Accelerated metabolism of nicotine and cotinine in pregnant smokers

Longitudinal Influence of Pregnancy on Nicotine Metabolic Pathways

Nicotine metabolism increases in pregnancy, which may contribute to the difficulties that pregnant women have in quitting smoking. We aimed to determine the extent and timing of changes in nicotine metabolic pathways, including C-oxidation, N-glucuronidation, and the pregnancy-induced influences on the activity of enzymes mediating these pathways (CYP2A6 and UGT2B10, respectively). Current smoking pregnant women (n = 47) provided a urine sample during early pregnancy (12.5 weeks), late pregnancy (28.9 weeks), and 6 months postpartum. Concentrations of urinary nicotine and metabolites were analyzed using liquid chromatography tandem mass spectrometry and compared using general linear repeated measures analyses. Nicotine C-oxidation was 1.07-fold (P = 0.12) and 1.11-fold (P < 0.001) higher at early and late pregnancy, respectively, compared with postpartum. Nicotine N-glucuronidation was 1.33-fold (P = 0.06) and 1.67-fold (P = 0.003) higher at early and late pregnancy, respectively, compared with postpartum. The CYP2A6 phenotype ratio (total 3'-hydroxycotinine/cotinine) was significantly higher at early and late pregnancy compared with postpartum (all P < 0.05) and correlated with nicotine C-oxidation (all P < 0.001), suggesting CYP2A6 activity is induced during pregnancy. The UGT2B10 phenotype ratio (nicotine glucuronide/nicotine) was higher at early and late pregnancy compared with postpartum (P = 0.07 and P < 0.05, respectively) and correlated with a second UGT2B10 phenotype ratio (cotinine glucuronide/cotinine) (all P < 0.001), suggesting UGT2B10 activity is induced during pregnancy. In conclusion, pregnancy-induced increases in nicotine metabolism start by 12 weeks gestation and continue as pregnancy progresses most likely due to induction of CYP2A6 and UGT2B10, resulting in potential reductions in the effectiveness of nicotine replacement therapies and an increase in metabolism of other CYP2A6 and UGT2B10 substrates during pregnancy.

Cigarette smoking is associated with an altered vaginal tract metabolomic profile

Cigarette smoking has been associated with both the diagnosis of bacterial vaginosis (BV) and a vaginal microbiota lacking protective Lactobacillus spp. As the mechanism linking smoking with vaginal microbiota and BV is unclear, we sought to compare the vaginal metabolomes of smokers and non-smokers (17 smokers/19 non-smokers). Metabolomic profiles were determined by gas and liquid chromatography mass spectrometry in a cross-sectional study. Analysis of the 16S rRNA gene populations revealed samples clustered into three community state types (CSTs) ---- CST-I (L. crispatus-dominated), CST-III (L. iners-dominated) or CST-IV (low-Lactobacillus). We identified 607 metabolites, including 12 that differed significantly (q-value < 0.05) between smokers and non-smokers. Nicotine, and the breakdown metabolites cotinine and hydroxycotinine were substantially higher in smokers, as expected. Among women categorized to CST-IV, biogenic amines, including agmatine, cadaverine, putrescine, tryptamine and tyramine were substantially higher in smokers, while dipeptides were lower in smokers. These biogenic amines are known to affect the virulence of infective pathogens and contribute to vaginal malodor. Our data suggest that cigarette smoking is associated with differences in important vaginal metabolites, and women who smoke, and particularly women who are also depauperate for Lactobacillus spp., may have increased susceptibilities to urogenital infections and increased malodor.

Clinician factors associated with prescribing nicotine replacement therapy in pregnancy: A cross-sectional survey of Australian obstetricians and general practitioners

The use of nicotine replacement therapy in pregnancy has been debated but evidence suggests that it is safer than smoking. A cross-sectional survey was conducted with: (i) general practitioners and obstetricians from a college database; and (ii) general practitioners with a special interest in Indigenous health. General practitioners had higher odds of prescribing compared to obstetricians. Reading guidelines, confidence, viewing nicotine replacement therapy as safe, effective and with good adherence, also significantly increased the odds of prescription. Clear guidance regarding safety and efficacy, with practical clinical protocols, are required in order to reduce variation in prescribing rates across these clinicians.

Prevalence and risk factors of secondhand smoke (SHS) exposure among pregnant women in Mongolia

This cross-sectional study investigated the prevalence of smoking and secondhand smoking (SHS) among pregnant women in Darkhan-Uul Province, Mongolia, using urinary cotinine (UC) levels, and clarified the factors related to SHS exposure. It targeted pregnant women who underwent antenatal health check-ups from November 2015 to January 2016. Self-administered questionnaires and urine samples were used to collect data. Using UC levels as the criterion, it was found that the prevalence of smokers (>100 ng/ml) among 493 pregnant women was 11.8%, while SHS exposure (≥5 ng/ml) among nonsmokers was 44.8%. Older and highly educated women had lower odds of SHS exposure (p = 0.006 and 0.002, respectively). Furthermore, nonsmoking pregnant women from homes where smoking was permitted had higher odds of SHS exposure compared to women from homes where smoking was not permitted. These results suggest that community guidance programs, such as home smoking cessation that include families, are necessary.

Slower nicotine metabolism among postmenopausal Polish smokers

BACKGROUND

A non-invasive phenotypic indicator of the rate of nicotine metabolism is nicotine metabolite ratio (NMR) defined as a ratio of two major metabolites of nicotine - trans-3'-hydroxycotinine/cotinine. The rate of nicotine metabolism has important clinical implications for the likelihood of successful quitting with nicotine replacement therapy (NRT). We conducted a study to measure NMR among Polish smokers.

METHODS

In a cross-sectional study of 180 daily cigarette smokers (42% men; average age 34.6±13.0), we collected spot urine samples and measured trans-3'-hydroxycotinine (3-HC) and cotinine levels with LC-MS/MS method. We calculated NMR (molar ratio) and analyzed variations in NMR among groups of smokers.

RESULTS

In the whole study group, an average NMR was 4.8 (IQR 3.4-7.3). The group of women below 51 years had significantly greater NMR compared to the rest of the population (6.4; IQR 4.1-8.8 vs. 4.3; IQR 2.8-6.4). No differences were found among group ages of male smokers.

CONCLUSIONS

This is a first study to describe variations in nicotine metabolism among Polish smokers. Our findings indicate that young women metabolize nicotine faster than the rest of population. This finding is consistent with the known effects of estrogen to induce CYP2A6 activity. Young women may require higher doses of NRT or non-nicotine medications for most effective smoking cessation treatment.

[Smoking cessation and pregnancy]

Active and passive smoking during pregnancy induce several deleterious effects that may have a negative impact on pregnancy progress, fetus development and both mother and newborn health. Smoking cessation should be a rule for any woman as soon as the beginning of her pregnancy, or better in anticipation of a pregnancy when contraception is no more taken. Every caregiver must help every pregnant woman who smokes to quit smoking. Smoking cessation interventions in pregnant women must combine a psychological support (mainly with cognitive behavioral therapy) and nicotine replacement therapy, which can also be used during breast feeding. It is recommended to adjust the dosage of nicotine replacement therapy according to the symptoms of under or over dosage at the end of the first week of use. On the other hand, vareniclin and bupropion are contra-indicated during pregnancy or breast-feeding. Electronic cigarette is not advised during pregnancy. Prevention of smoking relapse in postpartum period is essential since a percentage as high as 50% of women having quit during their pregnancy resume smoking during the 6 months following delivery.

Specification of Change Mechanisms in Pregnant Smokers for Malleable Target Identification: A Novel Approach to a Tenacious Public Health Problem

Maternal smoking during pregnancy (MSDP) continues to be a leading modifiable risk factor for perinatal complications and a range of neurodevelopmental and cardio-metabolic outcomes across the lifespan. Despite 40 years of intervention research less than one in five pregnant smokers who receive an intervention quit by delivery. Within this context, recognition of pregnancy is commonly associated with abrupt suspension or reduction of smoking in the absence of intervention, yet has not been investigated as a volitional target. The goal of this article is to provide the empirical foundation for a novel direction of research aimed at identifying malleable targets for intervention through the specification of behavior change mechanisms specific to pregnant women. To do so, we: (1) summarize progress on MSDP in the United States generated from conventional empirical approaches to health behavior change; (2) discuss the phenomenon of spontaneous change in the absence of intervention among pregnant smokers to illustrate the need for mechanistic specification of behavior change motivated by concern for fetal well-being; (3) summarize component processes in neurobiological models of parental and non-parental social behaviors as a conceptual framework for understanding change mechanisms during pregnancy; (4) discuss the evidence for the malleability of these processes to support their translational relevance for preventive interventions; and (5) propose a roadmap for validating the proposed change mechanism using an experimental medicine approach. A greater understanding of social and interpersonal processes that facilitate health behavior change among expectant mothers and how these processes differ interindividually could yield novel volitional targets for prenatal interventions. More broadly, explicating other-oriented mechanisms of behavior change during pregnancy could serve as a paradigm for understanding how social and interpersonal processes positively influence health behaviors across the lifespan.

