Prenatal cigarette smoking: Long-term effects on young adult behavior problems and smoking behavior

The effect of maternal prenatal tobacco smoking on offspring academic achievement: A systematic review and meta-analysis

BACKGROUND

Previous epidemiological studies examining the prospective association between maternal prenatal tobacco smoking and offspring academic achievement have reported conflicting results. Therefore, this systematic review and meta-analysis was conducted to examine the magnitude and consistency of association reported by those studies.

METHODS

This systematic review and meta-analysis was guided by the PRISMA protocol. Relevant epidemiological studies on the topic were extracted from four main databases (PubMed/Medline, Embase, PsycINFO, and Scopus). The Newcastle-Ottawa Scale (NOS) was used to appraise the methodological quality of the included studies. We conducted a narrative assessment of the studies that did not report effect estimates. Inverse variance-weighted random effect meta-analysis was used to combine studies reporting effect sizes to estimate pooled adjusted odds ratio with 95% confidence intervals (95% CI). The review was prospectively registered in PROSPERO (CRD42022350901).

RESULTS

Nineteen observational studies, published between 1973 and 2021 with a total of 1.25 million study participants were included in the final review. Of these, fifteen studies (79 %) reported reduced academic achievement in offspring exposed to maternal prenatal tobacco smoking. The eight primary studies (sample size = 723,877) included in the meta-analysis together suggested a 49 % higher risk of reduced academic achievement in offspring exposed to maternal prenatal tobacco smoking when compared to non-exposed offspring (Pooled odds ratio = 1.49, 95 % CI:1.17-1.91).

CONCLUSION

Our review found a positive association between maternal prenatal tobacco smoking and offspring reduced academic achievement. However, variation in the adjustment of potential confounders and significant heterogeneity across included studies limited more conclusive inference. Mechanistic studies to identify causal pathways and specific academic impacts are needed to inform targeted developmental programs to assist child learning and academic performance.

Perinatal and neonatal factors and mental disorders in children and adolescents: looking for the contributions of the early environment to common and dissociable aspects of psychopathology

High rates of co-occurrence of mental disorders have been hypothesized to represent a result of common susceptibility to overall psychopathology. The purpose of this study is to test the hypothesis that commonalities among psychiatric disorders might be partially driven by sharable perinatal and neonatal environmental factors for mental disorders. Participants were 6-14 years of age children and their parents. Primary caregivers provided data on perinatal and neonatal information assessed retrospectively (n = 2231). Psychiatric disorders diagnoses were assessed using the Development and Well Being Behavior Assessment (DAWBA). We used bifactor models to disentangle common from dissociable aspects of psychopathology. These models allow modeling psychiatric disorders as the result of a common domain of psychopathology (p-factor) and three dissociable domains (fear, distress, and externalizing symptoms). Associations were tested using linear and tobit regression models. The p-factor was associated with male sex, low socioeconomic status, gestational smoking, gestational drinking, low levels of maternal education and presence of mental disorder in the mother. Associations with specific factors also emerged suggesting some risk factors might also have some role for fear, distress and externalizing factors. Our study supports the hypothesis that overall susceptibility to psychopathology might be partially driven by sharable perinatal and neonatal factors.

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.

Higher blood nicotine concentrations following smokeless tobacco (pituri) and cigarette use linked to adverse pregnancy outcomes for Central Australian Aboriginal pregnancies

Background

In central Australia, Aboriginal women use wild tobacco plants, Nicotiana spp. (locally known as pituri) as a chewed smokeless tobacco, with this use continuing throughout pregnancy and lactation. Our aim was to describe the biological concentrations of nicotine and metabolites in samples from mothers and neonates and examine the relationships between maternal self-reported tobacco use and maternal and neonatal outcomes.

Methods

Central Australian Aboriginal mothers (and their neonates) who planned to birth at the Alice Springs Hospital (Northern Territory, Australia) provided biological samples: maternal blood, arterial and venous cord blood, amniotic fluid, maternal and neonatal urine, and breast milk. These were analysed for concentrations of nicotine and five metabolites.

Results

A sample of 73 women were enrolled who self-reported: no-tobacco use (n = 31), tobacco chewing (n = 19), or smoking (n = 23). Not all biological samples were obtained from all mothers and neonates. In those where samples were available, higher total concentrations of nicotine and metabolites were found in the maternal plasma, urine, breast milk, cord bloods and Day 1 neonatal urine of chewers compared with smokers and no-tobacco users. Tobacco-exposed mothers (chewers and smokers) with elevated blood glucose had higher nicotine and metabolite concentrations than tobacco-exposed mothers without elevated glucose, and this was associated with increased neonatal birthweight. Neonates exposed to higher maternal nicotine levels were more likely to be admitted to Special Care Nursery. By Day 3, urinary concentrations in tobacco-exposed neonates had reduced from Day 1, although these remained higher than concentrations from neonates in the no-tobacco group.

