Prenatal tobacco exposure: is it a risk factor for early tobacco experimentation?

Early developmental risks for tobacco addiction: A probabilistic epigenesis framework

Considerable progress has been made in elucidating the relationships between early life psychobiological and environmental risk factors and the development of tobacco addiction. However, a comprehensive understanding of the heterogeneity in tobacco addiction phenotypes requires integrating research findings. The probabilistic epigenesis meta-theory offers a valuable framework for this integration, considering systemic, multilevel, developmental, and evolutionary perspectives. In this paper, we critically review relevant research on early developmental risks associated with tobacco addiction and highlight the integrative heuristic value of the probabilistic epigenesis framework for this research. For this, we propose a four-level systems approach as an initial step towards integration, analyzing complex interactions among different levels of influence. Additionally, we explore a coaction approach to examine key interactions between early risk factors. Moreover, we introduce developmental pathways to understand interindividual differences in tobacco addiction risk during development. This integrative approach holds promise for advancing our understanding of tobacco addiction etiology and informing potentially effective intervention strategies.

Investigating Behavioral and Neuronal Changes in Adolescent Mice Following Prenatal Exposure to Electronic Cigarette (E-Cigarette) Vapor Containing Nicotine

A substantial percentage of pregnant smokers stop using traditional cigarettes and switch to alternative nicotine-related products such as e-cigarettes. Prenatal exposure to tobacco increases the risk of psychiatric disorders in children. Adolescence is a complex phase in which higher cognitive and emotional processes undergo maturation and refinement. In this study, we examined the behavioral and molecular effects of first-trimester prenatal exposure to e-cigarettes. Adult female mice were divided into normal air, vehicle, and 2.5%-nicotine-exposed groups. Our analyses indicated that the adolescents in the 2.5%-nicotine-exposed group exhibited a significant lack of normal digging behavior, elevated initial sucrose intake, and reduced recognition memory. Importantly, we identified a substantial level of nicotine self-administration in the 2.5%-nicotine-exposed group. At a molecular level, the mRNAs of metabotropic glutamate receptors and transporters in the nucleus accumbens were not altered. This previously undescribed work indicates that prenatal exposure to e-cigarettes might increase the risk of nicotine addiction during adolescence, reduce cognitive capacity, and alter normal adolescent behavior. The outcome will aid in translating research and assist healthcare practitioners in tackling addiction and mental issues caused by toxicological exposure. Further, it will inform relevant policymaking, such as recommended taxation, labeling e-cigarette devices with more detailed neurotoxic effects, and preventing their sale to pregnant women and adolescents.

Epigenetic and Long-Term Effects of Nicotine on Biology, Behavior, and Health

Tobacco and nicotine use are associated with disease susceptibility and progression. Health challenges associated with nicotine and smoking include developmental delays, addiction, mental health and behavioral changes, lung disease, cardiovascular disease, endocrine disorders, diabetes, immune system changes, and cancer. Increasing evidence suggests that nicotine-associated epigenetic changes may mediate or moderate the development and progression of a myriad of negative health outcomes. In addition, nicotine exposure may confer increased lifelong susceptibility to disease and mental health challenges through alteration of epigenetic signaling. This review examines the relationship between nicotine exposure (and smoking), epigenetic changes, and maladaptive outcomes that include developmental disorders, addiction, mental health challenges, pulmonary disease, cardiovascular disease, endocrine disorders, diabetes, immune system changes, and cancer. Overall, findings support the contention that nicotine (or smoking) associated altered epigenetic signaling is a contributing factor to disease and health challenges.

Protocol for iSISTAQUIT: Implementation phase of the supporting indigenous smokers to assist quitting project

Introduction

About 44% of Aboriginal and/or Torres Strait Islander women smoke during pregnancy compared to 12% of their general population counterparts. Evidence-based quit smoking advice received from health care professionals (HCPs) can increase smoking cessation rates. However, HCPs lack culturally appropriate smoking cessation training, which is a major barrier to provision of smoking cessation care for this population.

Methods and analysis

iSISTAQUIT is a multicentre, single arm study aiming to implement and evaluate the evidence-based, culturally competent iSISTAQUIT smoking cessation training among health practitioners who provide support and assistance to pregnant, Aboriginal and Torres Strait Islander women in Australia. This project will implement the iSISTAQUIT intervention in Aboriginal Medical Services and Mainstream Health Services. The proposed sample size is 10 of each of these services (total N = 20), however if the demand is higher, we will aim to accommodate up to 30 services for the training. Participating sites and their HCPs will have the option to choose one of the two iSISTAQUIT packages available: a) Evaluation- research package b) Training package (with or without continued professional development points). Training will be provided via an online eLearning platform that includes videos, text, interactive elements and a treatment manual. A social media campaign will be conducted from December 2021 to September 2022 to raise brand and issue awareness about smoking cessation for Aboriginal and Torres Strait Islander women in pregnancy. This national campaign will consist of systematic advertising and promotion of iSISTAQUIT and video messages through various social media platforms.

Analysis

We will use the RE-AIM framework (Reach, Effectiveness, Adoption, Implementation and Maintenance) to plan, evaluate and report the intervention impact of iSISTAQUIT. Effectiveness of social media campaign will be assessed via social media metrics, cross-sectional surveys, and interviews.

Discussion

This innovative research, using a multi-component intervention, aims to practically apply and integrate a highly translatable smoking cessation intervention in real-world primary care settings in Aboriginal Medical Services and Mainstream services. The research benefits Aboriginal women, babies and their family and community members through improved support for smoking cessation during pregnancy. The intervention is based on accepted Australian and international smoking cessation guidelines, developed and delivered in a culturally appropriate approach for Aboriginal communities.

Air pollution as an early determinant of COPD

COPD is a progressive and debilitating disease often diagnosed after 50 years of age, but more recent evidence suggests that its onset could originate very early on in life. In this context, exposure to air pollution appears to be a potential contributor. Although the potential role of air pollution as an early determinant of COPD is emerging, knowledge gaps still remain, including an accurate qualification of air pollutants (number of pollutants quantified and exact composition) or the "one exposure-one disease" concept, which might limit the current understanding. To fill these gaps, improvements in the field are needed, such as the use of atmosphere simulation chambers able to realistically reproduce the complexity of air pollution, consideration of the exposome, as well as improving exchanges between paediatricians and adult lung specialists to take advantage of reciprocal expertise. This review should lead to a better understanding of the current knowledge on air pollution as an early determinant of COPD, as well as identify the existing knowledge gaps and opportunities to fill them. Hopefully, this will lead to better prevention strategies to scale down the development of COPD in future generations.

A Pilot Study of Exposure to Nicotine in Human Pregnancy and Maternal and Fetal Testosterone Levels at Birth

Nicotine exposure in pregnant rats and sheep has shown a more than 50% increase in female fetal testosterone (FFT) levels. Increased testosterone levels have also been linked to infertility, increased anogenital distance (AGD), and reduced second to fourth digit (2D:4D) finger length ratios (FLR). In humans, we hypothesized that maternal total testosterone (MTT) levels would increase in smoking mothers and would cause increased FFT levels, increased AGD, and decreased 2D:4D FLR. This prospective study separated women expecting a female fetus into nonsmoking and smoking cohorts. Maternal cotinine (MC) was tested at 3rd trimester and delivery to assess nicotine exposure. MTT levels were drawn at delivery, and FFT levels were collected from cord blood. The AGD and 2D:4D FLRs were measured at birth. Data were analyzed using parametric and nonparametric tests. The data of 36 smokers and 28 nonsmokers were analyzed. Smoking mothers had higher parity, drug abuse history and were more likely white race. No statistical differences were seen among the primary outcomes of MTT and FFT. MTT was higher among nonsmokers versus smokers (144 versus 107 ng/dL). No correlations were noted between MC levels at delivery, MTT, and FFT levels. No statistical differences were noted among secondary outcomes of AGD and FLR. Although animal studies showed increased FFT levels after nicotine exposure, this was not seen in our human study. Placental differences in animals and humans may be at work. Our pilot study reveals a need for research on the effects of smoking in pregnancy on fetal hormones.

