Cigarette consumption and biomarkers of nicotine exposure during pregnancy and postpartum

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

OBJECTIVES

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

DESIGN

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

SETTING

Hokkaido, Japan.

PARTICIPANTS

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

MAIN OUTCOME MEASURES

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

RESULTS

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

CONCLUSION

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

Development and Validation of a Novel Placental DNA Methylation Biomarker of Maternal Smoking during Pregnancy in the ECHO Program

BACKGROUND

Maternal cigarette smoking during pregnancy (MSDP) is associated with numerous adverse health outcomes in infants and children with potential lifelong consequences. Negative effects of MSDP on placental DNA methylation (DNAm), placental structure, and function are well established.

OBJECTIVE

Our aim was to develop biomarkers of MSDP using DNAm measured in placentas (N = 96 ), collected as part of the Vitamin C to Decrease the Effects of Smoking in Pregnancy on Infant Lung Function double-blind, placebo-controlled randomized clinical trial conducted between 2012 and 2016. We also aimed to develop a digital polymerase chain reaction (PCR) assay for the top ranking cytosine-guanine dinucleotide (CpG) so that large numbers of samples can be screened for exposure at low cost.

METHODS

We compared the ability of four machine learning methods [logistic least absolute shrinkage and selection operator (LASSO) regression, logistic elastic net regression, random forest, and gradient boosting machine] to classify MSDP based on placental DNAm signatures. We developed separate models using the complete EPIC array dataset and on the subset of probes also found on the 450K array so that models exist for both platforms. For comparison, we developed a model using CpGs previously associated with MSDP in placenta. For each final model, we used model coefficients and normalized beta values to calculate placental smoking index (PSI) scores for each sample. Final models were validated in two external datasets: the Extremely Low Gestational Age Newborn observational study, N = 426 ; and the Rhode Island Children's Health Study, N = 237 .

RESULTS

Logistic LASSO regression demonstrated the highest performance in cross-validation testing with the lowest number of input CpGs. Accuracy was greatest in external datasets when using models developed for the same platform. PSI scores in smokers only (n = 72 ) were moderately correlated with maternal plasma cotinine levels. One CpG (cg27402634), with the largest coefficient in two models, was measured accurately by digital PCR compared with measurement by EPIC array (R 2 = 0.98 ).

DISCUSSION

To our knowledge, we have developed the first placental DNAm-based biomarkers of MSDP with broad utility to studies of prenatal disease origins. https://doi.org/10.1289/EHP13838.

Risk Identification in Perinatal Health Care Settings via Technology-Based Recruitment Methods: Comparative Study

BACKGROUND

Digital screening and intervention tools have shown promise in the identification and reduction of substance use in health care settings. However, research in this area is impeded by challenges in integrating recruitment efforts into ongoing clinical workflows or staffing multiple study clinics with full-time research assistants, as well as by the underreporting of substance use.

OBJECTIVE

The aim of the study is to evaluate pragmatic methods for facilitating study recruitment in health care settings by examining recruitment rates and participant characteristics using in-person-based versus flyer approaches.

METHODS

This study compared recruitment rates at a Women's Health clinic in the Midwest under 2 different recruitment strategies: in person versus via a flyer with a QR code. We also examined the disclosure of substance use and risk screener positivity for the 2 strategies. We also obtained information about the current use of technology and willingness to use it for study participation.

RESULTS

A greater percentage of patients recruited in person participated than those recruited via flyers (57/63, 91% vs 64/377, 17%). However, the final number recruited in each group was roughly equal (n=57 vs n=64). Additionally, participants recruited via flyers were more likely to screen positive for alcohol use risk on the Tolerance, Annoyed, Cut Down, Eye-Opener alcohol screen than those recruited at the clinic (24/64, 38% vs 11/57, 19%; χ21=4.9; P=.03). Participants recruited via flyers were also more likely to screen positive for drug use risk on the Wayne Indirect Drug Use Screener than those recruited at the clinic (20/64, 31% vs 9/57, 16%; χ21=4.0; P=.05). Furthermore, of the 121 pregnant women, 117 (96.7%) reported owning a smartphone, 111 (91.7%) had an SMS text message plan on their phone, and 94 (77.7%) reported being willing to receive SMS text messages or participate in a study if sent a link to their phone.