The Indigenous Counselling and Nicotine (ICAN) QUIT in Pregnancy Pilot Study protocol: a feasibility step-wedge cluster randomised trial to improve health providers' management of smoking during pregnancy

INTRODUCTION

Indigenous women have the highest smoking prevalence during pregnancy (47%) in Australia. Health professionals report lack of knowledge, skills and confidence to effectively manage smoking among pregnant women in general. We developed a behaviour change intervention aimed to improve health professionals' management of smoking in Indigenous pregnant women-the Indigenous Counselling And Nicotine (ICAN) QUIT in Pregnancy. This intervention includes webinar training for health professionals, an educational resources package for health professionals and pregnant women, free oral nicotine replacement therapy (NRT) for pregnant women, and audit and feedback on health professionals' performance.The aim of this study is to test the feasibility and acceptability of the ICAN QUIT in Pregnancy intervention to improve health professionals' provision of evidence-based culturally responsive smoking cessation care to Australian Indigenous pregnant smokers.

METHODS AND ANALYSIS

This protocol describes the design of a step-wedge cluster randomised pilot study. Six Aboriginal Medical Services (AMSs) are randomised into three clusters. Clusters receive the intervention staggered by 1 month. Health professionals report on their knowledge and skills pretraining and post-training and at the end of the study. Pregnant women are recruited and followed up for 3 months. The primary outcome is the recruitment rate of pregnant women. Secondary outcomes include feasibility of recruitment and follow-up of participating women, and webinar training of health professionals, measured using a designated log; and measures of effectiveness outcomes, including quit rates and NRT prescription rates.

ETHICS AND DISSEMINATION

In accordance with the Aboriginal Health and Medical Research Council guidelines, this study has been developed in collaboration with a Stakeholder and Consumer Aboriginal Advisory Panel (SCAAP). The SCAAP provides cultural consultation, advice and direction to ensure that implementation is acceptable and respectful to the Aboriginal communities involved. Results will be disseminated to AMSs, Aboriginal communities and national Aboriginal bodies.

REGISTRATION DETAILS

This protocol (version 4, 14 October 2016) is registered with the Australian and New Zealand Clinical Trials Registry (Ref #: ACTRN12616001603404).

Prevention and Treatment of Smoking and Tobacco Use During Pregnancy in Selected Indigenous Communities in High-Income Countries of the United States, Canada, Australia, and New Zealand: An Evidence-Based Review

Tobacco smoking during pregnancy is the most important modifiable risk factor for adverse pregnancy outcomes and long-term health complications for mother and baby. Tobacco use during pregnancy has decreased in high-income countries but not in Indigenous women in Australia, New Zealand, the United States, and Canada. This evidence-based review focuses on tobacco use among Indigenous pregnant women in high-income countries that share a history of European colonization. Indigenous women are more likely to use tobacco because of socioeconomic disadvantage, social norms, and poor access to culturally appropriate tobacco cessation support. Complications arising from tobacco smoking during pregnancy, such as low birth weight, prematurity, perinatal death, and sudden infant death syndrome, are much higher in Indigenous populations. Effective approaches to cessation in pregnant nonindigenous women involves behavioral counseling, with or without nicotine replacement therapy (NRT). Higher nicotine metabolism during pregnancy and poor adherence may affect therapeutic levels of NRT. Only two randomized trials were conducted among Indigenous women: neither found a statistically significant difference in cessation rates between the treatment and comparison arms. Considerations should be given to (1) whole life course approaches to reduce tobacco use in Indigenous women, (2) prohibiting tobacco promotion and reducing access to alcohol for minors to prevent smoking initiation in Indigenous youth, and (3) training health-care professionals in culturally appropriate smoking cessation care to improve access to services. It is critical to ensure acceptability and feasibility of study designs, consult with the relevant Indigenous communities, and preempt implementation challenges. Research is needed into the effect of reducing or stopping smoking during pregnancy when using NRT on subsequent maternal and infant outcomes.

In-utero exposure to nicotine alters the development of the rabbit cardiac conduction system and provides a potential mechanism for sudden infant death syndrome

In-utero exposure to tobacco smoke remains the highest risk factor for sudden infant death syndrome (SIDS). To alleviate the risks, nicotine replacement therapies are often prescribed to women who wish to quit smoking during their pregnancy. Cardiac arrhythmias is considered the final outcome leading to sudden death. Our goal in this study was to determine if exposing rabbit fetus to nicotine altered the cardiac conduction system of newborn kittens in a manner susceptible to cause SIDS. Using neuronal markers and a series of immunohistological and electrophysiological techniques we found that nicotine delayed the development of the cardiac pacemaker center (sinoatrial node) and decreased its innervation. At the molecular level, nicotine favored the expression of cardiac sodium channels with biophysical properties that will tend to slow heart rate and diminish electrical conduction. Our results show that alterations of the cardiac sodium current may contribute to the bradycardia, conduction disturbances and other cardiac arrhythmias often associated to SIDS and raise awareness on the use of replacement therapy during pregnancy.

Perinatal Biochemical Confirmation of Smoking Status by Trimester

Introduction:

Tobacco use during pregnancy is the most modifiable risk factor associated with poor pregnancy outcomes. Self-reported tobacco use has been demonstrated to have high misclassification rates. The aims were to examine misclassification rates of perinatal tobacco use during each trimester of pregnancy and 8 weeks postpartum, and to evaluate characteristics associated with misclassification of tobacco use status.

Methods:

This is secondary analysis of a prospective, multicenter trial of pregnant women, and it includes participants who were biochemically identified as tobacco users during their first trimester (N = 103). Each trimester and once postpartum, tobacco use was assessed via self-report and validated using a cutoff of 100 ng/mL for urine cotinine via NicAlert test strips to indicate current use. Those who self-reported as nonusers but were identified as users via urine cotinine were considered misclassified; misclassification rates were determined for each time period. Logistic regression assessed maternal factors associated with misclassification status.

Results:

Misclassification rates declined from 35.0% at first trimester to 31.9% and 26.6% at the second and third; the postpartum rate was 30.4%. These rates did not differ significantly from each other at the 0.05 level. Race/ethnicity was associated with misclassification status; white/non-Hispanic women were 87% less likely to be misclassified (p < .001).

Conclusion:

Misclassification of prenatal smoking status decreases as pregnancy progresses, though the observed rate change was not significant. Minority women may be at particular risk for non-disclosure of tobacco use. Biochemical validation should be considered when assessing perinatal tobacco use via self-report, given high misclassification rates throughout the perinatal period.

Implications:

These results demonstrate that regardless of trimester, more than one-quarter of tobacco-using pregnant women may not disclose tobacco use throughout pregnancy and early postpartum. Although the rate of misclassification decreased from first to third trimester and then increased in the immediate postpartum, these changes in misclassification rates were not significant. Minority groups may be at particular risk of misclassification compared with white/non-Hispanic women. Biochemical validation is warranted throughout pregnancy to encourage cessation as tobacco use is one of the most easily-modified risk factors for poor birth outcomes.

Cigarette Smoking During Pregnancy: Do Complete Abstinence and Low Level Cigarette Smoking Have Similar Impact on Birth Weight?

OBJECTIVES

Despite awareness of negative health outcomes associated with smoking, pregnant smokers might reduce their tobacco consumption thinking that a low smoking rate reduces smoking-related negative birth outcomes. We aimed to assess in a clinical sample whether there is a smoking rate that would not impact on birth weight (BW).

METHODS

Pregnant smokers ≥18 years, gestational age of 9-20 weeks of amenorrhea, motivated to quit smoking, smoking ≥5 cigarettes/day (cpd) and their newborns (381 singleton, live births) were included in this secondary analysis of a French smoking cessation trial.

RESULTS

The mean BW when the mother quit smoking was 3417 g (95 % CI: 3098-3738 g); when smoking >0<5 cpd, 3081g (3003-3159 g); when smoking 5-9 cpd, 3043 g (2930-3157 g); and when smoking ≥10 cpd, 2831 g (2596-3157 g) (p = .006). The corresponding effect sizes ranged from medium to large (Cohen's d for BW: 0.54, 0.57 and 0.85) compared to BW when the mother quit. In the multivariable analysis, adjusted for all significant confounders, when the mother smoked on average >0<5 cpd, the loss in BW was 228 g; when smoking 5-9 cpd, 251 g; and when smoking ≥10 cpd, 262 g (all p ≤ .02) compared to newborns' BW of mothers who stopped smoking since quit date.

CONCLUSIONS

Even low cigarette consumption during pregnancy is associated with BW loss. All efforts should be made to help pregnant smokers quit completely during their pregnancy.

IMPLICATIONS

As an alternative to quitting smoking, pregnant smokers reduce their smoking rate thinking that this diminishes smoking-related negative health outcomes. No study has established whether low smoking rate (more than 0 but less than 5 cpd) during pregnancy impacts BW compared to abstinence from smoking. Among treatment-seeking pregnant smokers BW of newborns of mothers who smoked even less than 5 cpd was significantly lower than of those whose mothers quit; effect sizes of different consumption levels on BW ranged from moderate (>0<5 cpd) to large (≥10 cpd). Even low smoking rate is associated with reduced BW compared to complete maternal smoking abstinence.