Prenatal Tobacco Exposure and the Risk of Tobacco Smoking and Dependence in Offspring: a Systematic Review and Meta-Analysis

BACKGROUND

There is some compelling, though not comprehensive, epidemiological evidence which suggests an association between prenatal tobacco exposure and tobacco smoking/dependence in offspring. We conducted a systematic review and meta-analysis to identify the magnitude and consistency of associations reported between prenatal tobacco exposure and subsequent tobacco smoking/dependence in offspring.

METHODS

Using the PRISMA guideline, we systematically searched PubMed, SCOPUS, EMBASE and Psych-INFO to identify relevant studies. The methodological quality of all identified studies was checked by the Newcastle-Ottawa Scale. Inverse variance weighted random effects meta-analysis was used to estimate pooled risk ratio (RR) and 95 % confidence intervals (CI). We stratified outcomes by tobacco smoking initiation, lifetime tobacco smoking, current tobacco smoking and tobacco dependence. We further performed subgroup and leave-one-out sensitivity analyses. The protocol of this review was registered in the PROSPERO.

RESULTS

Twenty-six cohort and one case-control study were included in the final meta-analysis. We found elevated pooled risks of tobacco smoking initiation [RR = 2.08, (95 % CI: 1.18-3.68)], ever tobacco smoking [RR = 1.21, (95 % CI: 1.05-1.38)], current tobacco smoking [RR = 1.70, (95 % CI: 1.48-1.95)] and tobacco dependence [RR = 1.50, (95 % CI: 1.31-1.73)] in offspring exposed to maternal prenatal tobacco use compared to non-exposed. We also noted higher risk estimate of current tobacco smoking in offspring exposed to heavy prenatal tobacco smoking [RR = 1.68, (95 % CI: 1.26-2.23)] when compared to prenatal exposure to lighter tobacco use [RR = 1.39, (95 % CI: 1.09-1.78)]. There was no association observed between paternal smoking during pregnancy and tobacco smoking in offspring.

CONCLUSION

Offspring exposed to maternal prenatal tobacco smoking are at an increased risk of tobacco smoking/dependence, indicating that tobacco smoking cessation during gestation may be imperative to reduce these risks in offspring.

DNA methylome perturbations: an epigenetic basis for the emergingly heritable neurodevelopmental abnormalities associated with maternal smoking and maternal nicotine exposure†

Maternal smoking during pregnancy is associated with an ensemble of neurodevelopmental consequences in children and therefore constitutes a pressing public health concern. Adding to this burden, contemporary epidemiological and especially animal model research suggests that grandmaternal smoking is similarly associated with neurodevelopmental abnormalities in grandchildren, indicative of intergenerational transmission of the neurodevelopmental impacts of maternal smoking. Probing the mechanistic bases of neurodevelopmental anomalies in the children of maternal smokers and the intergenerational transmission thereof, emerging research intimates that epigenetic changes, namely DNA methylome perturbations, are key factors. Altogether, these findings warrant future research to fully elucidate the etiology of neurodevelopmental impairments in the children and grandchildren of maternal smokers and underscore the clear potential thereof to benefit public health by informing the development and implementation of preventative measures, prophylactics, and treatments. To this end, the present review aims to encapsulate the burgeoning evidence linking maternal smoking to intergenerational epigenetic inheritance of neurodevelopmental abnormalities, to identify the strengths and weaknesses thereof, and to highlight areas of emphasis for future human and animal model research therein.

The Intergenerational Transmission of Developmental Nicotine Exposure-Induced Neurodevelopmental Disorder-Like Phenotypes is Modulated by the Chrna5 D397N Polymorphism in Adolescent Mice

Maternal tobacco smoking during pregnancy constitutes developmental nicotine exposure (DNE) and is associated with nicotine dependence and neurodevelopmental disorders in both children and grandchildren as well as animal models thereof. Genetic variants such as the CHRNA5 single nucleotide polymorphism (SNP) rs16969968, which leads to an aspartic acid to asparagine substitution at amino acid position 398 (D398N) in the alpha-5 nicotinic acetylcholine receptor subunit, can also confer risk for nicotine dependence and neurodevelopmental disorders in the absence of DNE. However, the degrees to which, the consequences of maternal smoking on offspring outcomes are influenced by genetic variants and interactions therewith are not well understood. Addressing this void in the literature, the present study utilizes a DNE mouse model engineered to possess the equivalent of the human D398N SNP in CHRNA5 (D397N SNP in mice) to assess how the N397 risk allele impacts the induction and intergenerational transmission of a range of neurodevelopmental disorder-related behavioral phenotypes in first- and second-generation DNE offspring. Results reveal that offspring possessing the N397 variant in the absence of DNE as well as DNE offspring and grand offspring possessing theD397 variant exhibit analogous neurodevelopmental disorder-like phenotypes including hyperactivity, risk-taking behaviors, aberrant rhythmicity of activity, and enhanced nicotine consumption. DNE amplified these behavioral anomalies in first-generation N397 progeny, but the severity of DNE-evoked behavioral perturbations did not significantly differ between first-generation D397 and N397 DNE mice for any measure. Remarkably, the behavioral profiles of second-generation N397 DNE progeny closely resembled DNE-naive D397 mice, suggesting that the N397 variant may protect against the intergenerational transmission of DNE-induced neurodevelopmental disorder-like behaviors.

Prenatal exposure to tobacco and cannabis, early cannabis initiation, and daily dual use of combustible cigarettes and cannabis during young adulthood

INTRODUCTION

Daily combustible cigarette use is common among cannabis users, and dual use of cigarettes and cannabis is associated with detrimental outcomes. This study addresses gaps in the literature by examining data from the prenatal and adolescent phases of a prospective, longitudinal study to predict adult daily dual use.

METHODS

Young adult offspring (M age = 22.8 years, 53% female) from a prenatal cohort reported on combustible cigarette and cannabis use (N = 500, 58% Black, 42% White). Pathways to daily dual use were modeled using variables from the gestational and adolescent phases of the study including prenatal tobacco, alcohol, and cannabis exposures; ages at initiation of cigarettes and cannabis; and adolescent learning/memory, impulsivity, and behavior problems.

RESULTS

Prenatal cannabis and tobacco use were not directly linked to adult daily dual use of cannabis and tobacco. However, structural equation modeling revealed three significant indirect pathways from prenatal cigarette and cannabis exposures to adult daily dual use of cigarettes and cannabis via early cigarette initiation, early cannabis initiation, and adolescent behavior problems.

CONCLUSIONS

This study identified pathways from prenatal cannabis and tobacco exposure to adult daily dual use, in addition to clarifying adolescent outcomes that may be part of the pathways. In a climate of growing acceptance of cannabis use and increasing legalization of recreational use, these findings serve as a warning that early exposure to cannabis may have an important role in shaping long-term dual use of tobacco and cannabis.

Factors associated with risk behaviors in adolescence: a systematic review

OBJECTIVE

Understanding the distal (≤ 6 years of age) and proximal (between 6 years of age and early adolescence) factors in adolescent risk behavior is important for preventing and reducing morbidity and mortality in this population. This study sought to investigate the factors associated with the following adolescent risk behaviors: i) aggressiveness and violence, ii) tobacco, alcohol, and illicit substance use, iii) depressive behavior and self-harm (including suicidal ideation and attempts), iv) sexual risk behavior, and v) multiple risk behavior.

METHODS

A systematic review was conducted to identify longitudinal studies that examined factors associated with adolescent risk behaviors. The PubMed, PsycINFO, and LILACS databases were searched.

RESULTS

Of the 249 included studies, 23% reported distal risk factors, while the remaining reported proximal risk factors. Risk factors were related to sociodemographic characteristics (neighborhood, school, and peers), family patterns, and the presence of other adolescent risk behaviors.

CONCLUSION

Distal and proximal factors in adolescent risk behavior that are not exclusively socioeconomic, familial, environmental, or social should be explored more thoroughly.

