokers (51.4 ± 3.3 vs. 49.6 ± 3.0 years, p = 0.001) when applying urinary cotinine cutoff values. However, no significant differences in menopausal age were observed based on NNAL cutoffs. These findings suggest urinary cotinine levels correlated more strongly with menopausal age than using urine NNAL levels for defining smoking status among postmenopausal Korean women. Heavy current smokers, as identified by urinary cotinine levels, experienced menopause at an earlier age compared to never smokers and SHSrs.

Survey of Secondhand Smoke for 3-Year-Old Children in the Current Era of New Tobacco Products

AIM

To investigate children's exposure to secondhand smoke and aerosols in the current era of new tobacco products.

METHODS

A total of 200 children were recruited from among children who had undergone health checkups for 3-year-olds at the clinic. We investigated the smoking status of their families using a questionnaire and measured urinary cotinine concentrations in their children. The children were divided into four groups based on their families' smoking status: no smokers (n = 114), exclusive combustion cigarette smokers (n = 35), both combustion cigarette and heated tobacco product smokers (n = 12) and exclusive heated tobacco product smokers (n = 39).

RESULTS

Of the 200 children, 53 (26.5%) had detectable urinary cotinine levels. Of these, 12 (6.0%) were classified as having heavy exposure to secondhand smoke (urinary cotinine concentration ≥ 5 ng/mL). Urinary cotinine concentrations among children living with exclusive heated tobacco product smokers were significantly lower than those among children living with exclusive combustion cigarette smokers, but higher than those in children whose family members did not smoke at all. Relative to exclusive combustion cigarette smokers, exclusive heated tobacco product smokers were significantly more likely to smoke indoors.

CONCLUSIONS

Secondhand aerosol exposure from heated tobacco products may be reduced but cannot be completely eliminated.

Association between prenatal tobacco exposure and attention-deficit/hyperactivity disorder related characteristics at 6 and 8 years: a birth cohort in Japan

OBJECTIVES

To examine the association between maternal plasma cotinine concentrations during pregnancy and attention-deficit/hyperactivity disorder (ADHD) related characteristics in children.

DESIGN

Prospective birth cohort study from the Hokkaido Study on Environment and Children's Health.

SETTING

Hokkaido, Japan.

PARTICIPANTS

A total of 7217 children were included in the analysis. Their mothers were recruited to this study between 2003 and 2012 during early pregnancy. Blood samples of mothers in their third trimester of pregnancy were obtained.

MAIN OUTCOME MEASURES

ADHD-related characteristics screened by the ADHD-Rating Scale (ADHD-RS) in children at 6 and 8 years of age.

RESULTS

The mothers were classified into three groups according to plasma cotinine levels (median=0.22 ng/mL)-non-smokers (≤0.21 ng/mL), passive smokers (0.22-11.48 ng/mL) and active smokers (≥11.49 ng/mL). ADHD was suspected in 302 (8.6%), 334 (10.9%) and 90 (14.5%) children in the non-smoker, passive smoker and active smoker groups, respectively. Children born to mothers in the smoking group had a statistically significant increased risk of ADHD-related characteristics (adjusted RR=1.49, 95% CI=1.19-1.86 and adjusted RR=1.20, 95% CI=1.03-1.40 for the active and passive smoking groups, respectively).

CONCLUSION

This large Japanese cohort study suggests an association between smoking during pregnancy and the risk of ADHD in children 6 and 8 years of age.

PlQC based highly sensitive and reproducible novel SERS active substrate for biomolecule detection with high specificity

Surface-enhanced Raman spectroscopy (SERS) is a powerful tool for biomolecule sensing. When combined with a broadband plasmonic structure, label-free, highly sensitive detection of specific molecules is possible. It is non-invasive, sensitive, fast, and can be used for in-situ analysis, unlike enzyme-linked immunosorbent assay, fluorescence immunoassay, and radioimmunoassay. However, one of the challenges is to have an active SERS substrate that is uniform, sensitive, and specific to molecules of interest. In this work, we report plasmonic quasicrystal (PlQC) as a highly sensitive (enhancement factor ≈ 1014), uniform, reproducible, and stable (concerning time and ambient conditions) SERS active substrate. Herein, we present the label-free sensing of standard cotinine (up to 1 ng/mL), the ideal biomarker for nicotine exposure due to its long lifetime compared to nicotine. In addition, up to 1 nanogram level of cotinine has also been detected in synthetic urine and saliva employing PlQC as a SERS-active substrate. Our results on the principal component analysis of Rhodamine 6G and Cotinine demonstrate that broadband, dispersionless PlQC is suitable for label-free detection of single biomolecules.

Smoking-informed methylation and expression QTLs in human brain and colocalization with smoking-associated genetic loci

Smoking is a leading cause of preventable morbidity and mortality. Smoking is heritable, and genome-wide association studies (GWASs) of smoking behaviors have identified hundreds of significant loci. Most GWAS-identified variants are noncoding with unknown neurobiological effects. We used genome-wide genotype, DNA methylation, and RNA sequencing data in postmortem human nucleus accumbens (NAc) to identify cis-methylation/expression quantitative trait loci (meQTLs/eQTLs), investigate variant-by-cigarette smoking interactions across the genome, and overlay QTL evidence at smoking GWAS-identified loci to evaluate their regulatory potential. Active smokers (N = 52) and nonsmokers (N = 171) were defined based on cotinine biomarker levels and next-of-kin reporting. We simultaneously tested variant and variant-by-smoking interaction effects on methylation and expression, separately, adjusting for biological and technical covariates and correcting for multiple testing using a two-stage procedure. We found >2 million significant meQTL variants (padj < 0.05) corresponding to 41,695 unique CpGs. Results were largely driven by main effects, and five meQTLs, mapping to NUDT12, FAM53B, RNF39, and ADRA1B, showed a significant interaction with smoking. We found 57,683 significant eQTL variants for 958 unique eGenes (padj < 0.05) and no smoking interactions. Colocalization analyses identified loci with smoking-associated GWAS variants that overlapped meQTLs/eQTLs, suggesting that these heritable factors may influence smoking behaviors through functional effects on methylation/expression. One locus containing MUSTN1 and ITIH4 colocalized across all data types (GWAS, meQTL, and eQTL). In this first genome-wide meQTL map in the human NAc, the enriched overlap with smoking GWAS-identified genetic loci provides evidence that gene regulation in the brain helps explain the neurobiology of smoking behaviors.

The link between serum cotinine levels and gallstones prevalence in adults: a cross-sectional analysis using NHANES data (2017-2020)

Background

Gallstones represent a prevalent health issue globally, resulting in significant annual healthcare costs. While tobacco exposure is recognized for its association with numerous diseases, its correlation with gallstones remains contentious. Serum cotinine, a metabolite of nicotine, serves as a widely utilized indicator for assessing tobacco exposure. Crucially, no research has yet examined the association between serum cotinine levels and the gallstones.

Methods

This study is designed as a cross-sectional analysis, utilizing data from the NHANES public database. The relationship between serum cotinine levels and gallstones was analyzed using multinomial logistic regression models and smooth curve fitting. Subgroup analyses and interaction tests were performed to examine the potential contributions of different populations and covariates to the findings.

Results

A total of 5,856 participants were included in this study. After adjusting for relevant covariates, the multiple logistic regression model results indicated that for each unit increase in serum cotinine concentration above 0.29 ng/mL, there was a 29% increase in the prevalence of gallstones. Furthermore, smooth curve fitting analysis revealed a positive correlation between these variables. These findings underscore the impact of tobacco exposure on gallstone prevalence.

Conclusion

This study demonstrates a positive correlation between tobacco exposure, as measured by serum cotinine levels, and the prevalence of gallstones, thus adding to the body of existing research on this relationship.

Self-reported smoking, urine cotinine, and risk of type 2 diabetes: Findings from the PREVEND prospective cohort study

BACKGROUND

Smoking is a major risk factor for type 2 diabetes (T2D), but the evidence has mostly relied on self-reports. We aimed to compare the associations of smoking exposure as assessed by self-reports and urine cotinine with T2D.

METHODS

Using the PREVEND prospective study, smoking status was assessed at baseline by self-reports and urine cotinine in 4708 participants (mean age, 53 years) without a history of diabetes. Participants were classified as never, former, light current and heavy current smokers according to self-reports and analogous cut-offs for urine cotinine. Hazard ratios (HRs) with 95% CIs were estimated for T2D.

RESULTS

During a median follow-up of 7.3 years, 259 participants developed T2D. Compared with self-reported never smokers, the multivariable adjusted HRs (95% CI) of T2D for former, light current, and heavy current smokers were 1.02 (0.75-1.4), 1.41 (0.89-2.22), and 1.30 (0.88-1.93), respectively. The corresponding adjusted HRs (95% CI) were 0.84 (0.43-1.67), 1.61 (1.12-2.31), and 1.58 (1.08-2.32), respectively, as assessed by urine cotinine. Urine cotinine-assessed but not self-reported smoking status improved T2D risk prediction beyond established risk factors.

CONCLUSION

Urine cotinine assessed smoking status may be a stronger risk indicator and predictor of T2D compared to self-reported smoking status.

Effect of children secondhand smoke exposure associated with GABA concentration: Influence from parents who are extremely heavy smokers in urban households

BACKGROUND

Secondhand smoke (SHS) poses the most considerable health risk to children in urban households. However, limited evidence exists regarding the impact of children exposure to SHS on gamma-aminobutyric acid (GABA) levels. This study aimed to investigate the level of cotinine and GABA and their association with variables related to children exposed to SHS.