CONCLUSIONS

The distribution of flyers with a QR code by medical staff appears to be an efficient and cost-effective method of recruitment that also facilitates disclosure while reducing the impact on clinic workflows. This method of recruitment can be useful for data collection at multiple locations and lead to larger samples across and between health systems. Participant recruitment via technology in perinatal health care appears to facilitate disclosure, particularly when participants can learn about the research and complete screening using their own device at a place and time convenient for them. Pregnant women in an urban Midwestern hospital had access to and were comfortable using technology.

Biochemical and genetic biomarkers associated with nicotine dependence in Mexican smokers

Cigarette smoking remains an important health concern and is still a leading cause of preventable mortality. Nicotine is the substance responsible for sustained tobacco use and dependence. Identification of biomarkers underlying nicotine dependence behavior is important to identify people at risk for this dependence. In the present study, we identified biochemical and genetic biomarkers of nicotine dependence detected by the Fagerström Test for Nicotine Dependence (FTDN) in Mexican smokers. The nicotine metabolites nicotine-N'-oxide, trans-3'-hydroxycotinine-glucuronide (3HC-O-Gluc), and nicotine-N-Gluc (Gluc) were useful to differentiate nicotine-dependent from non-dependent subjects (p < .0001) with an area under the curve (AUC) of 0.7818. Genetic variants in CYP2A6, FMO3, and UGT2B7 (rs2431413, rs28363545, and rs7439326, respectively) were associated with nicotine dependence (p = .03, p = .01, p = .01, respectively). Variations in the enzymatic activity of CYP2A6 were associated with altered nicotine-N'-oxide and 3HC-O-Gluc levels. Decreased urinary levels of 3HC-O-Gluc and increased nicotine-N'-oxide were associated with a decrease in the functional activity of CYP2A6. A strong positive correlation was observed between the ratio of urinary 3HC/cotinine, a measure of CYP2A6 activity, and the levels of 3HC-O-Gluc (p < .0001, r = .6835), while a strong negative correlation was observed with nicotine-N'-oxide (p < .0001, r = .6522) in nicotine-dependent subjects. No correlations were observed in non-nicotine-dependent subjects. These data suggest that particular urinary nicotine metabolites and genetic variants involved in nicotine metabolism are useful to identify subjects with nicotine dependence in the Mexican population.

Low level of urinary cotinine in pregnant women also matters: variability, exposure characteristics, and association with oxidative stress markers

China has relatively high indoor contamination of nicotine, according to recent publications. Therefore, nicotine exposure risks for sensitive populations such as pregnant women in China are of concern. The variability of its internal exposure levels across three trimesters among pregnant women is not well documented. Factors related with nicotine exposure across pregnancy and its associations with oxidative stress markers are also understudied. Based on a birth cohort, we measured concentrations of cotinine (a major metabolite of nicotine) and oxidative stress markers including 8-OHdG, 8-OHG, and HNE-MA in urine samples collected at three trimesters from 1,155 pregnant women enrolled between January 2014 and June 2017 in Wuhan, China. The variability of urinary cotinine across the trimesters, potential factors associated with it, as well as the relationships between urinary cotinine and oxidative stress markers were assessed in pregnant women with cotinine concentrations of < 50 ng/mL (the cutoff value to distinguish smokers and non-smokers). Urinary specific gravity adjusted median concentrations of cotinine (ng/mL) in the entire pregnancy, first, second, and third trimester were 3.04, 3.32, 3.36, and 2.50, respectively, which exhibited fair reliability (intraclass correlation coefficient: 0.47) across pregnancy. Most participants had an estimated daily intake of nicotine higher than the acceptable value (100 ng/kg-bw/day) recommended by the UK and the USA. Maternal age, education level, pre-pregnancy body mass index, and sampling seasons were related to urinary concentrations of cotinine. After adjusting for confounding factors, significant positive relationships (β; 95% confidence interval) were observed between urinary cotinine concentrations and 8-OHdG (0.28; 0.25, 0.30), 8-OHG (0.27; 0.25, 0.29), and HNE-MA (0.27; 0.21, 0.32), respectively (p < 0.01). These results lend insight into the major factors associated with nicotine exposure of pregnant women at environmentally relevant levels and its potential effect on oxidative stress with a large sample size, and warrant the necessity of reducing the exposure in sensitive populations.