Frontal Cortical Monoamine Release, Attention, and Working Memory in a Perinatal Nicotine Exposure Mouse Model Following Kappa Opioid Receptor Antagonism

Perinatal nicotine exposure (PNE) produces frontal cortical hypo-dopaminergic state and attention and working memory deficits consistent with neurodevelopmental disorders such as attention deficit hyperactivity disorder (ADHD). Methylphenidate alleviates ADHD symptoms by increasing extracellular dopamine and noradrenaline. Kappa opioid receptor (KOR) antagonism may be another mechanism to achieve the same results because KOR activation inhibits frontal cortical dopamine release. We administered the selective KOR antagonist norbinaltorphimine (norBNI) (20 mg/kg; intraperitoneal) or methylphenidate (0.75 mg/kg; intraperitoneal) to PNE mouse model and examined frontal cortical monoamine release, attention, and working memory. Both compounds increased dopamine and noradrenaline release but neither influenced serotonin release. Both compounds improved object-based attention and working memory in the PNE group, with norBNI's effects evident at 2.5 h and 5.5 h but absent at 24 h. Methylphenidate's effects were evident at 0.5 h but not at 2.5 h. norBNI's effects temporally coincided with frontal cortical c-Jun N-terminal kinase phosphorylation. norBNI did not alter tissue dopamine content in the nucleus accumbens, offering preliminary support for lack of reinforcement.

Health Disparities in Tobacco Use and Exposure: A Structural Competency Approach

Fourteen percent of US adults use tobacco products. Because many of those who use tobacco are parents and/or caregivers, children are disproportionately exposed to tobacco smoke. People who use tobacco products often become addicted to nicotine, resulting in tobacco dependence, a chronic, relapsing disease. Tobacco use and exposure are more likely to occur in vulnerable and marginalized groups, including those living in poverty. Although some view tobacco use as a personal choice, evidence suggests that structural forces play an important role in tobacco uptake, subsequent nicotine addiction, and perpetuation of use. Viewing tobacco use and tobacco dependence through a structural competency lens promotes recognition of the larger systemic forces perpetuating tobacco use, including deliberate targeting of groups by the tobacco industry, lack of enforcement of age-for-sale laws, inferior access to health insurance and health care, poor access to cessation resources, and economic stress. Each of these forces perpetuates tobacco initiation and use; in turn, tobacco use perpetuates the user's adverse health and economic conditions. Pediatricians are urged to view family tobacco use as a social determinant of health. In addition to screening adolescents for tobacco use and providing resources and treatment of tobacco dependence, pediatricians are encouraged to systematically screen children for secondhand smoke exposure and support family members who smoke with tobacco cessation. Additionally, pediatricians can address the structural issues perpetuating tobacco use by becoming involved in policy and advocacy initiatives.

[In Utero Exposure to Maternal Smoking: Impact on the Child from Birth to Adulthood - CNGOF-SFT Expert Report and Guidelines for Smoking Management during Pregnancy]

INTRODUCTION

Smoking during pregnancy leads to fetal passive smoking. It is associated with several obstetrical complications and is a major modifiable factor of maternal and fetal morbidity. Long-term consequences also exist but are less well known to health professionals and in the general population.

METHODS

Consultation of the Medline® database.

RESULTS

Maternal smoking during pregnancy is associated in the offspring with sudden infant death syndrome (NP2), impaired lung function (NP2), lower respiratory infections and asthma (NP2), overweight and obesity (NP2), cancers (NP3), risk of tobacco use, nicotine dependence and early smoking initiation (NP2). Unadjusted analyses show associations between in utero tobacco exposure and cognitive deficits (NP3), impaired school performance (NP3) and behavioral disorders in children (NP2), which are in a large part explained by environmental factors. There is a cross-generational effect of smoking during pregnancy. For example, an increased risk of asthma is observed in the grandchildren of smoking women (NP4). The respective roles of ante- and post-natal smoking remain difficult to assess.

CONCLUSION

These results highlight the importance of prevention measures against tobacco use in the general population, as well as screening measures and support for smoking cessation before or at the beginning of the pregnancy.

Influence of Family Environment and Tobacco Addiction: A Short Report from a Post-Graduate Teaching Hospital, India

Background: The initiation of tobacco addiction is complex, and several factors contribute to the onset of this behavior. It is presumed that the influence of family environment may pose a key factor in tobacco addiction. Tobacco-use has been highly observed in the Jamnagar district of Saurashtra region of Gujarat, India. No earlier study has focused on determining the pervasiveness of tobacco-use in families of tobacco users and non-users in this geographical area. Thus, this study aimed to assess the practice and pattern of tobacco-use (smoking and/or tobacco-chewing) in the families of tobacco-user patients. Methods: We studied the families of 65 tobacco-user patients (Group 1) who visited an outpatient clinic of an Ayurvedic post-graduate hospital with complaints of cough were studied and compared with age and gender-matched non-tobacco users (Group 2). The prevalence of tobacco use among the parents, siblings, and children of both groups was analyzed and compared. Results: The findings revealed that tobacco use among parents, siblings, and children in Group 1 was higher than Group 2 (p < 0.001). This meant that the problems of tobacco addiction are not always related to the individual, and therefore, tobacco-prevention strategies should focus on the entire family. Conclusions: These findings offer further insight into the promotion of smoking prevention interventions. Nevertheless, further research is warranted.

Concurrent nicotine exposure to prenatal alcohol consumption alters the hippocampal and cortical neurotoxicity

Aims

This study investigated the neurotoxic effects of prenatal alcohol and nicotine exposure in the cortex and hippocampus of rodents.

Main methods

Behavioral alterations, electrophysiological changes, and biochemical markers associated with cholinergic neurotransmission, neural oxidative stress, mitochondrial function, and apoptosis were evaluated.

Key findings

Prenatal alcohol exposure induced the generation of ROS, nitrite and lipid peroxide, decreased mitochondrial Complex-I and IV activities, increased Caspase-1 and 3 activities, had no effect on cholinergic neurotransmission, increased expression of PSD-95, decreased LTP and decreased performance on spatial memory tasks. However, nicotine exposure, in addition to alcohol exposure, was found to mitigate the negative effects of alcohol alone on ROS generation and spatial memory task performances. Furthermore, we also studied the role of ILK in prenatal alcohol and nicotine exposure.

Significance

Prenatal Smoking and/or drinking is a major health concern around the world. Thus, our current study may lead to better insights into the molecular mechanisms of fetal alcohol and nicotine exposure on the developing offspring.

Effects of Fetal Substance Exposure on Offspring Substance Use

Prenatal exposure to alcohol and drugs is associated with physical, cognitive, and behavioral problems across the offspring's lifespan and an increased risk of alcohol and drug use in adolescent and young adult offspring. These prenatal effects continue to be evident after control for demographic background and parental alcohol and drug use. Behavior problems in childhood and adolescence associated with prenatal exposures may serve as a mediator of the prenatal exposure effects on offspring substance use.

What components of smoking cessation care during pregnancy are implemented by health providers? A systematic review and meta-analysis

BACKGROUND

Pregnancy is an opportunity for health providers to support women to stop smoking.

OBJECTIVES

Identify the pooled prevalence for health providers in providing components of smoking cessation care to women who smoke during pregnancy.

DESIGN

A systematic review synthesising original articles that reported on (1) prevalence of health providers' performing the 5As ('Ask', 'Advise', 'Assess', 'Assist', 'Arrange'), prescribing nicotine replacement therapy (NRT) and (2) factors associated with smoking cessation care.

DATA SOURCES

MEDLINE, EMBASE, CINAHL and PsycINFO databases searched using 'smoking', 'pregnancy' and 'health provider practices'.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Studies included any design except interventions (self-report, audit, observed consultations and women's reports), in English, with no date restriction, up to June 2017.

PARTICIPANTS

Health providers of any profession.

DATA EXTRACTION, APPRAISAL AND ANALYSIS

Data were extracted, then appraised with the Hawker tool. Meta-analyses pooled percentages for performing each of the 5As and prescribing NRT, using, for example, 'often/always' and 'always/all'. Meta-regressions were performed of 5As for 'often/always'.

RESULTS

Of 3933 papers, 54 were included (n=29 225 participants): 33 for meta-analysis. Health providers included general practitioners, obstetricians, midwives and others from 10 countries. Pooled percentages of studies reporting practices 'often/always' were: 'Ask' (n=9) 91.6% (95% CI 88.2% to 95%); 'Advise' (n=7) 90% (95% CI 72.5% to 99.3%), 'Assess' (n=3) 79.2% (95% CI 76.5% to 81.8%), 'Assist (cessation support)' (n=5) 59.1% (95% CI 56% to 62.2%), 'Arrange (referral)' (n=6) 33.3% (95% CI 20.4% to 46.2%) and 'prescribing NRT' (n=6) 25.4% (95% CI 12.8% to 38%). Heterogeneity (I2) was 95.9%-99.1%. Meta-regressions for 'Arrange' were significant for year (p=0.013) and country (p=0.037).