Conclusions

This research provides the first evidence that maternal pituri chewing results in high nicotine concentrations in a wide range of maternal and neonatal biological samples and that exposure may be associated with adverse maternal and neonatal outcomes. Screening for the use of all tobacco and nicotine products during pregnancy rather than focusing solely on smoking would provide a more comprehensive assessment and contribute to a more accurate determination of tobacco and nicotine exposure. This knowledge will better inform maternal and foetal care, direct attention to targeted cessation strategies and ultimately improve long-term clinical outcomes, not only in this vulnerable population, but also for the wider population.

Note to readers

In this research, the central Australian Aboriginal women chose the term ‘Aboriginal’ to refer to themselves, and ‘Indigenous’ to refer to the broader group of Australian First Peoples. That choice has been maintained in the reporting of the research findings.

Maternal smoking during pregnancy and children's mental health at age 22 years: Results of a birth cohort study

BACKGROUND

Early exposures such as maternal smoking can be associated mental disorders. We aimed to analyze the association between maternal smoking during pregnancy (MSDP), generalized anxiety disorder (GAD), and depression in the 1993 birth cohort (Pelotas, Brazil).

METHODS

Data on maternal smoking were collected in the perinatal study, while information on GAD and depression was collected at age 22 years using the Mini International Neuropsychiatric Interview (MINI). Information on maternal mental health, the mediator, was collected at the 11-year follow-up. Simple and multiple logistic regressions were used to assess the association between exposure, outcomes, and analysis of negative controls.

RESULTS

3,781 participants presented complete data. The incidence of GAD was 10.4%, depression 2.9%, and smoking during pregnancy 32.6%. The children of mothers who smoked had a 45% higher chance of developing GAD at age 22 years (OR 1.45; 95%CI 1.18; 1.80) and 75% higher chance of depression (OR 1.75; 95%CI 1.18; 2.59). Also, the higher the number of cigarettes smoked. the higher was the chance for the development of GAD. Paternal smoking was not associated with the outcomes. The mother's mental health accounted for 18.2% of the association between maternal smoking and GAD, and for 13.4% for maternal smoking and depression.

LIMITATIONS

Data for smoking during pregnancy were collected through a self-report. Residual confusion due to important variables cannot be ruled out.

CONCLUSIONS

MSDP was associated with the mental health of children in early adulthood. However, a small part of the effect found was mediated by the mother's mental health.

Prenatal nicotine alters development of the laterodorsal tegmentum: Possible role for attention-deficit/hyperactivity disorder and drug dependence

As we cycle between the states of wakefulness and sleep, a bilateral cholinergic nucleus in the pontine brain stem, the laterodorsal tegmentum (LDT), plays a critical role in controlling salience processing, attention, behavioral arousal, and electrophysiological signatures of the sub- and microstates of sleep. Disorders involving abnormal alterations in behavioral and motivated states, such as drug dependence, likely involve dysfunctions in LDT signaling. In addition, as the LDT exhibits connectivity with the thalamus and mesocortical circuits, as well as receives direct, excitatory input from the prefrontal cortex, a role for the LDT in cognitive symptoms characterizing attention-deficit/hyperactivity disorder (ADHD) including impulsivity, inflexibility, and dysfunctions of attention is suggested. Prenatal nicotine exposure (PNE) is associated with a higher risk for later life development of drug dependence and ADHD, suggesting alteration in development of brain regions involved in these behaviors. PNE has been shown to alter glutamate and cholinergic signaling within the LDT. As glutamate and acetylcholine are major excitatory mediators, these alterations would likely alter excitatory output to target regions in limbic motivational circuits and to thalamic and cortical networks mediating executive control. Further, PNE alters neuronal development and transmission within prefrontal cortex and limbic areas that send input to the LDT, which would compound effects of differential processing within the PNE LDT. When taken together, alterations in signaling in the LDT are likely to play a role in negative behavioral outcomes seen in PNE individuals, including a heightened risk of drug dependence and ADHD behaviors.

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.