METHODS

A cross-sectional analysis was conducted to assess urinary cotinine and GABA levels in respondents. The study involved 85 participants aged 2-4 years who resided with parents exhibiting heavy smoking habits in urban households in Bangkok, Thailand. Urinary cotinine and GABA concentrations were utilized as biomarkers and measured using an enzyme-linked immunosorbent assay kit. An independent t-test was employed to compare contributing factors with urinary cotinine metabolites. Spearman's correlation test was utilized to assess the relationship between cotinine metabolites and GABA concentration.

RESULTS

The study found a correlation between urinary cotinine metabolites and GABA concentration among children's (r = 0.260, p-value = 0.016), particularly influenced by parents exhibiting extreme heavy smoking in urban households. Male children exhibited significantly higher urinary cotinine metabolite concentrations than females (p-value = 0.040). Moreover, significantly elevated levels of cotinine metabolites (57.37 ± 10.27 ng/ml) were observed in households where parents engaged in extreme heavy smoking.

CONCLUSIONS

This research establishes a link between urinary cotinine metabolite levels and GABA concentration among children exposed to extreme heavy smoking by their parents in urban households. Consequently, smoking might impact neurobehavioral effects, potentially leading to insomnia. The study emphasizes the importance of promoting and safeguarding non-smokers from exposure to SHS in indoor workplaces, public spaces, and households, advocating for the implementation of smoke-free public health regulations.

Arsenic Methyltransferase and Apolipoprotein E Polymorphism in Pregnant Women Exposed to Inorganic Arsenic in Drinking Water in Western Romania

Previous studies have shown that inorganic arsenic (iAs) exposure may be associated with genotoxic and cytotoxic effects. The aim of this study was to evaluate the relationship between several polymorphisms in AS3MT and APOE genes and urinary As and the relationship between these polymorphisms and pregnancy loss. We determined urinary As concentrations and performed genotyping analysis in 50 cases of spontaneous pregnancy loss and 50 controls, matched to cases on gestational age. The most frequently identified AS3MT polymorphisms in both cases and controls were in rs10748835 (80% cases and 68% controls), rs3740400 (78% cases and 64% controls), rs7085104 (74% cases and 48% controls), and rs1046778 (62% cases and 54% controls). We identified 30 different haplotypes in AS3MT SNPs, with four predominant haplotypes (>8%). Cases with Haplotype 1 had four-fold higher urinary DMA and two-fold higher MMA concentration than those without this haplotype, the MMA levels were lower in cases and controls with Haplotype 4 compared to Haplotype 1, and the DMA levels were significantly lower in cases with Haplotype 4 compared to Haplotype 3. Cases with Haplotype 1 had higher levels of all analyzed biomarkers, suggesting that Haplotype 1 may be associated with greater exposure to iAs and tobacco smoke. Our results suggest the importance of the AS3MT gene in iAs metabolism among pregnant women with low-level drinking water iAs exposure.

Prevalence of Underreported Nicotine Exposure Among US Nonsmoking Adults: A Comparison of Self-Reported Exposure and Serum Cotinine Levels From NHANES 2013-2020

INTRODUCTION

Secondhand smoke (SHS) poses a significant health risk. However, individuals who do not smoke may be unaware of their exposure, thereby failing to take protective actions promptly.

AIMS AND METHODS

We assessed the prevalence of underreported nicotine exposure in a nationally representative sample of US nonsmoking adults using data from the US National Health and Examination Survey. Individuals with underreported nicotine exposure were defined as those who reported no exposure to all tobacco products (traditional tobacco, nicotine replacements, and e-cigarettes) or SHS, yet had detectable levels of serum cotinine (>0.015 ng/mL). We fitted logistic regression models to determine sociodemographic and chronic condition factors associated with underreported nicotine exposure.

RESULTS

Our analysis included 13 503 adults aged 18 years and older. Between 2013 and 2020, the prevalence of self-reported SHS exposure, serum cotinine-assessed nicotine exposure, and underreported nicotine exposure among US nonsmokers were 22.0%, 51.2%, and 34.6%, respectively. Remarkably, 67.6% with detectable serum cotinine reported no SHS exposure. Males, non-Hispanic blacks, individuals of other races (including Asian Americans, Native Americans, and Pacific Islanders), and those without cardiovascular diseases were more likely to underreport nicotine exposure than their counterparts. The median serum cotinine value was higher in respondents who reported SHS exposure (0.107 ng/mL) than in those who reported no exposure (0.035 ng/mL). We estimate that approximately 56 million US residents had underreported nicotine exposure.

CONCLUSIONS

Over a third of US nonsmokers underreport their nicotine exposure, underlining the urgent need for comprehensive public awareness campaigns and interventions. Further research into sociodemographic determinants influencing this underreporting is needed.

IMPLICATIONS

Understanding the extent of underreported nicotine exposure is crucial for developing effective public health strategies and interventions. It is imperative to bolster public consciousness about the risks associated with SHS. Additionally, surveillance tools should also incorporate measures of exposure to outdoor SHS and e-cigarette vapor to enhance the quality of data monitoring. Findings from this study can guide tobacco control initiatives and inform smoke-free air legislation.

Influence of Half-life and Smoking/Nonsmoking Ratio on Biomarker Consistency between Waves 1 and 2 of the Population Assessment of Tobacco and Health Study

BACKGROUND

Biomarkers of exposure are tools for understanding the impact of tobacco use on health outcomes if confounders like demographics, use behavior, biological half-life, and other sources of exposure are accounted for in the analysis.

METHODS

We performed multiple regression analysis of longitudinal measures of urinary biomarkers of alkaloids, tobacco-specific nitrosamines, polycyclic aromatic hydrocarbons, volatile organic compounds (VOC), and metals to examine the sample-to-sample consistency in Waves 1 and 2 of the Population Assessment of Tobacco and Health (PATH) Study including demographic characteristics and use behavior variables of persons who smoked exclusively. Regression coefficients, within- and between-person variance, and intra-class correlation coefficients (ICC) were compared with biomarker smoking/nonsmoking population mean ratios and biological half-lives.

RESULTS

Most biomarkers were similarly associated with sex, age, race/ethnicity, and product use behavior. The biomarkers with larger smoking/nonsmoking population mean ratios had greater regression coefficients related to recency of exposure. For VOC and alkaloid metabolites, longer biological half-life was associated with lower within-person variance. For each chemical class studied, there were biomarkers that demonstrated good ICCs.

CONCLUSIONS

For most of the biomarkers of exposure reported in the PATH Study, for people who smoke cigarettes exclusively, associations are similar between urinary biomarkers of exposure and demographic and use behavior covariates. Biomarkers of exposure within-subject consistency is likely associated with nontobacco sources of exposure and biological half-life.

IMPACT

Biomarkers measured in the PATH Study provide consistent sample-to-sample measures from which to investigate the association of adverse health outcomes with the characteristics of cigarettes and their use.

Objective measures of smoking and caffeine intake and the risk of adverse pregnancy outcomes

BACKGROUND

In pregnancy, women are encouraged to cease smoking and limit caffeine intake. We employed objective definitions of smoking and caffeine exposure to assess their association with adverse outcomes.

METHODS

We conducted a case cohort study within the Pregnancy Outcome Prediction study to analyse maternal serum metabolomics in samples from 12, 20, 28 and 36 weeks of gestational age. Objective smoking status was defined based on detectable cotinine levels at each time point and objective caffeine exposure was based on tertiles of paraxanthine levels at each time point. We used logistic and linear regression to examine the association between cotinine, paraxanthine and the risk of pre-eclampsia, spontaneous pre-term birth (sPTB), fetal growth restriction (FGR), gestational diabetes mellitus and birthweight.

RESULTS

There were 914 and 915 women in the smoking and caffeine analyses, respectively. Compared with no exposure to smoking, consistent exposure to smoking was associated with an increased risk of sPTB [adjusted odds ratio (aOR) = 2.58, 95% CI: 1.14 to 5.85)] and FGR (aOR = 4.07, 95% CI: 2.14 to 7.74) and lower birthweight (β = -387 g, 95% CI: -622 g to -153 g). On univariate analysis, consistently high levels of paraxanthine were associated with an increased risk of FGR but that association attenuated when adjusting for maternal characteristics and objective-but not self-reported-smoking status.

CONCLUSIONS

Based on objective data, consistent exposure to smoking throughout pregnancy was strongly associated with sPTB and FGR. High levels of paraxanthine were not independently associated with any of the studied outcomes and were confounded by smoking.

Household smoking impact on the oral health of 5- to 7-years-old children

BACKGROUND

Children's exposure to secondhand smoke, particularly by their parents, could adversely affect their oral health. Thereby, this study aimed to assess the oral health status of children subjected to household smoking and the impact of smoking patterns on the severity of oral health deterioration.

METHODS

A total of 210 healthy children were enrolled in this case-control study and allocated into children subjected to household smoking (HS) and control groups. Participants' guardians were asked to complete a questionnaire regarding sociodemographic characteristics and parental smoking habits. All participants were subjected to clinical dental examination to assess dental caries (ICDAS), hypomineralized primary molars (HSPM), and gingival status (GI). Stimulated saliva samples were collected to assess saliva composition and characteristics. Urine samples were collected and analyzed for cotinine concentration. Data were analyzed using SPSS (v.25) software at a test value of p ≤ 0.05. The t-student test was used to find significant differences between participants' age, gingival index score, saliva pH, flow rate, sIgA, and cotinine level. The Chi-square test was used to test for the significance of parental employment, number of rooms, gender, sweets consumption, brushing frequency, and HMPM. The correspondence analysis was used to test for significance of parents' levels of education, type of house ventilation, ICDAS score, smoking form, frequency, and smoking pattern. The correlation between cotinine level and sIgA was tested for association using Bivariate correlation test.

