Determination of cotinine and 3-hydroxynicotinine in human serum by liquid chromatography-tandem mass spectrometry and its application.

In this study, we developed a method for determining cotinine and 3-hydroxycotinine in human serum and established a methodology for an in-depth study of tobacco exposure and health. After the proteins in the human serum samples were precipitated with acetonitrile, they were separated on a ZORBAX SB-Phenyl column with a mobile phase of methanol encompassing 0.3% formic acid-water encompassing 0.15% formic acid. The measurement was performed on an API5500 triple quadrupole mass spectrometer in the multiple reaction monitoring mode. Cotinine, 3-hydroxycotinine, and cotinine-d3 isotope internal standards were held for 2.56 minutes, 1.58 minutes, and 2.56 minutes, respectively. In serum, the linear range was 0.05 to 500 ng·mL-1 for cotinine and 0.50 to 1250 ng·mL-1 for 3-hydroxycotinine. The lower limit of quantification (LLOQ) was 0.05 ng·mL-1 and 0.5 ng·mL-1 for cotinine and 3-hydroxycotinine, respectively. The intra-day and inter-day relative standard deviations were <11%, and the relative errors were within ±â€…7%. Moreover, the mean extraction recoveries of cotinine and 3-hydroxycotinine were 98.54% and 100.24%, respectively. This method is suitable for the rapid determination of cotinine and 3-hydroxycotinine in human serum because of its rapidity, sensitivity, strong specificity, and high reproducibility. The detection of cotinine levels in human serum allows for the identification of the cutoff value, providing a basis for differentiation between smoking and nonsmoking populations.

Associations between smoking, sex steroid hormones, trouble sleeping, and depression among U.S. adults: a cross-sectional study from NHANES (2013-2016).

BACKGROUND: Dose-response and nonlinear relationships of cigarette exposure with sleep disturbances and depression are warranted, and the potential mechanism of sex hormones in such associations remains unclear. METHODS: Cigarette exposure, trouble sleeping, and depression were assessed by standard questionnaires, and the levels of cotinine and sex steroid hormones were determined among 9900 adults from the National Health and Nutrition Examination Survey (NHANES). Multiple linear regression, logistic regression, and mediation models were conducted to evaluate the associations between smoking, sex steroid hormones, trouble sleeping, and depression. RESULTS: With never smokers as a reference, current smokers had a higher prevalence of trouble sleeping (OR = 1.931, 95% CI: 1.680, 2.219) and depression (OR = 2.525, 95% CI: 1.936, 3.293) as well as testosterone level (ß = 0.083, 95% CI: 0.028, 0.140). Pack-years of smoking and cigarettes per day were positively associated with the prevalence of trouble sleeping and depression as well as testosterone level (Ptrend <0.05). The restricted cubic spline model showed linear relationships of cotinine with trouble sleeping, depression, and testosterone. The positive associations of cigarettes per day with trouble sleeping and depression were greater in females than that in males (Pmodification <0.05). However, the potential role of sex hormones was not observed in the association of cotinine with trouble sleeping or depression (Pmediation >0.05). CONCLUSION: Smoking may induce sex hormone disturbance and increase the risk of sleep problems and depression symptoms, and ceasing smoking may reduce the risk of such complications.

Association between serum cotinine and hepatic steatosis and liver fibrosis in adolescent: a population-based study in the United States.

Tobacco exposure is known to be associated with a higher prevalence and incidence of liver diseases. Cotinine, a metabolite of nicotine, is a typical indicator of tobacco exposure. However, the relationship of serum cotinine levels with hepatic steatosis and liver fibrosis remains controversial and these relationships need more research to explored in American teenagers. Cross-sectional data included 1433 participants aged 12-19 from the National Health and Nutrition Examination Survey (NHANES) from 2017 to 2020 were thoroughly used for this study. The linear relationships between serum cotinine levels and the Liver Stiffness Measurement (LSM) and Controlled Attenuation Parameter (CAP) were examined using multiple linear regression models. Subgroup analysis, interaction tests, and nonlinear interactions were also carried out. Serum cotinine levels > 2.99 ng/ml [ß = 0.41 (0.07, 0.76), p = 0.018] and 0.05-2.99 ng/ml [ß = 0.24 (0.00, 0.49), p = 0.048] showed a significant positive connection with LSM in multivariate linear regression analysis when compared to serum cotinine levels ≤ 0.05 ng/ml (p for trend = 0.006). Moreover, we discovered an inverted U-shaped association of log2-transformed cotinine with LSM with an inflection point of 4.53 using a two-stage linear regression model. However, according to multiple regression analysis, serum cotinine and CAP did not significantly correlate (p = 0.512). In conclusion, this study demonstrated that smoking cessation and keep away from secondhand smoking may beneficial for liver health in American teenagers.