Robust tobacco smoking self-report in two cohorts: pregnant women or men and women living with or without HIV

Understanding the true burden of tobacco smoking on adverse pregnancy outcomes is critical in generating appropriate interventions to improve outcomes. Self-reporting of human behaviour that is associated with stigma is associated with underreporting in general and may bias the impact of smoking in studies; however, self-reporting is frequently the most practical method of gleaning this information. The objective of this study was to evaluate concordance between self-reported smoking and concentrations of plasma cotinine, a biomarker of smoking, among participants enrolled in two related HIV cohorts. A total of 100 pregnant women (76 living with HIV [LWH] and 24 negative controls) in their third trimester, and 100 men and non-pregnant women (43 LWH and 57 negative controls) were included. Among all participants, 43 pregnant women (49% LWH and 25% negative controls) and 50 men and non-pregnant women (58% LWH and 44% negative controls) were self-reported smokers. The odds of discordance between self-reported smoking and cotinine levels were not significantly different between self-reported smokers and non-smokers, nor between pregnant women and others, but were significantly increased, regardless of self-reported status, among people LWH compared to negative controls. The overall concordance between plasma cotinine and self-reported data among all participants was 94% with a sensitivity and specificity of 90% and 96%, respectively. Taken together, these data demonstrate that participant surveying in a non-judgemental context can lead to accurate and robust self-report smoking data among both persons LWH and not, including in the context of pregnancy.

Measurement of cigarette smoking: Comparisons of global self-report, returned cigarette filters, and ecological momentary assessment

Prior work suggests that prospective measurement of cigarette use may be more reliable and valid than retrospective self-reports. Despite several studies comparing retrospective and prospective methods, there are a myriad of prospective methods that have not been directly compared, including spent cigarette filters that are returned to the laboratory by participants and diary logs of cigarette use on an electronic device via ecological momentary assessment. The current secondary data analysis compared the reliability of retrospective global self-report, returned cigarette filters, and electronic diary logs among a sample of cigarette smokers that also use smokeless tobacco (SLT; N = 51) over two consecutive weeks. CPD values also were compared to salivary cotinine levels to determine whether any method was associated more strongly with nicotine/tobacco exposure. Results indicated that CPD values via global self-report were significantly larger than returned filter and diary log daily averages across both weeks (t(50) = 8.28 to 9.35; p < .001). Both prospective measures showed less digit bias and more variation in smoking behavior across days than global self-reports. Only returned CPD values were correlated significantly with salivary cotinine levels (r(593) = 0.09, p = .024). Importantly, most reliability outcomes for returned filters and logged CPD did not differ significantly, suggesting that they may be comparable prospective methods for measuring cigarette use. Because returned filters and diary logs did not differ from one another, researchers' selection of a prospective measurement method should rely on considerations of participant compliance, protocol burden, and specific research questions. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

The effects of prenatal nicotine and THC E-cigarette exposure on motor development in rats

RATIONALE

In the USA, nicotine and cannabis are the most common licit and illicit drugs used among pregnant women. Importantly, nicotine and cannabis are now being combined for consumption via e-cigarettes, an increasingly popular delivery device. Both nicotine and tetrahydrocannabinol (THC), the primary psychoactive component of cannabis, cross the placenta barrier. However, the consequences of prenatal cannabis use are not well understood, and less is known about potential combination effects when consumed with nicotine, especially via e-cigarettes.

OBJECTIVE

The present study used a rodent model to examine how prenatal e-cigarette exposure to nicotine, THC, and the combination impacts motor development among offspring.