Pre- and postnatal maternal smoking and offspring smoking trajectories: Evidence from a 20-year birth cohort

Maternal smoking is associated with increased risk of smoking in the offspring. However, it remains unclear whether this association depends on the timing of exposure to maternal smoking. We investigated the association between prenatal and/or postnatal maternal smoking and offspring smoking during adolescence. Participants (N = 1661) were from the Québec Longitudinal Study of Child Development cohort. We identified longitudinal trajectories of maternal smoking from before pregnancy to child age 12 years using group-based trajectory modeling (GBTM). Adolescent (12-19 years) smoking trajectories were also identified using GBTM. Associations between maternal smoking and offspring smoking trajectories were estimated using multinomial logistic regressions. We used propensity score inverse probability weighting (IPW) to account for the differential distribution of maternal and familial characteristics across exposure groups. We identified four distinct groups for maternal smoking: no (66.1%), decreasing (5.6%), increasing (9.5%) and persistent (18.8%) smoking, and three adolescent smoking trajectories: abstinent, early-onset (before age 15) and late-onset (after age 15). In IPW-adjusted models, youth with mothers with decreasing, increasing and persistent smoking had higher risk of being early-onset smokers compared with youth with mothers in the non-smoking group. We also found that only youth whose mothers were persistent smokers had an increased risk of late-onset smoking. Regardless of timing, offspring exposure to maternal smoking is associated with increased risk of smoking during adolescence. More research is needed on how to create effective smoking cessation campaigns that span preconception, prenatal, and postnatal periods to help prevent intergenerational transmission of smoking behaviors.

Prenatal exposure to maternal, but not paternal, tobacco smoking is associated with smoking in adolescence

BACKGROUND

Mounting epidemiological evidence suggests an association between prenatal tobacco exposure and an increased risk of tobacco smoking in offspring. However, it is uncertain whether the association is due to the intrauterine or shared environmental exposures.

METHODS

Study participants were from the Raine Study, a prospective birth cohort study based in Perth, Western Australia (N = 2730). Tobacco smoking in adolescents, at age 17 years, was measured using a self-reported questionnaire. Log-binomial regression was used to estimate the relative risks (RRs) of tobacco smoking in offspring exposed to maternal prenatal tobacco use during the first and third trimesters of pregnancy. We have also calculated the E-values to investigate the potential effect of unmeasured confounding. Paternal smoking during pregnancy was used as a negative control for comparison.

RESULTS

A total of 1210 mothers-offspring pairs were included in the final analysis. After controlling for potential confounders, we found increased risks of tobacco smoking in offspring exposed to maternal prenatal tobacco use during the first trimester [RR 1.50 (95% CI: 1.13-1.97)] (E-value for point estimate = 2.37) and during both trimesters of pregnancy [RR 1.41 (95% CI: 1.03-1.89)] (E-value for point estimate = 2.17). However, we found insufficient statistical evidence for an association between paternal smoking during pregnancy and risk of tobacco smoking in offspring [RR 1.18 (95% CI: 0.84-1.67)].

CONCLUSION

Maternal prenatal tobacco exposure was associated with an increased risk of tobacco smoking in offspring at the age of 17 years. Tobacco smoking cessation at the early stages of gestation may reduce the risk of tobacco smoking in the next generation.

Trends in Tobacco Smoking in Pregnant Women: Data From French National Perinatal Surveys

Objectives: To describe maternal smoking trends in France between 1972 and 2016, and identify whether maternal characteristics associated with smoking in the 3rd trimester of pregnancy evolved between 2010 and 2016. Methods: Using French National Perinatal Surveys, we estimated proportions of smokers and the number of cigarettes smoked both just before pregnancy and during the 3rd trimester from 1972 to 2016. We used a Poisson model with robust variance to estimate prevalence ratios for smoking during pregnancy. Results: Proportions of mothers quitting smoking were relatively stable (46.0% in 1972 and 45.8% in 2016). The number of cigarettes smoked just before pregnancy and in the 3rd trimester decreased from 1995 onward. However, proportions of smokers remained high before (30.1%) and during the 3rd trimester in 2016 (16.2%). Smoking in the 3rd trimester was associated with a lower education level and lower income in both 2010 and 2016, whereas the association with age, country of birth and parity varied according to the survey year. Conclusion: Early targeted interventions are needed for smokers who plan to have a child and must take smokers' characteristics during pregnancy into account.

Stressful life events and electronic cigarette use during pregnancy

RATIONALE

Smoking during pregnancy poses a significant health risk for infant well-being. Prior research has linked experiencing stressful life events (SLEs) during pregnancy to prenatal smoking. However, extant research has not assessed whether SLEs experienced during pregnancy are a risk factor for prenatal electronic cigarette use.

OBJECTIVE

This study investigates the association between SLEs and electronic cigarette use during the third trimester of pregnancy.

METHODS

We employ data on 70,626 recent mothers from the 2016-2018 Pregnancy Risk Assessment Monitoring System. Logistic and multinomial logistic regression models were used to examine the association between SLEs and electronic cigarette use during the third-trimester of pregnancy.