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.

Child and Adolescent Manganese Biomarkers and Adolescent Postural Balance in Marietta CARES Cohort Participants.

BACKGROUND: Manganese (Mn) plays a significant role in both human health and global industries. Epidemiological studies of exposed populations demonstrate a dose-dependent association between Mn and neuromotor effects ranging from subclinical effects to a clinically defined syndrome. However, little is known about the relationship between early life Mn biomarkers and adolescent postural balance. OBJECTIVES: This study investigated the associations between childhood and adolescent Mn biomarkers and adolescent postural balance in participants from the longitudinal Marietta Communities Actively Researching Exposures Study (CARES) cohort. METHODS: Participants were recruited into CARES when they were 7-9 y old, and reenrolled at 13-18 years of age. At both time points, participants provided samples of blood, hair, and toenails that were analyzed for blood Mn and lead (Pb), serum cotinine, hair Mn, and toenail Mn. In adolescence, participants completed a postural balance assessment. Greater sway indicates postural instability (harmful effect), whereas lesser sway indicates postural stability (beneficial effect). Multivariable linear regression models were conducted to investigate the associations between childhood and adolescent Mn biomarkers and adolescent postural balance adjusted for age, sex, height-weight ratio, parent/caregiver intelligence quotient, socioeconomic status, blood Pb, and serum cotinine. RESULTS: CARES participants who completed the adolescent postural balance assessment (n=123) were 98% White and 54% female and had a mean age of 16 y (range: 13-18 y). In both childhood and adolescence, higher Mn biomarker concentrations were significantly associated with greater adolescent sway measures. Supplemental analyses revealed sex-specific associations; higher childhood Mn biomarker concentrations were significantly associated with greater sway in females compared with males. DISCUSSION: This study found childhood and adolescent Mn biomarkers were associated with subclinical neuromotor effects in adolescence. This study demonstrates postural balance as a sensitive measure to assess the association between Mn biomarkers and neuromotor function. https://doi.org/10.1289/EHP13381.

Association between secondhand smoke exposure and rheumatoid arthritis in US never-smoking adults: a cross-sectional study from NHANES.

While smoking is widely acknowledged as a risk factor for rheumatoid arthritis (RA), the connection between secondhand smoke (SHS) exposure and RA in never-smoking adults remains limited and inconsistent. This study aims to explore and quantify this association using serum cotinine levels. We conducted a cross-sectional study with 14,940 adults who self-report as never smokers, using National Health and Nutrition Examination Survey data from 1999 to 2018. Based on previous literature, SHS exposure was categorized into four groups according to serum cotinine levels. Compared to individuals in the unexposed group (serum cotinine < 0.05 ng/mL), the adjusted odds ratio (OR) for RA was 1.37 (95% CI 1.14-1.64, p = 0.001) in the low exposure group (serum cotinine at 0.05 to 0.99 ng/mL) after adjusting for covariates. However, no significant association was found in the moderate exposure group (serum cotinine at 1 to 10 ng/mL) or the heavy exposure group (serum cotinine ≥ 10 ng/mL). Furthermore, we detected a non-linear, positively saturated correlation between the cotinine levels after log2 transformation and RA, with a turning point at approximately - 2.756 ng/mL (OR = 1.163, 95% CI 1.073-1.261, p = 0.0002). The stability of the results was confirmed by subgroup analysis.

Changes in biomarkers of exposure and withdrawal symptom among Chinese adult smokers after completely or partially switching from combustible cigarettes to an electronic nicotine delivery system.