METHODS

Pregnant Sprague-Dawley rats were exposed to nicotine (36 mg/mL), THC (100 mg/mL), the combination, or vehicle via e-cigarette inhalation from gestational days (GD) 5-20. One sex pair per litter was tested on an early sensorimotor development task (postnatal days [PD] 12-20) and a parallel bar motor coordination task (PD 30-32).

RESULTS

Combined prenatal exposure to nicotine and THC delayed sensorimotor development, even though neither drug produced impairments on their own. In contrast, prenatal exposure to either nicotine or THC impaired motor coordination, whereas combined exposure exacerbated these effects, particularly among females.

CONCLUSIONS

These data illustrate that prenatal exposure to either nicotine or THC may alter motor development, and that the combination may produce more severe effects. These findings have important implications for pregnant women as we better understand the teratogenic effects of these drugs consumed via e-cigarettes.

Maternal nicotine metabolism moderates the impact of maternal cigarette smoking on infant birth weight: A Collaborative Perinatal Project investigation

BACKGROUND

Maternal cigarette smoking is an important modifiable risk factor for low birth weight in the US. We investigated the maternal nicotine metabolite ratio (NMR; trans-3'-hydroxycotinine/cotinine) - a genetically-informed biomarker of nicotine clearance - as a moderator of links between prenatal cigarette use and birth weight. We also explored the role of race in these associations.

METHODS

Participants were 454 pregnant women (M_age = 25 years; 11% Black) who smoked cigarettes and their 537 infants from the Collaborative Perinatal Project. Cigarettes smoked per day were assessed at each prenatal visit; maternal NMR was assayed from third trimester serum. Birth weight was obtained from medical records. Generalized estimating equations were used to evaluate associations between cigarette smoking, NMR, race, and birth weight.

RESULTS

NMR moderated continuous associations between cigarettes per day over pregnancy and infant birth weight (p = .025). Among women who smoked at moderate levels (<15 cigarettes per day), those with slower NMR showed ~50-100 g decrements in birth weight versus those with faster NMR., while there were no significant associations between NMR and birth weight among women who smoked 15+ cigarettes per day. Although effects of NMR on birthweight were similar for Black and white women, Black women showed significantly slower NMR (p < .001).

CONCLUSIONS

This is the first demonstration that the maternal nicotine metabolism phenotype moderates associations between maternal smoking during pregnancy and birth weight. Infants of women with slower nicotine metabolism - including disproportionate representation of Black women - may be at heightened risk for morbidity from maternal smoking.

Tobacco consumption from the 1st trimester of pregnancy to 7 months postpartum: Effects of previous tobacco consumption, and depression and anxiety symptoms

OBJECTIVE

Previous tobacco consumption, and depression and anxiety symptoms are major predictors of women's tobacco consumption during pregnancy and the postpartum period. However, the joint effect of these predictors is still unexplored. This study aimed to analyse the effects of previous tobacco consumption, and depression and anxiety symptoms on women's tobacco consumption status and quantity from the 1st trimester of pregnancy to 7 months postpartum.

METHOD

A sample of 803 Spanish women was assessed at the 1st and the 3rd trimester of pregnancy, and at 2 and 7 months postpartum. Previous tobacco consumption, and depression and anxiety symptoms were self-reported. Pregnancy and postpartum tobacco consumption were confirmed with biochemical tests.

RESULTS

Women with more previous tobacco consumption or more anxiety symptoms presented a steeper decrease in the number of cigarettes smoked per week from the 1st trimester of pregnancy to the childbirth, although smoking more cigarettes than women with less previous tobacco consumption or less anxiety symptoms. Women with more depression symptoms showed a higher tendency to relapse smoking during the first 2 months postpartum.

CONCLUSIONS

Previous tobacco consumption and anxiety symptoms were associated with higher smoking quantity during pregnancy, while depression symptoms were associated with consumption relapse during postpartum period.

