Methods for quantification of exposure to cigarette smoking and environmental tobacco smoke: focus on developmental toxicology

Development in competitive immunoassay of a point-of-care testing for cotinine (COT) detection in urine

We present a sensitive and selective lateral flow immunoassay (LFIA) for cotinine (COT), the primary metabolite of nicotine. COT is widely recognized as a superior biomarker to evaluate tobacco smoke exposure. The LFIA uses a competitive assay format where the COT-BSA capture competes with the target COT in urine samples for binding to the monoclonal antibody against COT (mAb-COT) conjugated with gold nanoparticles (mAb-COT-AuNPs). To improve the sensitivity and selectivity of the LFIA-COT, we focused on optimizing the diameter of AuNPs, the conjugation of mAb-COT, and the concentration of the COT-BSA capture. Our findings reveal that the utilization of 40 nm AuNPs in conjugation with a concentration of 4 mg mL-1 of mAb-COT demonstrated significantly greater efficacy compared to LFAs utilizing 20 nm AuNPs. Under the optimal conditions, the LFIA-COT demonstrated sensitive detection of COT at a level of 150 ng mL-1 within 15 min, as observed by the naked eye. It possesses a linear range of 25 to 200 ng mL-1 of COT, with the limit of detection (LOD) of 11.94 ng mL-1 in human urine samples when the color intensity is analyzed using ImageJ software. Our LFIA described here is simple and requires less time for COT detection. It can be used for the rapid and quantitative detection of COT in urine samples in clinical settings.

The rat as an animal model in chronic wound research: An update

The increasing global prevalence of chronic wounds underscores the growing importance of developing effective animal models for their study. This review offers a critical evaluation of the strengths and limitations of rat models frequently employed in chronic wound research and proposes potential improvements. It explores these models in the context of key comorbidities, including diabetes, venous and arterial insufficiency, pressure-induced blood flow obstruction, and infections. Additionally, the review examines important wound factors including age, sex, smoking, and the impact of anesthetic and analgesic drugs, acknowledging their substantial effects on research outcomes. A thorough understanding of these variables is crucial for refining animal models and can provide valuable insights for future research endeavors.

Association between secondhand smoke exposure and serum sex hormone concentrations among US female adults: a cross-sectional analysis using data from the National Health and Nutrition Examination Survey, 2013-2016

OBJECTIVE

To estimate the association between secondhand smoke (SHS) exposure and serum sex hormone concentrations in female adults (never smokers and former smokers).

DESIGN

Cross-sectional analysis.

SETTING

US National Health and Nutrition Examination Survey, 2013-2016.

OUTCOME MEASURES

Serum sex hormone measures included total testosterone (TT) and oestradiol (E2), sex hormone-binding globulin (SHBG), the ratio of TT and E2 and free androgen index (FAI). Isotope dilution-liquid chromatography tandem mass spectrometry was used to measure serum TT and E2. SHBG was measured using immunoassay. The ratio of TT and E2 and FAI were calculated. SHS exposure was defined as serum cotinine concentration of 0.05-10 ng/mL.

PARTICIPANTS

A total of 622 female participants aged ≥20 years were included in the analysis.

RESULTS

For never smokers, a doubling of serum cotinine concentration was associated with a 2.85% (95% CI 0.29% to 5.47%) increase in TT concentration and a 6.29% (95% CI 0.68% to 12.23%) increase in E2 in fully adjusted models. The never smokers in the highest quartile (Q4) of serum cotinine level exhibited a 10.30% (95% CI 0.78% to 20.72%) increase in TT concentration and a 27.75% (95% CI 5.17% to 55.17%) increase in E2 compared with those in the lowest quartile (Q1). For former smokers, SHBG was reduced by 4.36% (95% CI -8.47% to -0.07%, p for trend=0.049) when the serum cotinine level was doubled, and the SHBG of those in Q4 was reduced by 17.58% (95% CI -31.33% to -1.07%, p for trend=0.018) compared with those in Q1.

CONCLUSION

SHS was associated with serum sex hormone concentrations among female adults. In never smokers, SHS was associated with increased levels of TT and E2. In former smokers, SHS was associated with decreased SHBG levels.

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.

Nicotine exposure from packaged cigarettes in tobacco retail settings

BACKGROUND

Although many studies on exposure to environmental tobacco smoke from passive smoking have been conducted, most of such studies have only focused on the chemicals produced by active combustion. The current study examined the extent to which uncombusted and packaged cigarettes in cigarette racks at retail stores diffuse airborne nicotine.

METHODS

Airborne nicotine samples were collected for 15 days on passive monitors mounted near the indoor cigarette racks (Point 1) and farthest point from the cigarette racks (Point 2) in tobacco retailer stores (N=95) in South Korea (5 months, data collection from January to May in 2022.

RESULTS

The average airborne nicotine level was 0.0908 ug/m3 at Point 1 and 0.0345 ug/m3 at Point 2. We found a positive correlation (r=0.647, p <0.001) in nicotine concentration between the two measurement points. The interior size of the target stores was positively correlated (r=0.334, p <0.001) with the within-store difference in nicotine concentration between the two measurement points. The airborne nicotine concentration at Point 1 was statistically significantly higher than at Point 2 (z=-2.326, p=0.020, effect size: 0.2215), especially at larger stores.

CONCLUSIONS

Our findings indicate that packaged, unopened, and uncombusted cigarettes in cigarette racks at tobacco retailers emits airborne nicotine, which is a previously unrecognized source of nicotine exposure. This result has implications for policy considerations, such as the potential installation of ventilation systems on cigarette racks or the exploration of alternative packaging methods.

Combined and sequential exposure to prenatal second hand smoke and postnatal maternal distress is associated with cingulo-opercular global efficiency and attention problems in school-age children

BACKGROUND

Prenatal exposure to secondhand (environmental) tobacco smoke (SHS) is associated with adverse neurodevelopmental outcomes, including altered functional activation of cognitive control brain circuitry and increased attention problems in children. Exposure to SHS is more common among Black youth who are also disproportionately exposed to socioeconomic disadvantage and concomitant maternal distress. We examine the combined effects of exposure to prenatal SHS and postnatal maternal distress on the global efficiency (GE) of the brain's cingulo-opercular (CO) and fronto-parietal control (FP) networks in childhood, as well as associated attention problems.

METHODS

Thirty-two children of non-smoking mothers followed in a prospective longitudinal birth cohort at the Columbia Center for Children's Environmental Health (CCCEH) completed magnetic resonance imaging (MRI) at ages 7-9 years old. GE scores were extracted from general connectivity data collected while children completed the Simon Spatial Incompatibility functional magnetic resonance imaging (fMRI) task. Prenatal SHS was measured using maternal urinary cotinine from the third trimester; postnatal maternal distress was assessed at child age 5 using the Psychiatric Epidemiology Research Interview (PERI-D). The Child Behavior Checklist (CBCL) measured Attention and Attention Deficit Hyperactivity Disorder (ADHD) problems at ages 7-9. Linear regressions examined the interaction between prenatal SHS and postnatal maternal distress on the GE of the CO or FP networks, as well as associations between exposure-related network alterations and attention problems. All models controlled for age, sex, maternal education at prenatal visit, race/ethnicity, global brain correlation, and mean head motion.

RESULTS

The prenatal SHS by postnatal maternal distress interaction term associated with the GE of the CO network (β = 0.673, Bu = 0.042, t(22) = 2.427, p = .024, D = 1.42, 95% CI [0.006, 0.079], but not the FP network (β = 0.138, Bu = 0.006, t(22) = 0.434, p = .668, 95% CI [-0.022, 0.033]). Higher GE of the CO network was associated with more attention problems (β = 0.472, Bu = 43.076, t(23) = 2.780, p = .011, D = 1.74, n = 31, 95% CI [11.024, 75.128], n = 31) and ADHD risk (β = 0.436, Bu = 21.961, t(29) = 2.567, p = .018, D = 1.81, 95% CI [4.219, 39.703], n = 30).

CONCLUSIONS

These preliminary findings suggest that sequential prenatal SHS exposure and postnatal maternal distress could alter the efficiency of the CO network and increase risk for downstream attention problems and ADHD. These findings are consistent with prior studies showing that prenatal SHS exposure is associated with altered function of brain regions that support cognitive control and with ADHD problems. Our model also identifies postnatal maternal distress as a significant moderator of this association. These data highlight the combined neurotoxic effects of exposure to prenatal SHS and postnatal maternal distress. Critically, such exposures are disproportionately distributed among youth from minoritized groups, pointing to potential pathways to known mental health disparities.