This study assessed changes in biomarkers of exposure (BoE) after 5 days of completely or partially switching to an electronic nicotine delivery system (ENDS) use, compared with continued use of combustible cigarettes and smoking abstinence among Chinese adult smokers. A randomized, open-label, parallel-arm study was conducted among Chinese adult smokers who were naive ENDS users. Forty-six subjects were randomized to 4 study groups (n = 11-12 per group): exclusive ENDS use, dual use of ENDS and cigarettes, exclusive cigarettes use, and smoking abstinence. Subjects were confined in clinic for 5 consecutive days and product use was ad libitum. Nicotine and its metabolites (cotinine and 3-hydroxycotinine), and BoEs (AAMA, CEMA, HEMA, HMPMA, 3-HPMA, SPMA, exhaled CO, and exhaled NO) were measured. Withdrawal symptom was measured using MNWS throughout the 5-day period. Six urine BoEs of volatile organic compounds decreased by 55.1-84.1% in the exclusive ENDS use group, which is similar to the smoking abstinence group (67.2-87.4%). The level of decrease was 56.8-70.4% in the dual use group and 10.7-39.0% in the cigarettes group. Urine total nicotine exposure had a non-significant increase in the exclusive ENDS use group, and plasma nicotine and cotinine showed a trend of increasing day by day. After completely or partially switching to ENDS use among Chinese smokers, exposure to selected toxicants were significantly decreased. The results of this study add to the body of evidence that exposure to toxic substance decreased among smokers after complete or partial switch from combustible cigarettes to ENDS use. As part of transition to experienced ENDS use, this study found that smokers of the initial stage who have no prior ENDS experience may increase nicotine intake after switching to ENDS use.

Association Between Secondhand Smoke Exposure and Nonalcoholic Fatty Liver Disease in the General U.S. Adult Nonsmoker Population.

INTRODUCTION: Smoking is a cause of nonalcoholic fatty liver disease (NAFLD), but the dose-response relationship between secondhand smoke exposure (SHS) and NAFLD is unclear. This study sought to determine the relationship between SHS and NAFLD risk among adult nonsmokers in the United States. AIMS AND METHODS: Data from 7412 adult nonsmokers aged ≥20 years who participated in the National Health and Nutrition Examination Survey (NHANES) between 2007 and 2016 were used in this study. SHS was defined as a nonsmoker with a serum cotinine concentration of 0.05-10.00 ng/mL. NAFLD was identified using the U.S. fatty liver index (USFLI), hepatic steatosis index (HSI), and fatty liver index (FLI). Weighted multivariable logistic regression and restricted cubic spline models were applied to evaluate the relationship between SHS and NAFLD risk. RESULTS: The participants had a weighted mean age of 49.2 years, and 55.5% were female. SHS was associated with NAFLD (odds ratio [OR] 1.22; 95% confidence interval CI: 1.05 to 1.42), showing a linear dose-response relationship (natural log of cotinine level: OR 1.10, 95% CI: 1.05 to 1.17). Sensitivity analyses using different NAFLD definitions (HSI: OR 1.21, 95% CI: 1.01 to 1.46; FLI: OR 1.26, 95% CI: 1.06 to 1.49), excluding participants taking hepatotoxic drugs, and propensity score-adjusted analysis yielded similar results. The association between SHS and NAFLD was consistent in analyses stratified by age, sex, and race/ethnicity. CONCLUSIONS: Among this nationally representative sample of U.S. adults, SHS had a linear dose-response relationship with the risk of NAFLD, suggesting that measures to lower SHS might lower NAFLD risk. IMPLICATIONS: This study assessed the association between secondhand smoke exposure and the risk of nonalcoholic fatty liver disease (NAFLD) using data from 7412 adult nonsmokers aged 20 years or older who participated in the United States NHANES between 2007 and 2016. Secondhand smoke exposure was measured using serum cotinine levels. Three different noninvasive indexes were used to measure NAFLD. Secondhand smoke exposure was associated with an increased risk of NAFLD, with a linear dose-response relationship. The results of sensitivity analyses and subgroup analyses were consistent.

Serum Cotinine and Adverse Cardiovascular Outcomes: A Cross-sectional Secondary Analysis of the nuMoM2b Heart Health Study.