Use of electronic nicotine delivery systems (ENDS) among U.S. women of reproductive age: Prevalence, reported reasons for use, and toxin exposure

Given the rapidly expanding marketplace for Electronic Nicotine Delivery Systems (ENDS), it is important to monitor patterns of use, particularly among vulnerable populations. This study examined ENDS prevalence, reasons for use (i.e., to help quit smoking and for appealing flavors), and toxin exposure among U.S. women of reproductive age using data from the Population Assessment of Tobacco and Health (PATH) Study (2013-17). Exclusive ENDS users, dual users of ENDS and cigarettes, and exclusive cigarette smokers were compared within and between pregnant and not-pregnant women. Among pregnant women, prevalence of exclusive ENDS and dual use was similar (0.8%; 95%CI = 0.4-1.2% vs. 1.4%; 95%CI = 0.9-2.0%, respectively), but exclusive ENDS use was less prevalent than dual use among not-pregnant women (1.1%; 95%CI = 0.9-1.4% vs. 3.7%; 95%CI = 3.3-4.0%, respectively). Most women reported ENDs were used to help quit smoking (66.5-90.0%) and for appealing flavors (57.6-87.4%), and endorsement rates did not differ by use pattern or pregnancy status. Except for metals, toxin exposure was substantially lower for exclusive ENDS users relative to dual users and exclusive cigarette smokers regardless of pregnancy status. Pregnant and not-pregnant U.S. women regularly report using ENDS for help with quitting smoking and for appealing flavors. Although no type or pattern of tobacco/nicotine use is safe, especially during pregnancy, using ENDS exclusively is consistent with lower overall toxin exposure for pregnant and not-pregnant women. This study advances understanding of ENDS use and toxin exposure in women of reproductive age, a population highly vulnerable to the effects of nicotine/tobacco consumption.

Cotinine Fluctuation in Maternal Saliva During and After Pregnancy: Implications for Perinatal Outcomes

PURPOSE

The purpose of this study was to determine maternal cotinine levels in saliva at the first (T-1) and third trimesters of pregnancy (T-2), and postpartum (T-3) among women who reported smoking a consistent number of cigarettes. The goal was to generate data to provide suggestions about how nurses can improve patient outcomes for women who smoke.

METHODS

Saliva cotinine values obtained from the randomized controlled trial (BabyBEEP) were used for this secondary analysis. We examined variations in saliva cotinine between the first and third trimesters of pregnancy and postpartum among light and heavy smokers. Cotinine values for pregnant smokers who were in the control group (not randomized to any intervention) and reported smoking the same range of cigarettes during and after pregnancy were used for the analyses (n = 43). Descriptive statistics and repeated-measures ANOVA were used for analyses.

RESULTS

There were differences in maternal saliva cotinine levels across the different time points and between the groups. There was a significant interaction effect between time and group. Cotinine decreased from T-1 to T-2 in heavy smokers and increased from T-2 to T-3 among both light and heavy smokers. Cotinine at T-3 was higher than T-1 among light smokers.

CLINICAL IMPLICATIONS

Findings support accelerated nicotine metabolism during pregnancy and need for smoking cessation efforts throughout pregnancy to help women stay smoke free during postpartum.

Associations between electronic nicotine delivery systems and birth outcomes

OBJECTIVES

Nicotine crosses the placenta and is a known teratogen. The use of electronic nicotine delivery systems (ENDS) has increased among pregnant women in the US, but there is limited knowledge about their effects on birth outcomes. We examined the associations between ENDS and cigarette use during pregnancy with birth outcomes.

METHODS

We conducted a cross-sectional analysis of 57,046 respondents from 32 US states in the 2016-2017 Pregnancy Risk Assessment Monitoring System. Respondents self-reported use of ENDS and cigarettes during the last 3 months of pregnancy; this was linked with birth outcomes documented on the birth certificate, including birth weight, gestational age, small-for-gestational age, and preterm birth.

RESULTS

During the last 3 months of pregnancy, 0.5% of women used ENDS only, 0.8% were dual users of ENDS and cigarettes, and 8.0% used cigarettes only. In adjusted models, infants of women who used ENDS only weighed 57.8 grams less (95% CI -134.2, 18.6; p = .14) and were born 0.21 weeks earlier (95% CI -0.45, 0.03; p = .09) than infants of non-users. Infants born to dual users were 193.9 grams less (95% CI -274.9, -112.8; p < .01) and had a 1.93 higher odds of being born small-for-gestational age (95% CI 1.31, 2.83; p < .01) than infants of non-users.