RESULTS

The HS group showed a significantly increased risk for dental caries (p < 0.000), HSPM lesions (p = 0.007), and GI score (p < 0.000). A significant reduction in salivary flow rate, saliva pH, and sIgA were evident in HS group (p < 0.000). Parental consumption of more than 20 cigarettes/day was accompanied by increased dental caries activity (p < 0.000) and higher risk for increased severity of gingival inflammation (p < 0.000) of children in the HS group. Children of parents who smoke cigarettes and use the hubble/bubble anywhere in the house found to have greater distribution of HSPM (p < 0.000). Reduced sIgA values were found to be significantly associated with increased cotinine concentrations in HS children (p < 0.000).

CONCLUSIONS

Frequent exposure to household smoking could be associated with an increased risk of dental caries progression, enamel hypomineralization, gingival inflammation, and saliva characteristics changes in children.

Environmental tobacco smoke exposure is associated with increased levels of metals in children's saliva

BACKGROUND

Exposure to environmental tobacco smoke (ETS) has been associated with detectable levels of cotinine (a nicotine metabolite) in children's saliva. However, tobacco smoke also contains toxic and essential trace metals, including chromium (Cr), copper (Cu), lead (Pb), manganese (Mn), nickel (Ni) and zinc (Zn).

OBJECTIVE

The current study examines whether there is a relationship between ETS exposure, as gauged by salivary cotinine, and salivary levels of these metals in a subset (n = 238) of children from the Family Life Project.

METHODS

Using inductively-coupled-plasma optical emission spectrophotometry, we measured levels of metals in saliva from children at ~90 months of age. Salivary cotinine was measured using a commercial immunoassay.

RESULTS

We found that Cr, Cu, Mn, and Zn were detected in most samples (85-99%) with lower levels of detection for Pb and Ni (9.3% and 13.9% respectively). There were no significant differences in any of the metal concentrations between males and females, nor were levels associated with body mass index, although significant differences in salivary Cr and Mn by race, state and income-to-needs ratio were observed. Children with cotinine levels >1 ng/ml had higher levels of Zn (b = 0.401, 95% CI: 0.183 to 0.619; p = 0.0003) and Cu (b = 0.655, 95% CI: 0.206 to 1.104; p = 0.004) compared to children with levels <1 ng/ml, after controlling for multiple confounders, including sex, race, BMI and income-to-needs ratio. Further, we show that children whose cotinine levels were >1 μg/L were more likely to have detectable levels of Pb in their saliva (b = 1.40, 95% CI: 0.424 to 2.459; p = 0.006) compared to children with cotinine levels <1 ng/ml, also considering confounders.

IMPACT STATEMENT

This is the first study to demonstrate significant associations between salivary cotinine and salivary levels of Cu, Zn and Pb, suggesting that environmental tobacco smoke exposure my be one source of increased children's exposure to heavy metals. This study also demonstrates that saliva samples can be used to measure heavy metal exposure, and thus serve as a non-invasive tool for assessing a broader range of risk indicators.

Effect of educational intervention in reducing exposure to second hand tobacco smoke among 12-year-old children as determined by their salivary cotinine levels and knowledge, attitude and behavior - a randomized controlled trial

Background

Tobacco use is one of the most important public health concerns, with approximately 8.7 million tobacco-related deaths each year, primarily in low- and middle-income countries. Even more concerning is the fact that 1.3 million of these deaths are seen in nonsmokers, including babies and children. This study was performed to determine whether a school-based "tobacco-free" educational intervention program among 12-year-old children would be effective in reducing their exposure to second-hand tobacco smoke (SHS) by improving their knowledge, attitude and behavior post intervention and estimating salivary cotinine levels as markers of SHS exposure.

Materials and method

A randomized controlled trial was performed by a cluster random sampling technique, with 30 participants each in the experimental and control arms. A knowledge, attitude, avoidance behavior and self-efficacy of avoidance questionnaire was administered, followed by estimation of salivary cotinine levels. The experimental arm received the "tobacco-free" intervention, which comprised a 40-min health education session, with the first follow-up at 15 days and the second at 30 days after the intervention. After the intervention, the questionnaire was readministered, followed by re-estimation of salivary cotinine levels.

Results

One month after the intervention, the number of participants who had a smoker who lived with them and the number of people who smoked inside the house were reduced in the experimental group compared to the control group. In the knowledge domain and the attitude domain, 80% and 60% of the items showed a statistically significant improvement in the experimental group compared to the control group. In the avoidance behavior domain and the Self-Efficacy of Avoidance Domain, all the items showed improvement in the experimental group compared to the control group. When the mean salivary cotinine levels were compared pre- and postintervention, it was found that although the mean postintervention salivary cotinine levels increased in both the experimental and control groups, the increase was less in the experimental group than in the control group.

Conclusion

The present study has been shown to be effective in improving the knowledge, attitude and avoidance behavior of adolescents toward exposure to secondhand smoke.

Smoking-informed methylation and expression QTLs in human brain and colocalization with smoking-associated genetic loci

Smoking is a leading cause of preventable morbidity and mortality. Smoking is heritable, and genome-wide association studies (GWAS) of smoking behaviors have identified hundreds of significant loci. Most GWAS-identified variants are noncoding with unknown neurobiological effects. We used genome-wide genotype, DNA methylation, and RNA sequencing data in postmortem human nucleus accumbens (NAc) to identify cis-methylation/expression quantitative trait loci (meQTLs/eQTLs), investigate variant-by-cigarette smoking interactions across the genome, and overlay QTL evidence at smoking GWAS-identified loci to evaluate their regulatory potential. Active smokers (N=52) and nonsmokers (N=171) were defined based on cotinine biomarker levels and next-of-kin reporting. We simultaneously tested variant and variant-by-smoking interaction effects on methylation and expression, separately, adjusting for biological and technical covariates and using a two-stage multiple testing approach with eigenMT and Bonferroni corrections. We found >2 million significant meQTL variants (padj<0.05) corresponding to 41,695 unique CpGs. Results were largely driven by main effects; five meQTLs, mapping to NUDT12, FAM53B, RNF39, and ADRA1B, showed a significant interaction with smoking. We found 57,683 significant eQTLs for 958 unique eGenes (padj<0.05) and no smoking interactions. Colocalization analyses identified loci with smoking-associated GWAS variants that overlapped meQTLs/eQTLs, suggesting that these heritable factors may influence smoking behaviors through functional effects on methylation/expression. One locus containing MUSTIN1 and ITIH4 colocalized across all data types (GWAS + meQTL + eQTL). In this first genome-wide meQTL map in the human NAc, the enriched overlap with smoking GWAS-identified genetic loci provides evidence that gene regulation in the brain helps explain the neurobiology of smoking behaviors.

Urinary arsenic and spontaneous pregnancy loss - a hypothesis-generating case-control investigation in western Romania

Arsenic occurs as a natural contaminant of drinking water supplies in arsenic endemic areas, posing a threat to public health. Our aim was to evaluate the relationship between urinary arsenic concentrations and spontaneous pregnancy loss in a population with low-moderate level drinking water arsenic exposure (mostly <10 μg/L). We enrolled 150 women with incident spontaneous pregnancy losses and 150 controls with ongoing pregnancies matched by gestational age. We measured arsenic species in urine using high performance liquid chromatography paired to inductively coupled plasma mass spectrometry. Urinary arsenic was not related to spontaneous pregnancy loss in conditional logistic regression models adjusted for confounding factors. However, a 10 μg/L increase in urinary arsenic (III + V) salt concentrations was associated with 8.00-fold (95% CI: 0.68, 3.35 × 105) greater odds of spontaneous loss among women using prenatal vitamins in an interaction model (P for interaction = 0.07), although the effect estimate was imprecise. In an additional interaction model, prenatal vitamin use was associated with lower odds of loss (OR = 0.30; 95% CI: 0.13, 0.66), although the association was diminished in the presence of a 10 μg/L increase in urinary inorganic arsenic (OR = 0.44; 95% CI: 0.70, 3.22). Total urinary arsenic was associated with 1.48-fold (95% CI: 0.20, 11.35) greater odds for loss among women with urinary cotinine >50 μg/L in another interaction model (P for interaction = 0.07). These results suggest a potential modest increase in the odds of pregnancy loss associated with increased total urinary arsenic among women smoking during pregnancy (urinary cotinine >50 μg/L). Prenatal vitamin use may act as a protective factor for arsenic exposure associated pregnancy loss, but appears to be less protective with increasing urinary inorganic arsenic concentrations.

How missing value imputation is confounded with batch effects and what you can do about it

In data-processing pipelines, upstream steps can influence downstream processes because of their sequential nature. Among these data-processing steps, batch effect (BE) correction (BEC) and missing value imputation (MVI) are crucial for ensuring data suitability for advanced modeling and reducing the likelihood of false discoveries. Although BEC-MVI interactions are not well studied, they are ultimately interdependent. Batch sensitization can improve the quality of MVI. Conversely, accounting for missingness also improves proper BE estimation in BEC. Here, we discuss how BEC and MVI are interconnected and interdependent. We show how batch sensitization can improve any MVI and bring attention to the idea of BE-associated missing values (BEAMs). Finally, we discuss how batch-class imbalance problems can be mitigated by borrowing ideas from machine learning.