OBJECTIVE: We aimed to (1) compare serum cotinine with self-report for ascertaining smoking status among reproductive-aged women; (2) estimate the relative odds of adverse cardiovascular (CV) outcomes among women by smoking status; (3) assess whether the association between adverse pregnancy outcomes (APOs) and CV outcomes varies by smoking status. STUDY DESIGN: We conducted a cross-sectional study of the nuMoM2b Heart Health Study. Women attended a study visit 2 to 7 years after their first pregnancy. The exposure was smoking status, determined by self-report and by serum cotinine. Outcomes included incident chronic hypertension (HTN), metabolic syndrome (MetS), and dyslipidemia. Multivariable logistic regression estimated odds ratios (ORs) for each outcome by smoking status. RESULTS: Of 4,392 women with serum cotinine measured, 3,610 were categorized as nonsmokers, 62 as secondhand smoke exposure, and 720 as smokers. Of 3,144 women who denied tobacco smoke exposure, serum cotinine was consistent with secondhand smoke exposure in 48 (1.5%) and current smoking in 131 (4.2%) After adjustment for APOs, smoking defined by serum cotinine was associated with MetS (adjusted OR [aOR] = 1.52, 95% confidence interval [CI]: 1.21, 1.91) and dyslipidemia (aOR = 1.28, 95% CI: 1.01, 1.62). When stratified by nicotine exposure, nonsmokers with an APO in their index pregnancy had higher odds of stage 1 (aOR = 1.64, 95% CI: 1.32, 2.03) and stage 2 HTN (aOR = 2.92, 95% CI: 2.17, 3.93), MetS (aOR = 1.76, 95% CI: 1.42, 2.18), and dyslipidemia (aOR = 1.55, 95% CI: 1.25, 1.91) relative to women with no APO. Results were similar when smoking exposure was defined by self-report. CONCLUSION: Whether determined by serum cotinine or self-report, smoking is associated with subsequent CV outcomes in reproductive-aged women. APOs are also independently associated with CV outcomes in women. KEY POINTS: · Cotinine was detected in 5.7% of reported nonsmokers.. · Smoking and APOs were independently associated with CV health.. · Smoking was associated with MetS and dyslipidemia..

Sources of Tobacco Smoke Exposure and Their Associations With Serum Cotinine Levels Among US Children and Adolescents.

INTRODUCTION: We assessed tobacco smoke exposure (TSE) levels based on private and public locations of TSE according to race and ethnicity among US school-aged children ages 6-11 years and adolescents ages 12-17 years. AIMS AND METHODS: Data were from 5296 children and adolescents who participated in the National Health and Nutrition Examination Survey (NHANES) 2013-2018. Racial and ethnic groups were non-Hispanic white, black, other or multiracial, and Hispanic. NHANES assessed serum cotinine and the following TSE locations: homes and whether smokers did not smoke indoors (home thirdhand smoke [THS] exposure proxy) or smoked indoors (secondhand [SHS] and THS exposure proxy), cars, in other homes, restaurants, or any other indoor area. We used stratified weighted linear regression models by racial and ethnic groups and assessed the variance in cotinine levels explained by each location within each age group. RESULTS: Among 6-11-year-olds, exposure to home THS only and home SHS + THS predicted higher log-cotinine among all racial and ethnic groups. Non-Hispanic white children exposed to car TSE had higher log-cotinine (ß = 1.64, 95% confidence interval [CI] = 0.91% to 2.37%) compared to those unexposed. Non-Hispanic other/multiracial children exposed to restaurant TSE had higher log-cotinine (ß = 1.13, 95% CI = 0.23% to 2.03%) compared to those unexposed. Among 12-17-year-olds, home SHS + THS exposure predicted higher log-cotinine among all racial and ethnic groups, except for non-Hispanic black adolescents. Car TSE predicted higher log-cotinine among all racial and ethnic groups. Non-Hispanic black adolescents with TSE in another indoor area had higher log-cotinine (ß = 2.84, 95% CI = 0.85% to 4.83%) compared to those unexposed. CONCLUSIONS: TSE location was uniquely associated with cotinine levels by race and ethnicity. Smoke-free home and car legislation are needed to reduce TSE among children and adolescents of all racial and ethnic backgrounds. IMPLICATIONS: Racial and ethnic disparities in TSE trends have remained stable among US children and adolescents over time. This study's results indicate that TSE locations differentially contribute to biochemically measured TSE within racial and ethnic groups. Home TSE significantly contributed to cotinine levels among school-aged children 6-11 years old, and car TSE significantly contributed to cotinine levels among adolescents 12-17 years old. Racial and ethnic differences in locations of TSE were observed among each age group. Study findings provide unique insight into TSE sources, and indicate that home and car smoke-free legislation have great potential to reduce TSE among youth of all racial and ethnic backgrounds.

Application of HPLC-QQQ-MS/MS and New RP-HPLC-DAD System Utilizing the Chaotropic Effect for Determination of Nicotine and Its Major Metabolites Cotinine, and trans-3'-Hydroxycotinine in Human Plasma Samples.