DNA Methylation Score as a Biomarker in Newborns for Sustained Maternal Smoking during Pregnancy

BACKGROUND

Maternal smoking during pregnancy, especially when sustained, leads to numerous adverse health outcomes in offspring. Pregnant women disproportionately underreport smoking and smokers tend to have lower follow-up rates to repeat questionnaires. Missing, incomplete, or inaccurate data on presence and duration of smoking in pregnancy impairs identification of novel health effects and limits adjustment for smoking in studies of other pregnancy exposures. An objective biomarker in newborns of maternal smoking during pregnancy would be valuable.

OBJECTIVES

We developed a biomarker of sustained maternal smoking in pregnancy using common DNA methylation platforms.

METHODS

Using a dimension reduction method, we developed and tested a numeric score in newborns to reflect sustained maternal smoking in pregnancy from data on cotinine, a short-term smoking biomarker measured mid-pregnancy, and Illumina450K cord blood DNA methylation from newborns in the Norwegian Mother and Child Cohort Study (MoBa).

RESULTS

This score reliably predicted smoking status in the training set (n = 1,057; accuracy = 96%, sensitivity = 80%, specificity = 98%). Sensitivity (58%) was predictably lower in the much smaller test set (n = 221), but accuracy (91%) and specificity (97%) remained high. Reduced birth weight, a well-known effect of maternal smoking, was as strongly related to the score as to cotinine. A three-site score had lower, but acceptable, performance (accuracy_train = 82%, accuracy_test = 83%).

CONCLUSIONS

Our smoking methylation score represents a promising novel biomarker of sustained maternal smoking during pregnancy easily calculated with Illumina450K or IlluminaEPIC data. It may help identify novel health impacts and improve adjustment for smoking when studying other risk factors with more subtle effects.

Exposure to Secondhand Smoke Impairs Fracture Healing in Rats

BACKGROUND

Nonsmokers may be affected by environmental tobacco smoke (secondhand smoke), but the effects of such exposure on fracture healing have not been well studied.

QUESTIONS/PURPOSES

To explore the possible effects of passive inhalation of tobacco smoke on the healing of a diaphyseal fracture in femurs of rats. We hypothesized that secondhand exposure to tobacco smoke adversely affects fracture healing.

METHODS

A mid-diaphyseal fracture was created in the femur of 41 female Wistar rats and fixed with an intramedullary metallic pin; 14 rats were excluded (nine for inadequate fractures and five for K wire extrusion). Tobacco exposure was provided by a smoking machine on a daily basis of four cigarettes a day. Each cigarette yielded 10 mg tar and 0.8 mg nicotine, and was puffed by alternating injections of fresh air for 30 seconds and smoke air for 15 seconds. The smoke exposure was previously adjusted to provide serum levels of cotinine similar to human secondhand tobacco exposure. Cotinine is a predominant catabolite of nicotine that is used as a biological biomarker for exposure to tobacco smoke. In one group (n = 11), the animals were intermittently exposed to tobacco smoke before sustaining the fracture but not afterward. In another group (n = 7), the exposure occurred before and after the fracture. The control group (n = 9) was sham-exposed before and after the fracture. We evaluated the specimens 28 days after bone fracture. The callus quality was measured by dual-energy x-ray absorptiometry (bone mineral density [BMD], bone mineral content [BMC], and callus area), μCT (callus volume and woven bone fraction), and mechanical bending (maximum force and stiffness).

RESULTS

Tobacco exposure resulted in delayed bone callus formation, which is represented by decreased BMD (Control: 0.302 ± 0.008 g/cm² vs Preexposed: 0.199 ± 0.008 g/cm² and Pre- and Postexposed: 0.146 ± 0.009 g/cm²; mean difference = 0.103 g/cm², 95% CI, 0.094-0.112 g/cm²and mean difference = 0.156 g/cm², 95% CI, 0.147-0.167 g/cm²; p < 0.01), BMC (Control: 0.133 ± 0.005 g vs Preexposed: 0.085 ± 0.0034 g and Pre- and Postexposed: 0.048 ± 0.003 g; mean difference = 0.048 g, 95% CI, 0.045-0.052 g and mean difference = 0.085 g, 95% CI, 0.088-0.090 g; p < 0.01), callus volume (Control: 7.656 ± 1.963 mm³ vs Preexposed: 17.952 ± 1.600 mm³ and Pre- and Postexposed: 40.410 ± 3.340 mm³; mean difference = -10.30 mm³, 95% CI, -14.12 to 6.471 mm³ and mean difference, -32.75 mm³, 95% CI, -36.58 to 28.93 mm³; p < 0.01), woven bone fraction (Control: 42.076 ± 3.877% vs Preexposed: 16.655 ± 3.021% and Pre- and Postexposed: 8.015 ± 1.565%, mean difference = 0.103%, 95% CI, 0.094-0.112% and mean difference = 0.156%, 95% CI, 0.147-0.166%; p < 0.01), maximum force (Control: 427.122 ± 63.952 N.mm vs Preexposed: 149.230 ± 67.189 N.mm and Pre- and Postexposed: 123.130 ± 38.206 N.mm, mean difference = 277.9 N.mm, 95% CI, 201.1-354.7 N.mm and mean difference = 304 N.mm, 95% CI, 213.2-394.8 N.mm; p < 0.01) and stiffness (Control: 491.397 ± 96.444 N.mm/mm vs Preexposed: 73.157 ± 36.511 N.mm/mm and Pre- and Postexposed: 154.049 ± 134.939 N.mm/mm, mean difference = 418.2 N.mm/mm, 95% CI, 306.3-530.1 N.mm/mm and mean difference = 337.3 N.mm/mm, 95% CI, 188.8-485.9 N.mm/mm; p < 0. 01).

CONCLUSIONS

Rats exposed to tobacco smoke showed delayed fracture healing and callus that was characterized by decreased maturity, density, and mechanical resistance, which was confirmed by all assessment methods of this study. Such effects were more evident when animals were exposed to tobacco smoke before and after the fracture. Future studies should be done in human passive smokers to confirm or refute our findings on fracture callus formation.

CLINICAL RELEVANCE

The potential hazardous effects of secondhand smoke on fracture healing in rodents should stimulate future clinical studies in human passive smokers.

Estimation of Saliva Cotinine Cut-Off Points for Active and Passive Smoking during Pregnancy-Polish Mother and Child Cohort (REPRO_PL)

A reliable assessment of smoking status has significant public health implications and is essential for research purposes. The aim of this study was to determine optimal saliva cotinine cut-off values for smoking during pregnancy. The analyses were based on data from 1771 women from the Polish Mother and Child Cohort. Saliva cotinine concentrations were assessed by high performance liquid chromatography coupled with tandem mass spectrometry (HPLC-ESI + MS/MS). The saliva cotinine cut-off value for active smoking was established at 10 ng/mL (sensitivity 96%, specificity 95%) and for passive smoking at 1.5 ng/mL (sensitivity 63%, specificity 71%). About 5% of the self-reported non-smoking women were classified as smokers based on the cotinine cut-off value. Significantly more younger, single, and less educated self-reported non-smokers had a cotinine concentration higher than 10 ng/mL compared to those who were older, married, and who had a university degree. Close to 30% of the non-smokers who indicated that smoking was not allowed in their home could be classified as exposed to passive smoking based on the cut-off value. The study suggests that self-reported smoking status is a valid measure of active smoking, whereas in the case of passive smoking, a combination of questionnaire data and biomarker verification may be required.

Tobacco smoking and breastfeeding: Effect on the lactation process, breast milk composition and infant development. A critical review

Approximately 10% of women report smoking during pregnancy. The number of breastfeeding women who relapse back to smoking is even greater. Smoking may cause adverse changes to the milk's composition by not only reducing its protective properties, but also by affecting the infant's health. The pathophysiological mechanisms underlying these adverse effects are not entirely known. This article is a review of previous reports about the effects of smoking on the lactation process, breast milk composition and infant development. A systematic search for English language articles published until 2015 was made, using a MEDLINE data. The key search terms were "smoking and breastfeeding", "smoking and lactation", "smoking and milk composition", "nicotine and breast milk". Studies have shown that nicotine levels in breast milk of women who smoke are three times higher than those in the plasma levels. Breast milk volume is reduced and the duration of lactation period is shorter. Smoking causes adverse changes to the milk's composition by not only reducing its protective properties, but also affecting infants' response to breastfeeding and to breast milk.

Self-reported and laboratory evaluation of late pregnancy nicotine exposure and drugs of abuse

OBJECTIVE

The objective of this study was to evaluate the prevalence of late pregnancy nicotine exposures, including secondhand smoke exposures, and to evaluate the associated risk of exposure to drugs of abuse.

STUDY DESIGN

The study was a retrospective single-center cohort analysis of more than 18 months. We compared self-reported smoking status from vital birth records with mass spectrometry laboratory results of maternal urine using a chi-square test. Logistic regression estimated adjusted odds for detection of drugs of abuse based on nicotine detection.