CONCLUSIONS

Health providers 'Ask', 'Advise' and 'Assess' most pregnant women about smoking. 'Assist', 'Arrange' and 'prescribing NRT' are reported at lower rates: strategies to improve these should be considered.

PROSPERO REGISTRATION NUMBER

CRD42015029989.

Developmental nicotine exposure precipitates multigenerational maternal transmission of nicotine preference and ADHD-like behavioral, rhythmometric, neuropharmacological, and epigenetic anomalies in adolescent mice

Maternal smoking during pregnancy, a form of developmental nicotine exposure (DNE), is associated with increased nicotine use and neurodevelopmental disorders such as ADHD in children. Here, we characterize the behavioral, rhythmometric, neuropharmacological, and epigenetic consequences of DNE in the F1 (first) and F2 (second) generation adolescent offspring of mice exposed to nicotine prior to and throughout breeding. We assessed the effects of passive oral methylphenidate (MPH) administration and voluntary nicotine consumption on home cage activity rhythms and activity and risk-taking behaviors in the open field. Results imply a multigenerational predisposition to nicotine consumption in DNE mice and demonstrate ADHD-like diurnal and nocturnal hyperactivity and anomalies in the rhythmicity of home cage activity that are reversibly rescued by MPH and modulated by voluntary nicotine consumption. DNE mice are hyperactive in the open field and display increased risk-taking behaviors that are normalized by MPH. Pharmacological characterization of nicotinic and dopaminergic systems in striatum and frontal cortex reveals altered expression and dysfunction of nicotinic acetylcholine receptors (nAChRs), hypersensitivity to nicotine-induced nAChR-mediated dopamine release, and impaired dopamine transporter (DAT) function in DNE mice. Global DNA methylation assays indicate DNA methylome deficits in striatum and frontal cortex of DNE mice. Collectively, our data demonstrate that DNE enhances nicotine preference, elicits hyperactivity and risk-taking behaviors, perturbs the rhythmicity of activity, alters nAChR expression and function, impairs DAT function, and causes DNA hypomethylation in striatum and frontal cortex of both first and second-generation adolescent offspring. These findings recapitulate multiple domains of ADHD symptomatology.

Trajectories of pre- and postnatal co-use of cannabis and tobacco predict co-use and drug use disorders in adult offspring

Co-use of cannabis and tobacco is increasingly common among women and is associated with tobacco and cannabis dependence and poorer cessation outcomes. However, no study has examined maternal patterns of co-use over time, or the impact of maternal co-use on co-use and drug problems in adult offspring. Pregnant women (M age = 23, range = 18-42; 52% African American, 48% White) were asked about substance use during each trimester of pregnancy, and at 8 and 18 months, 3, 6, 10, 14, 16, and 22 years postpartum. We examined patterns of any maternal cigarette and cannabis use during pregnancy and the postpartum years. As young adults (M age = 22.8 years, range = 21-26), 603 offspring completed the Diagnostic Interview Schedule (DIS). Growth mixture modeling (GMM) was used to identify four maternal trajectories through 16 years postpartum: (1) no co-use (66%), (2) decreasing co-use (16%), (3) postpartum-only co-use (11%), and (4) chronic co-use (7%). Offspring whose mothers were in the decreasing co-use group (co-users primarily during prenatal and preschool periods) were more likely to be co-users than the offspring of non-co-users. Offspring whose mothers were chronic co-users of cigarettes and cannabis were more than twice as likely to have a drug use disorder than young adults whose mothers were not co-users. The results of this study highlight the heterogeneity in maternal co-use of tobacco and cannabis over time, with some women quitting during pregnancy but resuming co-use in the postpartum, and other women co-using during pregnancy but desisting co-use over time. Maternal trajectories of co-use were associated with inter-generational transfer of risk for substance use and dependence in adult offspring.

Neuroendocrine and immune pathways from pre- and perinatal stress to substance abuse

Early life adversity is a documented risk factor for substance abuse and addiction. The pre- and perinatal period (i.e., from implantation, through pregnancy, to 6 months of age) is a critical period marked by high biological plasticity and vulnerability, making perinatal stress a particularly robust form of adversity. The neuroendocrine and immune systems are key mechanisms implicated in the transmission of addiction risk. We review animal and human studies that provide preliminary evidence for links between perinatal stress, neuroendocrine and immune dysregulation, and risk for substance abuse and addiction. A translational neuroscience perspective is employed to elucidate pre- and perinatally-induced biological mechanisms linked to addiction and discuss implications for prevention and intervention efforts. Significant evidence supports associations between pre- and perinatal stress and dysregulation of the hypothalamic-pituitary-adrenal axis and immune systems as well as links between neuroendocrine/immune functioning and addiction risk. More work is needed to explicitly examine the interplay between pre- and perinatal stress and neuroendocrine/immune disruptions that together heighten substance abuse risk. Future work is needed to fully understand how pre- and perinatal stress induces biological alterations to predispose individuals to higher risk for addiction. Such knowledge will strengthen theoretically-driven and empirically-supported prevention efforts for substance abuse and addiction.

Prenatal exposures to tobacco and cannabis: Associations with adult electronic cigarette use

INTRODUCTION

Prenatal exposures to tobacco and cannabis are associated with combustible cigarette use. This study evaluated pathways from these prenatal exposures to adult electronic cigarette use. We tested whether there were indirect effects of these prenatal exposures via childhood behavior dysregulation, early tobacco use, and adolescent tobacco dependence.

METHODS

Telephone interviews were conducted with 427 adult offspring (22-33 years old) from 3 prenatal cohorts with trimester-specific data on exposures to tobacco, alcohol, and cannabis. The offspring were 59% Black and 41% White (61% female). Prenatal exposures included quantity/frequency of tobacco, alcohol, and cannabis use by mothers during the first trimester. Using logistic regression and structural equation modeling, we examined the effects of gestational exposures on adult electronic cigarette use via early cigarette use (prior to age 14), controlling for covariates of combustible and electronic cigarette use.

RESULTS

There were no effects of childhood behavioral dysregulation on electronic cigarette use. However, there was a significant indirect effect of prenatal exposures to tobacco and cannabis on electronic cigarette use via early adolescent combustible cigarette use and adolescent risk for tobacco dependence.

CONCLUSIONS

One implication of these findings is that the inter-generational risk for tobacco use conferred via gestational exposures to tobacco and cannabis generalizes to novel products such as electronic cigarettes. These results have implications for public health, as more women use cannabis and co-use cigarettes and cannabis during pregnancy.

Prenatal tobacco exposure, birthweight, and offspring psychopathology

Although prenatal tobacco exposure (PTE) is associated with several adverse offspring mental health outcomes, mechanisms remain unclear. We test whether associations between PTE and offspring psychopathology are explained by birthweight, one of the earliest-occurring outcomes of PTE. The analysis focuses on 238 offspring from a family study of depression with (1) collected prenatal histories and (2) at least one clinical interview in adulthood to assess psychiatric problems. Exposure was categorized by maternal smoking of ≥10 cigarettes daily/nearly daily; diagnostic outcomes were confirmed by clinicians using the best-estimate procedure, blind to exposure. After adjusting for potential confounders, PTE was associated with 0.7lb(9%) lower birthweight (p=0.0002), increased rates of disruptive behavior disorders [males: OR=2.66(1.15,6.16), and (trend) substance use disorders [females: OR=2.23(0.98,5.09)], and decreased rates of mood disorders (males: OR=0.42(0.17,0.98)]. Birthweight was not independently associated with diagnoses and did not mediate the association between exposure and psychopathology. Maternal smoking has long-term adverse consequences for offspring. Although birthweight cannot be manipulated, smoking is a modifiable risk factor. Thus, cessation efforts focused on pregnant women may not only improve maternal wellbeing, but also mitigate adverse proximal (e.g., birthweight) and long-term (psychopathology) outcomes in offspring.

Prenatal tobacco exposure, maternal postnatal nicotine dependence and adolescent risk for nicotine dependence: Birth cohort study

AIMS

The goals of this study are to determine if there is (a) a threshold effect for prenatal tobacco exposure (PTE) on adolescent risk for nicotine dependence, and (b) an additive effect of PTE and maternal postnatal nicotine dependence on adolescent risk for nicotine dependence.