RESULTS

The prevalence of electronic cigarette use increased alongside an accumulating history of SLEs (0 SLEs = 0.4%; 1-2 SLEs = 0.9%; 3-5 SLEs = 1.9%; 6+ SLEs = 5.0%). Logistic regression models found 6 or more SLEs were associated with 4.7 times higher odds of electronic cigarette use relative to 0 SLEs after adjusting for demographic and socioeconomic characteristics (AOR = 4.705, 95% CI = 2.960, 7.479). Study findings also showed that women who experienced greater levels of SLEs had a higher prevalence of using any nicotine products (i.e., exclusive electronic cigarette user, exclusive cigarette user, dual user), relative to being a non-smoker. Findings from multinomial logistic regression models revealed that a higher number of SLEs was associated with an increased relative risk of all smoking outcomes. Still, these associations were particularly pronounced in the case of exclusive electronic cigarette user (ARR = 8.485, 95% CI = 4.900, 14.692) and dual-use (ARR = 8.348, 95% CI = 4.113, 16.945) when participants experienced 6 or more SLEs (relative to 0 SLEs).

CONCLUSIONS

Considering the potentially harmful ramifications of electronic cigarette use during pregnancy there is a need for interventions that reduce stressful experiences and decrease smoking during pregnancy.

Incarceration exposure and electronic cigarette use during pregnancy: Findings from the pregnancy risk assessment monitoring system, 2016-2018

Smoking during pregnancy is a serious public health concern that poses risks for maternal and infant health. Considering the rise of electronic cigarette use in recent years, there is also growing concern about electronic cigarette use during pregnancy. Recent research has begun to explore correlates of electronic cigarette use among pregnant women. While research has revealed a strong connection between incarceration and smoking, scholars have yet to examine the connection between a woman's exposure to incarceration in the year prior to birth - either personally or vicariously through her husband or partner - and prenatal electronic cigarette use. The current study uses data from 74,554 recent mothers from the 2016-2018 Pregnancy Risk Assessment Monitoring System. Logistic regression and multinomial logistic regression models were used to assess the association between incarceration exposure and electronic cigarette use. The findings indicate a robust association between incarceration exposure and electronic cigarette use during pregnancy. Specifically, analyses demonstrate that incarceration-exposed women were approximately 2.7 times (AOR = 2.699, 95% CI = 1.939, 3.755) as likely to use electronic cigarettes after adjusting for a host of demographic, economic, health, and pregnancy related characteristics. Additional analyses reveal this association remains after accounting for conventional cigarette use during pregnancy. Considering the potential harmful health ramifications for electronic cigarette use during pregnancy, these findings suggest a need for interventions targeting electronic cigarette use among incarceration-exposed populations and point to electronic cigarette use among pregnant women in particular as an important area of focus for both criminal justice and public health practitioners.

[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.

Prenatal Nicotine Exposure in Rodents: Why Are There So Many Variations in Behavioral Outcomes?

Introduction

The World Health Organization (WHO) reported that smoking cessation rates among women have stagnated in the past decade and estimates that hundreds of millions of women will be smokers in the next decade. Social, environmental, and biological conditions render women more susceptible to nicotine addiction, imposing additional challenges to quit smoking during gestation, which is likely why more than 8% of pregnancies in Europe are associated with smoking. In epidemiological investigations, individuals born from gestational exposure to smoking exhibit a higher risk of development of attention-deficit/hyperactive disorder (ADHD) and liability to drug dependence. Among other teratogenic compounds present in tobacco smoke, nicotine actions during neuronal development could contribute to the observed outcomes as nicotine misleads signaling among progenitor cells during brain development. Several experimental approaches have been developed to address the consequences of prenatal nicotine exposure (PNE) to the brain and behavior but, after four decades of studies, inconsistent data have been reported and the lack of consensus in the field has compromised the hypothesis that gestational nicotine exposure participates in cognitive and emotional behavioral deficits.

Aims

In this review, we discuss the most commonly used PNE models with focus on their advantages and disadvantages, their relative validity, and how the different technical approaches could play a role in the disparate outcomes.

Results

We propose methodological considerations, which could improve the translational significance of the PNE models.

Conclusions

Such alterations might be helpful in reconciling experimental findings, as well as leading to development of treatment targets for maladaptive behaviors in those prenatally exposed.

Implications

In this article, we have reviewed the advantages and disadvantages of different variables of the commonly used experimental models of PNE. We discuss how variations in the nicotine administration methods, the timing of nicotine exposure, nicotine doses, and species employed could contribute to the disparate findings in outcomes for PNE offspring, both in behavior and neuronal changes. In addition, recent findings suggest consideration of epigenetic effects extending across generations. Finally, we have suggested improvements in the available PNE models that could contribute to the enhancement of their validity, which could assist in the reconciliation of experimental findings.

Does early maternal responsiveness buffer prenatal tobacco exposure effects on young children's behavioral disinhibition?