Cotinine concentrations in maternal serum and amniotic fluid during pregnancy and risk of testicular germ cell cancer in the offspring: A prospective nested case-control study

Maternal smoking in pregnancy may increase the risk of testicular germ cell cancer (TGCC) in offspring, but current evidence remains inconclusive. We performed a nested case-control study using cotinine measurements in maternal serum and amniotic fluid as a biomarker for tobacco exposure during pregnancy. A total of 654 males with maternal serum (n = 359, ncases/controls  = 71/288) and/or amniotic fluid (n = 295, ncases/controls  = 66/229) samples were included. Data on TGCC diagnoses and relevant covariates were derived from nationwide Danish health registries. Cotinine was quantified by liquid chromatography tandem mass spectrometry. An adapted cox regression model estimated the risk of TGCC considering active and inactive tobacco use defined according to cotinine concentrations of <, ≥15 ng/ml. Overall, the concentrations of cotinine were comparable in maternal serum and amniotic fluid (medianserum/amniotic fluid : 2.1/2.6 ng/ml). A strong statistically significant correlation was detected in 14 paired samples (Spearman rho: 0.85). Based on maternal serum cotinine concentrations, exposure to active tobacco use was not associated with risk of TGCC in offspring (HR 0.88, 95% CI 0.51; 1.52). Similarly, based on amniotic fluid cotinine concentrations, exposure to active tobacco use was not associated with risk of TGCC (HR 1.11, 95% CI 0.64; 1.95). However, different risks were observed for seminomas and nonseminomas in both matrices, but none were statistically significant. Our findings did not provide convincing evidence supporting that exposure to tobacco during pregnancy is associated with TGCC.

Secondhand Smoking and the Fetus: A Bibliometric Analysis

Background

Bibliometric analysis may indicate the most active specialist, authors, and journals in a given research field. To the authors' knowledge, there is no bibliometric analysis to provide a macroscopic overview in the field of secondhand smoke that harms non-smoker.

Methods

Using the bibliometric method, 644 articles that were present in the Scopus database between 1973-2020 on the subject were considered. The data were analyzed by two visualization and science-mapping software called Bibliometrix and VoS Viewer. Also, reference publication year stereoscopy and Co-Citation historiography were used. In the qualitative analysis, 52 articles were selected that had the most citation and were analyzed.

Results

In this paper, the findings show that the documents were published in 364 sources with an average citation per document of 25.14 and more than 3 authors or nearly 4 authors per document. The peak reference publication year stereoscopy happened in the year 199 with 974 references. The countries with the highest number of MCP were the USA, China, and Spain. The "International Journal of Environmental Research" and "Public Health", has raised their publications in the field of secondhand smoke and pregnancy rapidly since 2003. Among the titles, "passive smoking" was the most used.

Conclusion

The study highlights the importance of understanding the harmful effects of secondhand smoke on the developing fetus. The findings also shed light on key research trends, influential authors, and active research areas, which can guide future studies and support evidence-based decision-making in the field of maternal and child health.

Biological exposure indices of occupational exposure to benzene: A systematic review

The current study aimed to systematically review the studies concerning the biological monitoring of benzene exposure in occupational settings. A systematic literature review was conducted in Scopus, EMBASE, Web of Science, and Medline from 1985 through July 2021. We included peer-reviewed original articles that investigated the association between occupational exposure to benzene and biological monitoring. We identified 4786 unique citations, of which 64 cross-sectional, one case-control, and one cohort study met our inclusion criteria. The most studied biomarkers were urinary trans-trans muconic acid, S- phenyl mercapturic acid, and urinary benzene, respectively. We found the airborne concentration of benzene as a key indicator for choosing a suitable biomarker. We suggest considering urinary benzene at low (0.5-5.0 TLV), urinary SPMA and TTMA at medium (5.0-25 and 25-50 TLV, respectively), and urinary phenol and hydroquinone and catechol at very high concentrations (500 and 1000 TLV ≤, respectively). Genetic polymorphism of glutathione S-transferase and oral intake of sorbic acid have confounding effects on the level of U-SPMA and U-TTMA, respectively. The airborne concentration, smoking habit, oral consumption of sorbic acid, and genetic polymorphism of workers should be considered in order to choose the appropriate indicator for biological monitoring of benzene exposure.

Association between smoking and peri-implant diseases: A retrospective study

OBJECTIVES

To determine the association between tobacco and peri-implant diseases in a sample of patients who had received implant-supported restorations in a university dental clinic. Furthermore, the study aimed to investigate patient- and implant-related variables associated with peri-implant diseases.

MATERIALS AND METHODS

The present retrospective study analyzed data from 117 patients treated with implant-supported restorations from 2001 to 2013. A total of 450 implants were evaluated. Patients were selected from an electronic database, and patient- and implant-related variables were evaluated. Detailed information regarding the smoking history (i.e., smoking status, lifetime cumulative dose, duration of exposure, intensity of the habit, and smoking cessation) was recorded. The primary study outcome was peri-implant status [i.e., health (H), peri-implant mucositis (PM) and peri-implantitis (PI)]. Univariate and multinomial regression models comparing PM and PI versus peri-implant health were conducted.

RESULTS

A total of 117 subjects [55 (47%) females and 62 (53%) males] with a mean age at examination of 64.2 years (SD 11.6) and rehabilitated with 450 implants were included. The average number of implants per patient was 4.6 (SD 3.3) with a mean time in function of 8.0 years (SD 1.9). Fifty-six patients (47.9%) were non-smokers, 42 (35.9%) were former-smokers, and 19 (16.2%) were current-smokers. Thirty-nine subjects (33.4%) were H, whereas 41 (35%) and 37 (31.6%) exhibited PM and PI, respectively. At implant level, the corresponding values were 142 (31.6%), 230 (51.1%) and 78 (17.3%). In the multinomial regression model, significant associations for peri-implant diseases were observed for the mean number of implants per patient (p = .016), function time (p = .048), implants placed simultaneously with guided bone regeneration (p = .016), implant surface (p = .020), keratinized mucosa at the buccal aspect (p = .032), and access to interproximal hygiene (p < .001). In addition, ever smokers >23 pack-years exhibited a significantly higher risk for peri-implantitis (p = .002). Finally, the multinomial regression analysis revealed that subjects who had stopped smoking more than 21 years before the last examination presented a significantly lower risk of peri-implant diseases than a smoking cessation of ≤21 years (p = .028).

CONCLUSIONS

Smoke intensity was associated with an increased risk of the development of peri-implantitis. Moreover, the risk of peri-implant diseases might be similar in those subjects who had stopped smoking for more than 21 years with respect to never-smokers.

Association of secondhand smoke exposure and health-related lifestyle behaviors among male university employees in Japan

Secondhand smoke (SHS) exposure causes various health problems associated with an unhealthy lifestyle. However, the lifestyles of individuals exposed to SHS have not been characterized extensively. Therefore, this cross-sectional study aimed to investigate the association between SHS exposure and lifestyle behaviors. The participants were 2379 healthy male employees at Osaka University who underwent health examinations. Physical and biochemical parameters and lifestyle behavior data were obtained from all the participants. Participants with SHS exposure had significantly higher body mass index, waist circumference, and serum levels of triglycerides and uric acid than that of those without SHS exposure. SHS exposure was significantly correlated with several lifestyle behaviors, including TV time, frequency of breakfast consumption and fried food consumption, vegetable and fruit intake, alcohol consumption frequency and daily alcohol intake, and smoking status. Thus, SHS exposure may be associated with an unhealthy lifestyle. The lifestyle behaviors of the smoke-excluded population were assessed further; however, SHS exposure was still associated with dietary and drinking habits. Since participants with SHS exposure are likely to have an unhealthy life and combined unhealthy lifestyle behaviors, the confounding effect of these factors should be considered when assessing the impact of SHS exposure on health.

Environmental tobacco smoke at home and in public places prior to smoking ban enforcement: Assessment by hair analysis in a population of young adult students

Despite inititatives to reduce tobacco consumption, smoking remains a primary cause of death for both smokers and nonsmokers exposed to environmental tobacco smoke (ETS). The characteristics of some specific groups can make them more exposed to ETS or limit the benefit of prevention measures. This study investigated determinants of ETS in a population of young adult students, considered at higher risk of exposure due to their specific lifestyle. This cross-sectional study involved 90 students aged 20 ± 1.7 years, from the University of Luxembourg, prior to the smoking ban enforcement in public places in the country. Participants reported their tobacco consumption and exposure to ETS at home and/or in public places, and provided a hair sample analyzed for nicotine and cotinine. Nicotine and cotinine were significantly higher in smokers than in nonsmokers' hair in general (median: 2.6 vs. 0.9 ng/mg and 87.1 vs. 22.5 pg/mg respectively). However, nonsmokers exposed to ETS at home and in public places had comparable concentrations to smokers (nic = 2.2 ng/mg; cot = 56.2 pg/mg), whereas unexposed nonsmokers presented significantly lower values (nic = 0.4 ng/mg, cot = 8.5 pg/mg). Nonsmokers exposed to ETS only at home presented higher values than nonsmokers only exposed in public places (nic: 1.3 vs. 0.8 ng/mg, cot: 70.4 vs. 15.0 pg/mg). The study shows the widespread exposure to ETS in this population, the importance of exposure assessment, and the relevance of hair analysis for this purpose. Results suggest that ETS can lead to equivalent exposure to active smoking and that exposure at home can highly contribute to ETS, which is not solved by smoking ban in public places.