The routine techniques currently applied for the determination of nicotine and its major metabolites, cotinine, and trans-3'-hydroxycotinine, in biological fluids, include spectrophotometric, immunoassays, and chromatographic techniques. The aim of this study was to develop, and compare two new chromatographic methods high-performance liquid chromatography coupled to triple quadrupole mass spectrometry (HPLC-QQQ-MS/MS), and RP-HPLC enriched with chaotropic additives, which would allow reliable confirmation of tobacco smoke exposure in toxicological and epidemiological studies. The concentrations of analytes were determined in human plasma as the sample matrix. The methods were compared in terms of the linearity, accuracy, repeatability, detection and quantification limits (LOD and LOQ), and recovery. The obtained validation parameters met the ICH requirements for both proposed procedures. However, the limits of detection (LOD) were much better for HPLC-QQQ-MS/MS (0.07 ng mL-1 for trans-3'-hydroxcotinine; 0.02 ng mL-1 for cotinine; 0.04 ng mL-1 for nicotine) in comparison to the RP-HPLC-DAD enriched with chaotropic additives (1.47 ng mL-1 for trans-3'-hydroxcotinine; 1.59 ng mL-1 for cotinine; 1.50 ng mL-1 for nicotine). The extraction efficiency (%) was concentration-dependent and ranged between 96.66% and 99.39% for RP-HPLC-DAD and 76.8% to 96.4% for HPLC-QQQ-MS/MS. The usefulness of the elaborated analytical methods was checked on the example of the analysis of a blood sample taken from a tobacco smoker. The nicotine, cotinine, and trans-3'-hydroxycotinine contents in the smoker's plasma quantified by the RP-HPLC-DAD method differed from the values measured by the HPLC-QQQ-MS/MS. However, the relative errors of measurements were smaller than 10% (6.80%, 6.72%, 2.04% respectively).

Multilevel Intervention for Low-Income Maternal Smokers in the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC).

Objectives. To test the efficacy of Babies Living Safe and Smokefree (BLiSS), a multilevel intervention initiated in a citywide safety net health system to improve low-income maternal smokers' abstinence and reduce child tobacco smoke exposure. Methods. This randomized controlled trial in Philadelphia, Pennsylvania (2015-2020), recruited low-income maternal smokers who received a brief smoking intervention (Ask, Advise, Refer [AAR]) from nutrition professionals in the Special Supplemental Nutrition Program for Women, Infants, and Children before randomization to (1) a multilevel intervention (AAR + multimodal behavioral intervention [MBI]; n = 199) or (2) an attention control intervention (AAR + control; n = 197). Results. AAR + MBI mothers had significantly higher 12-month bioverified abstinence rates than did AAR + control mothers (odds ratio [OR] = 9.55; 95% confidence interval [CI] = 1.54, 59.30; P = .015). There were significant effects of time (b = -0.15; SE = 0.04; P < .001) and condition by time (b = -0.19; SE = 0.06; P < .001) on reported child exposure favoring AAR + MBI, but no group difference in child cotinine. Presence of other residential smokers was related to higher exposure. Higher baseline nicotine dependence was related to higher child exposure and lower abstinence likelihood at follow-up. Conclusions. The multilevel BLiSS intervention was acceptable and efficacious in a population that experiences elevated challenges with cessation. Public Health Implications. BLiSS is a translatable intervention model that can successfully improve efforts to address the persistent tobacco-related burdens in low-income communities. Trial Registration. Clinical Trials.gov identifier: NCT02602288. (Am J Public Health. 2022;112(3):472-481. https://doi.org/10.2105/AJPH.2021.306601).

Trans-placental transfer of nicotine: Modulation by organic cation transporters.

Nicotine is a highly addictive substance and harmful to the developing foetus. However, few studies have investigated the transporter mechanism responsible for regulating the transfer of nicotine across the blood-placental interface. A multiple in-vivo microdialysis system coupled to ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was developed to monitor simultaneously nicotine and cotinine in the blood, placenta, foetus, and amniotic fluid of pregnant rats. The pharmacological mechanism of nicotine transfer across the placenta was investigated by co-administering corticosterone, an inhibitor of organic cation transporters (OCTs) that partly mediate the exchange of nicotine across the placenta. The results revealed that intravenously administered nicotine (1 mg/kg) was rapidly metabolised to cotinine with a transformation ratio (AUCcotinine/AUCnicotine) of 0.67 ± 0.08, 0.21 ± 0.05, 0.25 ± 0.12, 0.31 ± 0.05 in maternal blood, placenta, amniotic fluid, and foetus, respectively. The tissue transformation ratios (AUCtissue/AUCblood) were 0.83 ± 0.16, 0.65 ± 0.17, 0.57 ± 0.13 for nicotine, and 0.25 ± 0.06, 0.24 ± 0.12, 0.26 ± 0.04 for cotinine at placenta, amniotic fluid and foetus, respectively. Following the co-administration of corticosterone (2 mg/kg), the tissue transformation ratio of nicotine was significantly reduced in the placenta but was significantly increased in the foetus. Levels of cotinine were not significantly altered by the administration of corticosterone. These findings implicate OCT in mediating the transfer of nicotine across the blood-placenta barrier. Understanding the mechanism of nicotine transfer through the placenta may inform therapeutic strategies to lessen the exposure of the developing foetus to nicotine in the maternal bloodstream.