Children with prenatal tobacco exposure (PTE) exhibit early self-regulatory impairments, reflecting a life-course persistent propensity toward behavioral disinhibition. Previously, we demonstrated the protective role of parental responsiveness for reducing the risk of exposure-related disruptive behavior in adolescence. Here, we expanded this line of inquiry, examining whether responsiveness moderates the relation of PTE to a broader set of behavioral disinhibition features in early childhood and testing alternative diathesis-stress versus differential susceptibility explanatory models. PTE was assessed prospectively using interviews and bioassays in the Midwestern Infant Development Study (MIDS). Mother-child dyads (N = 276) were re-assessed at approximately 5 years of age in a preschool follow-up. We quantified maternal responsiveness and child behavioral disinhibition using a combination of directly observed activities in the lab and developmentally sensitive questionnaires. Results supported a diathesis-stress pattern. Children with PTE and less responsive mothers showed increased disruptive behavior and lower effortful control compared with children without PTE. In contrast, exposed children with more responsive mothers had self-regulatory profiles similar to their non-exposed peers. We did not observe sex differences. Findings provide greater specification of the protective role of maternal responsiveness for self-regulation in children with PTE and help clarify mechanisms that may underscore trajectories of exposure-related behavioral disinhibition.

Maternal smoking and low family income during pregnancy as predictors of the relationship between depression and adiposity in young adults

There is an increasing incidence of overweight/obesity and mental health disorders in young adults and the two conditions often coexist. We aimed to investigate the influence of antenatal and postnatal factors that may underlie this association with a focus on maternal prenatal smoking, socio-economic status and gender. Data from the Western Australian Pregnancy Cohort (Raine) Study (women enrolled 1989-1991) including 1056 offspring aged 20 years (cohort recalled 2010-2012) were analyzed (2015-2016) using multivariable models for associations between offspring depression scores (DASS-21 Depression-scale) and body mass index (BMI), adjusting for pregnancy and early life factors and offspring behaviours. There was a significant positive relationship between offspring depression-score and BMI independent of gender and other psychosocial covariates. There was a significant interaction between maternal prenatal smoking and depression-score (interaction coefficient=0.096; 95% CI: 0.006, 0.19, P=0.037), indicating the relationship between depression-score and BMI differed according to maternal prenatal smoking status. In offspring of maternal prenatal smokers, a positive association between BMI and depression-score (coefficient=0.133; 95% CI: 0.05, 0.21, P=0.001) equated to 1.1 kg/m2 increase in BMI for every 1standard deviation (8 units) increase in depression-score. Substituting low family income during pregnancy for maternal prenatal smoking in the interaction (interaction coefficient=0.091; 95% CI: 0.01, 0.17, P=0.027) showed a positive association between BMI and depression score only among offspring of mothers with a low family income during pregnancy (coefficient=0.118; 95% CI: 0.06, 0.18, P<0.001). There were no significant effects of gender on these associations. Whilst further studies are needed to determine whether these associations are supported in other populations, they suggest potentially important maternal behavioural and socio-economic factors that identify individuals vulnerable to the coexistence of obesity and depression in early adulthood.

Maternal smoking during pregnancy and academic achievement of offspring over time: A registry data-based cohort study

Few studies have assessed the cumulative impact of maternal smoking during pregnancy (MSDP) on scholastic outcomes over time. We examined the relations between MSDP and academic achievement in the 4th, 7th and 10th grades using registry data collected at birth, during the neonatal period, and at each grade level from the 2000, LIFECOURSE study birth cohort in Reykjavik, Iceland (N = 1151, girls = 49.3%). Latent growth modeling showed that MSDP influenced Icelandic achievement scores, standardized to a range from 0 to 60, at baseline (β = -0.04), and over time (β = -0.05). Likewise, MSDP was negatively associated with standardized mathematics scores at baseline (ß = -0.09) and continued to exert a negative impact on mathematics scores over time (ß = -0.08) after controlling for gender, income, cohabitation, and baseline mathematics and Icelandic achievement scores. Results provide evidence of the persistent negative impact of MSDP on academic achievement in offspring. Findings support the proposition that children whose mothers smoke during the first trimester of pregnancy are, on average, at greater risk for poor scholastic outcomes over time than children whose mothers do not smoke during their first trimester. To our knowledge, this is the first study using a longitudinal cohort design to assess whether the impacts of maternal smoking during pregnancy may persist over time. This study contributes to the current state of knowledge by providing an assessment that focuses on the impact of smoking during pregnancy on academic achievement from childhood into early adolescence.

Maternal smoking during pregnancy and scholastic achievement in childhood: evidence from the LIFECOURSE cohort study

Background

Research on the impact of maternal smoking during pregnancy (MSDP) on scholastic achievement in the offspring has shown conflicting findings. The objective of this study was to assess the impact of MSDP on scholastic achievement in a birth cohort of children in 4th, 7th and 10th grades.