METHODS

Pregnant women were recruited in their 4th or 5th gestational month and asked about cigarette use during the first trimester. Mothers reported on third trimester cigarette use at delivery. Sixteen years post-partum, mothers and offspring reported on current levels of cigarette use (N=784). Nicotine dependence was assessed in both using a modified Fagerström questionnaire.

RESULTS

Based on the results of a threshold analysis for PTE, four groups were created: threshold PTE only (10+ cigarettes per day), maternal nicotine postnatal dependence with no-low PTE (0-<10 cigarettes per day), threshold PTE+maternal postnatal nicotine dependence, and a referent group with no-low PTE and no maternal postnatal nicotine dependence. Adolescents in the PTE-only group and the PTE+maternal postnatal nicotine dependence group were significantly more likely to be at risk for nicotine dependence than the offspring from the referent group. However, there was no evidence for an additive effect of maternal postnatal nicotine dependence, and maternal nicotine dependence was not a significant predictor of adolescent risk for nicotine dependence in regression models including prenatal tobacco exposure.

CONCLUSIONS

Bivariate analysis revealed a threshold effect for PTE of 10 cigarettes per day. In multivariate analysis, PTE remained significantly related to risk for offspring nicotine dependence, after controlling for maternal postnatal nicotine dependence and other covariates associated with adolescent cigarette use.

Maternal trajectories of cigarette use as a function of maternal age and race

BACKGROUND

Patterns of smoking vary as a function of age and race. The goals of this study were to identify trajectories of maternal cigarette use over a 17-year span, and to determine if maternal age at first birth and race were associated with smoking trajectories.

METHODS

Pregnant women (N=690) were recruited at an urban prenatal clinic. The women (13-42years old; 62% African-American, 38% White) were interviewed about cigarette use during pregnancy and 6, 10, 14, and 16years postpartum. Growth mixture modeling (GMM) was used to identify trajectories. Regressions were used to determine if maternal age at first birth and race predicted trajectory class membership.

RESULTS

A GMM of maternal cigarette use delineated 5 groups: none/unlikely to use (33%), decreasing likelihood of use (6%), late desistance (5%), increasing likelihood of use (17%), and chronic use (39%). Women who became mothers at a younger age were more likely to be classified as late desisters or increasingly likely to smoke. White mothers were more likely to be chronic smokers. Different smoking trajectories and predictors of trajectories were identified for the African-American and White mothers. Covariates including prenatal substance use, hostility, education, and economic hardship also differentiated smoking trajectories.

CONCLUSIONS

Both prevention and treatment of smoking should be targeted to specific groups by age of first pregnancy and race. Pregnant smokers should be provided with more information and resources to help them avoid cigarettes during pregnancy and maintain abstinence after pregnancy.

The effect of prenatal smoking exposure on daily smoking among teenage offspring

AIMS

To study the predictive associations between maternal smoking and the impact of quitting smoking during pregnancy and offspring daily smoking at age 15-16 years.

DESIGN

The Northern Finland Birth Cohort 1986 (NFBC86) includes 99% of all births in the region and has an ongoing follow-up. Data were collected using questionnaires at 24th gestational week during pregnancy and after delivery, and at follow-up in 2001-02, when the offspring were aged 15-16 years.

SETTING

Northern Finland.

PARTICIPANTS

NFBC86 included 9432 live born children. Data regarding maternal smoking during pregnancy and offspring smoking at age 15-16 years were available for 4462 subjects (47.3% of the original sample).

MEASUREMENTS

The outcome was offspring's self-reported daily smoking. Maternal smoking during pregnancy was considered using a four-class variable: (1) no smoking, (2) mother had smoked, but had quit smoking before becoming pregnant, (3) mother quit smoking during the 1st trimester and (4) mother quit smoking after the 1st trimester or continued smoking throughout the pregnancy. Information regarding paternal smoking during pregnancy, maternal and paternal smoking and education level, family structure and dwelling at offspring's age 15-16 years were considered potential confounding variables.

FINDINGS

Continuing smoking after the 1st trimester increased the odds of daily smoking among offspring, independently of confounding factors [odds ratio (OR) = 1.8, 95% confidence interval (CI) = 1.3-2.5]. Continuing to smoke after the 1st trimester was associated with higher odds compared with quitting smoking during the 1st trimester. Also, parental smoking at offspring age 15-16 years increased the odds of offspring daily smoking, independently of prenatal smoking exposure.

CONCLUSIONS

Prenatal smoking exposure increases the risk for offspring adolescent daily smoking. Quitting smoking during the early stages of pregnancy may decrease the odds for offspring smoking.

Brain derived neurotrophic factor moderates associations between maternal smoking during pregnancy and offspring behavioral disorders

Maternal smoking during pregnancy is associated with a number of adverse offspring outcomes. In the present study, based on 209 offspring from a 3-generation family study of depression, we show that the effects of prenatal exposure on offspring externalizing psychopathology (conduct, substance use disorder) is more pronounced in the presence of lower-expressing brain derived neurotrophic factor (BDNF) gene variants. BDNF plays an important role in the development and survival of neural circuits. Individuals with low-expressing variants who are further exposed to prenatal tobacco smoke may be most vulnerable to a spectrum of behavioral disorders that depend on these circuits.

A Propensity Scoring Approach to Characterizing the Effects of Maternal Smoking During Pregnancy on Offspring's Initial Responses to Cigarettes and Alcohol

When examining the effects of prenatal exposure to maternal smoking during pregnancy (MSDP) on later offspring substance use, it is critical to consider familial environments confounded with MSDP. The purpose of this study was to examine the effect of MSDP on offspring's initial reactions to cigarettes and alcohol, which are indicators of future substance-use related problems. We tested these effects using two propensity score approaches (1) by controlling for confounding using the MSDP propensity score and (2) examining effects of MSDP across the MSDP risk distribution by grouping individuals into quantiles based on their MSDP propensity score. This study used data from 829 unrelated mothers with a reported lifetime history of smoking to determine the propensity for smoking only during their first trimester (MSDP-E) or throughout their entire pregnancy (MSDP-T). Propensity score analyses focused on the offspring (N = 1616 female twins) of a large subset of these mothers. We examined the effects of levels of MSDP-E/T on offspring initial reactions to their first experiences with alcohol and cigarettes, across the distribution of liability for MSDP-E/T. MSDP-E/T emerged as significant predictors of offspring reactions to alcohol and cigarettes, but the effects were confounded by the familial liability for MSDP. Further, the unique MSDP effects that emerged were not uniform across the MSDP familial risk distribution. Our findings underscore the importance of properly accounting for correlated familial risk factors when examining the effects of MSDP on substance related outcomes.

Prenatal and Postnatal Maternal Trajectories of Cigarette Use Predict Adolescent Cigarette Use

INTRODUCTION

The goal of this study was to identify maternal patterns of prenatal and postnatal cigarette smoking associated with adolescent smoking. We hypothesized that maternal use at multiple time points, especially at later assessments when the offspring were adolescents, would predict offspring use.

METHODS

Pregnant women (N = 456: ages 13-42) were recruited from a prenatal clinic and interviewed during pregnancy and at delivery, providing data on cigarette use (any/none) for the first and third trimesters. Mothers were re-assessed at 6, 10, 14, and 16 years postpartum. Offspring reported cigarette use at age 16. Covariates included maternal race, age, education, family income, child age, parenting behavior, and other maternal and child substance use.

RESULTS

A growth mixture model revealed five patterns of tobacco use: infrequent/nonuse (39%), postpartum quitters (5%), later quitters (7%), increasing likelihood of being smokers (17%), and chronic users (32%). Offspring of postpartum quitters and the increasing likelihood of being smokers groups were more likely to use cigarettes, compared to adolescents of mothers from the infrequent/nonuse group, controlling for significant covariates.

CONCLUSIONS

This is the first study to examine trajectories of maternal cigarette use from pregnancy to 16 years postpartum, linking prenatal and postnatal patterns of maternal use to use in adolescent offspring. Our findings highlight the risk associated with prenatal exposure, because mothers who used during pregnancy but quit by 6 years postpartum still had offspring who were 3.5 times more likely to smoke than non/infrequent users.