Secondhand Smoke Exposure in Childhood and Mortality from Coronary Heart Disease in Adulthood: the Japan Collaborative Cohort Study for Evaluation of Cancer Risk

AIMS

We examined whether secondhand smoke exposure in childhood affects the risk of coronary heart disease (CHD) in adulthood.

METHODS

In the Japan Collaborative Cohort Study, we analyzed data on 71,459 participants aged 40-79 years, with no history of CHD, stroke, or cancer at baseline (1988-1990) and who completed a lifestyle questionnaire including the number of smoking family members in childhood (0, 1, 2, and 3+ members) and followed them up until the end of 2009. The Cox proportional hazards model was used to calculate the multivariable hazard ratios (HRs) with 95% confidence intervals (CIs) of CHD mortality according to the number of smoking family members in childhood.

RESULTS

During the median 18.9 years' follow-up, 955 CHD deaths were reported. There was a dose-response relationship between the number of smoking family members at home and CHD mortality among middle-aged individuals (40-59 years); the multivariable HRs (95% CIs) were 1.08 (0.76-1.54) for 1, 1.35 (0.87-2.08) for 2, and 2.49 (1.24-5.00) for 3+ smoking family members compared with 0 members (p for trend=0.03). The association for 3+ smoking family members among the middle-aged group was more evident in men than in women (the multivariable HRs [95% CIs] were 2.97 [1.34-6.58] and 1.65 [0.36-7.52], respectively) and more evident in non-current smokers than in current smokers (the multivariable HRs [95% CIs] were 4.24 [1.57-11.45] and 1.93 [0.72-5.15], respectively).

CONCLUSIONS

Secondhand smoke exposure in childhood was associated with an increased risk of CHD mortality in adulthood, primarily in middle-aged men and non-current smokers.

Trends in adolescent secondhand smoke exposure at home over 15 years in Korea: Inequality by parental education level

INTRODUCTION

Low parental education level and parental smoking are major risk factors for household secondhand smoke (SHS) exposure among adolescents. We investigated the trend in household SHS exposure according to sex, school, and parental education level to determine whether the decline in household SHS exposure over time depends on parental education level.

METHODS

We used cross-sectional Korea Youth Risk Behavior datasets (2006-2020; 806829 subjects were eligible). We applied binary logistic regression to assess household SHS exposure trends and evaluated the interaction between period and parental education level.

RESULTS

Household SHS exposure over 15 years has declined. The difference (0.121) was the smallest for male middle school students with low-educated parents. The slope for the estimated probability of household SHS exposure among students with high-educated parents was steeper than that for those with low-educated parents, except for female high school students (difference=0.141). Students with low-educated parents were at higher risk of household SHS exposure (male middle school students, adjusted odds ratio, AOR=1.52; 95% CI: 1.47-1.56; male high school students, AOR=1.42; 95% CI: 1.38-1.47; female middle school students, AOR=1.62; 95% CI: 1.58-1.67; female high school students, AOR=1.62; 95% CI: 1.57-1.67). The interaction between parental education level and period was significant. We also found a significant interaction between parental education level and parental smoking (other × present interaction, AOR=0.64; 95% CI: 0.60-0.67; low-low × present interaction, AOR=0.89; 95% CI: 0.83-0.95).

CONCLUSIONS

Changes in parental education level over time mainly contributed to changes in adolescents' household SHS exposure. Adolescents with low-educated parents were at higher risk of household SHS exposure, with a slower decline. These gaps must be considered when creating and implementing interventions. Campaigns and community programs to prevent household SHS need to be emphasized among vulnerable adolescents.

The Benefit of a Retrospective Pregnancy Anamnesis in Child and Adolescent Psychiatry: The Reliability of Maternal Self-Report during Childhood Development

Pregnancy anamnesis is a crucial part of child and adolescent psychiatry diagnostics. In previous works, the reliability of retrospective maternal self-report on perinatal characteristics was heterogeneous. This prospective longitudinal study aimed to evaluate women's recall of prenatal events in a within-subject design. A sample of 241 women gave a self-report on prenatal alcohol, smoking, partnership quality, pregnancy satisfaction, and obstetric complications during the 3rd trimester (t0), childhood (t1, 6-10 y), and adolescence (t2, 12-14 y). The intra-individual agreement was examined. The t0-t1-(t2) agreement was poor to substantial; this was highest for smoking and worst for obstetric complications, followed by alcohol (Fleiss' κ = 0.719 to -0.051). There were significant t0-t1-(t2) differences for all pregnancy variables (p < 0.017), except for 3rd trimester satisfaction (p = 0.256). For alcohol (t0 25.8%, t1 17.4%, t2 41.0%) and smoking (t0 11.9%, t1 16.4%, t2 22.6%), the highest self-reported rates were found during adolescence. During childhood, fewer obstetric complications (t0 84.9%, t1 42.2%) and worse partnerships were reported (t0 M = 8.86, t1 M = 7.89). Thought to be due to social stigmata and memory effects, pregnancy self-reports cannot be precisely reproduced. Creating a respectful and trusting atmosphere is essential for mothers to give honest self-reports that are in the best interest of their children.

The Associations of Trans-3'-Hydroxy Cotinine, Cotinine, and the Nicotine Metabolite Ratio in Pediatric Patients with Tobacco Smoke Exposure

(1) Background: Trans-3'-hydroxy cotinine (3HC) and cotinine (COT) are tobacco smoke exposure (TSE) biomarkers and the 3HC/COT ratio is a marker of CYP2A6 activity, an enzyme which metabolizes nicotine. The primary objective was to assess the associations of these TSE biomarkers with sociodemographics and TSE patterns in children who lived with ≥1 smoker. (2) Methods: A convenience sample of 288 children (mean age (SD) = 6.42 (4.8) years) was recruited. Multiple linear regression models were built to assess associations of sociodemographics and TSE patterns with urinary biomarker response variables: (1) 3HC, (2) COT, (3) 3HC+COT sum, and (4) 3HC/COT ratio. (3) Results: All children had detectable 3HC (Geometric Mean [GeoM] = 32.03 ng/mL, 95%CI = 26.97, 38.04) and COT (GeoM = 10.24 ng/mL, 95%CI = 8.82, 11.89). Children with higher cumulative TSE had higher 3HC and COT (β^ = 0.03, 95%CI = 0.01, 0.06, p = 0.015 and β^ = 0.03, 95%CI = 0.01, 0.05, p = 0.013, respectively). Highest 3HC+COT sum levels were in children who were Black (β^ = 0.60, 95%CI = 0.04, 1.17, p = 0.039) and who had higher cumulative TSE (β^ = 0.03, 95%CI = 0.01, 0.06, p = 0.015). Lowest 3HC/COT ratios were in children who were Black (β^ = -0.42, 95%CI = -0.78, -0.07, p = 0.021) and female (β^ = -0.32, 95%CI = -0.62, -0.01, p = 0.044). (4) Conclusion: Results indicate that there are racial and age-related differences in TSE, most likely due to slower nicotine metabolism in non-Hispanic Black children and in younger children.

Variability in Urinary Nicotine Exposure Biomarker Levels Between Waves 1 (2013-2014) and 2 (2014-2015) in the Population Assessment of Tobacco and Health Study

INTRODUCTION

To date, no studies have evaluated the consistency of biomarker levels in people who smoke over a long-time period in real-world conditions with a large number of subjects and included use behavior and measures of nicotine metabolism. We evaluated the variability of biomarkers of nicotine exposure over approximately a 1-year period in people who exclusively smoke cigarettes, including intensity and recency of use and brand switching to assess impact on understanding associations with product characteristics.

AIMS AND METHODS

Multivariate regression analysis of longitudinal repeated measures of urinary biomarkers of nicotine exposure from 916 adults in the Population Assessment of Tobacco and Health (PATH) Study with demographic characteristics and use behavior variables. Intraclass correlation coefficients (ICCs) were calculated to examine individual variation of nicotine biomarkers and the uncertainty of repeat measures at two time points (Waves 1 and 2).

RESULTS

Age, race, and urinary creatinine were significant covariates of urinary cotinine. When including use behavior, recency, and intensity of use were highly significant and variance decreased to a higher extent between than within subjects. The ICC for urinary cotinine decreased from 0.7530 with no use behavior variables in the model to 0.5763 when included. Similar results were found for total nicotine equivalents.

CONCLUSIONS

Urinary nicotine biomarkers in the PATH Study showed good consistency between Waves 1 and 2. Use behavior measures such as time since last smoked a cigarette and number of cigarettes smoked in the past 30 days are important to include when assessing factors that may influence biomarker concentrations.

IMPLICATIONS

The results of this study show that the consistency of the nicotine biomarkers cotinine and total nicotine equivalents in spot urine samples from Waves 1 to 2 of the PATH Study is high enough that these data are useful to evaluate the association of cigarette characteristics with biomarkers of exposure under real-world use conditions.

Verifying the accuracy of self-reported smoking behavior in female volunteer soldiers

Smoking rates in the military are evaluated through questionnaire surveying. Because the accurate identification of smokers facilitates the provision of smoking cessation services, this study conducted urine cotinine concentration testing to verify the accuracy of self-reported smoking behavior by female volunteer soldiers and analyzed the effects of second-hand smoking on urine cotinine concentrations. This study is a cross-sectional study conducted using purposive sampling on female volunteer soldiers receiving training at the Taichung Recruit Training Center in May 2014. This study simultaneously collected questionnaires and urine samples, and urine samples were analyzed with an enzyme-linked immunosorbent assay. The self-reported smoking rate of female volunteer soldiers was 19.3%, whereas the smoking rate as determined by urine cotinine concentration testing was 26.3%, indicating an overall underestimation of 7.0%. Chi-square (χ2) goodness of fit test results indicated that the distribution of self-reported smoking behaviors and that verified from urine cotinine concentration testing were significantly different. The sensitivity of self-reported smoking behavior was 66.7% with a specificity of 97.6%. There was no significant association between second-hand smoking and urine cotinine concentrations. Questionnaire survey self-reporting methods could underestimate the smoking behavior of female volunteer soldiers and routine testing with biochemical verification is necessary.