Methods

We analysed data from the LIFECOURSE study, a cohort study of risk and protective factors in all children born in Reykjavik, Iceland, in the year 2000 (N = 1151, girls = 49.3%). Retrospective registry data for 2014–2015 were merged with prospective survey data that were collected in April 2016. Data on MSDP were assessed during regular antenatal visits at the end of the first trimester. Standardized academic achievement scores were obtained from official school transcripts. Data were analysed using OLS regressions that were entered in three hierarchical blocks.

Results

Children of mothers who smoked tobacco during the first trimester consistently revealed between 5% and 7% lower scores on standardized academic achievement in 4th, 7th and 10th grade (∼6–8 points on a normally distributed 120 point scale) than those of mothers who had not smoked tobacco during this period (P < 0.05). These findings held after controlling for several factors associated with the time of birth (e.g. birth weight, maternal age at birth, birth order, parental cohabitation and household income), as well as the year of scholastic assessment (parental cohabitation, household income and parental education).

Conclusions

Maternal smoking during pregnancy was negatively related to scholastic achievement in the offspring during 4th, 7th and 10th grade.

Prenatal nicotine exposure alters postsynaptic AMPA receptors and glutamate neurotransmission within the laterodorsal tegmentum (LDT) of juvenile mice

Despite dissemination of information regarding the harm on fetal development of smoking while pregnant, the number of pregnancies associated with nicotine exposure appears to have stagnated. Presence of nicotine during neural formulation is associated with a higher susceptibility of drug dependence, suggesting an altered development of neurons in circuits involved in saliency and motivation. The laterodorsal tegmental nucleus (LDT) plays a role in coding stimuli valence via afferents to mesolimbic nuclei. Accordingly, alterations in development of neural mechanisms in the LDT could be involved in vulnerability to drug dependency. Therefore, we examined the effect of prenatal nicotine exposure (PNE) on glutamatergic functioning of LDT neurons in mouse brain slices using whole-cell, patch clamp concurrent with fluorescence-based calcium imaging. PNE was associated with larger amplitudes of AMPA-induced currents, and greater AMPA-mediated rises in intracellular calcium. AMPA/NMDA ratios and the AMPA-current rectification index were lower and higher, respectively, consistent with changes in the functionality of AMPA receptors in the PNE, which was substantiated by a greater inhibition of evoked and spontaneous glutamatergic synaptic events by a selective inhibitor of GluA2-lacking AMPA receptors. Paired pulse ratios showed a decreased probability of glutamate release from presynaptic inputs, and fluorescent imaging indicated a decreased action potential-dependent calcium increase associated with PNE. When taken together, our data suggest that PNE alters LDT glutamatergic functioning, which could alter output to mesolimbic targets. Such an alteration could play a role in altered coding of relevancy of drug stimuli that could enhance risk for development of drug dependency.

Counseling Women on Smoking Relapse Prevention During Postpartum

Many women who quit smoking after learning they are pregnant revert back to smoking after birth of their baby. The high rate of recidivism suggests that women need education about risk of relapse and effective strategies to remain smoke free even before they are discharged from the hospital. Despite evidence that smoking cessation and relapse prevention counseling is effective during early postpartum, many nurses do not provide their patients with this important information, perhaps because they feel inadequately prepared to do so. Helping Women Stop Smoking in Pregnancy and Beyond is an education program designed to help perinatal nurses inform women of negative risks of smoking and offer women strategies to avoid the high probability of resuming smoking after birth. It includes evidence-based interventions that can be used by nurses to provide effective smoking relapse prevention counseling to women during postpartum.

Camellia sinensis Prevents Perinatal Nicotine-Induced Neurobehavioral Alterations, Tissue Injury, and Oxidative Stress in Male and Female Mice Newborns

Nicotine exposure during pregnancy induces oxidative stress and leads to behavioral alterations in early childhood and young adulthood. The current study aimed to investigate the possible protective effects of green tea (Camellia sinensis) against perinatal nicotine-induced behavioral alterations and oxidative stress in mice newborns. Pregnant mice received 50 mg/kg C. sinensis on gestational day 1 (PD1) to postnatal day 15 (D15) and were subcutaneously injected with 0.25 mg/kg nicotine from PD12 to D15. Nicotine-exposed newborns showed significant delay in eye opening and hair appearance and declined body weight at birth and at D21. Nicotine induced neuromotor alterations in both male and female newborns evidenced by the suppressed righting, rotating, and cliff avoidance reflexes. Nicotine-exposed newborns exhibited declined memory, learning, and equilibrium capabilities, as well as marked anxiety behavior. C. sinensis significantly improved the physical development, neuromotor maturation, and behavioral performance in nicotine-exposed male and female newborns. In addition, C. sinensis prevented nicotine-induced tissue injury and lipid peroxidation and enhanced antioxidant defenses in the cerebellum and medulla oblongata of male and female newborns. In conclusion, this study shows that C. sinensis confers protective effects against perinatal nicotine-induced neurobehavioral alterations, tissue injury, and oxidative stress in mice newborns.