Cigarette Smoke Exposure and Stunting Among Under-five Children in Rural and Poor Families in Indonesia

Cigarette smoke exposure in mothers and children is highly prevalent in Asia, especially among rural and poor families. Second-hand smoke exposure might affect the nutritional status of children. Despite the emerging double burden of malnutrition and the very high prevalence of smoking in Indonesia, few studies have examined the effects of parental smoking on children's nutritional status. This study aims to measure the relationship between family smoking behavior and the occurrence of stunting in children under 5 years. This cross-sectional study used a purposive sampling technique, with 221 households with children aged 0 to 59 months from poor areas in Indonesia. Exposure to cigarette smoke is assessed using The Secondhand Smoke Exposure Scale questionnaire. The outcome measured is child stunting (height-for-age Z-score). The prevalence of stunting was estimated at 145 (65.6%). Children living with smoking parents were counted for 157 (71%), and most smoking exposure comes from fathers 147 (67.4%). The predictors of stunting in children under 5 years were a smoker father with (AOR 1.8; 95% CI 1.281-4.641), both parents are smokers increasing the risk of stunting with (COR 3.591; 95% CI 1.67-3.77), being exposed of smoke for more than 3 hours a day increase the risk of stunted children (COR 2.05; 95% CI 1.214-3.629), and using traditional cigarette or kretek expand the risk of stunting (AOR 3.19; 95% CI 1.139-67.785). The findings demonstrate the negative impact of parental smoking on children's growth, reinforcing the importance of reducing smoking prevalence by imposing a smoke-free home policy in the stunting prevention strategy.

Epigenetic biomarkers for smoking cessation

Cigarette smoking has been associated with epigenetic alterations that may be reversible upon cessation. As the most-studied epigenetic modification, DNA methylation is strongly associated with smoking exposure, providing a potential mechanism that links smoking to adverse health outcomes. Here, we reviewed the reversibility of DNA methylation in accessible peripheral tissues, mainly blood, in relation to cigarette smoking cessation and the utility of DNA methylation as a biomarker signature to differentiate current, former, and never smokers and to quantify time since cessation. We summarized thousands of differentially methylated Cytosine-Guanine (CpG) dinucleotides and regions associated with smoking cessation from candidate gene and epigenome-wide association studies, as well as the prediction accuracy of the multi-CpG predictors for smoking status. Overall, there is robust evidence for DNA methylation signature of cigarette smoking cessation. However, there are still gaps to fill, including (1) cell-type heterogeneity in measuring blood DNA methylation; (2) underrepresentation of non-European ancestry populations; (3) limited longitudinal data to quantitatively measure DNA methylation after smoking cessation over time; and (4) limited data to study the impact of smoking cessation on other epigenetic features, noncoding RNAs, and histone modifications. Epigenetic machinery provides promising biomarkers that can improve success in smoking cessation in the clinical setting. To achieve this goal, larger and more-diverse samples with longitudinal measures of a broader spectrum of epigenetic marks will be essential to developing a robust DNA methylation biomarker assay, followed by meeting validation requirements for the assay before being implemented as a clinically useful tool.

Novel proposed cutoff values for anatabine and anabasine in differentiating smokers from non-smokers

OBJECTIVES

Anatabine and anabasine are two tobacco alkaloids used to differentiate between tobacco users and abstainers, including users of nicotine replacement therapy. Cutoff values (>2 ng/mL for both alkaloids) have not been revised since their implementation in 2002. These values may be too high, leading to increased likelihood of misclassification between smokers and abstainers. This results in major consequences, especially adverse outcomes of transplantation when smokers were incorrectly identified as being abstinent. This study proposes that a lower threshold for anatabine and anabasine will better distinguish tobacco users from non-users and thereby improve patients' care.

DESIGN AND METHODS

A new and more sensitive analytical method by liquid chromatography-mass detection was developed to allow the quantification of low concentrations. Anatabine and anabasine were measured in urine samples of 116 self-reported daily smokers and 47 long-term non-smokers (confirmed by the analysis of nicotine and its metabolites). The best compromise between sensitivity and specificity allowed us to determine new cutoff values.

RESULTS

The thresholds >0.097 ng/mL for anatabine and >0.236 ng/mL for anabasine were associated with a sensitivity of 97% (anatabine) and 89% (anabasine) and a specificity of 98% for both alkaloids. These cutoff values greatly increased the sensitivity given that it dropped to 75% (anatabine) and 47% (anabasine) when using the reference value (>2 ng/mL).

CONCLUSIONS

The cutoff values >0.097 ng/mL for anatabine and >0.236 ng/mL for anabasine appear to better differentiate tobacco users from abstainers than the current reference threshold (>2 ng/mL for both alkaloids). It may considerably impact patients' care, especially in transplantation settings in which smoking abstinence is essential to avoid adverse outcomes of transplantation.

Cigarette smoking cessation, duration of smoking abstinence, and head and neck squamous cell carcinoma prognosis

BACKGROUND

Tobacco use is a major risk factor for developing head and neck squamous cell carcinoma (HNSCC). However, the prognostic associations with smoking cessation are limited. The authors assessed whether smoking cessation and increased duration of abstinence were associated with improved overall (OS) and HNSCC-specific survival.

METHODS

Clinicodemographic and smoking data from patients with HNSCC at Princess Margaret Cancer Center (2006-2019) were prospectively collected. Multivariable Cox and Fine and Gray competing-risk models were used to assess the impact of smoking cessation and duration of abstinence on overall mortality and HNSCC-specific/noncancer mortality, respectively.

RESULTS

Among 2482 patients who had HNSCC, former smokers (adjusted hazard ratio [aHR], 0.71; 95% CI, 0.58-0.87; p = .001; N = 841) had a reduced risk of overall mortality compared with current smokers (N = 931). Compared with current smokers, former smokers who quit >10 years before diagnosis (long-term abstinence; n = 615) had the most improved OS (aHR, 0.72; 95% CI, 0.56-0.93; p = .001). The 5-year actuarial rates of HNSCC-specific and noncancer deaths were 16.8% and 9.4%, respectively. Former smokers (aHR, 0.71; 95% CI, 0.54-0.95; p = .019) had reduced HNSCC-specific mortality compared with current smokers, but there was no difference in noncancer mortality. Abstinence for >10 years was associated with decreased HNSCC-specific death compared with current smoking (aHR, 0.64; 95% CI, 0.46-0.91; p = .012). Smoking cessation with a longer duration of quitting was significantly associated with reduced overall and HNSCC-specific mortality in patients who received primary radiation.

CONCLUSIONS

Smoking cessation before the time of diagnosis reduced overall mortality and cancer-specific mortality among patients with HNSCC, but no difference was observed in noncancer mortality. Long-term abstinence (>10 pack-years) had a significant OS and HNSCC-specific survival benefit.

Maternal smoking in pregnancy and blood pressure during childhood and adolescence: a meta-analysis

Arterial hypertension during childhood or adolescence is rising, and smoking during pregnancy may constitute a modifiable risk factor. This study aims to evaluate the effect of maternal smoking during pregnancy on diastolic (DBP) and systolic blood pressure (SBP) in childhood and adolescence. A bibliographic search was conducted in PubMed, Embase, and CENTRAL databases in March 2022. Meta-analysis was performed with the difference in mean-adjusted SBP/DBP of children and adolescents aged 3-17 years, according to maternal smoking/non-smoking in pregnancy. A random effects model was applied; a leave-one-out analysis and meta-analysis by subgroups were performed. A modified Newcastle-Ottawa scale was used to assess the quality of the studies. Evidence levels were rated using the GRADE system. Fifteen studies were included in the meta-analysis; all of them evaluated the mean-adjusted SBP difference in children or adolescents (N = 73,448), and 6 also that of DBP (N = 31,459). Results showed that maternal smoking during pregnancy significantly increased SBP (β = 0.31 mmHg 95% CI 0.14-0.49). A greater increase in mean-adjusted SBP was observed in those studies that completed the recruitment before 1990, were conducted in non-European countries, used standard mercury or manual sphygmomanometry, adjusted for birth weight, and were in the lowest quality subgroup. No significant association was found for DBP. The GRADE level of evidence was low for SBP and very low for DBP.

CONCLUSION

Smoking in pregnancy might increase SBP in childhood and adolescence. Due to the low level of evidence, solid inferences cannot be drawn about the clinical relevance of these findings.

WHAT IS KNOWN

• AHT is the leading cause of premature death among adults worldwide. • Deleterious effects derived from SHS exposure on children's health have been documented since early 1970. To date, there are contradictory results about the effects of prenatal SHS exposure on children's BP.

WHAT IS NEW

• Smoking in pregnancy may increase SBP during childhood and adolescence. • Maternal smoking during pregnancy could have greater influence on their offspring's SBP than on DBP.