RESULTS

Compared with 8.6% self-reporting cigarette use, mass spectrometry detected high-level nicotine exposures for 16.5% of 708 women (P<0.001) and an additional 7.5% with low-level exposures. We identified an increased likelihood of exposure to drugs of abuse, presented as adjusted odds ratios, (95% confidence interval (CI), for both low-level (5.69, CI: 2.09 to 15.46) and high-level (13.93, CI: 7.06 to 27.49) nicotine exposures.

CONCLUSION

Improved measurement tactics are critically needed to capture late pregnancy primary and passive nicotine exposures from all potential sources.

Precision Medicine for Tobacco Dependence: Development and Validation of the Nicotine Metabolite Ratio

Quitting smoking significantly reduces the risk of tobacco-related morbidity and mortality, yet there is a high rate of relapse amongst smokers who try to quit. Phenotypic biomarkers have the potential to improve smoking cessation outcomes by identifying the best available treatment for an individual smoker. In this review, we introduce the nicotine metabolite ratio (NMR) as a reliable and stable phenotypic measure of nicotine metabolism that can guide smoking cessation treatment among smokers who wish to quit. We address how the NMR accounts for sources of variation in nicotine metabolism including genotype and other biological and environmental factors such as estrogen levels, alcohol use, body mass index, or menthol exposure. Then, we highlight clinical trials that validate the NMR as a biomarker to predict therapeutic response to different pharmacotherapies for smoking cessation. Current evidence supports the use of nicotine replacement therapy for slow metabolizers, and non-nicotine treatments such as varenicline for normal metabolizers. Finally, we discuss future research directions to elucidate mechanisms underlying NMR associations with treatment response, and facilitate the implementation of the NMR as biomarker in clinical practice to guide smoking cessation.

Telephone Intervention for Pregnant Smokers: A Randomized Controlled Trial

INTRODUCTION

Pregnant smokers are advised to quit; however, many struggle to do so. Behavioral counseling can increase quitting success, but the efficacy of telephone counseling for pregnant smokers has not been established. This study tests the efficacy of pregnancy-specific counseling, embedded in the ongoing operations of a state quitline.

DESIGN

In this two-group RCT, participants were randomly assigned to the intervention (telephone counseling plus self-help materials, n=584) or the control group (self-help materials only, n=589).

SETTING/PARTICIPANTS

Participants were pregnant smokers (N=1,173) in the first 27 weeks of gestation who called a state quitline between September 2000 and May 2003 for help with quitting.

INTERVENTION

The primary component of the intervention was telephone counseling using a semi-structured protocol developed specifically for pregnant smokers. It drew its basic structure and clinical content from a previously tested counseling protocol for adult quitline callers, while including pregnancy-specific content and additional counseling sessions (nine rather than the standard five).

MAIN OUTCOME MEASURES

Subjects were evaluated on prolonged abstinence at the third trimester (about 29 weeks' gestation) and at 2 and 6 months postpartum. Data were analyzed in 2015.

RESULTS

Abstinence was higher for the intervention than the control group at the end of pregnancy (30-day abstinence, 29.6% vs 20.1%; p<0.001); 2 months postpartum (90-day abstinence, 22.1% vs 14.8%; p<0.001); and 6 months postpartum (180-day abstinence, 14.4% vs 8.2%; p<0.001). Cotinine-corrected (≤13 ng/mL) 7-day abstinence rates at the end of pregnancy supported the intervention effect (35.8% vs 22.5%, p<0.001).

CONCLUSIONS

A pregnancy-specific counseling protocol, embedded in a state quitline, was effective in helping pregnant smokers quit and stay quit postpartum. Wide adoption of this intervention could help reduce the rate of maternal smoking and prevent its devastating health consequences.

TRIAL REGISTRATION

This study is registered at www.clinicaltrials.gov NCT02144883.

Smoking Cessation Therapy in Pregnancy

Objective:

To determine the safety and efficacy of pharmacologic therapy for smoking cessation in pregnancy by conducting a review of current literature, focusing on controlled clinical trials.

Data Sources:

A MEDLINE search (1966–May 2006) of English-language, human clinical trials was conducted. Key search terms included nicotine, nicotine replacement therapy, bupropion, smoking cessation, and pregnancy. In addition, relevant articles were cross-referenced to screen for additional information.

Study Selection/Data Extraction:

Studies were chosen for further review if they were randomized, controlled, long-term evaluations of the safety and/or efficacy of pharmacologic therapy for smoking cessation in pregnancy. A total of 5 trials met the criteria for review.

Data Synthesis:

Controlled clinical trials of smoking cessation therapy in pregnant women are limited. Three trials have examined the long-term use of nicotine replacement products. Neither of the 2 placebo-controlled trials found a statistically significant difference in abstinence rates between women receiving transdermal nicotine replacement therapy (NRT) and placebo. However, transdermal nicotine products appeared to be safe in this population. No long-term studies have evaluated use of other nicotine replacement products in pregnant women. Bupropion has demonstrated efficacy in smoking cessation in pregnancy, but the data are limited.

Conclusions:

Transdermal NRT appears to be safe in pregnant women, although its efficacy is unclear. Information on other NRT formulations in pregnancy is unavailable. Bupropion may be a nonnicotine alternative for smoking cessation in pregnancy, but data are currently incomplete. Further studies are needed to determine the ideal population for treatment, the timing of initiation, appropriate monitoring, and the optimal length of therapy.

Acute fetal heart rate tracing changes secondary to cigarette smoking in third trimester pregnancies

OBJECTIVE

In this study, we aimed to assess the acute alterations on some features of fetal heart rate (FHR) tracings in third trimester pregnancies.

METHODS

Data of FHR tracing records were obtained from 79 otherwise healthy pregnant women aged between 18 and 41. Among 79 women, 39 were nonsmokers while the remaining were chronic smokers (six or more cigarettes per day, with an average of 10 cigarettes per day). The baseline of tracings, the number of accelerations and decelerations of FHR, as well as the FHR mean, standard deviation, short-term variability of FHR were all calculated for each participant. The results of smokers and nonsmokers, then the results of smokers before and after smoking were compared.

RESULTS

Comparison of some demographic and FHR tracing characteristics between smoker and nonsmoker groups indicated significantly decreased variability in smoker group. All FHR tracing characteristics were compared before and, immediately after cigarette smoking and revealed significantly higher mean baseline, lower variability and acceleration after smoking a cigarette.

CONCLUSION

Even in a short time period, smoking is associated with some changes in FHR monitorization characteristics, detailed analyses of these changes may clarify the pathophysiology of smoking associated perinatal outcome.

Getting over the shock: taking action on Indigenous maternal smoking

Smoking rates are slow to decline among pregnant Indigenous women. One in two pregnant Indigenous Australian women is a tobacco smoker compared with one in eight in the non-Indigenous population. The National Close the Gap strategy ambitiously aims to reduce Indigenous smoking prevalence to half by 2018, but this goal is unlikely to be achieved. Evidence is growing to better inform targeted strategies for Indigenous pregnant women based on national and international studies. It is proposed to be an appropriate time to refine translational approaches for anti-tobacco messages and cessation support in this population, rather than waiting for further empirical research before making these essential changes. Systemic barriers to Indigenous pregnant women receiving equitable primary health care have been identified, are remediable, and urgently require addressing. These barriers include: (1) lack of subsidised access to suitable oral forms of nicotine replacement therapy; (2) lack of clinician training in the complex area of management of maternal Indigenous smoking; and (3) lack of targeted health promotion programs addressing the psychosocial challenges that Indigenous women face. In the interim, translational strategies to target tobacco control and cessation in pregnant Indigenous women need to be based on current evidence.

Cessation of alcohol consumption decreases rate of nicotine metabolism in male alcohol-dependent smokers

BACKGROUND

Rate of nicotine metabolism is an important factor influencing cigarette smoking behavior, dependence, and efficacy of nicotine replacement therapy. The current study examined the hypothesis that chronic alcohol abuse can accelerate the rate of nicotine metabolism. Nicotine metabolite ratio (NMR, a biomarker for rate of nicotine metabolism) and patterns of nicotine metabolites were assessed at three time points after alcohol cessation.

METHODS

Participants were 22 Caucasian men randomly selected from a sample of 165 smokers entering a 7-week alcohol dependence treatment program in Poland. Data were collected at three time points: baseline (week 1, after acute alcohol detoxification), week 4, and week 7. Urine was analyzed for nicotine and metabolites and used to determine the nicotine metabolite ratio (NMR, a biomarker for rate of nicotine metabolism), and total nicotine equivalents (TNE, a biomarker for total daily nicotine exposure).

RESULTS AND CONCLUSIONS

There was a significant decrease in urine NMR over the 7 weeks after alcohol abstinence (F(2,42)=18.83, p<0.001), indicating a decrease in rate of nicotine metabolism. On average NMR decreased 50.0% from baseline to week 7 (9.6±1.3 vs 4.1±0.6). There was no change in urine TNE across the three sessions, indicating no change daily nicotine intake. The results support the idea that chronic alcohol abuse may increase the rate of nicotine metabolism, which then decreases over time after alcohol cessation. This information may help to inform future smoking cessation interventions in this population.