Daughters of Mothers Who Smoke: A Population-based Cohort Study of Maternal Prenatal Tobacco use and Subsequent Prenatal Smoking in Offspring

BACKGROUND

Prenatal exposure to tobacco is associated with adverse health outcomes for the mother and child, and has been associated with an increased risk of tobacco smoking and nicotine dependence in offspring. The objective of this study was to examine the risk of prenatal smoking, among daughters, associated with maternal prenatal smoking.

METHODS

We used a population-based cohort study design, with linked vital records data of mothers and daughters delivering 1984-96 and 1996-2013, respectively, in Washington State. The exposure of interest was mothers' prenatal smoking (any vs. no smoking at any time during pregnancy), while the outcome was daughters' prenatal smoking (similarly assessed). We used multivariable log-binomial regression to obtain estimates of the relative risk (RR) and 95% confidence interval (CI).

RESULTS

Daughters exposed to maternal prenatal smoking were more likely to smoke during their pregnancy, compared to unexposed daughters (RR 1.78, 95% CI 1.72, 1.84, adjusted for the year the daughter delivered, her marital status and educational attainment, and the mothers' race/ethnicity).

CONCLUSIONS

In this relatively young population, we found that daughters exposed to maternal prenatal smoking have an increased risk of smoking later on during their own pregnancy, emphasizing the importance of exposures during the prenatal period. The mechanisms leading to prenatal smoking are multifactorial and likely include behavioural, genetic, epigenetic and environmental factors. An understanding of this risk factor for prenatal smoking may guide health care providers to better target smoking cessation interventions to at-risk populations.

Maternal smoking during pregnancy and offspring's tobacco dependence. A study of exposure-discordant sibling pairs

BACKGROUND

Prenatal exposure to maternal smoking has previously been linked to tobacco dependence, but confounding from genetic and early-environmental factors is of concern. The aim of this study was to clarify if maternal smoking during pregnancy may affect the onset and manifestations of tobacco dependence after taking such factors into account.

METHODS

The study is based on a matched cohort of 1538 siblings discordant for prenatal exposure to maternal smoking, who participated in a survey conducted in 2010 in Sweden. Analyses were based on pairs where both siblings had been daily smokers (193 pairs) or snus users (173 pairs) at some time in their life. Participants were 19-27 years old at the time of participation. Outcomes were tobacco dependence measured with the Cigarette Dependence Scale (CDS-12) in smokers and with the adapted Smokeless Tobacco Dependence Scale (STDS-12) in snus users, and previous quit attempts. Exposure to maternal smoking during pregnancy was retrieved from the Swedish Medical Birth Register.

RESULTS

There was no difference in dependence scores in exposure-discordant siblings (mean difference 0.36 on CDS-12 [95% confidence interval: -1.23 to 1.95] and 0.61 on STDS-12 [95% confidence interval: -1.20 to 2.43]). Neither did the siblings differ with regard to previous quit attempts.

CONCLUSIONS

Maternal smoking during pregnancy does not appear to influence tobacco dependence in adult offspring. A potential effect of heavy maternal smoking during pregnancy cannot be excluded, but genetic and environmental influences seem to be more influential for the onset of tobacco dependence.

PREDICTORS OF EMOTIONAL AND BEHAVIORAL PROBLEMS IN 1-YEAR-OLD CHILDREN: A LONGITUDINAL PERSPECTIVE

Emotional and behavioral problems at an early age can reasonably be considered a high-risk factor for later mental health disorders. The aim of the article is to reveal predictive factors of 1½-year-old children's emotional and behavioral problems. The study was a part of a prospective birth-cohort study. The study sample consisted of 172 full-term infants (born during Gestational Weeks 37-42) and their mothers. Emotional and behavioral problems at the age of 1½ years were measured using the Child Behavior Checklist for Ages 1½-5 (T. Achenbach & L. Rescorla, 2000), which was completed by mothers. Emotional and behavioral problems at age of 1½ years were more prevalent in infants born via cesarean section, as compared to infants born vaginally without administration of medication. Newborns' suboptimal functioning after birth, complicated emotional acceptance of pregnancy, a couple's nonsatisfactory relationship during pregnancy, maternal distress during pregnancy and in the first months after childbirth, and inflexible and parent-oriented attitudes toward infant-rearing also predicted children's emotional and behavioral problems independent of sociodemographic factors. Results suggest that biomedical and psychosocial factors which manifest themselves in the prenatal and perinatal periods can have associations with later infant and child mental health.