Maternal Exposure to Cigarette Smoke during Pregnancy and Testicular Cancer in Offspring: A Systematic Review and Meta-Analysis

Background: Maternal exposure to cigarette smoke in pregnancy may play a role in the development of testicular cancer in offspring. An updated and comprehensive systematic review of the available evidence is needed. Objective: To identify and evaluate current evidence on maternal exposure to cigarette smoke during pregnancy and testicular cancer in offspring. Methods: A systematic search of English peer-reviewed original literature in PubMed through a block search approach. Publications were considered if assessing maternal exposure to cigarette smoke and the risk of testicular cancer in offspring. Results: Among the 636 identified records, 14 publications were eligible for review and 10 for meta-analysis. Quality assessment of the publications was conducted. Most included publications were case-control studies (n = 11, 79%), while the remaining were ecological studies (n = 3, 21%). Completeness of reporting was high, but more than half were considered subject to potential bias. The trend synthesis showed that half (n = 7) of the included publications demonstrated a higher risk of testicular cancer in the sons of mothers exposed to cigarette smoke during pregnancy. The meta-analysis generated an overall summary risk estimate of 1.00 (95% CI: 0.88; 1.15) (n = 10 publications), with a lower risk for seminoma (0.79, 95% CI: 0.59; 1.04) and nonseminoma (0.96, 95% CI: 0.74; 1.26) (n = 4 publications). Conclusions: This systematic review did not provide evidence of an association between maternal exposure to cigarette smoke and risk of testicular cancer in offspring. An overall positive trend was suggested, but it had low statistical precision. The methodological limitations across publications encourage further research based on valid exposure data.

Tobacco Smoke Exposure According to Location of Home Smoking in Israel: Findings from the Project Zero Exposure Study

Young children are particularly vulnerable to harms from tobacco smoke exposure (TSE). This study aimed to compare TSE: (1) between children who live in smoking families and those who do not; and (2) among children who live in smoking households with varying smoking locations. The data came from two studies that were conducted concurrently in Israel (2016-2018). Study 1: a randomized controlled trial of smoking families (n = 159); Study 2: a cohort study of TSE among children in non-smoking families (n = 20). Hair samples were collected from one child in each household. Baseline hair nicotine data were analyzed for 141 children in Study 1 and 17 children in Study 2. Using a logistic regression analysis (exposed vs. not exposed as per laboratory determination) and a linear regression (log hair nicotine), we compared TSE between: (1) children in Study 1 vs. Study 2; (2) children in families with different smoking locations in Study 1: balcony; garden, yard, or other place outside of the home; or inside the home (designated smoking areas within the home (DSAs) or anywhere). A higher proportion of children living in smoking households were measurably exposed to tobacco smoke (68.8%) compared to children living in non-smoking households (35.3%, p = 0.006). Among children from smoking families, 75.0% of those whose parents smoked in the house were exposed, while 61.8% of children whose parents restricted smoking to the porch (n = 55) were exposed, and 71.4% of those whose parents smoked outside the home (including gardens and yards) (n = 42) were exposed. In univariable and multivariable models, smoking location was not significantly associated with exposure. The majority of children in smoking families were measurably exposed to TSE, even if smoking was restricted to designated areas in the home, balconies, orgarden/yard/other outdoor areas. Reducing population smoking rates, particularly among parents, restricting smoking to at least 10 meters from homes and children, and denormalizing smoking around others are recommended to reduce population-level child TSE and tobacco-attributable disease and death.

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.

Host, technical, and environmental factors affecting QuantiFERON-TB Gold In-Tube performance in children below 5 years of age

Interferon-gamma release assays performance can be impaired by host-related, technical and environmental factors, but data in young children are limited. We performed a cross-sectional study of children < 5 years-of-age at risk of tuberculosis (TB), using QuantiFERON-TB Gold In-Tube (QFT-GIT) assays. The impact of the following was evaluated: (i) host-related [age; hematological parameters; erythrocyte sedimentation rate (ESR); C-reactive protein (CRP); and tobacco smoke exposure (TSE) based on serum cotinine concentrations], (ii) technical (pre-analytical delay) and (iii) environmental factors (annual season; monthly temperatures). Of 204 children, 35 (17.2%) were diagnosed with latent TB infection or TB disease. QFT-GIT results were indeterminate in 14 (6.9%) patients. In multivariate analysis, younger age and higher ESR were associated with lower positive control responses (beta: 0.247, p = 0.002 and - 0.204, p = 0.007, respectively), and increasing age was associated with lower rates of indeterminate QFT-GIT results [OR (95% CI) 0.948 (0.903-0.996) per month, p = 0.035]. In children with positive QFT-GIT results, average monthly temperatures correlated with antigen responses (r = 0.453, p = 0.020); also, antigen responses were lower in winter than in other seasons (p = 0.027). Serum cotinine concentrations determined in a subgroup of patients (n = 41) indicated TSE in 36 (88%), positive control responses being lower in children with TSE (p = 0.034). In children < 5 years-of-age, young age, elevated ESR, temperature, annual season and TSE can affect the performance of QFT-GIT assays.

Human circadian rhythm studies: Practical guidelines for inclusion/exclusion criteria and protocol

As interest in circadian rhythms and their effects continues to grow, there is an increasing need to perform circadian studies in humans. Although the constant routine is the gold standard for these studies, there are advantages to performing more naturalistic studies. Here, a review of protocols for such studies is provided along with sample inclusion and exclusion criteria. Sleep routines, drug use, shift work, and menstrual cycle are addressed as screening considerations. Regarding protocol, best practices for measuring melatonin, including light settings, posture, exercise, and dietary habits are described. The inclusion/exclusion recommendations and protocol guidelines are intended to reduce confounding variables in studies that do not involve the constant routine. Given practical limitations, a range of recommendations is provided from stringent to lenient. The scientific rationale behind these recommendations is discussed. However, where the science is equivocal, recommendations are based on empirical decisions made in previous studies. While not all of the recommendations listed may be practical in all research settings and with limited potential participants, the goal is to allow investigators to make well informed decisions about their screening procedures and protocol techniques and to improve rigor and reproducibility, in line with the objectives of the National Institutes of Health.

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.

A Time-Varying Effect Model (TVEM) of the Complex Association of Tobacco Use and Smoke Exposure on Mean Telomere Length: Differences between Racial and Ethnic Groups Assessed in the National Health and Nutrition Examination Survey

Telomere length is affected by lifestyle and environmental factors and varies between racial and ethnic groups; however, studies are limited, with mixed findings. This study examined the effects of tobacco use and smoke exposure on mean telomere length to identify critical age periods by race/ethnicity. We used time-varying effect modeling on the National Health and Nutrition Examination Survey for continuous years 1999-2002 to observe the effects of active tobacco use and environmental tobacco smoke-measured through serum cotinine-and mean telomere length for adults 19 to 85 and older (N = 7826). Models were run for Mexican American, other Hispanic, non-Hispanic White, non-Hispanic Black, and other/multi-race categories to allow for time-varying group differences, and controlled for biological sex, socioeconomic status, education, and ever-smoker status. Serum cotinine was found to have an increasing effect on telomere length from age 37 to approximately age 74 among Mexican Americans. Among other/multi-race individuals serum cotinine was found to have a decreasing effect at approximately age 42, and among Blacks, it had an overall decreasing effect from age 61 to 78. Findings reveal a further need to focus additional support and resources to intervene regarding disparate health effects from tobacco use and environmental smoke exposure for already vulnerable groups at particular ages.

AhRR methylation contributes to disease progression in urothelial bladder cancer

BACKGROUND

Bladder Cancer (BCa) is the tenth most incidental malignancy worldwide. BCa is mostly attributed to environmental exposure and lifestyle, particularly tobacco smoking. The Aryl Hydrocarbon Receptor Repressor (AhRR) participates in the induction of many enzymes involved in metabolizing carcinogens, including tobacco smoke components. Additionally, studies have shown that smoking demethylates the (AhRR) gene in blood, suggesting AhRR demethylation as a specific serum smoking biomarker.

OBJECTIVE

This study aimed to validate AhRR demethylation as a smoking biomarker in the target tissue and investigate its contribution to bladder carcinogenesis.

METHODS

AhRR percent methylation was tested for its association with patient smoking status and oncogenic outcome indicators, particularly p53, RB1, and FGFR3 activating mutations, muscle-invasiveness, and tumor grade, in 180 BCa tissue-based DNA.

RESULTS

Results showed significantly higher AhRR percent methylation in muscle-invasive compared to non-muscle invasive tumors (42.86% vs. 33.98%; p= 0.011), while lower AhRR methylation was significantly associated with FGFR3 Codon 248 mutant genotype compared to wild-type (28.11% ± 9.44 vs. 37.87% ± 22.53; p= 0.036). All other tested associations were non-statistically significant.

CONCLUSIONS

Although AhRR methylation did not predict smoking status in BCa tumors, it seems to play a role in carcinogenesis and disease progression. Our findings make a basis for further research.

The Effect of Smoking on Long-term Gray Matter Atrophy and Clinical Disability in Patients with Relapsing-Remitting Multiple Sclerosis

Background and Objectives

The relationship between smoking, long-term brain atrophy, and clinical disability in patients with multiple sclerosis (MS) is unclear. Here, we assessed long-term effects of smoking by evaluating MRI and clinical outcome measures after 10 years in smoking and nonsmoking patients with relapsing-remitting MS (RRMS).