Maternal Smoking During Pregnancy and Offspring Birth Weight: A Genetically-Informed Approach Comparing Multiple Raters

Maternal smoking during pregnancy (SDP) is a significant public health concern with adverse consequences to the health and well-being of the fetus. There is considerable debate about the best method of assessing SDP, including birth/medical records, timeline follow-back approaches, multiple reporters, and biological verification (e.g., cotinine). This is particularly salient for genetically-informed approaches where it is not always possible or practical to do a prospective study starting during the prenatal period when concurrent biological specimen samples can be collected with ease. In a sample of families (N = 173) specifically selected for sibling pairs discordant for prenatal smoking exposure, we: (1) compare rates of agreement across different types of report-maternal report of SDP, paternal report of maternal SDP, and SDP contained on birth records from the Department of Vital Statistics; (2) examine whether SDP is predictive of birth weight outcomes using our best SDP report as identified via step (1); and (3) use a sibling-comparison approach that controls for genetic and familial influences that siblings share in order to assess the effects of SDP on birth weight. Results show high agreement between reporters and support the utility of retrospective report of SDP. Further, we replicate a causal association between SDP and birth weight, wherein SDP results in reduced birth weight even when accounting for genetic and familial confounding factors via a sibling comparison approach.

The Association Between Treatment Adherence to Nicotine Patches and Smoking Cessation in Pregnancy: A Secondary Analysis of a Randomized Controlled Trial

Introduction:

In nonpregnant “quitters,” adherence to nicotine replacement therapy (NRT) increases smoking cessation. We investigated relationships between adherence to placebo or NRT patches and cessation in pregnancy, including an assessment of reverse causation and whether any adherence: cessation relationship is moderated when using nicotine or placebo patches.

Methods:

Using data from 1050 pregnant trial participants, regression models investigated associations between maternal characteristics, adherence and smoking cessation.

Results:

Adherence during the first month was associated with lower baseline cotinine concentrations (β −0.08, 95% confidence interval [CI] −0.15 to −0.01) and randomization to NRT (β 2.59, 95% CI 1.50 to 3.68). Adherence during both treatment months was associated with being randomized to NRT (β 0.51, 95% CI 0.29 to 0.72) and inversely associated with higher nicotine dependence. Adherence with either NRT or placebo was associated with cessation at 1 month (odds ratio [OR] 1.11, 95% CI 1.08 to 1.13) and delivery (OR 1.06, 95% CI 1.03 to 1.09), but no such association was observed in the subgroup where reverse causation was not possible. Amongst all women, greater adherence to nicotine patches was associated with increased cessation (OR 2.47, 95% CI 1.32 to 4.63) but greater adherence to placebo was not (OR 0.98, 95% CI: 0.44 to 2.18).

Conclusion:

Women who were more adherent to NRT were more likely to achieve abstinence; more nicotine dependent women probably showed lower adherence to NRT because they relapsed to smoking more quickly. The interaction between nicotine-containing patches and adherence for cessation suggests that the association between adherence with nicotine patches and cessation may be partly causal.

Implications:

This study used placebo randomized controlled trial data to investigate both associations between women’s characteristics and adherence to NRT patch treatment, and the relationship between adherence to NRT patch treatment and odds of cessation in pregnant quitters. Greater adherence was seen with NRT patches, and greater adherence with NRT patches increased the odds of smoking cessation. A likely explanation for findings is that NRT patches, if used sufficiently, may be effective for at least some pregnant women who try to stop smoking. Trials testing interventions which encourage women’s adherence to higher dose NRT are indicated.

Understanding Inequalities of Maternal Smoking--Bridging the Gap with Adapted Intervention Strategies

Women who are generally part of socially disadvantaged and economically marginalized groups are especially susceptible to smoking during pregnancy but smoking rates are underreported in both research and interventions. While there is evidence to support the short-term efficacy of nicotine replacement therapy (NRT) use in pregnancy, long-term abstinence rates are modest. Current health strategies and interventions designed to diminish smoking in pregnancy have adopted a simplified approach to maternal smoking-one that suggests that they have a similar degree of choice to non-pregnant smokers regarding the avoidance of risk factors, and overlooks individual predictors of non-adherence. As a result, interventions have been ineffective among this high-risk group. For this reason, this paper addresses the multiple and interacting determinants that must be considered when developing and implementing effective strategies that lead to successful smoking cessation: socioeconomic status (SES), nicotine dependence, social support, culture, mental health, and health services. Based on our review of the literature, we conclude that tailoring cessation programs for pregnant smokers may ultimately optimize NRT efficacy and reduce the prevalence of maternal smoking.

Nicotine Dependence Measures for Perinatal Women

This integrative review provides an overview of nicotine dependence measures used with perinatal women and an evaluation of their psychometric properties. Fifty-five articles that met inclusion and exclusion criteria were identified from five different databases. Most of the studies used the Fagerström Test for Nicotine Dependence (FTND). Other approaches included diagnostic tests, the Wisconsin Inventory of Smoking Dependence Motives (WISDM), the Tobacco Dependence Screener, and single-item measures. This review indicated that the FTND may not be the best option for measuring nicotine dependence in this population. The WISDM is a newer instrument that has excellent psychometric properties and captures nonnicotinic dimensions of nicotine dependence relevant to women. Future research is needed to assess its reliability in the perinatal population. Other recommendations from this review include the use of biomarker validation, thorough psychometric reporting on nicotine dependence instruments, and the use of multiple instruments to maximize comparability between nicotine dependence instruments.

Chronic Nicotine Exposure Abolishes Maternal Systemic and Renal Adaptations to Pregnancy in Rats

Pregnancy is characterized by maternal systemic and intrarenal vasodilation, leading to increases in the renal plasma flow (RPF) and glomerular filtration rate (GFR). These responses are mainly mediated by nitric oxide (NO) and relaxin. The impact of cigarette smoking on the maternal adaptations to pregnancy is unclear. Here we evaluated the effects of chronic exposure to nicotine on systemic and intrarenal parameters in virgin (V) and 14-day pregnant (P) Wistar rats. V and P groups received saline or nicotine (6 mg·kg^-1·day^-1) respectively, via osmotic minipumps for 28 days, starting 14 days before pregnancy induction. Nicotine induced a 10% increase in blood pressure in the V group and minimized the characteristic pregnancy-induced hypotension. Renal sympathetic nerve activity (rSNA) and baroreflex sensitivity were impaired by nicotine mainly in the P group, indicating that the effect of nicotine on blood pressure was not mediated by nervous system stimulation. Nicotine had no effect on GFR in the V rats but reduced GFR of the P group by 30%. Renal expression of sodium and water transporters was downregulated by nicotine, resulting in increased fractional sodium excretion mainly in the P group, suggesting that nicotine compromised the sodium and water retention required for normal gestation. There was a reduction in the expression of inducible NO synthase (iNOS) in both the kidney tissue and renal artery, as well as in the expression of the relaxin receptor (LGR7). These results clearly show that nicotine induced deleterious effects in both virgin and pregnant animals, and abolished the maternal capacity to adapt to pregnancy.

Stress is a principal factor that promotes tobacco use in females

Tobacco use is a major economic and health problem. It is particularly concerning that women consume more tobacco products, have a more difficult time quitting smoking, and are less likely to benefit from smoking cessation therapy than men. As a result, women are at higher risk of developing tobacco-related diseases. Clinical evidence suggests that women are more susceptible to anxiety disorders, and are more likely to smoke in order to cope with stress than men. During smoking abstinence, women experience more intense anxiety than men and report that the anxiety-reducing effects of smoking are the main reason for their continued tobacco use and relapse. Consistent with this, pre-clinical studies using rodent models suggest that females display more intense stress during nicotine withdrawal than males. This review posits that in women, stress is a principal factor that promotes the initiation of tobacco use and relapse behavior during abstinence. Studies are reviewed at both the clinical and pre-clinical levels to provide support for our hypothesis that stress plays a central role in promoting tobacco use vulnerability in females. The clinical implications of this work are also considered with regard to treatment approaches and the need for more research to help reduce health disparities produced by tobacco use in women.

Comparison of nicotine dependence indicators in predicting quitting among pregnant smokers

Research in the general population of smokers indicates that across various measures of nicotine dependence, time to first cigarette (TTFC) is the strongest single-item predictor of quitting success. Whether those findings generalize to pregnant smokers is unclear. To investigate this matter, we compared TTFC with cigarettes per day (CPD) and the Heaviness of Smoking Index (HSI; Kozlowski, Porter, Orleans, Pope, & Heatherton, 1994) in predicting late-pregnancy abstinence among 289 pregnant women enrolled in 4 smoking-cessation trials assessing the efficacy of financial incentives. Logistic regression was used to compare predictors, with model fit measured using the c statistic (range = 0.5, poor prediction to 1.0, perfect prediction). In simple regressions, model fit was comparable across the 3 measures although strongest for CPD alone (c = 0.70, 0.68, 0.66 for CPD, HSI, and TTFC, respectively). In a stepwise multiple regression, treatment was entered first (c = 0.67), then CPD (c = 0.77), quit attempts prepregnancy (c = .81), TTFC (c = .82), and quit attempts during pregnancy (c = .83). We saw no evidence supporting TTFC as the optimal predictor of quitting among pregnant smokers. Instead, the evidence supported using CPD and TTFC together or CPD alone if using only a single predictor.