IMPLICATIONS

This is the first study to examine trajectories of maternal cigarette use from the prenatal period to 16 years postpartum, and to link prenatal and postnatal patterns of use to use in adolescent offspring. We identified two long-term patterns of maternal cigarette use that were associated with offspring smoking at age 16, including one where offspring were exposed prenatally, but much less likely to be exposed to maternal cigarette use postpartum. Our findings highlight the risk associated with prenatal exposures for cigarette use in offspring, even if mothers quit in the postpartum.

Associations between early alcohol and tobacco use and prolonged time to puberty in boys

BACKGROUND

Previous research has demonstrated a relationship between prepubertal alcohol and tobacco use and delayed pubertal characteristics in girls. Although, laboratory research indicates that alcohol and tobacco use inhibits sexual maturation in male rats, human research in this area is lacking. To address this question among boys, we conducted a study to explore the association between early use of alcohol and tobacco and time to development of secondary sexual characteristics.

METHODS

The study population included 3199 boys interviewed between the ages of 11 and 21. Participants reported the ages at which they first experienced body hair growth, deepening of the voice and facial hair growth. Early alcohol and tobacco use were defined as first use preceding the age of pubertal development among those reporting regular consumption patterns. Hazard ratios (HR) and 95% confidence intervals (CI) were calculated using Cox proportional hazard models.

RESULTS

Early alcohol use was associated with longer time to body hair growth (HR 0.77; 95% CI 0.69-0.87), voice changes (HR 0.72; 95% CI 0.64-0.82) and facial hair growth (HR 0.77; 95% CI 0.68-0.86), after adjusting for tobacco use and age at interview. Tobacco use was not independently associated with the puberty indicators after controlling for alcohol use and age at interview.

CONCLUSIONS

Our findings are consistent with the hypothesis that alcohol may inhibit puberty onset in boys, an association that has been previously observed among young girls. Thus, alcohol may be an exposure deserving more scrutiny as a disruptor to normal pubertal development.

Predictors of intentions to quit smoking in Aboriginal tobacco smokers of reproductive age in regional New South Wales (NSW), Australia: quantitative and qualitative findings of a cross-sectional survey

OBJECTIVES

To assess the predictors of intentions to quit smoking in a community sample of Aboriginal smokers of reproductive age, in whom smoking prevalence is slow to decline.

DESIGN, SETTING AND PARTICIPANTS

A cross-sectional survey involved 121 Aboriginal smokers, aged 18-45 years from January to May 2014, interviewed at community events on the Mid-North Coast NSW. Qualitative and quantitative data were collected on smoking and quitting attitudes, behaviours and home smoking rules. Perceived efficacy for quitting, and perceived threat from smoking, were uniquely assessed with a validated Risk Behaviour Diagnosis (RBD) Scale.

MAIN OUTCOME MEASURES

Logistic regression explored the impact of perceived efficacy, perceived threat and consulting previously with a doctor or health professional (HP) on self-reported intentions to quit smoking, controlling for potential confounders, that is, protection responses and fear control responses, home smoking rules, gender and age. Participants' comments regarding smoking and quitting were investigated via inductive analysis, with the assistance of Aboriginal researchers.

RESULTS

Two-thirds of smokers intended to quit within 3 months. Perceived efficacy (OR=4.8; 95% CI 1.78 to 12.93) and consulting previously with a doctor/HP about quitting (OR=3.82; 95% CI 1.43 to 10.2) were significant predictors of intentions to quit. 'Smoking is not doing harm right now' was inversely associated with quit intentions (OR=0.25; 95% CI 0.08 to 0.8). Among those who reported making a quit attempt, after consulting with a doctor/HP, 40% (22/60) rated the professional support received as low (0-2/10). Qualitative themes were: the negatives of smoking (ie, disgust, regret, dependence and stigma), health effects and awareness, quitting, denial, 'smoking helps me cope' and social aspects of smoking.

CONCLUSIONS

Perceived efficacy and consulting with a doctor/HP about quitting may be important predictors of intentions to quit smoking in Aboriginal smokers of reproductive age. Professional support was generally perceived to be low; thus, it could be improved for these Aboriginal smokers. Aboriginal participants expressed strong sentiments about smoking and quitting.

Impact of prenatal nicotine on the structure of midbrain dopamine regions in the rat

In utero exposure of rats to nicotine (NIC) provides a useful animal model for studying the impact of smoking during pregnancy on human offspring. Certain sequelae of prenatal NIC exposure suggest an impact on the development of the midbrain dopamine (DA) system, which receives a robust cholinergic innervation from the mesopontine tegmentum. We therefore investigated whether prenatal NIC induced structural changes in cells and synapses within the midbrain that persisted into adulthood. Osmotic minipumps delivering either sodium bitartrate (vehicle; VEH) or NIC bitartrate at 2 mg/kg/day were implanted into nine timed-pregnant dams at E4. At birth, rat pups were culled to litters of six males each, and the litters were cross-fostered. Plasma levels of NIC and cotinine from killed pups provided evidence of NIC exposure in utero. Pups separated from dams at weaning showed a trend toward reduced locomotor activity at this time point but not when tested again in adulthood. Adult rats were killed for anatomical studies. Estimates of brain size and volume did not vary with NIC treatment. Midbrain sections stained for Nissl or by immunoperoxidase for tyrosine hydroxylase and analyzed using unbiased stereology revealed no changes in volume or cell number in the substantia nigra compacta or ventral tegmental area as a result of NIC exposure. Within the ventral tegmental area, electron microscopic physical disector analysis showed no significant differences in the number of axon terminals or the number of asymmetric (putative excitatory) or symmetric (putative inhibitory) synapses. Although too infrequent to estimate by unbiased stereology, no obvious difference in the proportion of cholinergic axons was noted in NIC- versus VEH-treated animals. These data suggest that activation of nicotinic receptors during prenatal development induces no significant modifications in the structure of cells in the ventral midbrain when assessed in adulthood.

Nicotine during pregnancy: changes induced in neurotransmission, which could heighten proclivity to addict and induce maladaptive control of attention

Prenatal exposure to nicotine, occurring either via maternal smoking or via use of transdermal nicotine patches to facilitate cigarette abstinence by pregnant women, is associated with ∼ 13% of pregnancies worldwide. Nicotine exposure during gestation has been correlated with several negative physiological and psychosocial outcomes, including heightened risk for aberrant behaviors involving alterations in processing of attention as well as an enhanced liability for development of drug dependency. Nicotine is a terotogen, altering neuronal development of various neurotransmitter systems, and it is likely these alterations participate in postnatal deficits in attention control and facilitate development of drug addiction. This review discusses the alterations in neuronal development within the brain's major neurotransmitter systems, with special emphasis placed on alterations within the laterodorsal tegmental nucleus, in light of the role this cholinergic nucleus plays in attention and addiction. Changes induced within this nucleus by gestational exposure to nicotine, in combination with changes induced in other brain regions, are likely to contribute to the transgenerational burden imposed by nicotine. Although neuroplastic changes induced by nicotine are not likely to act in isolation, and are expected to interact with epigenetic changes induced by preconception exposure to drugs of abuse, unraveling these changes within the developing brain will facilitate eventual development of targeted treatments for the unique vulnerability for arousal disorders and development of addiction within the population of individuals who have been prenatally exposed to nicotine.

Prenatal nicotine is associated with reduced AMPA and NMDA receptor-mediated rises in calcium within the laterodorsal tegmentum: a pontine nucleus involved in addiction processes

Despite huge efforts from public sectors to educate society as to the deleterious physiological consequences of smoking while pregnant, 12–25% of all babies worldwide are born to mothers who smoked during their pregnancies. Chief among the negative legacies bestowed to the exposed individual is an enhanced proclivity postnatally to addict to drugs of abuse, which suggests that the drug exposure during gestation changed the developing brain in such a way that biased it towards addiction. Glutamate signalling has been shown to be altered by prenatal nicotine exposure (PNE) and glutamate is the major excitatory neurotransmitter within the laterodorsal tegmental nucleus (LDT), which is a brainstem region importantly involved in responding to motivational stimuli and critical in development of drug addiction-associated behaviours, however, it is unknown whether PNE alters glutamate signalling within this nucleus. Accordingly, we used calcium imaging, to evaluate AMPA and NMDA receptor-mediated calcium responses in LDT brain slices from control and PNE mice. We also investigated whether the positive AMPA receptor modulator cyclothiazide (CYZ) had differential actions on calcium in the LDT following PNE. Our data indicated that PNE significantly decreased AMPA receptor-mediated calcium responses, and altered the neuronal calcium response to consecutive NMDA applications within the LDT. Furthermore, CYZ strongly potentiated AMPA-induced responses, however, this action was significantly reduced in the LDT of PNE mice when compared with enhancements in responses in control LDT cells. Immunohistochemical processing confirmed that calcium imaging recordings were obtained from the LDT nucleus as determined by presence of cholinergic neurons. Our results contribute to the body of evidence suggesting that neurobiological changes are induced if gestation is accompanied by nicotine exposure. We conclude that in light of the role played by the LDT in motivated behaviour, the cellular changes in the LDT induced by exposures to nicotine prenatally, when combined with alterations in other reward-related regions, could contribute to the increased susceptibility to smoking observed in the offspring.