CONCLUSIONS

Our results provide some indication that prenatal ENDS use may adversely affect birth outcomes by reducing birth weight and gestational age. Estimates were imprecise, suggesting that larger samples of ENDS users with more detailed information about patterns of use are needed.

High Rates of Menthol Cigarette Use Among Pregnant Smokers: Preliminary Findings and Call for Future Research

INTRODUCTION

Smoking during pregnancy remains widespread and is causally associated with infant morbidity and mortality. Despite links between menthol cigarette use and decreased smoking cessation, little is known regarding rates or characteristics of pregnant menthol cigarette smokers.

METHODS

Participants were drawn from two low-income, racially/ethnically diverse cohorts of pregnant smokers recruited from 2006 to 2015 (N = 166, Mage = 25 ± 5). Demographics, menthol cigarette use, daily cigarette use, quit status, and consecutive weeks quit were assessed by prospective interviews. Nicotine dependence was assessed using the Fagerström Test of Nicotine Dependence. Nicotine levels were assessed via saliva cotinine.

RESULTS

High rates of menthol use were found in both cohorts (85% and 87%). Across both cohorts, menthol smokers were more likely to identify as racial/ethnic minorities, were less educated, and reported lower income than non-menthol smokers (ps < .03). Menthol smokers also reported fewer continuous weeks quit (8.4 vs. 14.5 weeks quit; p < .03) and a tendency toward decreased likelihood of quitting smoking over pregnancy (29% vs. 48%; p < .08) in unadjusted but not in covariate-adjusted analyses. No differences emerged in cigarettes per day, nicotine dependence or nicotine exposure.

CONCLUSIONS

We found very high rates of menthol cigarette use in pregnant smokers-particularly among racial/ethnic minority and low socioeconomic status smokers-and some evidence for associations with reduced smoking cessation in pregnancy. Consideration of pregnant smokers as a uniquely vulnerable population is warranted in evaluating regulation of menthol in cigarettes. Further research is needed regarding the impact of menthol on smoking persistence in pregnancy and on maternal and infant health outcomes.

IMPLICATIONS

This study highlights high rates of menthol cigarette use in pregnant women in the Northeast, United States, with evidence for higher rates of menthol use among racial/ethnic minority, less educated and low-income pregnant smokers, and preliminary evidence for associations between menthol cigarette use and reduced smoking cessation. Consideration of the effects of menthol on smoking persistence in pregnant women and on the health of their offspring is warranted in the development of regulations regarding menthol in cigarettes.

Intensive Behavioural and Pharmacological Treatment for Tobacco Dependence in Pregnant Women with Complex Psychosocial Challenges: A Case Report

Up to 95% of women who use other substances also smoke tobacco during pregnancy. Challenging psychosocial circumstances and other barriers that contribute to high levels of tobacco dependence result in few quitting successfully. This case report describes the treatment of a highly tobacco dependent 34-year-old pregnant woman with a history of recent substance use, mental illness and trauma, enrolled in the Incentives to Quit Tobacco in Pregnancy program. Heavy smoking, both during the day and overnight, was reported. An extensive history of quit attempts, as well as a strong desire to cease tobacco use during pregnancy, was also noted. Treatment utilising extensive behavioural supports, including financial incentives for carbon monoxide verified abstinence and telephone-based counselling, in combination with nicotine replacement therapy (NRT), was offered to assist cessation. Excellent uptake and adherence to all aspects of treatment saw tobacco cessation achieved and maintained for 24 weeks while on the program. NRT used at doses well above those recommended for pregnancy was required to alleviate strong withdrawal symptoms and maintain abstinence. Daily monitoring of carbon monoxide, financial incentives for continued abstinence and regular phone support were critical to maintaining motivation and preventing relapse to smoking. Post-program relapse to smoking did occur, as is common, and highlights the need for longer-term intensive support for pregnant women with complex behavioural and social problems. Given the prevalence of tobacco smoking in such populations, long-term harm reduction treatment models using extensive behavioural support in combination with NRT should be considered for inclusion in current smoking cessation guidelines.