Feasibility of mailed biomarker data collection among U.S. young adults: Saliva-based cotinine and self-reported nicotine use

BACKGROUND

Nationally representative self-report studies are the standard for data on the prevalence of substance use. Newly emerging biomarker assessments can add objective measurements of exposure. However, biomarker assessment has typically depended on in-person sample collection. The current study examined whether young adults in a national sample would be willing and able to provide a saliva sample via mail, and the correspondence of cotinine in the saliva sample with self-reported vaping and smoking.

METHODS

Data collection for the Monitoring the Future (MTF) Vaping Supplement was from September to November 2020. Eligible participants (N = 4358) were selected from a nationally-representative sample of US 12th-grade students in MTF in spring 2019. The MTF Vaping Supplement surveyed individuals nationally about one year after the 12th grade MTF survey (in 2020, mean age = 19.6 years; N = 1244). Survey weights accounted for design and attrition.

RESULTS

Of those surveyed, 66.2% consented to provide a saliva sample and, of those, 73.8% mailed a sample. There were no significant differences in providing a saliva sample across any demographic characteristic, but those who reported nicotine use were less likely to provide a sample. Cotinine cut-off measures of > 3 ng/mL and > 10 ng/mL had good correspondence with self-reported measures.

CONCLUSIONS

Results support the feasibility of collecting saliva via the mail in a national sample and the validity of data collected in this way. These findings support future research innovations to expand existing survey research protocols to include biomarker data collection in representative samples of young adults.

Cotinine as a Sentinel of Canine Exposure to Tobacco Smoke

The adverse health effects of both active and passive tobacco smoke have been well-known in humans for a long time. It is presumable that even pets, which intimately share the owner's lifestyle, may be exposed to the same risks. This study aimed to detect and quantify cotinine (a metabolite of nicotine) in the serum and hair of dogs using a specific commercial ELISA immunoassay kit. A total of 32 dogs, 16 exposed and 16 unexposed to the owner's smoke, were enrolled. The cotinine concentration was higher in the exposed than the unexposed group in both matrices (p < 0.001), with greater values in serum than in hair (p < 0.001). Exposed bitches had higher hair cotinine than male dogs (p < 0.001). Conversely, serum and fur cotinine concentrations were lower in female than male dogs of the unexposed group (p < 0.01). The exposure intensity, age, and weight of the dogs did not affect cotinine concentrations. A cut-off value of 2.78 ng/mL and 1.13 ng/mL cotinine concentration in serum and fur, respectively, was estimated to distinguish between the exposed and unexposed dogs. Cotinine was confirmed as a valuable marker of passive smoking also in dogs. Although owners do not perceive secondhand smoke as a risk for their dogs, greater awareness should be advisable, especially in pregnant animals.

Differences between Self-Report and Biomarkers in Smoking Indicators: The Necessity of Biomonitoring in Global Surveillance

Tobacco causes premature death through cardiovascular disease, cancer, and respiratory disease [...].

Time trend of exposure to secondhand tobacco smoke and polycyclic aromatic hydrocarbons between 1995 and 2019 in Germany - Showcases for successful European legislation

Starting in 2002, regulations and legislative amendments in Germany focused on the non-smoker protection with several measures to reduce exposure to secondhand tobacco smoke (SHS). The present work aimed to evaluate the relationship between polycyclic aromatic hydrocarbons (PAHs) and SHS exposure and to determine to which extent enforced non-smoking regulations and smoking bans affected the exposure of the non-smoking population in Germany since their implementation in the early 2000s until today. For this purpose, cotinine and selected monohydroxylated PAHs (OH-PAHs) were analyzed by means of (UP)LC-MS/MS in 510 24-h-urine samples of the Environmental Specimen Bank collected over a time span of 24 years from 1995 to 2019. Median urinary cotinine levels were found to steadily and significantly decline by 82% from 1995 to 2019. A significant decrease of urinary 3-hydroxybenzo[a]pyrene (19%), 1-OH-pyrene (39%), 1-naphthol (66%), 1- (17%), 2- (25%), and 3-OH-phenanthrene (22%) was also observed throughout the same time span. The decline in urinary levels of cotinine and several OH-PAHs can most likely be attributed to smoking bans and regulations limiting SHS and PAH exposure. This study therefore emphasizes the relevance of human biomonitoring to investigate the exposure of humans to chemicals of concern, assess the effectiveness of regulatory measures, and help policies to enforce provisions to protect public health.

Association between cigarette smoking and ovarian reserve among women seeking fertility care

INTRODUCTION

This study examined the association of smoking with ovarian reserve in a cross-sectional study of 207 women enrolled in the Louisville Tobacco Smoke Exposure, Genetic Susceptibility, and Infertility (LOUSSI) Study and assessed effect modification by NAT2 acetylator phenotype.

METHODS

Information on current smoking status was collected using a structured questionnaire and confirmed by cotinine assay. Serum anti-Müllerian hormone (AMH) levels were used to assess ovarian reserve. Diminished ovarian reserve (DOR) was defined as AMH <1ng/mL. Single nucleotide polymorphisms in the NAT2 gene, which metabolizes toxins found in cigarette smoke, were analyzed to determine NAT2 acetylator status. Linear and logistic regression were used to determine the effects of smoking on ovarian reserve and evaluate effect modification by NAT2. Regression analyses were stratified by polycystic ovary syndrome (PCOS) status and adjusted for age.

RESULTS

Current smoking status, either passive or active as measured by urinary cotinine assay, was not significantly associated with DOR. For dose-response assessed using self-report, the odds of DOR increased significantly for every additional cigarette currently smoked (Odds ratio, OR:1.08; 95% confidence interval, 95%CI:1.01-1.15); additionally, every 1 pack-year increase in lifetime exposure was associated with an increased odds of DOR among women without PCOS (OR: 1.08 95%CI: 0.99-1.18). These trends appear to be driven by the heavy or long-term smokers. Effect modification by NAT2 genotype was not established.

CONCLUSION

A history of heavy smoking may indicate increased risk of diminished ovarian reserve.

Gender differences in the association between biomarkers of environmental smoke exposure and developmental disorders in children and adolescents

Effects of environmental tobacco smoke (ETS) exposure on children and adolescent health outcomes have been attracted more and more attention. In the present study, we seek to examine the gender-specific difference association of environmental smoke exposure biomarkers and developmental disorders in children and adolescents aged 6-15 years. US nationally representative sample collected from the National Health and Nutrition Examination Survey (NHANES) 2007-2014 was enrolled (N = 4428). Developmental disorders (DDs) are defined as a positive answer to the question, "Does your child receive special education or early intervention services?" Serum cotinine and urinary 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) were utilized as acute and chronic exposure biomarkers of ETS, respectively. Participants with serum cotinine >0.015 ng/mL were considered as with acute ETS exposure, and participants with creatinine-adjusted NNAL >0.0006 ng/mL were considered as with chronic ETS exposure. A survey logistic regression model was used to estimate the association between ETS exposure biomarkers and DDs. Additive interaction was utilized to examine the interaction of gender and biomarkers of ETS. Overall, approximately 9% of children were defined as DDs, and 65% of children had serum cotinine and urinary NNAL levels above the limit of detection. In the adjusted models, the association of ETS exposure biomarkers with DDs was only observed in girls. Girls with low cotinine levels and high urinary NNAL levels had 2.074 (95% CI: 1.012-4.247) and 1.851 (95% CI: 1.049-3.265) times higher odds of being DDs than those without ETS exposure, respectively. However, the effects of boys and NNAL exposure on DDs have additively interacted. Our findings first provided strong evidence for gender differences in the association between two tobacco metabolites and DDs in children, disclosing the public health implications and economic burdens of environmental tobacco smoke exposure.

Development of LC-HRMS untargeted analysis methods for nasal epithelial lining fluid exposomics

BACKGROUND

The nasal mucosa, as a primary site of entry for inhaled substances, contains both inhaled xenobiotic and endogenous biomarkers. Nasal mucosa can be non-invasively sampled (nasal epithelial lining fluid "NELF") and analyzed for biological mediators. However, methods for untargeted analysis of compounds inhaled and/or retained in the nasal mucosa are needed.

OBJECTIVES

This study aimed to develop a high resolution LC-MS untargeted method to analyze collected NELF. Profiling of compounds in NELF samples will also provide baseline data for future comparative studies to reference.

METHODS

Extracted NELF analytes were injected to LC-ESI-MS. After spectrum processing, an in-house library provided annotations with high confidence, while more tentative annotation proposals were obtained via ChemSpider database matching.

RESULTS

The established method successfully detected unique molecular signatures within NELF. Baseline profiling of 27 samples detected 2002 unknown molecules, with 77 and 463 proposed structures by our in-house library and Chemspider matching. High confidence annotations revealed common metabolites and tentative annotations implied various environmental exposure biomarkers are also present in NELF.

SIGNIFICANCE

The experimental pipeline for analyzing NELF samples serves as simple and robust method applicable for future studies to characterize identities/effects of inhaled substances and metabolites retained in the nasal mucosa.