Methods

We included 85 treatment-naive patients with RRMS with recent inflammatory disease activity who participated in a 10-year follow-up visit after a multicenter clinical trial of 24 months. Smoking status was decided for each patient by 2 separate definitions: by serum cotinine levels measured regularly for the first 2 years of the follow-up (during the clinical trial) and by retrospective patient self-reporting. At the 10-year follow-up visit, clinical tests were repeated, and brain atrophy measures were obtained from MRI using FreeSurfer. Differences in clinical and MRI measurements at the 10-year follow-up between smokers and nonsmokers were investigated by 2-sample t tests or Mann-Whitney tests and linear mixed-effect regression models. All analyses were conducted separately for each definition of smoking status.

Results

After 10 years, smoking (defined by serum cotinine levels) was associated with lower total white matter volume (β = −21.74, p = 0.039) and higher logT2 lesion volume (β = 0.22, p = 0.011). When defining smoking status by patient self-reporting, the repeated analyses found an additional association with lower deep gray matter volume (β = −2.35, p = 0.049), and smoking was also associated with a higher score (higher walking impairment) on the log timed 25-foot walk test (β = 0.050, p = 0.039) after 10 years and a larger decrease in paced auditory serial addition test (attention) scores (β = −3.58, p = 0.029).

Discussion

Smoking was associated with brain atrophy and disability progression 10 years later in patients with RRMS. The findings imply that patients should be advised and offered aid in smoking cessation shortly after diagnosis, to prevent long-term disability progression.

[Situations of Passive Smoking by Urine Cotinine Levels and Recognition of Passive Smoking in High School Students -Effectiveness of Smoking Prevention Education Using a Video Made by High School Students]

We investigated a situation of passive smoking and its damaging effects among high school students. Urine cotinine concentration was measured and quantified. Additionally, we evaluated the awareness of passive smoking and smoking regulations in high school students, and the educational effect on passive smoking using a questionnaire survey and educational videos produced by high school students. We conducted a self-reporting questionnaire survey with high school students before and after watching the video produced by the high school students. We gathered the scores of the Kano Social Nicotine Dependence Questionnaire (KTSND) and awareness of smoking restrictions. Consent was obtained through the questionnaire before watching the video and collecting urine samples. Urine cotinine concentrations from 54 samples were evaluated and indicated within the low value. The KTSND score significantly decreased for those who responded to both questionnaires, after watching the video. Furthermore, analysis of the KTSND questionnaire items showed a significant decrease in scores for lifestyle, stress, and smoking location. This suggests that the video produced in this study has a certain amount of educational effect on passive smoking and that the student-led educational method is effective. The survey using the KTSND revealed that there were some students who were not exposed to passive smoking, but instead had high smoking tolerance. Going forward, it will be necessary to promote education on passive smoking and smoking prevention by incorporating the video lecture and urine cotinine concentration was measured, as in this study, to encourage behavior that decreases passive smoking among high school students.

Exposure to second-hand smoke is an independent risk factor of small airway dysfunction in non-smokers with chronic cough: A retrospective case-control study

Objectives

This study aimed to identify the potential risk factors for small airway dysfunction (SAD) in non-smokers with chronic cough.

Methods

Non-smokers with chronic cough who underwent lung function tests at Xiangya Hospital from May 2019 to May 2020 were enrolled, and divided into the derivation and validation cohorts based on their hospital admission time. SAD was determined based on the presence of at least two of the following three indicators of lung function being less than 65% of predicted: maximal mid-expiratory flow, forced expiratory flow at 50% of forced vital capacity (FVC), and forced expiratory flow at 75% of FVC. Clinical data of these patients were collected. Risk factors for SAD were identified by logistic regression analysis in the derivation cohort and further confirmed in the validation cohort.

Results

In total, 316 patients (152 in the non-SAD group and 164 in the SAD group) were included in the derivation cohort. Compared with the non-SAD group, the SAD group had a higher proportion of female patients (82.3 vs. 59.2%, P < 0.001), was more commonly exposed to second-hand smoke (SHS) (61.6 vs. 27.6%, P < 0.001), and tended to be older (median age, 45.5 vs. 40.0 years old, P = 0.004). The median FVC, forced expiratory volume in one second (FEV₁) % pred, FEV₁/FVC ratio, and peak expiratory flow (PEF) % pred were slightly lower in the SAD group. Multivariable logistic analysis showed that exposure to SHS was an independent risk factor (OR 4.166 [95% CI 2.090–8.302], P < 0.001) for SAD in non-smokers with chronic cough after adjusting for related variables. In the validation cohort (n = 146), patients with SHS exposure had a relative risk of 1.976 (95% CI 1.246–3.135, P = 0.004) for SAD compared to those without SHS exposure. Multivariable logistic analysis consistently confirmed that exposure to SHS was an independent risk factor (OR 3.041 [95% CI 1.458–6.344], P = 0.003) for SAD in non-smokers.

Conclusions

Exposure to SHS is independently associated with a higher risk of SAD in non-smokers with chronic cough. Reduction in SHS exposure may ameliorate lung function, thus lowering the risk of irreversible airway obstruction.

Predictive Patient Factors for Poor Outcomes Following Stapedotomy for Otosclerosis

OBJECTIVE

To assess patient-related risk factors associated with poor outcomes following stapedotomy for otosclerosis.

STUDY DESIGN

Retrospective study.

SETTING

Academic tertiary care center.

METHODS

Retrospective chart review of 107 patients with otosclerosis who underwent stapedotomy between 2013 and 2020. Demographics, comorbidities, and smoking history were obtained. Preoperative and postoperative audiogram data, including air-bone gap (ABG), and complications were collected. Data were analyzed using t test and Fischer's exact test for continuous and categorical variables, respectively.

RESULTS

Among 107 patients, 29.5% were smokers and 70.1% non-smokers. Overall, the average ABG-gain 3-months postoperatively was 20.2 dB, and intraoperative and postoperative complications were 3.74 and 13.1%, respectively. Those with a history of otologic procedures had a lower mean ABG gain at 3 months compared with those without previous otologic surgery (14.4 dB versus 20.4 dB, p = 0.018). The average ABG gain at 3-months was not significantly different between those with current, former, or no smoking history, respectively (13.5 versus 18.1 versus 20.6, p = 0.08). Current smokers had 4.5 times greater odds of complications compared with non-smokers, although not statistically significant (95% CI 0.9-22.8, p = 0.1912).

CONCLUSION

Age and history of otologic procedures as independent risk factors did impact hearing outcomes among our patient cohort; however, smoking history did not. Future prospective studies are required to further investigate complication rates by various modifiable risk factors, such as smoking status, body mass index (BMI), and obstructive sleep apnea (OSA) with continuous positive airway pressure (CPAP) use, for stapedotomy surgeries.

Serum cotinine cut-points for secondhand smoke exposure assessment in children under 5 years: A systemic review

Background

Serum cotinine has become the most widely used biomarker of secondhand smoke exposure (SHS) over time in all ages. The aim of this study was to review the serum cotinine cut-points used to classify children under 5 years as exposed to SHS.

Methods

A systematic review performed in the Pubmed (MEDLINE) and EMBASE databases up to April 2021 was conducted using as key words "serum cotinine", “tobacco smoke pollution” (MeSH), "secondhand smoke", "environmental tobacco smoke" and “tobacco smoke exposure”. Papers which assessed SHS exposure among children younger than 5 years old were included. The PRISMA 2020 guidelines were followed. Analysis was pre-registered in PROSPERO (registration number: CRD42021251263).

Results

247 articles were identified and 51 fulfilled inclusion criteria. The selected studies were published between 1985–2020. Most of them included adolescents and adults. Only three assessed postnatal exposure exclusively among children under 5 years. None of the selected studies proposed age-specific cut-points for children < 5 years old. Cut-point values to assess SHS exposure ranged from 0.015 to 100 ng/ml. The most commonly used cut-point was 0.05 ng/ml, derived from the assay limit of detection used by the National Health and Nutrition Examination Survey (NHANES).

Conclusions

No studies have calculated serum cotinine age-specific cut-points to ascertained SHS exposure among children under 5 years old. Children’s age-specific cut-points are warranted for health research and public health purposes aimed at accurately estimating the prevalence of SHS exposure and attributable burden of disease to such exposure, and at reinforcing 100% smoke-free policies worldwide, both in homes, private vehicles and public places.

Association between Environmental Tobacco Smoke Exposure and Adaptive Behavior in Individuals with Autism Spectrum Disorder

The study focuses on current issues of adaptive behavior in individuals with autism spectrum disorder (ASD) and on the possible risk factor of environmental tobacco smoke (ETS). Children examined at the Academic Research Center for Autism (ARCA) in Bratislava were involved in the study. The study sample included 84 children (71 boys) with ASD (average age 5.35 years) and a non-ASD group of 24 children (20 boys; average age 8.10 years). The “ETS Questionnaire” focused on the detection of parental smoking habits and other ETS exposures. The concentrations of cotinine in urine were measured by ELISA kit. A significant delay in adaptive behavior of children with ASD in comparison with the non-ASD group was identified. The significant differences were in adaptive behavior, communication, and everyday skills. Children with ASD were more likely to be exposed to ETS, especially in the household. Good agreement was found between objective and subjective ETS exposure indicators (kappa = 0.613). Self-reported exposure to ETS corresponded significantly with the median levels of urinary cotinine. In addition to evaluation and assessment of the quality of adaptive behavior, an important goal of further research should be to identify, investigate, and eliminate environmental factors that interfere with adaptive behavior.