Pregnancy-Induced Increases in the Nicotine Metabolite Ratio: Examining Changes During Antepartum and Postpartum

INTRODUCTION

Pregnancy-induced increases in nicotine metabolism may contribute to difficulties in quitting smoking during pregnancy. However, the time course of changes in nicotine metabolism during early and late pregnancy is unclear. This study investigated how pregnancy alters the nicotine metabolite ratio (NMR), a common biomarker of nicotine metabolism among nonpregnant smokers.

METHODS

Urinary NMR (trans-3'-hydroxycotinine [3HC]/cotinine [COT]) was assessed using total (free + glucuronide) and free compounds among women (N = 47) from a randomized controlled trial for smoking cessation who self-reported smoking and provided a urine sample during early pregnancy (M ± SD = 12.5 ± 4.5 weeks' gestation), late pregnancy (28.9 ± 2.0 weeks' gestation), and 6 months postpartum (24.7 ± 1.2 weeks since childbirth). Urine samples were analyzed using liquid chromatography-tandem mass spectrometry and NMR were calculated as Total 3HC/Free COT, Free 3HC/Free COT, and Total 3HC/Total COT.

RESULTS

NMR was significantly higher during early and late pregnancy compared to postpartum and significantly increased from early to late pregnancy as measured by Total 3HC/Free COT (0.76, 0.89, 0.60; all p's < .05) and Free 3HC/Free COT (0.68, 0.80, 0.51; all p's < .05). Total 3HC/Total COT did not vary over time (p = .81).

CONCLUSIONS

Total 3HC/Free COT and Free 3HC/Free COT increased in the first trimester and continued to increase throughout pregnancy, suggesting a considerable increase in nicotine metabolism over gestation. Future analyses are needed to interpret the changes in NMR in the context of nicotine pharmacokinetics, as well as its impact on changes in smoking behavior and cessation outcomes.

IMPLICATIONS

We observed that the NMR was significantly higher as early as 12 weeks' gestation and increased further as a function of gestational age. Among nonpregnant smokers, elevated NMR is associated with smoking phenotypes such as smoking more cigarettes per day and poorer response to nicotine patch; therefore, pregnancy-induced increases in the NMR may contribute to smoking during the first trimester of pregnancy and reducing or quitting smoking may become more challenging as the rate of nicotine metabolism accelerates over the course of pregnancy.

A review of tobacco regulatory science research on vulnerable populations

In 2013 the U.S. Food and Drug Administration and National Institutes of Health established fourteen Tobacco Centers of Regulatory Science (TCORS) to advance scientific knowledge relevant to conducting evidence-based tobacco regulation. This report reviews TCORS-funded research with adult vulnerable populations. The literature search included a list of all TCORS-funded publications compiled by the TCORS coordinating center; all TCORS were requested to share publications not in the coordinating-center's list. Only TCORS-funded reports describing an empirical study with an adult vulnerable population published in a peer-reviewed journal between September 2013 and June 2018 were included. 71 reports met inclusion criteria; 39% (28/71) examined tobacco use among those with mental health and medical comorbidities, 34% (24/71) socioeconomic disadvantage, 31% (22/71) women of reproductive age, 30% (21/71) racial/ethnic minorities, 18% (13/71) rural residents, and 3% (2/71) each among active military/veterans and sexual/gender minorities. Regarding scientific domains, 63% (45/71) investigated behavior, 37% (26/71) addiction, 24% (17/71) health effects, 20% (14/71) impact analyses, 18% (13/71) toxicity, 8% (6/71) marketing influences, and 7% (5/71) communications. Totals exceed 100% because some reports addressed multiple populations/domains. TCORS funding has generated a substantial, multidisciplinary body of new scientific knowledge on tobacco use in adult vulnerable populations. However, considerable variability was noted in the amount of research conducted across the various vulnerable populations and scientific domains. Most notably, relatively few studies focused on active military/veterans or sexual/gender minorities, and the scientific domains of marketing influences and communications were conspicuously underrepresented. These are important knowledge gaps to address going forward.