IMPACT STATEMENT

The nasal mucosa contains exogenous and endogenous compounds. The development of an untargeted analysis is necessary to characterize the nasal exposome by deciphering the identity and influence of inhaled compounds on nasal mucosal biology. This study established a high resolution LC-MS based untargeted analysis of non-invasively collected nasal epithelial lining fluid. Baseline profiling of the nasal mucosa (n = 27) suggests the presence of environmental pollutants, along with detection of endogenous metabolites. Our results show high potential for the analytical pipeline to facilitate future respiratory health studies involving inhaled pollutants or pharmaceutical compounds and their effects on respiratory biology.

Development of an Ultra-High Performance Liquid Chromatography method for the simultaneous mass detection of tobacco biomarkers in urine

The quantification of tobacco exposure biomarkers is relevant to follow the patients' tobacco use. They allow to discriminate between tobacco users, non-users, passive smokers, and nicotine products users, such as in nicotine replacement therapy. The aim of this study was to develop and validate a quantification method of tobacco biomarkers of choice - nicotine, cotinine, trans-3'-hydroxycotinine, anatabine and anabasine - in urine. The challenge was to develop an easy and rapid liquid chromatography method requiring only one extraction step and allowing simultaneous detections. Some methods are described in the literature but need specific investment in terms of instrumentation and users training. Here, the developed method had to be carried out with instrumentation easily accessible for medical laboratories. The extraction of the analytes was performed by Supported Liquid Extraction (SLE), which consists in liquid-liquid extraction but supported by a sorbent. It allows to insure efficient neutrals extraction with less organic solvent and without any emulsion formation. 200 µl of basified urine - analytes of interest are neutral in this condition - were loaded on Novum SLE 96-Well Plates (Phenomenex) and analytes were eluted with 1 % formic acid in dichloromethane/propan-2-ol (95/5). After solvent evaporation, samples were reconstituted with 100 µl of water for injection. A mass detector (QDa, Waters) was used to detect analytes, this pre-optimised quadrupole mass analyser being less expensive and requiring less adjustments than traditional mass spectrometers while benefiting of the reliability of mass spectral data. This detector was integrated after an Ultra-high performance liquid chromatography (UHPLC) separation on a BEH C18 column (Waters) at a flow rate of 0.5 ml/min. A gradient elution of H₂O (pH 10 with NH₄OH) and CH₃CN was used. Finally, the developed method was validated. This new method is conclusive to assess the patients' tobacco exposure and is easy to implement in medical laboratories.

Thirdhand Exposures to Tobacco-Specific Nitrosamines through Inhalation, Dust Ingestion, Dermal Uptake, and Epidermal Chemistry

Tobacco-specific nitrosamines (TSNAs) are emitted during smoking and form indoors by nitrosation of nicotine. Two of them, N'-nitrosonornicotine (NNN) and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), are human carcinogens with No Significant Risk Levels (NSRLs) of 500 and 14 ng day-1, respectively. Another TSNA, 4-(methylnitrosamino)-4-(3-pyridyl) butanal (NNA), shows genotoxic and mutagenic activity in vitro. Here, we present additional evidence of genotoxicity of NNA, an assessment of TSNA dermal uptake, and predicted exposure risks through different pathways. Dermal uptake was investigated by evaluating the penetration of NNK and nicotine through mice skin. Comparable mouse urine metabolite profiles suggested that both compounds were absorbed and metabolized via similar mechanisms. We then investigated the effects of skin constituents on the reaction of adsorbed nicotine with nitrous acid (epidermal chemistry). Higher TSNA concentrations were formed on cellulose and cotton substrates that were precoated with human skin oils and sweat compared to clean substrates. These results were combined with reported air, dust, and surface concentrations to assess NNK intake. Five different exposure pathways exceeded the NSRL under realistic scenarios, including inhalation, dust ingestion, direct dermal contact, gas-to-skin deposition, and epidermal nitrosation of nicotine. These results illustrate potential long-term health risks for nonsmokers in homes contaminated with thirdhand tobacco smoke.

Study protocol of a multiphase optimization strategy trial (MOST) for delivery of smoking cessation treatment in lung cancer screening settings

BACKGROUND

There is widespread agreement that the integration of cessation services in lung cancer screening (LCS) is essential for achieving the full benefits of LCS with low-dose computed tomography (LDCT). There is a formidable knowledge gap about how to best design feasible, effective, and scalable cessation services in LCS facilities. A collective of NCI-funded clinical trials addressing this gap is the Smoking Cessation at Lung Examination (SCALE) Collaboration.

METHODS

The Cessation and Screening to Save Lives (CASTL) trial seeks to advance knowledge about the reach, effectiveness, and implementation of tobacco treatment in lung cancer screening. We describe the rationale, design, evaluation plan, and interventions tested in this multiphase optimization strategy trial (MOST). A total of 1152 screening-eligible current smokers are being recruited from 18 LCS sites (n = 64/site) in both academic and community settings across the USA. Participants receive enhanced standard care (cessation advice and referral to the national Quitline) and are randomized to receive additional tobacco treatment components (motivational counseling, nicotine replacement patches/lozenges, message framing). The primary outcome is biochemically validated, abstinence at 6 months follow-up. Secondary outcomes are self-reported smoking abstinence, quit attempts, and smoking reduction at 3 and 6 months. Guided by the Implementation Outcomes Framework (IOF), our evaluation includes measurement of implementation processes (reach, fidelity, acceptability, appropriateness, sustainability, and cost).

CONCLUSION

We will identify effective treatment components for delivery by LCS sites. The findings will guide the assembly of an optimized smoking cessation package that achieves superior cessation outcomes. Future trials can examine the strategies for wider implementation of tobacco treatment in LDCT-LCS sites.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03315910.

Association between objective measures and parent-reported measures of child tobacco smoke exposure: A secondary data analysis of four trials

INTRODUCTION

Tobacco smoke exposure (TSE) harms children and adults. Studies of childhood TSE exposure often relies on parental reports, but may benefit from objective measures. The objective of our study was to study the relationship between reported and objective measures of TSE.

METHODS

We analyzed data from four intervention trials, conducted in clinical or community settings, to identify objective measures most closely associated with parent-reported measures and the optimal set of parent-reported measures for predicting objective measures. We also assessed whether there was a learning curve in reported exposure over time, and the importance of replicate biomarker measures.

RESULTS

Correlations between objective and parent-reported measures of child TSE were modest at best, ranging from zero to 0.41. Serum cotinine and urinary cotinine were most strongly associated with parental reports. Parental questions most closely related to biomarkers were number of cigarettes and home smoking rules; together these formed the best set of predictive questions. No trial included all objective measures and all questions, precluding definitive statements about relative advantages. Within-subject repeatability of biomarker measures varied across studies, suggesting that direct pilot data are needed to assess the benefit of replicate measurements.

CONCLUSIONS

Improvements in objective and parent-reported child exposure measurements are needed to accurately monitor child TSE, evaluate efforts to reduce such exposure, and better protect child health.

An in Vitro Study of Constituents Released from Smokeless Tobacco Products into Human Saliva

Smokeless tobacco (ST) products are used worldwide, and consumption is increasing in the USA. Although ST products are considered to occupy a different position on the tobacco product continuum of risk compared to combusted tobacco products, they can still lead to health problems, including cancer, dental problems and changes in heart rate and blood pressure. Therefore, the determination of harmful and potentially harmful constituents released from ST products into human saliva is important. Four certified reference ST products were tested in this study: loose leaf chewing tobacco (3S1), Swedish-style snus (1S4), snus (1S5) and moist snuff (3S3). These certified reference ST products are manufactured for research purposes, not for human consumption. The reference ST products were used in this study because they have been well characterized and are intended and designed to represent commercial ST products. The reference ST products were incubated in human saliva at 37°C with a range of incubation times for the evaluation of constituents released from these products into human saliva. In this study, alkaloids (nicotine and cotinine), tobacco-specific N-nitrosamines (TSNAs) (N'-nitrosornicotine and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone) and benzo[α]pyrene (B[α]P) in the reference ST products and saliva samples were determined by gas chromatography--mass spectrometry (GC--MS), gas chromatography--flame ionization detection (GC--FID), or ultra-performance liquid chromatography--tandem mass spectrometry (UPLC--MS-MS). Our results indicate that the amounts of each constituent released from the reference ST products were altered by the tobacco cut size and product format (pouched or unpouched). The constituents (TSNAs and alkaloids) in moist snuff and loose leaf chewing tobacco were released faster compared to those in Swedish-style snus and snus. B[α]P was only detected in reference moist snuff samples, and only 3.4% of the total B[α]P was released into human saliva after incubation for 60 min, whereas higher percentages of total TSNAs and alkaloids were released at different rates from the four reference ST products.