Smoking cessation reduces systemic inflammation and circulating endothelin-1.

Smoking increases systemic inflammation and circulating endothelin-1 (ET-1), both of which contribute to an elevated risk of cardiovascular disease (CVD). The present study sought to test the hypothesis that a 12-week smoking cessation intervention would contribute to a long-term reduction in circulating ET-1, tumor necrosis factor-alpha (TNF-α), and interleukin-6 (IL-6). 30 individuals participated in a 12-week evidence-based smoking cessation program at Augusta University. Serum cotinine, plasma inflammatory cytokines, and plasma ET-1 were determined at baseline, immediately after the 12-week cessation program (end of treatment, EOT), and 12-months (12M) following the cessation program. Serum cotinine was significantly reduced (p < 0.001) at EOT and 12M following the smoking cessation program. Compared to BL (7.0 ± 1.6 pg/mL), TNF-α was significantly reduced at EOT (6.3 ± 1.5 pg/mL, p = 0.001) and 12M (5.2 ± 2.7 pg/mL, p < 0.001). ET-1 was significantly lower at EOT (1.9 ± 0.6 pg/mL, p = 0.013) and at 12M (2.0 ± 0.8 pg/mL, p = 0.091) following smoking cessation compared with BL (2.3 ± 0.6 pg/mL). BL concentrations of cotinine were significantly associated with basal ET-1 (r = 0.449, p = 0.013) and the change in cotinine at 12M following smoking cessation was significantly associated with the change in plasma ET-1 at 12M (r = 0.457, p = 0.011). Findings from the present pilot investigation demonstrate that a 12-week smoking cessation program reduces circulating concentrations of ET-1 and TNF-α for at least a year. The reduction in serum cotinine was associated with the decrease in circulating ET-1. The attenuation in ET-1 and inflammation may in part, contribute to the lower risk of CVD that is observed with smoking cessation.

Association between early gestation passive smoke exposure and neonatal size among self-reported non-smoking women by race/ethnicity: A cohort study.

Understanding implications of passive smoke exposure during pregnancy is an important public health issue under the Developmental Origins of Health and Disease paradigm. In a prospective cohort of low-risk non-smoking pregnant women (NICHD Fetal Growth Studies-Singletons, 2009-2013, N = 2055), the association between first trimester passive smoke exposure and neonatal size was assessed by race/ethnicity. Plasma biomarker concentrations (cotinine, nicotine) assessed passive smoke exposure. Neonatal anthropometric measures included weight, 8 non-skeletal, and 2 skeletal measures. Linear regression evaluated associations between continuous biomarker concentrations and neonatal anthropometric measures by race/ethnicity. Cotinine concentrations were low and the percent above limit of quantification varied by maternal race/ethnicity (10% Whites; 14% Asians; 15% Hispanics; 49% Blacks). The association between cotinine concentration and infant weight differed by race/ethnicity (Pinteraction = 0.034); compared to women of the same race/ethnicity, per 1 log-unit increase in cotinine, weight increased 48g (95%CI -44, 139) in White and 51g (95%CI -81, 183) in Hispanic women, but decreased -90g (95%CI -490, 309) in Asian and -93g (95%CI -151, -35) in Black women. Consistent racial/ethnic differences and patterns were found for associations between biomarker concentrations and multiple non-skeletal measures for White and Black women (Pinteraction<0.1). Among Black women, an inverse association between cotinine concentration and head circumference was observed (-0.20g; 95%CI -0.38, -0.02). Associations between plasma cotinine concentration and neonatal size differed by maternal race/ethnicity, with increasing concentrations associated with decreasing infant size among Black women, who had the greatest biomarker concentrations. Public health campaigns should advocate for reducing pregnancy exposure, particularly for vulnerable populations.

Tobacco smoke exposure and fractional exhaled nitric oxide levels among U.S. adolescents.