Ovarian hormones, menstrual cycle phase, and smoking: a review with recommendations for future studies

Cigarette smoking continues to be the leading cause of preventable morbidity and mortality. Similar to other addictive substances, the prevalence of cigarette smoking is greater among men than women, yet women are less successful at quitting smoking. Preclinical and clinical research suggests that ovarian hormones (i.e., estradiol and progesterone), which fluctuate over the course of the menstrual cycle, may contribute to these sex differences. Specifically, research suggests that progesterone may protect against cigarette smoking and nicotine addiction; whereas estradiol may underlie enhanced vulnerability. In this review, we discuss new research on ovarian hormone and menstrual cycle phase effects on smoking-related responses and behavior in women, including studies examining neural responses to smoking cues, hormonal influences on medication-assisted smoking cessation, and acute smoking abstinence. We highlight innovative studies with strong research methodology and provide suggestions for future research that may allow evidence-based knowledge for immediate translation to the clinic to guide novel, hormonally-informed treatment strategies. Thus, rigorous scientific study holds the potential to reduce relapse rates, thus improving the health and saving the lives of the many thousands of women who unfortunately do not respond to current treatments.

Benefits of Incentives for Breastfeeding and Smoking cessation in pregnancy (BIBS): a mixed-methods study to inform trial design

BACKGROUND

Smoking in pregnancy and/or not breastfeeding have considerable negative health outcomes for mother and baby.

AIM

To understand incentive mechanisms of action for smoking cessation in pregnancy and breastfeeding, develop a taxonomy and identify promising, acceptable and feasible interventions to inform trial design.

DESIGN

Evidence syntheses, primary qualitative survey, and discrete choice experiment (DCE) research using multidisciplinary, mixed methods. Two mother-and-baby groups in disadvantaged areas collaborated throughout.

SETTING

UK.

PARTICIPANTS

The qualitative study included 88 pregnant women/recent mothers/partners, 53 service providers, 24 experts/decision-makers and 63 conference attendees. The surveys included 1144 members of the general public and 497 health professionals. The DCE study included 320 women with a history of smoking.

METHODS

(1) Evidence syntheses: incentive effectiveness (including meta-analysis and effect size estimates), delivery processes, barriers to and facilitators of smoking cessation in pregnancy and/or breastfeeding, scoping review of incentives for lifestyle behaviours; (2) qualitative research: grounded theory to understand incentive mechanisms of action and a framework approach for trial design; (3) survey: multivariable ordered logit models; (4) DCE: conditional logit regression and the log-likelihood ratio test.

RESULTS

Out of 1469 smoking cessation and 5408 breastfeeding multicomponent studies identified, 23 smoking cessation and 19 breastfeeding studies were included in the review. Vouchers contingent on biochemically proven smoking cessation in pregnancy were effective, with a relative risk of 2.58 (95% confidence interval 1.63 to 4.07) compared with non-contingent incentives for participation (four studies, 344 participants). Effects continued until 3 months post partum. Inconclusive effects were found for breastfeeding incentives compared with no/smaller incentives (13 studies) but provider commitment contracts for breastfeeding show promise. Intervention intensity is a possible confounder. The acceptability of seven promising incentives was mixed. Women (for vouchers) and those with a lower level of education (except for breastfeeding incentives) were more likely to disagree. Those aged ≤ 44 years and ethnic minority groups were more likely to agree. Agreement was greatest for a free breast pump and least for vouchers for breastfeeding. Universal incentives were preferred to those targeting low-income women. Initial daily text/telephone support, a quitting pal, vouchers for > £20.00 per month and values up to £80.00 increase the likelihood of smoking cessation. Doctors disagreed with provider incentives. A 'ladder' logic model emerged through data synthesis and had face validity with service users. It combined an incentive typology and behaviour change taxonomy. Autonomy and well-being matter. Personal difficulties, emotions, socialising and attitudes of others are challenges to climbing a metaphorical 'ladder' towards smoking cessation and breastfeeding. Incentive interventions provide opportunity 'rungs' to help, including regular skilled flexible support, a pal, setting goals, monitoring and outcome verification. Individually tailored and non-judgemental continuity of care can bolster women's capabilities to succeed. Rigid, prescriptive interventions placing the onus on women to behave 'healthily' risk them feeling pressurised and failing. To avoid 'losing face', women may disengage.

LIMITATIONS

Included studies were heterogeneous and of variable quality, limiting the assessment of incentive effectiveness. No cost-effectiveness data were reported. In surveys, selection bias and confounding are possible. The validity and utility of the ladder logic model requires evaluation with more diverse samples of the target population.

CONCLUSIONS

Incentives provided with other tailored components show promise but reach is a concern. Formal evaluation is recommended. Collaborative service-user involvement is important.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42012001980.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Increasing awareness of sex differences in airway diseases

There is growing epidemiologic data demonstrating sex differences with respect to prevalence and progression of airway diseases, including asthma, chronic obstructive pulmonary disease (COPD), cystic fibrosis (CF) and non-CF-related bronchiectasis. In asthma, for example, young boys have increased exacerbations and higher morbidity than girls which distinctly reverses after adolescence and into adulthood. In COPD, a disease that was historically considered an illness of men, the number of women dying per year is now greater than in men. Finally, women with CF-related bronchiectasis have a decreased median life expectancy relative to men and a higher risk of respiratory infections despite equal prevalence of the disease. A number of studies now exist demonstrating mechanisms behind these sex differences, including influences of genetic predisposition, sex hormones and comorbidities. The notable sex disparity has potential diagnostic, therapeutic and prognostic implications and for the practicing respiratory or general physician, a familiarity with these distinctions may augment effective management of patients with airway diseases. This review seeks to concisely summarize the data regarding gender-based differences in airway diseases, outline the current understanding of contributing factors and discuss therapeutic implications for clinicians.

The Collection and Analysis of Carbon Monoxide Levels as an Indirect Measure of Smoke Exposure in Pregnant Adolescents at a Multidisciplinary Teen Obstetrics Clinic

STUDY OBJECTIVE

In this study we aimed to collect and analyze CO levels as an indirect measure of smoke exposure in pregnant adolescents.

DESIGN, SETTING, AND PARTICIPANTS

Participants included pregnant adolescents who received antenatal care over 18 months (2012-2013) at the Multidisciplinary Teen Obstetrics Clinic at a tertiary-care hospital in Southeastern Ontario.

INTERVENTIONS

The CO breath test is a noninvasive method that is used to assess smoke exposure, in which nonsmokers have levels of 0-6 ppm, and levels of 7-10, 11-20 and more than 20 ppm are consistent with light, typical, and heavy smokers, respectively. Expired CO, smoking status, cigarette number, and home secondhand smoke exposure were documented at 3 clinic visits.

MAIN OUTCOME MEASURES

To determine mean CO levels as a measure of smoke exposure and prevalence of secondhand smoke exposure.

RESULTS

The mean age of participants was 17.6 years. CO means (ppm) across 3 visits were 6.0, 5.9, and 4.8. Sixty-two percent of patients were self-reported nonsmokers, 38% were self-reported smokers (n = 93). CO means (standard error of the mean) were consistently different for nonsmokers vs smokers at visits 1 to 3, respectively: 2.9 (0.79) vs 9.7 (1.8); 3.0 (0.71) vs 12.9 (2.2), and 2.4 (0.71) vs 8.8 (1.5; P < .01, t test; n = 91). Of patient's highest CO (COmax), 62%, 9%, 15%, and 12% had levels of 6 or less, 7-10, 11-20, and greater than 20, respectively. Eighty-four percent of pregnant adolescents had home secondhand smoke exposure, which included 40% of nonsmokers and 100% of smokers (n = 57). Although most nonsmokers had a COmax of 6 or fewer ppm, 56% of smokers had COmax greater than 10 ppm (P < .05, χ(2)).

CONCLUSION

Emphasis on smoking cessation is imperative in pregnant adolescents and should particularly target partners and families, because secondhand smoke exposure was very prevalent.

Associations Between Genetic Ancestries and Nicotine Metabolism Biomarkers in the Multiethnic Cohort Study

Differences in internal dose of nicotine and tobacco-derived carcinogens among ethnic/racial groups have been observed. In this study, we explicitly examined the relationships between genetic ancestries (genome-wide average) and 19 tobacco-derived biomarkers in smokers from 3 admixed groups in the Multiethnic Cohort Study (1993-present), namely, African ancestry in African Americans (n = 362), Amerindian ancestry in Latinos (n = 437), and Asian and Native Hawaiian ancestries in Native Hawaiians (n = 300). After multiple comparison adjustment, both African and Asian ancestries were significantly related to a greater level of free cotinine; African ancestry was also significantly related to lower cotinine glucuronidation (P's < 0.00156). The predicted decrease in cotinine glucuronidation was 8.6% (P = 4.5 × 10(-6)) per a 20% increase in African ancestry. Follow-up admixture mapping revealed that African ancestry in a 12-Mb region on chromosome 4q was related to lower cotinine glucuronidation (P's < 2.7 × 10(-7), smallest P = 1.5 × 10(-9)), although this is the same region reported in our previous genome-wide association study. Our results implicate a genetic ancestral component in the observed ethnic/racial variation in nicotine metabolism. Further studies are needed to identify the underlying genetic variation that could potentially be ethnic/racial specific.