The long-term effects of prenatal nicotine exposure on verbal working memory: an fMRI study of young adults

BACKGROUND

Using functional magnetic resonance imaging (fMRI), the long-term effects of prenatal nicotine exposure on verbal working memory were investigated in young adults. Participants were members of the Ottawa Prenatal Prospective Study, a longitudinal study that collected a unique body of information on participants from infancy to young adulthood. This allowed for the measurement of an unprecedented number of potentially confounding drug exposure variables including: prenatal marijuana and alcohol exposure and current marijuana, nicotine and alcohol use.

METHODS

Twelve young adults with prenatal nicotine exposure and 13 non-exposed controls performed a 2-Back working memory task while fMRI blood oxygen level-dependent responses were examined. Despite similar task performance, participants with more prenatal nicotine exposure demonstrated significantly greater activity in several regions of the brain that typically subserve verbal working memory including the middle frontal gyrus, precentral gyrus, the inferior parietal lobe and the cingulate gyrus.

RESULTS

These results suggest that prenatal nicotine exposure contributes to altered neural functioning during verbal working memory that continues into adulthood. Working memory is critical for a wide range of cognitive skills such as language comprehension, learning and reasoning.

CONCLUSION

Thus, these findings highlight the need for continued educational programs and public awareness campaigns to reduce tobacco use among pregnant women.

Is it safe to use smoking cessation therapeutics during pregnancy?

INTRODUCTION

Worldwide, 10 to 35% of pregnant women smoke. It is clear that smoking cessation has positive impacts for both the mother and child, yet many women are still unable to quit due to the addictive properties of nicotine. There are limited data surrounding their safety and efficacy in pregnancy.

AREAS COVERED

This review highlights evidence from clinical studies and animal experiments regarding the effects of smoking cessation therapeutics on pregnancy, neonatal and long-term postnatal outcomes.

EXPERT OPINION

There are insufficient data at this time to recommend the use of varenicline and/or bupropion for smoking cessation during pregnancy. In addition, the efficacy and safety of nicotine replacement therapy use for smoking cessation in pregnant women has not been clearly demonstrated. Until further studies are completed, there will continue to be considerable uncertainty regarding the use of these drugs in pregnancy despite the well-documented benefits of smoking cessation.

Maternal cigarette smoking during pregnancy predicts drug use via externalizing behavior in two community-based samples of adolescents

BACKGROUND AND AIMS

Prenatal exposure to maternal cigarette smoking (PEMCS) is associated with a higher probability of substance use in adolescence. We explore if externalizing behavior mediates this relationship, while controlling for a number of potential covariates of this mediation process.

METHODS

We used data obtained in two geographically distinct community samples of adolescents. The first (cross-sectional) sample consisted of 996 adolescents (12-18 years of age) recruited from the Saguenay Youth Study (SYS) in Canada (47% with PEMCS). The second (longitudinal) sample consisted of 1141 adolescents (49% with PEMCS) from the Northern Finland Birth Cohort (NFBC1986). In both samples, externalizing behavior and substance use were assessed during adolescence. In the NFBC1986 cohort, externalizing behavior was also assessed in childhood.

RESULTS

In both populations, PEMCS is associated with a higher likelihood of adolescent drug experimentation. In the NFBC1986 cohort, exposed (versus non-exposed) adolescents experiment with an extra 1.27 [B = 0.24, 95% confidence intervals (CI) = 0.15, 0.33 P < 0.001] drugs. In the SYS cohort, a clear protective effect of not being exposed is shown: non-exposed (versus exposed) adolescents are 1.5 times [B = -0.42, 95% CI = -0.75, -0.09, P = 0.013] less likely to take drugs. These associations between PEMCS and drug experimentation remain in the multivariate and mediational analyses.

CONCLUSIONS

Prenatal exposure to maternal cigarette smoking appears to be associated with a higher probability of experimenting with drugs during adolescence, both directly and indirectly via externalizing behavior and the number of peers reported as using drugs.

Cigarette smoking among intimate partner violence perpetrators and victims: findings from the National Epidemiologic Survey on Alcohol and Related Conditions

BACKGROUND AND OBJECTIVES

Cigarette smoking and intimate partner violence (IPV) are preventable, major public health issues that result in severe physical and psychological consequences. The primary aim of the current study was to examine the consistency and strength of the association between these highly variable behaviors using a nationally representative sample.

METHODS

Self-reported IPV perpetration, victimization, and smoking data were collected from 25,515 adults (54% female) through the National Epidemiologic Survey on Alcohol and Related Conditions. Multinomial logistic regression models were constructed to determine the relationships among smoking status (current daily, intermittent, former, and never smoker) and IPV (minor and sever victimization as well as perpetration).

RESULTS

Results indicated a robust relationship between IPV and smoking among both victims and perpetrators. The odds for current daily and intermittent smoking were significantly elevated among those who reported both minor and severe IPV relative to their non-violent counterparts. Mood and anxiety disorders were significant comorbid conditions in the interpretation of the relationship between severe IPV and smoking.

CONCLUSIONS

The current study provides strong evidence for a robust relationship between IPV and smoking across current smoking patterns, IPV severity levels, and IPV experience patterns.

SCIENTIFIC SIGNIFICANCE

Findings emphasize the need to better understand the mechanisms by which smoking and IPV are associated and how this interdependence may impact approaches to treatment. Specifically, research is required to assess the efficacy of integrated smoking cessation and IPV treatment or recovery programs over more traditional, exclusive approaches.

Exposure to neurotoxicants and the development of attention deficit hyperactivity disorder and its related behaviors in childhood

The purpose of this manuscript is to review the literature to determine evidence of associations between exposure to prenatal and postnatal environmental agents and the development of attention deficit hyperactivity disorder (ADHD) and related behaviors. A review of published research literature was conducted on associations between exposures to prenatal and postnatal cigarette smoke, prenatal exposure to alcohol, cocaine, and heroin, childhood exposure to lead, and prenatal exposure to organophosphate pesticides and outcomes of ADHD or behaviors related to ADHD. Review of the literature in these areas provides some evidence of associations between each of the exposures and ADHD-related behaviors, with the strongest evidence from prenatal cigarette and alcohol exposure and postnatal lead exposure. However, research on each exposure also produced evidence of weaknesses in these hypothesized links due to imprecise research methodologies and issues of confounding and inaccurate covariate adjustment. More rigorous studies are needed to provide definitive evidence of associations between each of these prenatal or postnatal exposures and the development of ADHD or symptoms of ADHD. Future studies need to clarify the underlying mechanisms between these exposures and the increased risk for ADHD and associated behaviors. More research is also needed utilizing study designs that include genetic information, as ADHD is highly heritable and there appear to be some protective mechanisms offered by certain genetic characteristics as evidenced in gene by environmental studies. Finally, while studies focusing on individual drugs and chemicals are an important first step, we cannot ignore the fact that children are exposed to combinations of drugs and chemicals, which can interact in complex ways with each other, as well as with the child's genetic makeup and psychosocial environment to influence ADHD risk.