BACKGROUND: Fractional exhaled nitric oxide (FeNO) can objectively guide clinical practice in the assessment, diagnosis, and treatment of eosinophilic airway inflammation. FeNO values may be affected by current smoking, but the role of tobacco smoke exposure (TSE) is understudied. OBJECTIVE: This study investigated the associations between biochemically validated and self-reported TSE and FeNO levels among U.S. nonsmoking adolescents without asthma. METHODS: National Health and Nutrition Examination Survey 2007-2012 data were used. TSE was assessed via serum cotinine and self-reported measures. We assessed FeNO continuously and using cutpoints of >35 ppb and >50 ppb to indicate likely eosinophilic inflammation in children and adults, respectively. We conducted linear and logistic regression adjusting for potential covariates. RESULTS: Overall, 34.0% of adolescents had low cotinine (0.05-2.99 ng/ml), 6.2% had high cotinine (≥3.00 ng/ml), and 11.9% had home TSE. Compared to adolescents with no/minimal cotinine, adolescents with high cotinine were at reduced odds to have FeNO >35 ppb (adjusted odds ratio [aOR] = 0.54, 95%CI = 0.43,0.69). Adolescents with low cotinine had lower FeNO values (ß = -2.05, 95%CI = -3.61,-0.49), and were also at decreased odds to have FeNO >35 ppb (aOR = 0.74, 95%CI = 0.66,0.83) and FeNO >50 ppb (aOR = 0.62, 95%CI = 0.53,0.72). Adolescents with home TSE were at reduced odds to have FeNO >50 ppb (aOR = 0.72, 95%CI = 0.57,0.91) than adolescents without home TSE. Adolescents with a higher number of cigarettes/day smoked inside their home were at reduced odds to have FeNO >35 ppb (OR = 0.98, 95%CI = 0.97,0.99) and FeNO >50 ppb (OR = 0.98, 95%CI = 0.96,0.99). CONCLUSIONS: TSE was associated with decreased FeNO levels. The addition of TSE may be clinically important when interpreting thresholds for FeNO.

Serum levels of TGF-ß1, cytokines, angiogenic, and anti-angiogenic factors in pregnant women who smoke.

INTRODUCTION: Women who smoke during pregnancy have a reduced risk of preeclampsia. The mechanism of this association is poorly understood. Preeclampsia is an anti-angiogenic and inflammatory state. Transforming growth factor beta 1 (TGF-ß1) is a multi-functional anti-inflammatory cytokine that activates membrane bound endoglin on endothelial cells causing a myriad of vascular actions including vasorelaxation. The objective of the study was to determine serum levels of cytokines, angiogenic factors, placental growth factor (PlGF), TGF-ß-1 and anti-angiogenic factors, soluble endoglin (sEng) and soluble vascular endothelial growth factor 1 (sVEGFR1) in smoking and non-smoking pregnant women. METHODS: Using enzyme-linked immunosorbent and multiplex assays we prospectively analyzed serum levels of PIGF, TGF-ß1, sEng, sVEGFR1 and cytokines in normotensive pregnant smokers and non-smokers. Exclusion criteria included maternal hypertension, autoimmune disorders, rupture of membranes, evidence of labor and drug use. RESULTS: There were 59 women in the smoking and 66 in the non-smoking group. Compared to non-smoking mothers. maternal age was lower in smoking mothers with no significant difference in other demographic variables. There was no difference in levels of cytokines, anti-angiogenic factors and PlGF between the two groups. Median TGF-ß1 levels were significantly higher in the smoking group (8120 pg/mL vs 6040 pg/mL, p < 0.001) and remained significant after controlling for confounders. TGF-ß1 levels correlated positively with cotinine levels in the smoking group. CONCLUSIONS: We speculate that higher TGF-ß1 levels may explain the reduced incidence of preeclampsia in mothers who smoke by being available for action on maternal endothelium even after inactivation by circulating maternal sEng.

Rapid, sensitive, and reliable quantitation of nicotine and its main metabolites cotinine and trans-3'-hydroxycotinine by LC-MS/MS: Method development and validation for human plasma.