Assessment of passive human exposure to tobacco smoke by environmental and biological monitoring in different public places in Wuhan, central China

Passive exposure to tobacco smoke is a global public health problem, while there are few data on public place monitoring and general population exposure assessment in central China. This study aimed to examine the levels of airborne nicotine (n = 256) in ten kinds of different public places in Wuhan, central China, and assess short-term and long-term smoke exposure in 340 non-smokers aged 18-67 who worked in these public places using tobacco biomarkers [i.e., cotinine and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), respectively]. The highest median concentration of airborne nicotine (17.0 μg/m3) was observed in internet cafes, approximately 304-fold of the lowest value found in nurseries (55.9 ng/m3). Among the other studied public places, restaurants had the highest median concentrations (ng/m3) of airborne nicotine (3,120), followed by subway stations (810), hotels (624), government officess (286), middle schools (269), health institutions (268), public institutions (190), and primary schools (140). Urinary cotinine and NNAL were found in almost all the participants, and the highest concentrations were found in non-smokers from the internet cafes [specific gravity (SG)-corrected urinary median concentrations: 23.1 ng/mL, geometric mean (GM): 24.1 ng/mL, range: 0.62-1679 ng/mL] for cotinine and 104 pg/mL (GM: 97.6 pg/mL, range: 32.3-236 pg/mL) for NNAL, respectively]. Urinary cotinine concentrations in male non-smokers (median: 2.02 ng/mL) were significantly higher than those in female non-smokers (1.44) (P < 0.01). Participants aged 18-27 were detected with the highest urinary cotinine and NNAL concentrations. Urinary cotinine and NNAL concentrations were significantly correlated with daily and monthly working hours, respectively. Besides, a positive correlation was observed between log-transformed urinary concentrations of cotinine and NNAL (r = 0.32, P < 0.001). This is the first time to report matched data on airborne nicotine and urinary cotinine/NNAL among employees in different public places. This study demonstrated ubiquitous exposure to environmental tobacco smoke in the studied public places.

Association Between Place of Secondhand Smoke Exposure and Depression Among Nonsmoking Children and Adolescents: A Systematic Review

Secondhand smoke (SHS) exposure patterns of children and adolescents are different from those of adults because children and adolescents spend a majority of their time in the home and school. It was aimed to conduct a systematic review of the published literature regarding the association between depression and the place of SHS exposure among children and adolescents. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) reporting guidelines, PubMed, ScienceDirect, and Cochrane Library databases were used for the literature review. The studies were screened and selected by two independent reviewers based on the inclusion criteria. All eight studies included in the systematic review measured SHS exposure in participants' own homes. Two studies measured SHS exposure at school and one study in cars. The majority of the studies showed a positive association between depression and SHS exposure in both private and public places among nonsmoking children and adolescents. Also, they concluded a dose-response relationship between SHS exposure and depression. Health practitioners would be encouraged to work with stakeholders to create smoke-free policies in both private and public places to avoid the adverse effects of SHS exposure.

Secondhand smoke exposure in school children in Malta assessed through urinary biomarkers

School children may be exposed to secondhand smoke (SHS) either at home, in transit or in social gatherings permitting smoking in their presence. Questionnaires about SHS often underestimate prevalence and extent of exposure. A more accurate tool is the use of biomarkers such as cotinine (COT) and trans-3'-hydrocycotinine (3HC) as biomarkers of SHS exposure, alongside 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), a reduction product in the body of the tobacco-specific nitrosamine, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), both potent carcinogens. We measured urinary COT, 3HC and total NNAL using sensitive and specific high-performance LC-MS/MS methods. The limit of quantification (LOQ) for each assay were 0.05 ng/mL, 0.1 ng/mL and 0.25 pg/mL respectively. The aim of this study was to evaluate the exposure to SHS of school children (9-11 years), from five public schools in the island of Malta, from questionnaire information about smoking at home and verify it by urinary biomarker data of COT, 3HC and NNAL. These biomarkers were measurable in 99.4%, 95.4% and 98.3% of the participating children respectively. From the children reporting smoking at home, 11% had a history of asthma and had COT, 3HC and NNAL geometric mean concentrations double compared to the non-asthmatic group. In has been confirmed that non-smokers exposed to SHS and THS have a higher NNAL/COT ratio than the group identified as smokers according to specific and defined COT threshold levels (despite the fact that a priori, the entire study group was composed of non-smokers). The implication of high measured levels of urinary NNAL in children should be of concern given its potency. A main effects multifactor ANOVA model was developed and the children's house and school locations and the smoking frequency were statistically significant to predict the levels of the three metabolites. For 3HC only, the status of the employment of the mother was also an important predictor.

Review of HPLC-MS methods for the analysis of nicotine and its active metabolite cotinine in various biological matrices

In recent years, tobacco smoking is a risk factor for a series of diseases including cardiovascular diseases, cerebrovascular diseases, and cancers. Nicotine, the primary component of tobacco smoke, is mainly transformed to its active metabolite cotinine, which is often used as biomarker for tobacco exposure for its higher blood concentration and longer residence time than nicotine. Various analytical methods have been developed for the determination of nicotine and cotinine in biological matrices. This article reviewed the HPLC-MS based methods for nicotine and/or cotinine analysis in various biological matrices. The sample preparation, mass and chromatographic conditions and method validation results of these methods have been summarized and analyzed. Sample was mainly pretreated by protein precipitation and/or extraction. Separation was achieved using methanol and/or acetonitrile:water (with or without ammonium acetate) on C18 columns, and acetonitrile:water (with formic acid, ammonium acetate/formate) on HILIC columns. Nicotine-d3, nicotine-d4 and cotinine-d3 were commonly used internal standards. Other non-deuterated IS were also used such as ritonavir, N-ethylnorcotinine, and milrinone. For both nicotine and cotinine, the calibration range was 0.005-35000 ng/mL, the matrix effect was 75.96% - 126.8% and the recovery was 53% - 124.5%. The two analytes were stable at room temperature for 1-10 days, at -80 °C for up to 6 months, and after 3-6 freeze-thaw cycles. Comedications did not affect nicotine and cotinine analysis.

Hair and nail nicotine levels of mothers and their infants as valid biomarkers of exposure to intrauterine tobacco smoke

INTRODUCTION

Tobacco use remains the single most modifiable cause of adverse pregnancy outcomes. It is crucial to be able to accurately quantify the burden of tobacco exposure on both the mother and fetus to have better measures of efficacy with interventions being studied.

METHODS

This is a descriptive and exploratory study conducted within a randomized controlled trial. Pregnant smoking and non-smoking women were followed from ≤22 weeks' gestation through delivery with monthly maternal smoking questionnaires, urine cotinine levels, and collection of maternal and infant hair and nail samples, at delivery. Nicotine was extracted and measured (ng/mg) using high-performance liquid chromatography with electrochemical detection.

RESULTS

Forty-six mother-infant dyads (34 pregnant smokers and 12 pregnant non-smokers) had successful completion of maternal and infant hair and nails samples. The median hair nicotine levels of the smoking mothers and their infants was significantly higher than those of the non-smokers (1.015 vs 0.037 ng/ mg, p<0.05 for the mothers; 0.445 vs 0.080 ng/mg, p<0.01 for the infants). Similarly, the median nail nicotine levels for smoking mothers and their infants were significantly higher than the non-smokers (2.130 vs 0.056 ng/mg, p<0.01 for the mothers; 0.594 vs 0.132 ng/mg, p<0.05 for the infants). We found a moderate but significant correlation between maternal hair and nail nicotine (r=0.64, p<0.001), infant hair and nail nicotine (r=0.64; p<0.001), maternal and infant hair nicotine (r=0.61, p<0.001), and maternal and infant nail nicotine levels (r=0.58, p<0.001).

CONCLUSIONS

Our study shows that both infant hair and nail nicotine levels are valid biomarkers of intrauterine tobacco smoke exposure, and can be used to identify prenatal smoke exposure, correlating well with the level of maternal nicotine exposure.

Urinary cotinine assessment of maternal smoking and environmental tobacco smoke exposure status and its associations with perinatal outcomes: a cross-sectional birth study

Tobacco consumption and environmental tobacco smoke (ETS) exposure remains an important public health concern. Pregnant women require particular attention as active and passive smoking during pregnancy are associated with multiple adverse perinatal outcomes. This study aimed to biochemically validate self-reported smoking and ETS exposure status among pregnant women, to more precisely ascertain its association with adverse perinatal outcomes. Data refers to 595 pregnant women who sought prenatal care in a public hospital in Porto, Portugal. A standard questionnaire on smoking and ETS-related variables was completed. Urinary cotinine (UC) concentrations were assessed by solid-phase competitive ELISA, in maternal urine samples collected on the day of delivery. The results showed that the optimal UC cut-off value to distinguish smokers from non-smokers and within non-smokers those who were exposed to ETS from those non-exposed in the third trimester of pregnancy was 74.1 ng/mL (sensitivity and specificity of 96.7% and 98.0%, respectively) and 1.6 ng/mL (sensitivity of 66.2% and specificity of 75.7%, respectively). The agreement between maternal self-reported and UC-based smoking status was very good (κ=0.919, p<0.001), but much lower for ETS exposure (κ=0.386, p<0.001). Maternal active smoking in the third trimester of pregnancy was associated with a significant decrease in birth weight, length and head circumference of 157.66 g (95% CI: -245.81, -69.52; p<0.001), 0.78 cm (95% CI: -1.22, -0.34; p=0.001) and 0.39 cm (95% CI: -0.70, -0.07; p=0.016), respectively. Maternal ETS exposure in the third trimester of pregnancy was associated with a non-significant increase in birth weight of 38.37 g (95% CI: -28.91, 105.64; p=0.263). Furthermore, maternal smoking cessation was associated with the increase of approximately 172 g in birth weight (95% CI: 50.00, 293.19). As such, there is an urgent need for increased public health awareness campaigns to encourage smoking cessation during pregnancy, in order to improve perinatal outcomes.