Maternal Smoking and Metabolic Health Biomarkers in Newborns

Background

Maternal smoking has been associated with elevated risk of type 2 diabetes among the offspring in adulthood. The mechanisms underlying this fetal “programming” effect remain unclear. The present study sought to explore whether maternal smoking affects metabolic health biomarkers in fetuses/newborns.

Methods

In a prospective singleton pregnancy cohort (n = 248), we compared metabolic health biomarkers in the newborns of smoking and non-smoking mothers. Outcomes included cord plasma insulin, proinsulin, insulin-like growth factor I (IGF-I), IGF-II, leptin and adiponectin concentrations, glucose-to-insulin ratio (an indicator of insulin sensitivity) and proinsulin-to-insulin ratio (an indicator of β-cell function).

Results

Independent of maternal (glucose tolerance, age, ethnicity, parity, education, body mass index, alcohol use) and infant (sex, gestational age, birth weight z score, mode of delivery, cord blood glucose concentration) characteristics, the newborns of smoking mothers had lower IGF-I concentrations (mean: 6.7 vs. 8.4 nmol/L, adjusted p = 0.006), and marginally higher proinsulin-to-insulin ratios (0.94 vs. 0.72, adjusted p = 0.06) than the newborns of non-smoking mothers. Cord plasma insulin, proinsulin, IGF-II, leptin and adiponectin concentrations and glucose-to-insulin ratios were similar in the newborns of smoking and non-smoking mothers.

Conclusions

Maternal smoking was associated with decreased fetal IGF-I levels, and borderline lower fetal β-cell function. Larger cohort studies are required to confirm the latter finding. The preliminary findings prompt the hypothesis that these early life metabolic changes may be involved in the impact of maternal smoking on future risk of metabolic syndrome related disorders in the offspring.

Separating Family-Level and Direct Exposure Effects of Smoking During Pregnancy on Offspring Externalizing Symptoms: Bridging the Behavior Genetic and Behavior Teratologic Divide

Maternal smoking during pregnancy (MSDP) has been robustly associated with externalizing problems and their developmental precursors in offspring in studies using behavioral teratologic designs (Wakschlag et al., Am J Public Health 92(6):966-974, 2002; Espy et al., Dev Psychol 47(1):153-169, 2011). In contrast, the use of behavior genetic approaches has shown that the effects commonly attributed to MSDP can be explained by family-level variables (D'Onofrio et al., Dev Psychopathol 20(01):139-164, 2008). Reconciling these conflicting findings requires integration of these study designs. We utilize longitudinal data on a preschool proband and his/her sibling from the Midwest Infant Development Study-Preschool (MIDS-P) to test for teratologic and family level effects of MSDP. We find considerable variation in prenatal smoking patterns both within and across pregnancies within families, indicating that binary smoking measures are not sufficiently capturing exposure. Structural equation models indicate that both conduct disorder and oppositional defiant disorder symptoms showed unique effects of MSDP over and above family level effects. Blending high quality exposure measurement with a within-family design suggests that it is premature to foreclose the possibility of a teratologic effect of MSDP on externalizing problems. Implications and recommendations for future studies are discussed.

Changes in the rate of nicotine metabolism across pregnancy: a longitudinal study

AIMS

Increased nicotine metabolism during pregnancy could explain why nicotine replacement therapy (NRT) appears to be less effective on smoking cessation in pregnancy than in non-pregnant smokers, but little is known about nicotine metabolism across pregnancy. This study was conducted to determine when changes in nicotine metabolism occur during pregnancy and to describe the magnitude of these changes.

DESIGN

Longitudinal cohort study of pregnant smokers' nicotine metabolite ratio (NMR).

SETTING AND PARTICIPANTS

101 pregnant smokers recruited from hospital antenatal clinics in Nottingham, UK were asked to provide saliva samples at 8-14 weeks (n = 98), 18-22 weeks (n = 65), 32-36 weeks gestation (n = 47), 4 weeks postpartum (n = 44) and 12 weeks postpartum (n = 47).

MEASUREMENTS

Nicotine metabolite ratio (NMR) was measured using the ratio of cotinine to its primary metabolite trans-3'-hydroxycotinine. Multi-level modelling was used to detect any overall difference in NMR between time points. The 12 week postpartum NMR was compared with the NMRs collected antenatally and 4 weeks postpartum.

FINDINGS

NMR changed over time (p = 0.0006). Compared with NMR at 12 weeks postpartum, NMR was significantly higher at 18-22 weeks (26% higher, 95% CI 12% to 38%) and 32-36 weeks (23% higher, 95% CI 9% to 35%). There was no significant difference between the 8-14 weeks gestation or 4 weeks postpartum NMR and 12 weeks postpartum.

CONCLUSIONS

Nicotine metabolism appears to be faster during pregnancy; this faster metabolism is apparent from 18 to 22 weeks of pregnancy and appears to fall by 4 weeks after childbirth.

Optimal Carbon Monoxide Criteria to Confirm Smoking Status Among Postpartum Women

INTRODUCTION

Although expired-air carbon monoxide (CO) is a well characterized biomarker of cigarette smoking, limited research has assessed whether the standard clinical CO cutoffs need to be altered for postpartum women and whether these cutoffs remain constant across the postpartum year. Accordingly, the present study evaluated the effectiveness of using CO as a method to confirm smoking status relative to salivary cotinine among postpartum women and assessed optimal CO criteria to confirm smoking status across the postpartum year. Differences in optimal CO criteria to confirm smoking status also were examined between black and white postpartum women.

METHODS

Women (N = 208) for the present study had quit smoking for their current pregnancy and were enrolled in a larger postpartum relapse prevention intervention. Smoking status was assessed at 12, 24, and 52 weeks postpartum using both expired-air CO and salivary cotinine.

RESULTS

Receiver-operating characteristic analyses indicated that CO provided moderately high diagnostic accuracy to distinguish between women who were and were not smoking when using salivary cotinine as the reference criterion to confirm smoking status. CO cutoffs of 2 and 3 parts per million (ppm) had the highest overall efficiency and combined sensitivity and specificity across the postpartum year. Results were consistent for black and white women.

CONCLUSIONS

These findings indicate that optimal CO criteria to confirm smoking status remains stable throughout the postpartum year and support a need to utilize CO cutoffs much lower than the standard clinical CO criterion of 8 ppm to confirm abstinence among postpartum women.

IMPLICATIONS

Findings from the present study confirm the value of CO as a biomarker of smoking status among postpartum women. Results indicate that CO cutoffs of 2 and 3 ppm were optimal for confirming smoking status across the entire postpartum year in both black and white women. These findings offer a replication and extension of previous work and indicate that optimal CO criteria to confirm smoking status remain stable throughout the postpartum period and further support a need to utilize CO cutoffs much lower than the standard clinical criterion of 8 ppm to confirm smoking status among postpartum women.

Cross validation of the prognostic and diagnostic utility of tobacco craving in a general and a pregnant sample of treatment-seeking smokers

BACKGROUND

Valid and reliable brief measures of tobacco craving are necessary for research and clinical purposes. However, comparisons of the utility of single-item and brief multidimensional craving measures are scarce.

METHODS

We analyzed two tobacco craving measures, the French versions of the 12-item Tobacco Craving Questionnaire (FTCQ-12) and the single craving item on the Minnesota Nicotine Withdrawal Scale, in pregnant and non-pregnant (females and males) French smokers from two independent smoking cessation trials. Using data from pregnant smokers, we estimated first a prognostic model for each measure and compared their ability to predict relapse from one visit to the next. We next used cutoff values for both measures to determine how well craving distinguished current smokers from abstainers. For cross-validation, we tested how well the same cut-off values generalized to non-pregnant smokers.

RESULTS

Two FTCQ-12 factors (Expectancy and Purposefulness) predicted smoking status; scores were higher in pregnant non-abstainers than abstainers. The sum of these two factors, FTCQ-12 risk score (RS), yielded higher sensitivity both in prognostic and diagnostic models than single-item MNWS craving. FTCQ-12 RS had higher sensitivity among pregnant than non-pregnant smokers. Specificity of both tobacco craving measures was similar among pregnant smokers, but higher with MNWS craving than with FTCQ-12 RS in non-pregnant smokers.

CONCLUSIONS

FTCQ-12 RS and MNWS craving can be used together in clinical practice to rapidly predict smoking status. Interventions targeting Expectancy and Purposefulness may result in higher likelihood of abstinence, especially among pregnant smokers.