Optimization and validation of a procedure using the dried saliva spots approach for the determination of tobacco markers in oral fluid

Exposure to tobacco smoke is one of the most common causes of premature death worldwide and is the cause of 8 million deaths annually. We have developed, optimized, and validated a procedure for the detection of nicotine, cotinine and trans-3-hydroxycotinine (biomarkers of tobacco exposure) in oral fluid using the dried saliva spots sampling approach and gas chromatography coupled to tandem mass spectrometry, thus allowing the distinction between active and passive smokers. For optimization, four parameters were evaluated, namely extraction solvent, extraction solvent volume, extraction time and spots drying time. During method validation, the parameters selectivity, linearity, precision and accuracy, recovery, stability, and dilution factor were assessed. Linearity was obtained for all target analytes in the concentration range of 10-200 ng/mL allowing the quantification of compounds up to 1000 ng/mL considering the dilution factor. The method recoveries ranged from 29.2% to 43.30% for nicotine, 66.60-89.10% for cotinine and 80.30-92.80% for trans-3-hydroxycotinine, while achieving intra-day, inter-day and intermediate precision and accuracy values never higher than 10.37% and ±6.62% respectively for all compounds. The herein described analytical method is the first to allow the determination of tobacco biomarkers in oral fluid using dried saliva spots, which is considered a sensitive, simple and low-cost alternative to conventional methods.

Secondhand smoke exposure is associated with abnormal P-wave axis

OBJECTIVES

Secondhand smoke exposure (SHSE) is associated with increased risk of cerebrovascular accident (CVA). Abnormal P-wave axis (aPWA) is a marker for atriopathy that is also associated with CVA risk. We hypothesized that SHSE is associated with aPWA.

METHODS

This analysis included 5986 non-smokers (age 61.7 ± 13.8 years, 45.8% men, 77.4% Whites) from the Third National Health and Nutrition Examination Survey. SHSE was defined as serum cotinine ≥1 ng/ml aPWA was defined as any P-wave axis outside of 0-75°. Multivariable logistic regression was used to examine the association between SHSE and aPWA, overall and among subgroups stratified by demographics and comorbidities.

RESULTS

About 18.5% (n = 1109) of the participants had SHSE. aPWA was more prevalent among those with SHSE than those without (23.9% versus 19.8%, respectively, P-value = 0.003). In a model adjusted for sociodemographic and potential confounders, presence (versus absence) of SHSE was associated with increased odds of aPWA (odds ratio [95% confidence interval]: 1.28 [1.09, 1.50]; P-value = 0.003). This association was stronger among Whites vs non-Whites (interaction P-value = 0.04) and non-obese versus obese (interaction P-value = 0.04). Higher levels of serum cotinine were associated with increased odds of aPWA. Compared with serum cotinine level <1 ng/ml, serum cotinine ≥3 ng/ml and ≥6 ng/ml were associated with 35% (P-value = 0.002) and 38% (P-value = 0.002) increased odds of aPWA, respectively.

CONCLUSIONS

SHSE is associated with abnormal atrial conduction, measured as aPWA, with possible effect modification by ethnicity and obesity. These findings underscore the harmful effects of SHSE on cardiovascular health which merits a personalized risk assessment when counseling patients on SHSE.

Neighborhood Deprivation is Associated with Increased Risk of Prenatal Smoke Exposure

Despite years of advisories against the behavior, smoking among pregnant women remains a persistent public health issue in the USA. Recent estimates suggest that 9.4% of women smoke before pregnancy and 7.1% during pregnancy in the USA. Epidemiological research has attempted to pinpoint individual-level and neighborhood-level factors for smoking during pregnancy, including educational attainment, employment status, housing conditions, poverty, and racial demographics. However, most of these studies have relied upon self-reported measures of smoking, which are subject to reporting bias. To more accurately and objectively assess smoke exposure in mothers during pregnancy, we used Bayesian index models to estimate a neighborhood deprivation index (NDI) for block groups in Durham County, North Carolina, and its association with cotinine, a marker of smoke exposure, in pregnant mothers (n = 887 enrolled 2005-2011). Results showed a significant positive association between NDI and log cotinine (beta = 0.20, 95% credible interval = [0.11, 0.29]) after adjusting for individual covariates (e.g., race/ethnicity and education). The two most important variables in the NDI according to the estimated index weights were percent females without a high school degree and percent Black population. At the individual level, Hispanic and other race/ethnicity were associated with lowered cotinine compared with non-Hispanic Whites. Higher education levels were also associated with lowered cotinine. In summary, our findings provide stronger evidence that the socio-geographic variables of educational attainment and neighborhood racial composition are important factors for smoking and secondhand smoke exposure during pregnancy and can be used to target intervention efforts.

Low-cost apparatus for cigarette smoke exposure in rats

BACKGROUND

The effects of tobacco smoke on the central nervous system are usually studied with isolated nicotine, ignoring other compounds present in cigarette smoke. The few studies that use in vivo whole-body cigarette smoke exposure are usually performed in expensive commercial apparatus.

NEW METHOD

We presented a feasible, safe, and low-cost apparatus for cigarette smoke exposure in rodents.

RESULTS

Rats exposed to cigarette smoke in this apparatus showed cotinine levels similar to human active smokers. Additional results showed that cigarette smoke exposure increased glutamate and aspartic acid levels and decreased leucine, isoleucine, ornithine, phenylalanine, and tryptophan levels in the cerebrospinal fluid of rats.

COMPARISON WITH EXISTING METHOD(S)

Our apparatus is feasible, safe, and costs 67-fold less than a commercial automatized smoking machine. Beyond the low cost, it does not require specialized knowledge for building or maintenance.

CONCLUSIONS

We concluded that our low-cost apparatus is reliable and reproduces cigarette smoke use in humans.

Smokeless Tobacco Exposure and Fetal Iron Status: An Analytical Study

Objectives:

To compare the cord serum ferritin and fetal iron status in newborns with and without maternal occupational smokeless tobacco exposure and determine the influencing factors.

Methods:

This cross-sectional study included mother–infant dyads with occupational tobacco exposure (exposed) and an unexposed group. Umbilical cord serum ferritin was compared in both groups. Fetal nicotine absorption was established by cord cotinine.

Results:

A total of 140 newborns each were analyzed in each group. There was no significant mean difference (MD) (P = 0.900) between the cord serum ferritin in the tobacco exposed and unexposed group. Fetal nicotine absorption was seen in 43.6% of the exposed group. Cord serum ferritin was 14.1 μg/L (95% confidence interval [(95% CI:-43.1, 14.9); P=0.338] lower in this group compared with the group without fetal nicotine absorption. A higher adjusted MD for ferritin was present for maternal hypertension (12.5 [95% CI: −75.5, 100.5]; P = 0.777) and gestational diabetes mellitus (21.4 [95% CI: −54.0, 96.9]; P = 0.571) in the group with fetal nicotine absorption. Fetal nicotine absorption exaggerated fetal iron depletion in maternal anemia [aOR 4.8 (95%CI: 1.2, 19.0); P=0.025].

Conclusion:

Cord serum ferritin and fetal iron status were comparable in tobacco exposed and unexposed groups. In those with fetal nicotine absorption, cord ferritin levels reflect the fetal inflammatory state.

DNA methylation differentiates smoking from vaping and non-combustible tobacco use

Increasing use of non-combusted forms of nicotine such as e-cigarettes poses important public health questions regarding their specific risks relative to combusted tobacco products such as cigarettes. To fully delineate these risks, improved biomarkers that can distinguish between these forms of nicotine use are needed. Prior work has suggested that methylation status at cg05575921 may serve as a specific biomarker of combusted tobacco smoke exposure. We hypothesized combining this epigenetic biomarker with conventional metabolite assays could classify the type of nicotine product consumption. Therefore, we determined DNA methylation and serum cotinine values in samples from 112 smokers, 35 e-cigarette users, 19 smokeless tobacco users, and 269 controls, and performed mass spectroscopy analyses of urine samples from all nicotine users and 22 verified controls to determine urinary levels of putatively nicotine product-specific substances; propylene glycol, 2-cyanoethylmercapturic acid (CEMA), and anabasine. 1) Cigarette smoking was associated with a dose dependent demethylation of cg05575921 and increased urinary CEMA and anabasine levels, 2) e-cigarette use did not demethylate cg05575921, 3) smokeless tobacco use also did not demethylate cg05575921 but was positively associated with anabasine levels 4) CEMA and cg05575921 levels were highly correlated and 5) propylene glycol levels did not reliably distinguish use groups. Cg05575921 assessments distinguish exposure to tobacco smoke from smokeless sources of nicotine including e-cigarettes and smokeless tobacco, neither of which are associated with cg05575921 demethylation. A combination of methylomic and metabolite profiling may allow for accurate classification use status of a variety of nicotine containing products.