New nicotine delivery products are gaining market share. For evaluation of their characteristics, toxicokinetic investigations are in current research focus. For reliable determination of blood plasma levels of nicotine and its main metabolites cotinine and trans-3'-hydroxycotinine, a quantitation method based on LC-ESI-MS/MS was developed and validated. Addition of isotope labeled internal standards prior to rapid sample preparation using protein precipitation with methanol was chosen for sample preparation. Different stationary phases were tested and phenyl-hexyl separation was found to be superior to HILIC, C18, and C8 stationary phases. Ion suppression effects caused by hydrophilic early eluting matrix were eliminated by the adjustment of an adequate retention utilizing a phenyl-hexyl separation stationary phase. Exchange of acetonitrile as organic mobile phase by methanol and elevation of pH value of aqueous mobile phase containing 5 mM NH4Ac to 4.50 improved the chromatographic resolution. The limits of quantitation for nicotine, cotinine, and hydroxycotinine were 0.15, 0.30, and 0.40 ng/mL, respectively. Linearity was proven by matrix matched calibration for the whole working range from 0.50 ng/mL to 35.0 ng/mL for nicotine and from 6.00 to 420 ng/mL for cotinine and hydroxycotinine (Mandel's fitting test with R2 > 0.995). Quality control samples at four different levels (0.50, 1.50, 17.5, 28.0 ng/mL for nicotine and 6.00, 18.0, 210, 336 ng/mL for cotinine and hydroxycotinine) in plasma were analyzed six times on three days. Mean accuracies ranged from 87.7% to 105.8% for nicotine, from 90.3% to 102.9% for cotinine, and from 99.9% to 109.9% for hydroxycotinine. Intra- and inter-day precisions (RSD %) were below 15% for all analytes (<20% for LLOQ). As proof of concept, the method was successfully applied to a real plasma sample from a cigarette smoking volunteer.

Blood lead levels and lung cancer mortality: An updated analysis of NHANES II and III.

Previous analyses within the National Health and Nutrition Examination Survey (NHANES) II and III cycles suggested an association between blood lead levels (BLLs) and lung cancer mortality, although the evidence was limited by small case numbers. To clarify this relationship, we conducted updated analyses of 4,182 and 15,629 participants in NHANES II and III, respectively, (extending follow-up 20 and 8 years) aged ≥20 with BLL measurements and mortality follow-up through 2014. We fit multivariable Cox models to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) relating BLLs and lung cancer with adjustment for smoking and other factors. We did not observe an overall association between BLLs and lung cancer after adjustment for smoking (both surveys) and serum cotinine and environmental tobacco smoke exposure (NHANES III), although suggestive associations were observed among women (NHANES II: HR 2.7, 95% CI 0.7, 10.0 for ≥20.0 µg/dl vs. <10.0 µg/dl, Ptrend = 0.07; NHANES III: HR 11.2, 95% CI 2.1, 59.4 for ≥10.0 µg/dl vs. <2.5 µg/dl, Ptrend = 0.04). After stratifying on smoking status, an association with elevated BLLs was observed in NHANES II only among former smokers (HR 3.2, 95% CI 1.3, 8.0 for ≥15 vs. <15 µg/dl) and in NHANES III only among current smokers (HR 1.7, 95% CI 1.1, 2.8 for ≥5 vs. <5 µg/dl). In summary, we found elevated BLLs to be associated with lung cancer mortality among women in both NHANES II and III. Given the absence of an association among non-smokers, we cannot rule out residual confounding as an explanation for our findings.

Racial disparities in intensity of smoke exposure and nicotine intake among low-dependence smokers.

BACKGROUND: Compared to white smokers, Black smokers are at disproportionately higher risk for smoking-related disease, despite consuming fewer cigarettes per day (CPD). To examine racial disparities in biobehavioral influences on smoking and disease risk, we analyzed the relationship between self-reported tobacco dependence and intensity of tobacco smoke exposure per cigarette, on the one hand, and intensity of nicotine intake per cigarette, on the other. METHODS: In 270 Black and 516 white smokers, smoke exposure was measured by expired carbon monoxide (CO), and nicotine intake was measured by plasma cotinine (COT) and cotinine+3'-hydroxycotinine ([COT + 3HC]). Using linear regression analyses, we analyzed how the Fagerström Test for Cigarette Dependence (FTCD) predicted intensity of smoke exposure per cigarette (CO/CPD) and intensity of nicotine intake per cigarette (COT/CPD; [COT + 3HC]/CPD), and how race moderated these relations. RESULTS: Overall, Black smokers consumed fewer CPD than white smokers and had higher levels of CO/CPD, COT/CPD, and [COT + 3HC]/CPD. These elevations were most pronounced at lower levels of dependence: amongst Black smokers, FTCD negatively predicted intensity of smoke exposure as measured by CO/CPD (B = -0.12, 95% CI = -0.18, -0.05, p = 0.0003) and intensity of nicotine intake as measured by [COT + 3HC]/CPD (B = -1.31, 95% CI = -2.15, -0.46, p = 0.002). CONCLUSIONS: Low-dependence Black smokers had higher intensities of both smoke exposure and nicotine intake per cigarette compared to similarly dependent white smokers, suggesting that measures of dependence, exposure, and intake underestimate incremental risk of each cigarette to Black smokers.