Risk Assessment of Passive Smoking Based on Analysis of Hair Nicotine and Cotinine as Exposure Biomarkers by In-Tube Solid-Phase Microextraction Coupled On-Line to LC-MS/MS

Passive smoking due to environmental tobacco smoke is a serious public health concern because it increases the risk of lung cancer and cardiovascular disease. However, the current status and effect of passive smoking in various lifestyles are not fully understood. In this study, we measured hair nicotine and cotinine levels as exposure biomarkers in non-smokers and assessed the risk from the actual situation of passive smoking in different lifestyle environments. Nicotine and cotinine contents in hair samples of 110 non-smoker subjects were measured by in-tube solid-phase microextraction with on-line coupling to liquid chromatography-tandem mass spectrometry, and self-reported lifestyle questionnaires were completed by the subjects. Nicotine and cotinine were detected at concentrations of 1.38 ng mg⁻¹ and 12.8 pg mg⁻¹ respectively in the hair of non-smokers, with levels significantly higher in subjects who reported being sensitive to tobacco smoke exposure. These levels were also affected by type of food intake and cooking method. Nicotine and cotinine in hair are useful biomarkers for assessing the effects of passive smoking on long-term exposure to environmental tobacco smoke, and our analytical methods can measure these exposure levels in people who are unaware of passive smoking. The results of this study suggest that the environment and places of tobacco smoke exposure and the lifestyle behaviors therein are important for the health effects of passive smoking.

Comparison of Levels of Three Tobacco Smoke Exposure Biomarkers in Children of Smokers

Objectives: Cotinine, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), and N-oxides are biomarkers of tobacco smoke exposure (TSE) used to assess short- and longer-term TSE. The objective of this study was to assess the associations between these TSE biomarkers, sociodemographics, parental smoking, and child TSE patterns among 0–17-year-olds. Methods: A convenience sample of 179 pediatric patients (mean (SD) age = 7.9 (4.3) years) who lived with ≥1 smoker and who had parental assessments completed and urine samples analyzed for the three TSE biomarkers of interest were included. Biomarker levels were log-transformed, univariate regression models were built and Pearson correlations were assessed. Results: In total, 100% of children had detectable levels of cotinine and >96% had detectable NNAL and N-oxide levels. The geometric means of cotinine, NNAL, and N-oxide levels were 10.1 ng/mL, 25.3 pg/mL, and 22.9 pg/mL, respectively. The mean (SD) number of daily cigarettes smoked by parents was 10.6 (6.0) cigarettes. Child age negatively correlated with urinary cotinine (r = −0.202, p = 0.007) and log NNAL levels (r = −0.275, p < 0.001). The highest log-cotinine levels were in children who were younger, of African American race, and whose parents had a lower education, an annual income ≤USD15,000, and no smoking bans. The highest log-NNAL and N-oxide levels were in children whose parents had a lower education, had no smoking bans, and were around higher numbers of cigarettes. Conclusion: Children of smokers who were younger, African American, and had no smoking bans had the highest TSE biomarker levels. Targeted interventions are needed to reduce TSE levels among high-risk children.

Association between urine cotinine and depressive symptoms in non-smokers: National representative sample in Korea

BACKGROUND

Secondhand smoke (SHS) exposure is known to have negative effects on mental as well as physical health. However, the association between SHS and mental health problems has not been assessed in non-smokers. To evaluate the association of exposure to tobacco smoke and depressive symptoms, and that of the prevalence of having depressive symptoms and urinary cotinine (UCo) concentrations in non-exposed subjects.

METHODS

Data was extracted from the Korea National Health and Nutrition Examination Survey (KNHANES). Depressive symptoms were determined based on a patient's overall score on the Patient Health Questionnaire (PHQ)-9, and SHS exposure was evaluated using self-reported data and UCo concentration. Overall, 13,219 non-smokers, ≥ 19 years were included in the study. Multinomial logistic regression analysis was conducted to identify factors related to depressive symptoms; independent t-test was conducted to confirm the differences in UCo concentration according to the prevalence of depression.

RESULTS

Among the non-exposure groups, 2.0% of the males and 5.6% of the females showed depressive symptoms. Lower social-economic status, higher UCo concentration, and SHS exposure increased the prevalence of depressive symptoms. The UCo concentration of females with depressive symptoms was significantly higher than those of females without depressive symptoms.

LIMITATIONS

This study only demonstrated an association between SHS exposure and depression, not the causal effects, because of the cross-sectional study design.

CONCLUSION

SHS exposure and depressive symptoms are correlated. The association was also confirmed by evaluating the UCo concentration of those who were not exposed to SHS based on self-reported data.

Differential associations of hand nicotine and urinary cotinine with children's exposure to tobacco smoke and clinical outcomes

BACKGROUND

Children's overall tobacco smoke exposure (TSE) consists of both inhalation of secondhand smoke (SHS) and ingestion, dermal uptake, and inhalation of thirdhand smoke (THS) residue from dust and surfaces in their environments.

OBJECTIVES

Our objective was to compare the different roles of urinary cotinine as a biomarker of recent overall TSE and hand nicotine as a marker of children's contact with nicotine pollution in their environments. We explored the differential associations of these markers with sociodemographics, parental smoking, child TSE, and clinical diagnoses.

METHODS

Data were collected from 276 pediatric emergency department patients (Median age = 4.0 years) who lived with a cigarette smoker. Children's hand nicotine and urinary cotinine levels were determined using LC-MS/MS. Parents reported tobacco use and child TSE. Medical records were reviewed to assess discharge diagnoses.

RESULTS

All children had detectable hand nicotine (GeoM = 89.7ng/wipe; 95 % CI = [78.9; 102.0]) and detectable urinary cotinine (GeoM = 10.4 ng/ml; 95%CI = [8.5; 12.6]). Although hand nicotine and urinary cotinine were highly correlated (r = 0.62, p < 0.001), urinary cotinine geometric means differed between racial groups and were higher for children with lower family income (p < 0.05), unlike hand nicotine. Independent of urinary cotinine, age, race, and ethnicity, children with higher hand nicotine levels were at increased risk to have discharge diagnoses of viral/other infectious illness (aOR = 7.49; 95%CI = [2.06; 27.24], p = 0.002), pulmonary illness (aOR = 6.56; 95%CI = [1.76; 24.43], p = 0.005), and bacterial infection (aOR = 5.45; 95%CI = [1.50; 19.85], p = 0.03). In contrast, urinary cotinine levels showed no associations with diagnosis independent of child hand nicotine levels and demographics.

DISCUSSION

The distinct associations of hand nicotine and urinary cotinine suggest the two markers reflect different exposure profiles that contribute differentially to pediatric illness. Because THS in a child's environment directly contributes to hand nicotine, additional studies of children of smokers and nonsmokers are warranted to determine the role of hand nicotine as a marker of THS exposure and its potential role in the development of tobacco-related pediatric illnesses.

Defining the Scope of Exposome Studies and Research Needs from a Multidisciplinary Perspective

The concept of the exposome was introduced over 15 years ago to reflect the important role that the environment exerts on health and disease. While originally viewed as a call-to-arms to develop more comprehensive exposure assessment methods applicable at the individual level and throughout the life course, the scope of the exposome has now expanded to include the associated biological response. In order to explore these concepts, a workshop was hosted by the Gunma University Initiative for Advanced Research (GIAR, Japan) to discuss the scope of exposomics from an international and multidisciplinary perspective. This Global Perspective is a summary of the discussions with emphasis on (1) top-down, bottom-up, and functional approaches to exposomics, (2) the need for integration and standardization of LC- and GC-based high-resolution mass spectrometry methods for untargeted exposome analyses, (3) the design of an exposomics study, (4) the requirement for open science workflows including mass spectral libraries and public databases, (5) the necessity for large investments in mass spectrometry infrastructure in order to sequence the exposome, and (6) the role of the exposome in precision medicine and nutrition to create personalized environmental exposure profiles. Recommendations are made on key issues to encourage continued advancement and cooperation in exposomics.

Nicotine metabolism predicted by CYP2A6 genotypes in relation to smoking cessation: A systematic review

INTRODUCTION

Identifying genetic factors associated with smoking cessation could inform precision cessation interventions. Of major interest is genetic variation in nicotine metabolism, largely predicted by CYP2A6 variations.

METHODS

We conducted a systematic literature review to summarize the population-based evidence of the association between CYP2A6 and smoking cessation.In the 12 studies meeting the inclusion criteria, the known functional metabolic effect of CYP2A6 variants was used to classify nicotine metabolism as normal (>75% metabolic activity), intermediate (50.1 - 75% activity), slow (25 - 50% activity), and poor (<25% activity). Summary odds ratios of smoking cessation were calculated across metabolic groups, stratified by ancestry and whether participants received pharmacotherapy or placebo/no treatment.

RESULTS

Among untreated people of European ancestry (n = 4 studies), those with CYP2A6 reduced metabolism were more likely to quit smoking than those with normal metabolism [Summary OR = 2.05, 95% CI 1.23 - 3.42] and the likelihood of cessation increased as nicotine metabolism decreased. Nicotine replacement therapy attenuated the association at end-of-treatment, while bupropion modified the association such that intermediate/slow metabolizers were less likely to quit than normal metabolizers [Summary OR = 0.86, 95% CI 0.79 - 0.94]. Among untreated Asian people (n = 3 studies), results differed compared to those with European ancestry: those with slow metabolism were less likely to have quit smoking than normal metabolizers [Summary OR = 0.52, 95% CI 0.38 - 0.71]. Evidence for people of African ancestry (n = 1 study) suggested the CYP2A6 association with cessation may differ compared to those of European ancestry.

IMPLICATIONS

Most studies included in this review were of European ancestry populations; these showed slower nicotine metabolism was associated with increased likelihood of smoking cessation in a dose-related manner. Pharmacotherapy appeared to attenuate or modify this association among people of European ancestry, but it is unclear whether the change in the association remains consistent after treatment ceases. This finding has implications for precision medicine cessation interventions. Based on only a few studies of people of Asian or African ancestry, the association between CYP2A6 variants and cessation may differ from that observed among those of European ancestry, but more evidence is needed.