How to manage cigarette smoking in kidney transplant candidates and recipients?

Tobacco smoking is a frequent problem affecting many kidney transplant (KT) candidates and recipients. The negative impact of active smoking on KT outcomes has been demonstrated. Consequently, most guidelines strongly recommend quitting smoking before considering kidney transplantation. However, nicotine addiction is a complex multifactorial disease and only 3–5% of the patients who try to quit by themselves achieve prolonged abstinence. Smoking cessation programmes (SCPs) have proven their efficacy in the general population to increase the rate of quitting and should therefore be proposed to all smoking KT candidates and recipients. Nevertheless, SCPs have not been evaluated in the KT field and not all KT centres have easy access to these programmes. In this work, we aim to review the current knowledge on the subject and provide an overview of the available interventions to help smoking patients quit. We detail non-pharmaceutical and pharmaceutical approaches and discuss their use in KT candidates and recipients.

Protecting Children From Tobacco Smoke Exposure: A Randomized Controlled Trial of Project Zero Exposure

INTRODUCTION

Young children are vulnerable to harm from tobacco smoke exposure (TSE). This study assessed the effect of Project Zero Exposure-an intervention program designed to help parents protect children from TSE-on children's exposure.

METHODS

Randomized controlled trial of a home-based, theory-driven intervention. Parents of young children (<8 y) in families with a smoking parent were eligible. The intervention included feedback on child TSE (hair nicotine), and home air quality (PM2.5), with motivational interviewing. Families were randomized to: intervention group (IG, N = 69), regular control group (RCG, N = 70), or to a secondary enhanced control group, (ECG, N = 20). Child hair samples were taken at baseline and follow-up. We report on child TSE in the IG versus RCG at six months.

RESULTS

Most enrolled families completed the trial (IG: 98.6%[68/69], RCG: 97.1%[68/70]). Log hair nicotine (LHN [ng/mg]) decreased in both the IG (Baseline: -1.78 ± 1.91, Follow-up: -2.82 ± 1.87, p = .003) and RCG (Baseline: -1.79 ± 1.54, Follow-up: -2.85 ± 1.73, p = .002), but did not differ between groups at study end (p = .635). Three of five parentally-reported outcomes showed improvement over time in the IG, and one in the RCG. Among IG participants, 90% found hair nicotine feedback useful.

CONCLUSIONS

No difference between the intervention and control groups was found on the objective biomarker, LHN. Child TSE decreased during the trial in intervention and control groups. Trial participation, which included hair nicotine monitoring, may have contributed to decreasing exposure in both groups. Concurrent control group improvements may partially explain lack of proven intervention benefit. Biomarker monitoring warrants further investigation for reduction of child TSE.

IMPLICATIONS

Project Zero Exposure is an intervention program designed to help parents protect their children from TSE. Results from the randomized controlled trial of the program showed no difference between groups at study end, but a clear and substantial reduction in child exposure to tobacco smoke from beginning to end of the trial, in both intervention and control groups. Biomarker monitoring, a key element of the trial, was used with all participants. Biomarker monitoring of child exposure to tobacco smoke may help parents become aware of their child's exposure and better protect them, and should be explored as a means to reduce child TSE. Clinical Trial Registration: NCT02867241.

The relationship of smoking to cg05575921 methylation in blood and saliva DNA samples from several studies

Numerous studies have shown that cg05575921 methylation decreases in response to smoking. However, secondary to methodological issues, the magnitude and dose dependency of that response is as of yet unclear. This lack of certainty is a barrier to the use of DNA methylation clinically to assess and monitor smoking status. To better define this relationship, we conducted a joint analysis of methylation sensitive PCR digital (MSdPCR) assessments of cg05575921 methylation in whole blood and/or saliva DNA to smoking using samples from 421 smokers and 423 biochemically confirmed non-smokers from 4 previously published studies. We found that cg05575921 methylation manifested a curvilinear dose dependent decrease in response to increasing cigarette consumption. In whole blood DNA, the Receiver Operating Characteristic (ROC) Area Under the Curve (AUC) of cg05575921 methylation for predicting daily smoking status was 0.98. In saliva DNA, the gross AUC was 0.91 with correction for cellular heterogeneity improving the AUC to 0.94. Methylation status was significantly associated with the Fagerstrom Test for Nicotine Dependence score, but with significant sampling heterogeneity. We conclude that MSdPCR assessments of cg05575921 methylation are a potentially powerful, clinically implementable tool for the assessment and management of smoking.

Associations between Second-Hand Tobacco Smoke Exposure and Cardiorespiratory Fitness, Physical Activity, and Respiratory Health in Children

BACKGROUND

Cardiorespiratory fitness (CRF) and physical activity (PA) are associated with a plethora of positive health effects. Many UK children fail to meet the recommended level of PA, with an observed decline in CRF levels over recent decades. Second-hand tobacco smoke (SHS) is responsible for a significant proportion of the worldwide burden of disease, but little is understood regarding the impact of SHS exposure on CRF and PA in children. The aim of this study was to test the associations between SHS exposure and CRF, PA, and respiratory health in children.

METHOD

Children (9-11 years) from UK primary schools in deprived areas participated (n = 104, 38 smoking households). Surveys determined household smoking, and exhaled carbon monoxide was used to indicate children's recent SHS exposure. CRF (VO_2peak) was assessed via maximal treadmill protocol using breath-by-breath analysis. Fractional exhaled nitric oxide and spirometry were utilised as indicators of respiratory health.

RESULTS

Linear regression models demonstrated that SHS exposure was negatively associated with allometrically scaled VO_2peak (B = -3.8, p = 0.030) but not PA or respiratory health.

CONCLUSION

The results indicate that SHS is detrimental to children's CRF; given that approximately one-third of children are regularly exposed to SHS, this important finding has implications for both public health and the sport and exercise sciences.

Altered Development of Mesencephalic Dopaminergic Neurons in SIDS: New Insights into Understanding Sudden Infant Death Pathogenesis

Sudden infant death syndrome (SIDS) is defined as the unexpected sudden death of an infant under 1 year of age that remains unexplained after a thorough case investigation. The SIDS pathogenesis is still unknown; however, abnormalities in brain centers that control breathing and arousal from sleep, including dramatic changes in neurotransmitter levels, have been supposed in these deaths. This is the first study focusing on mesencephalic dopaminergic neurons, so far extensively studied only in animals and human neurological diseases, in SIDS. Dopaminergic structures in midbrain sections of a large series of sudden infant deaths (36 SIDS and 26 controls) were identified using polyclonal rabbit antibodies against tyrosine hydroxylase, the rate-limiting enzyme in catecholamine biosynthesis, and the dopamine transporter, a membrane protein specifically expressed in dopaminergic cells. Dopamine-immunolabeled neurons were observed concentrated in two specific structures: the pars compacta of the substantia nigra and in the subnucleus medialis of the periaqueductal gray matter. Anatomical and functional degenerations of dopaminergic neurons in these regions were observed in most SIDS cases but never in controls. These results indicate that dopamine depletion, which is already known to be linked especially to Parkinson's disease, is strongly involved even in SIDS pathogenesis.

Prenatal environmental tobacco smoke exposure alters children's cognitive control circuitry: A preliminary study

BACKGROUND AND OBJECTIVES

Prenatal exposure to environmental tobacco smoke (ETS) is associated with increased attention problems in children, however, the effects of such exposure on children's brain structure and function have not been studied. Herein, we probed effects of prenatal ETS on children's cognitive control circuitry and behavior.

METHODS

Forty-one children (7-9 years) recruited from a prospective longitudinal birth cohort of non-smoking mothers completed structural and task-functional magnetic resonance imaging to evaluate effects of maternal ETS exposure, measured by maternal prenatal urinary cotinine. Attention problems and externalizing behaviors were measured by parent report on the Child Behavior Checklist.

RESULTS

Compared to non-exposed children, exposed children had smaller left and right thalamic and inferior frontal gyrus (IFG) volumes, with large effect sizes (p-FDR < .05, Cohen's D range from 0.79 to 1.07), and increased activation in IFG during the resolution of cognitive conflict measured with the Simon Spatial Incompatibility Task (38 voxels; peak t(25) = 5.25, p-FWE = .005). Reduced thalamic volume was associated with increased IFG activation and attention problems, reflecting poor cognitive control. Mediation analyses showed a trend toward left thalamic volume mediating the association between exposure and attention problems (p = .05).

CONCLUSIONS

Our findings suggest that maternal ETS exposure during pregnancy has deleterious effects on the structure and function of cognitive control circuitry which in turn affects attentional capacity in school-age children. These findings are consistent with prior findings documenting the effects of active maternal smoking on chidlren's neurodevleoment, pointing to the neurotixicity of nicotine regardless of exposure pathway.

Indoor Environmental Factors May Modify the Response to Mouse Allergen Reduction Among Mouse-Sensitized and Exposed Children with Persistent Asthma

BACKGROUND

Whether concomitant home exposures modify the effectiveness of mouse allergen reduction among mouse-sensitized children with asthma is unknown.