Exposure to maternal smoking during pregnancy as a risk factor for tobacco use in adult offspring

Nicotine from maternal smoking during pregnancy can cross the placental barrier, possibly resulting in fetal brain sensitization, as indicated by studies in which prenatal exposure to maternal smoking was associated with an increased risk of tobacco use among adolescent offspring. We investigated whether this association persists beyond adolescence by studying cigarette smoking and the use of snus (Swedish oral moist snuff) among 983 young adults from a prospective cohort study conducted in Stockholm, Sweden, between 2006 and 2010. Self-reported questionnaire data were linked with data from national population-based registers from 1983 onward. Maternal smoking during pregnancy was consistently associated with snus use in offspring (e.g., for lifetime daily snus use, adjusted odds ratio = 2.04, 95% confidence interval: 1.32, 3.16; for use of >3 cans of snus per week vs. less, odds ratio = 3.85, 95% confidence interval: 1.57, 10.15). No association was apparent with offspring's smoking, age at onset of tobacco use, or changes in use between 2006 and 2010. These findings indicate that prenatal exposure to maternal smoking is associated with regular and heavy nicotine intake from smokeless tobacco rather than from smoking. This should be further explored in epidemiologic studies that simultaneously address the roles of genetics and social environments.

In-utero exposure to maternal smoking is not linked to tobacco use in adulthood after controlling for genetic and family influences: a Swedish sibling study

Previous studies have linked maternal smoking during pregnancy with regular tobacco use in offspring, but findings are not consistent and confounding from genetic and environmental factors have not fully been taken into account. A comparison between siblings discordant for prenatal smoking exposure adjusts for confounding by shared familial (i.e., genetic and environmental) factors. We investigated the association between prenatal exposure to maternal smoking during pregnancy and the risk of regular smoking or snus (Swedish moist smokeless tobacco) use in young adult offspring, using a population based matched cohort study. The cohort consisted of 1,538 randomly sampled same-sex sibling pairs, discordant for maternal smoking during pregnancy, 19-27 years old, participating in a survey conducted in Sweden 2010-2011. Lifetime and current history of tobacco use was self-reported in the survey, and information about maternal smoking during pregnancy was retrieved from the Medical Birth Register. Conditional logistic regression and stratified Cox proportional hazards regression were used to calculate odds ratios, hazard ratios, and corresponding 95% confidence intervals. Analyses of exposure-discordant siblings did not reveal significant associations between prenatal exposure to maternal smoking and lifetime or current daily tobacco use, intensity of use, or time to onset of daily tobacco use. These findings suggest that the previously reported higher risks of tobacco use in offspring of mothers who smoked during pregnancy, compared with offspring of non-smoking mothers, were likely due to confounding from genetic or environmental factors.

Externalizing behavior and substance use related problems at 15 years in prenatally cocaine exposed adolescents

The effect of prenatal cocaine exposure (PCE) on externalizing behavior and substance use related problems at 15 years of age was examined. Participants consisted of 358 adolescents (183 PCE, 175 non-cocaine exposed (NCE)), primarily African-American and of low socioeconomic status, prospectively enrolled in a longitudinal study from birth. Regression analyses indicated that the amount of PCE was associated with higher externalizing behavioral problems (β = .15, p = .02). Adolescents with PCE were also 2.8 times (95% CI = 1.38-5.56) more likely to have substance use related problems than their NCE counterparts. No differences between PCE adolescents in non-kinship adoptive/foster care (n = 44) and PCE adolescents in maternal/relative care (n = 139) were found in externalizing behavior or in the likelihood of substance use related problems. Findings demonstrate teratologic effects of PCE persisting into adolescence. PCE is a reliable marker for the potential development of problem behaviors in adolescence, including substance use related problems.

Prenatal tobacco exposure and brain morphology: a prospective study in young children

It is well known that smoking during pregnancy can affect offspring health. Prenatal tobacco exposure has been associated with negative behavioral and cognitive outcomes in childhood, adolescence, and young adulthood. These associations between prenatal tobacco exposure and psychopathology in offspring could possibly be explained by the influence of prenatal tobacco exposure on brain development. In this prospective study, we investigated the association between prenatal tobacco exposure, behavioral and emotional functioning and brain morphology in young children. On the basis of age and gender, we matched 113 children prenatally exposed to tobacco with 113 unexposed controls. These children were part of a population-based study in the Netherlands, the Generation R Study, and were followed from pregnancy onward. Behavioral and emotional functioning was assessed at age 6 with the Child Behavior Checklist. We assessed brain morphology using magnetic resonance imaging techniques in children aged 6-8 years. Children exposed to tobacco throughout pregnancy have smaller total brain volumes and smaller cortical gray matter volumes. Continued prenatal tobacco exposure was associated with cortical thinning, primarily in the superior frontal, superior parietal, and precentral cortices. These children also demonstrated increased scores of affective problems. In addition, thickness of the precentral and superior frontal cortices was associated with affective problems. Importantly, brain development in offspring of mothers who quit smoking during pregnancy resembled that of nonexposed controls (no smaller brain volumes and no thinning of the cortex). Our findings suggest an association between continued prenatal tobacco exposure and brain structure and function in school-aged children.

Effects of prenatal cocaine/polydrug exposure on substance use by age 15

OBJECTIVE

Examined effects of prenatal cocaine exposure (PCE) on tobacco, alcohol, marijuana and cocaine use by age 15.

METHODS

Adolescent (n=358; 183 PCE, 175 non-prenatally cocaine exposed; NCE) drug use was assessed using urine, hair, and/or blood spot samples and self-report (Youth Risk Behavior Surveillance System; YRBSS) at ages 12 and 15. Logistic regression assessed effects of PCE on drug use controlling for other drug exposures, environment and blood lead levels (BLL).

RESULTS

Adjusted percentages of drug use (PCE vs. NCE) were: tobacco 35% vs. 26% (p<.04), marijuana 33% vs. 23% (p<.04), alcohol 40% vs. 35% (p<.01), and any drugs 59% vs. 50% (p<.005). PCE adolescents were twice as likely to use tobacco (OR=2.02, 95% CI=1.05-3.90, p<.04), 2.2 times more likely to use alcohol (OR=2.16, 95% CI=1.21-3.87, p<.01) and 1.8 times more likely to use marijuana (OR=1.81, 95% CI=1.02-3.22, p<.04) than NCE adolescents. A race-by-cocaine-exposure interaction (p<.01) indicated PCE non-African American adolescents had greater probability of tobacco use (65%) than NCE non-African American youth (21%). PCE was associated with any drug use (OR=2.16, CI=1.26-3.69, p<.005), while higher BLL predicted alcohol use (p<.001). Violence exposure was a predictor of tobacco (p<.002), marijuana (p<.0007) and any drug (p<.04).

CONCLUSIONS

PCE and exposure to violence increased the likelihood of tobacco, marijuana or any drug use by age 15, while PCE and higher early BLL predicted alcohol use. Prevention efforts should target high risk groups prior to substance use initiation.

Fetal nicotine exposure increases preference for nicotine odor in early postnatal and adolescent, but not adult, rats

Human studies demonstrate a four-fold increased possibility of smoking in the children of mothers who smoked during pregnancy. Nicotine is the active addictive component in tobacco-related products, crossing the placenta and contaminating the amniotic fluid. It is known that chemosensory experience in the womb can influence postnatal odor-guided preference behaviors for an exposure stimulus. By means of behavioral and neurophysiologic approaches, we examined whether fetal nicotine exposure, using mini-osmotic pumps, altered the response to nicotine odor in early postnatal (P17), adolescent (P35) and adult (P90) progeny. Compared with controls, fetal exposed rats displayed an altered innate response to nicotine odor that was evident at P17, declined in magnitude by P35 and was absent at P90 - these effects were specific to nicotine odor. The behavioral effect in P17 rats occurred in conjunction with a tuned olfactory mucosal response to nicotine odor along with an untoward consequence on the epithelial response to other stimuli – these P17 neural effects were absent in P35 and P90 animals. The absence of an altered neural effect at P35 suggests that central mechanisms, such as nicotine-induced modifications of the olfactory bulb, bring about the altered behavioral response to nicotine odor. Together, these findings provide insights into how fetal nicotine exposure influences the behavioral preference and responsiveness to the drug later in life. Moreover, they add to a growing literature demonstrating chemosensory mechanisms by which patterns of maternal drug use can be conveyed to offspring, thereby enhancing postnatal vulnerability for subsequent use and abuse.

[Tabacco during pregnancy: a risk factor for addiction and psychiatric diseases?]

The use of tobacco during pregnancy is a risk factor for cognitive and comportemental disorders in childhood and adolescent. TDHA, addiction and psychiatric diseases are more frequent in adolescent and adult with tobacco use during pregnancy. Strategies to quit smoking in pregnant women may improve mental health.