A Comparison of the Fagerström Test for Cigarette Dependence and Cigarette Dependence Scale in a Treatment-Seeking Sample of Pregnant Smokers

INTRODUCTION

Valid and reliable brief measures of cigarette dependence are essential for research purposes and effective clinical care. Two widely-used brief measures of cigarette dependence are the six-item Fagerström Test for Cigarette Dependence (FTCD) and five-item Cigarette Dependence Scale (CDS-5). Their respective metric characteristics among pregnant smokers have not yet been studied.

METHODS

This was a secondary analysis of data of pregnant smokers (N = 476) enrolled in a smoking cessation study. We assessed internal consistency, reliability, and examined correlations between the instruments and smoking-related behaviors for construct validity. We evaluated predictive validity by testing how well the measures predict abstinence 2 weeks after quit date.

RESULTS

Cronbach's alpha coefficient for the CDS-5 was 0.62 and for the FTCD 0.55. Measures were strongly correlated with each other, although FTCD, but not CDS-5, was associated with saliva cotinine concentration. The FTCD, CDS-5, craving to smoke, and withdrawal symptoms failed to predict smoking status 2 weeks following the quit date.

CONCLUSIONS

Suboptimal reliability estimates and failure to predict short-term smoking call into question the value of including either of the brief measures in studies that aim to explain the obstacles to smoking cessation during pregnancy.

Disparities in prevalence of smoking and smoking cessation during pregnancy: a population-based study

Objective. To examine time trends in prevalence of smoking and smoking cessation during pregnancy by family income, maternal level of education, skin color, and age. Methods. We conducted three population-based surveys in 2007, 2010, and 2013 with newly delivered mothers living in the municipality of Rio Grande, Southern Brazil. Data were collected using questionnaires administered after delivery in all (two) maternity units in the city, at Dr. Miguel Riet Corrêa Júnior Hospital and at Santa Casa de Misericórdia. Time trends were analyzed using chi-square test for linear trend. Results. Data of 7,572 women showed that the prevalence of smoking before pregnancy decreased from 28% (26.2–29.7) in 2007 to 22% (20.8–24.0) in 2013 (P < 0.001). Prevalence of smoking during pregnancy decreased from 22% (20.4–23.7) in 2007 to 18% (16.6–19.5) in 2013 (P < 0.001). This reduction varied across income ranging from 17% (poorest) to 35% (richest) (P < 0.001). The lower the income, the higher the smoking prevalence during pregnancy. Smoking cessation was more prevalent among women of higher level of education and income. Conclusions. Smoking before and during pregnancy is still highly prevalent and the prevalence of cessation is low pointing to a need to strengthen actions targeting low-income, less educated, black pregnant women.

The SNAP trial: a randomised placebo-controlled trial of nicotine replacement therapy in pregnancy--clinical effectiveness and safety until 2 years after delivery, with economic evaluation

BACKGROUND

Smoking during pregnancy causes many adverse pregnancy and birth outcomes. Nicotine replacement therapy (NRT) is effective for cessation outside pregnancy but efficacy and safety in pregnancy are unknown. We hypothesised that NRT would increase smoking cessation in pregnancy without adversely affecting infants.

OBJECTIVES

To compare (1) at delivery, the clinical effectiveness and cost-effectiveness for achieving biochemically validated smoking cessation of NRT patches with placebo patches in pregnancy and (2) in infants at 2 years of age, the effects of maternal NRT patch use with placebo patch use in pregnancy on behaviour, development and disability.

DESIGN

Randomised, placebo-controlled, parallel-group trial and economic evaluation with follow-up at 4 weeks after randomisation, delivery and until infants were 2 years old. Randomisation was stratified by centre and a computer-generated sequence was used to allocate participants using a 1 : 1 ratio. Participants, site pharmacies and all study staff were blind to treatment allocation.

SETTING

Seven antenatal hospitals in the Midlands and north-west England.

PARTICIPANTS

Women between 12 and 24 weeks' gestation who smoked ≥ 10 cigarettes a day before and ≥ 5 during pregnancy, with an exhaled carbon monoxide (CO) reading of ≥ 8 parts per million (p.p.m.).

INTERVENTIONS

NRT patches (15 mg per 16 hours) or matched placebo as an 8-week course issued in two equal batches. A second batch was dispensed at 4 weeks to those abstinent from smoking.

MAIN OUTCOME MEASURES

PARTICIPANTS

self-reported, prolonged abstinence from smoking between a quit date and childbirth, validated at delivery by CO measurement and/or salivary cotinine (COT) (primary outcome). Infants, at 2 years: absence of impairment, defined as no disability or problems with behaviour and development. Economic: cost per 'quitter'.

RESULTS

One thousand and fifty women enrolled (521 NRT, 529 placebo). There were 1010 live singleton births and 12 participants had live twins, while there were 14 fetal deaths and no birth data for 14 participants. Numbers of adverse pregnancy and birth outcomes were similar in trial groups, except for a greater number of caesarean deliveries in the NRT group. Smoking: all participants were included in the intention-to-treat (ITT) analyses; those lost to follow-up (7% for primary outcome) were assumed to be smoking. At 1 month after randomisation, the validated cessation rate was higher in the NRT group {21.3% vs. 11.7%, odds ratio [OR], [95% confidence interval (CI)] for cessation with NRT, 2.05 [1.46 to 2.88]}. At delivery, there was no difference between groups' smoking cessation rates: 9.4% in the NRT and 7.6% in the placebo group [OR (95% CI), 1.26 (0.82 to 1.96)]. Infants: at 2 years, analyses were based on data from 888 out of 1010 (87.9%) singleton infants (including four postnatal infant deaths) [445/503 (88.5%) NRT, 443/507 (87.4%) placebo] and used multiple imputation. In the NRT group, 72.6% (323/445) had no impairment compared with 65.5% (290/443) in placebo (OR 1.40, 95% CI 1.05 to 1.86). The incremental cost-effectiveness ratio for NRT use was £4156 per quitter (£4926 including twins), but there was substantial uncertainty around these estimates.

CONCLUSIONS

Nicotine replacement therapy patches had no enduring, significant effect on smoking in pregnancy; however, 2-year-olds born to women who used NRT were more likely to have survived without any developmental impairment. Further studies should investigate the clinical effectiveness and safety of higher doses of NRT.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN07249128.

FUNDING

This project was funded by the NIHR Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 18, No. 54. See the NIHR Journals Library programme website for further project information.

Respiratory disease in pregnancy

Many physiological and anatomical changes of pregnancy affect the respiratory system. These changes often affect the presentation and management of the various respiratory illnesses in pregnancy. This article focuses on several important respiratory issues in pregnancy. The management of asthma, one of the most common chronic illnesses in pregnancy, remains largely unchanged compared to the nonpregnant state. Infectious respiratory illness, including pneumonia and tuberculosis, are similarly managed in pregnancy with antibiotics, although special attention may be needed for antibiotic choices with more pregnancy safety data. When mechanical ventilation is necessary, consideration should be given to the maternal hemodynamics of pregnancy and fetal oxygenation. Maintaining maternal oxygen saturation above 95% is recommended to sustain optimal fetal oxygenation. Cigarette smoking has known risks in pregnancy, and current practice guidelines recommend offering cognitive and pharmacologic interventions to pregnant women to assist in smoking cessation.

Effect of mild-to-moderate smoking on viral load, cytokines, oxidative stress, and cytochrome P450 enzymes in HIV-infected individuals

Mild-to-moderate tobacco smoking is highly prevalent in HIV-infected individuals, and is known to exacerbate HIV pathogenesis. The objective of this study was to determine the specific effects of mild-to-moderate smoking on viral load, cytokine production, and oxidative stress and cytochrome P450 (CYP) pathways in HIV-infected individuals who have not yet received antiretroviral therapy (ART). Thirty-two human subjects were recruited and assigned to four different cohorts as follows: a) HIV negative non-smokers, b) HIV positive non-smokers, c) HIV negative mild-to-moderate smokers, and d) HIV positive mild-to-moderate smokers. Patients were recruited in Cameroon, Africa using strict selection criteria to exclude patients not yet eligible for ART and not receiving conventional or traditional medications. Those with active tuberculosis, hepatitis B or with a history of substance abuse were also excluded. Our results showed an increase in the viral load in the plasma of HIV positive patients who were mild-to-moderate smokers compared to individuals who did not smoke. Furthermore, although we did not observe significant changes in the levels of most pro-inflammatory cytokines, the cytokine IL-8 and MCP-1 showed a significant decrease in the plasma of HIV-infected patients and smokers compared with HIV negative non-smokers. Importantly, HIV-infected individuals and smokers showed a significant increase in oxidative stress compared with HIV negative non-smoker subjects in both plasma and monocytes. To examine the possible pathways involved in increased oxidative stress and viral load, we determined the mRNA levels of several antioxidant and cytochrome P450 enzymes in monocytes. The results showed that the levels of most antioxidants are unaltered, suggesting their inability to counter oxidative stress. While CYP2A6 was induced in smokers, CYP3A4 was induced in HIV and HIV positive smokers compared with HIV negative non-smokers. Overall, the findings suggest a possible association of oxidative stress and perhaps CYP pathway with smoking-mediated increased viral load in HIV positive individuals.