OBJECTIVE

To determine whether a lower baseline home mouse allergen level, lower particulate matter 10 μ or less (PM₁₀), and the absence of sensitization and exposure to other indoor allergens are associated with greater improvements in asthma associated with mouse allergen reduction.

METHODS

A secondary analysis of a randomized clinical trial of a home mouse allergen intervention was performed to examine the effect of 3 indoor factors on the relationship between mouse allergen reduction and a range of asthma outcomes.

RESULTS

Participants (N = 297) were predominantly minority (78% African American, 22% Hispanic) and publicly insured (88%). Higher baseline mouse allergen levels were associated with a greater response to mouse allergen reduction for several symptom and exacerbation outcomes. Lower indoor PM₁₀ levels were associated with a greater response to mouse allergen reduction for several symptom outcomes, but not exacerbation outcomes. Overall, sensitization and exposure to other indoor allergens did not appear to modify the effect of mouse allergen reduction.

CONCLUSIONS

In this population of predominantly low-income children with persistent asthma and mouse sensitization, mouse allergen reduction was associated with improvements in asthma, especially among those with high baseline mouse allergen exposure. Lower indoor PM₁₀ was associated with greater improvements in asthma symptoms.

Epigenetic Analyses of Alcohol Consumption in Combustible and Non-Combustible Nicotine Product Users

Alcohol and tobacco use are highly comorbid and exacerbate the associated morbidity and mortality of either substance alone. However, the relationship of alcohol consumption to the various forms of nicotine-containing products is not well understood. To improve this understanding, we examined the relationship of alcohol consumption to nicotine product use using self-report, cotinine, and two epigenetic biomarkers specific for smoking (cg05575921) and drinking (Alcohol T Scores (ATS)) in n = 424 subjects. Cigarette users had significantly higher ATS values than the other groups (p < 2.2 × 10⁻¹⁶). Using the objective biomarkers, the intensity of nicotine and alcohol consumption was correlated in both the cigarette and smokeless users (R = −0.66, p = 3.1 × 10⁻¹⁴; R² = 0.61, p = 1.97 × 10⁻⁴). Building upon this idea, we used the objective nicotine biomarkers and age to build and test a Balanced Random Forest classification model for heavy alcohol consumption (ATS > 2.35). The model performed well with an AUC of 0.962, 89.3% sensitivity, and 85% specificity. We conclude that those who use non-combustible nicotine products drink significantly less than smokers, and cigarette and smokeless users drink more with heavier nicotine use. These findings further highlight the lack of informativeness of self-reported alcohol consumption and suggest given the public and private health burden of alcoholism, further research into whether using non-combustible nicotine products as a mode of treatment for dual users should be considered.

Association between Self-Reported Survey Measures and Biomarkers of Second-Hand Tobacco Smoke Exposure in Non-Smoking Pregnant Women

Second-hand tobacco smoke (SHS) causes adverse health outcomes in adults. Further studies are needed to evaluate psychosocial SHS exposure measures in comparison to SHS exposure biomarkers, particularly in pregnant women. This study aimed to compare self-reported SHS exposure to urinary cotinine levels in pregnant women. A cross-sectional correlation design was conducted using a convenience sample of 70 non-smoking pregnant women. Measures included self-reported questionnaires and laboratory confirmation of cotinine levels in the urinary samples. Multiple regression analysis was used to assess the correlation after controlling for potential confounding variables. The average level of urinary cotinine among non-smoking pregnant women was 6.77 ng/mL. Medium-strength correlations were found among psychosocial SHS exposure measures and urine cotinine levels. Questions regarding ‘instances of smoking in front of the individual’ and ‘subjective perceived frequency of SHS exposure in past 7 days’ are feasible items for pregnant women in clinics (particularly the first question). Hence, we suggest that these simple questions should be used to assist pregnant women in reducing the harm associated with SHS exposure.

Secondhand Smoke Exposure is Associated with Prevalent Heart Failure: Longitudinal Examination of the National Health and Nutrition Examination Survey

INTRODUCTION

Serum cotinine is a sensitive and specific biomarker for tobacco exposure including second-hand smoke exposure (SHS). We sought to examine whether SHS is associated with heart failure (HF) among non-hospitalized adults.

METHODS

This analysis included 11 219 non-smokers (age 48.4 ± 20.5 years, 55.9% women, 70.5% whites) from the United States Third National Health and Nutrition Examination (NHANES) years 1988-1994. SHS was defined as serum cotinine ≥1 ng/mL. To assess dose-response, cut-points of serum cotinine ≥3 ng/mL and ≥6 ng/mL were used. Multivariable logistic regression was used to examine the association between SHS and HF. The consistency of this association was tested among subgroups stratified by race, gender, and comorbidities. NHANES years 2003-2006 were examined for longitudinal comparison.

RESULTS

18.9% (n = 2125) of participants had SHS exposure while 3.7% (n = 416) had HF. After adjusting for covariates, SHS was associated with a 35% increased odds of HF with a dose-response relationship between levels of serum cotinine and HF. This association was stronger in males than females (interaction p-value = 0.03) and those with a history of CVD versus those without (interaction p-value < 0.001). This association persisted in the NHANES 2003-2006 analysis.

CONCLUSION

There is a dose-response relationship between SHS and HF with possible effect modification by gender and prior CVD. This is a novel finding that underscores the harmful effects of passive smoking on the cardiovascular system and highlights the needs for further prohibition of smoking in public areas and a personalized risk assessment among high-risk groups, especially in regions with less-stringent public health policies.

IMPLICATIONS

This study showed a novel association between secondhand smoke exposure and prevalent heart failure among non-smokers, adding to the list of harmful cardiovascular manifestations of secondhand smoke exposure. This was more apparent in men and those with a prior history of cardiovascular disease. Heart failure is a debilitating disease process, so this finding has important policy implications in low-income countries and poor communities with less-stringent health policies because they are known to have the highest levels of exposure. Smoke-free policies targeting these regions would thus yield substantial public health benefits.

Secondhand tobacco smoke exposure among children under 5 years old: questionnaires versus cotinine biomarkers: a cohort study

OBJECTIVES

Cotinine is the gold standard to estimate prevalence of secondhand tobacco smoke (SHS) exposure, and assay limit of detection (LOD) cut-points are typically used regardless of age. Our aim was to compare the concordance between mother-reported SHS exposure and serum cotinine categorising children as exposed with the assay LOD or age-specific cut-points.

DESIGN

Data from the Health Outcomes and Measures of the Environment (HOME) Study, a prospective pregnancy and birth cohort.

SETTING

Hospital or participants' homes.

PARTICIPANTS

389 pregnant women aged 18 years and older, between 13 and 19 weeks of gestation, living in a five-county region of the Cincinnati, Ohio metropolitan area, and with follow-up on their children at birth and ages 12, 24, 36 and 48 months.

PRIMARY AND SECONDARY OUTCOME MEASURES

Children's serum cotinine, mother-reported active smoking and SHS exposure were available at birth and during follow-up visits. We used Cohen's kappa index to assess concordance between maternal self-report and child's serum cotinine concentrations. We estimated optimal age-specific cut-points, their sensitivity-specificity and positive-negative predictive values with receiver operating characteristic curves.

RESULTS

Self-reported exposure and cotinine data were available for 280 women who gave birth to singleton child. When applying the assay LOD (0.015 ng/mL), concordance between maternal report and serum cotinine, without accounting for age, was below 0.23 at all times. When using age-specific cut-points (12 months: 0.11 ng/mL; 24 months: 0.08 ng/mL; 36 months: 0.05 ng/mL and 48 months: 0.04 ng/mL), concordance improved, being low at 12 months (0.39), moderate at 24 and 36 months (0.47 and 0.43) and high at 48 months (0.62).

CONCLUSIONS

Concordance between mother-reported SHS exposure among children under 5 years and serum cotinine improved considerably after applying the cohort-specific and age-specific cut-points. Future studies are necessary to verify these results.

Developing Analytical Applications for Parahydrogen Hyperpolarization: Urinary Elimination Pharmacokinetics of Nicotine

Nuclear magnetic resonance spectroscopy (NMR) is a valuable analytical tool with applications in a vast array of research fields from chemistry and biology to medicine and beyond. NMR is renowned for its straightforward data interpretation and quantitative properties, making it attractive for pharmacokinetic applications, where drug metabolism pathways, concentrations, and kinetics need to be evaluated. However, pharmacologically active compounds and their metabolites in biofluids often appear in minute concentrations, well below the detection limit of NMR. Herein, we demonstrate how parahydrogen hyperpolarization overcomes this sensitivity barrier, allowing us to detect mid-nanomolar concentrations of a drug and a drug metabolite in a biofluid matrix. The performance of the method is demonstrated by monitoring nicotine and cotinine urinary elimination, reflected by their concentrations in urine during the onset and withdrawal from nicotine consumption. An NMR limit of detection of 0.1 μM and a limit of quantitation of 0.7 μM is achieved in a practical pharmacokinetics scenario where precise quantitative and qualitative analysis is desired.