Intravenous Prenatal Nicotine Exposure Alters METH-Induced Hyperactivity, Conditioned Hyperactivity, and BDNF in Adult Rat Offspring

In the USA, approximately 15% of women smoke tobacco cigarettes during pregnancy. In utero tobacco smoke exposure produces somatic growth deficits like intrauterine growth restriction and low birth weight in offspring, but it can also negatively influence neurodevelopmental outcomes in later stages of life, such as an increased incidence of obesity and drug abuse. Animal models demonstrate that prenatal nicotine (PN) alters the development of the mesocorticolimbic system, which is important for organizing goal-directed behavior. In the present study, we determined whether intravenous (IV) PN altered the initiation and/or expression of methamphetamine (METH)-induced locomotor sensitization as a measure of mesocorticolimbic function in adult rat offspring. We also determined whether PN and/or METH exposure altered protein levels of BDNF (brain-derived neurotrophic factor) in the nucleus accumbens, the dorsal striatum, and the prefrontal cortex of adult offspring. BDNF was of interest because of its role in the development and maintenance of the mesocorticolimbic pathway and its ability to modulate neural processes that contribute to drug abuse, such as sensitization of the dopamine system. Dams were injected with IV nicotine (0.05 mg/kg/injection) or saline, 3×/day on gestational days 8-21. Testing was conducted when offspring reached adulthood (around postnatal day 90). Following 3 once daily habituation sessions the animals received a saline injection and baseline locomotor activity was measured. PN and prenatal saline (PS)-exposed offspring then received 10 once daily injections of METH (0.3 mg/kg) to induce locomotor sensitization. The animals received a METH injection (0.3 mg/kg) to assess the expression of sensitization following a 14-day period of no injections. A day later, all animals were injected with saline and conditioned hyperactivity was assessed. Brain tissue was harvested 24 h later. PN animals habituated more slowly to the activity chambers compared to PS controls. PN rats treated with METH showed significant enhancement of locomotor behavior compared to PS rats following acute and repeated injections; however, PN did not produce differential initiation or expression of behavioral sensitization. METH produced conditioned hyperactivity, and PN rats exhibited a greater conditioned response of hyperactivity relative to controls. PN and METH exposure produced changes in BDNF protein levels in all three regions, and complex interactions were observed between these two factors. Logistic regression revealed that BDNF protein levels, throughout the mesocorticolimbic system, significantly predicted the difference in the conditioned hyperactive response of the animals: both correlations were significant, but the predicted relationship between BDNF and context-elicited activity was stronger in the PN (r = 0.67) compared to the PS rats (r = 0.42). These findings indicate that low-dose PN exposure produces long-term changes in activity and enhanced sensitivity to the locomotor effects of METH. The enhanced METH-induced contextual conditioning shown by the PN animals suggests that offspring of in utero tobacco smoke exposure have greater susceptibility to learn about drug-related conditional stimuli, such as the context. The PN-induced alterations in mesocorticolimbic BDNF protein lend further support for the hypothesis that maternal smoking during pregnancy produces alterations in neuronal plasticity that contribute to drug abuse vulnerability. The current findings demonstrate that these changes are persistent into adulthood.

The effects of nicotine on human fetal development

Maternal smoking during pregnancy continues to represent a major public health concern. Nicotine is extremely harmful to the developing fetus through many different mechanisms, and the harms increase with later gestational age at exposure. Pregnancies complicated by maternal nicotine use are more likely to have significant adverse outcomes. Nicotine-exposed children tend to have several health problems throughout their lives, including impaired function of the endocrine, reproductive, respiratory, cardiovascular, and neurologic systems. Poor academic performance and significant behavioral disruptions are also common, including ADHD, aggressive behaviors, and future substance abuse. To diminish the adverse effects from cigarette smoking, some women are turning to electronic cigarettes, a new trend that is increasing in popularity worldwide. They are largely perceived as being safer to use in pregnancy than traditional cigarettes, although there is not adequate evidence to support this claim. At this time, electronic cigarette use during pregnancy cannot be recommended. Birth Defects Research (Part C) 108:181-192, 2016. © 2016 Wiley Periodicals, Inc.

Prenatal and Early Postnatal Exposure to Cigarette Smoke Decreases BDNF/TrkB Signaling and Increases Abnormal Behaviors Later in Life

BACKGROUND

Cigarette smoke exposure during prenatal and early postnatal periods increases the incidence of a variety of abnormal behaviors later in life. The purpose of this study was to identify the possible critical period of susceptibility to cigarette smoke exposure and evaluate the possibe effects of cigarette smoke during early life on brain-derived neurotrophic factor/neurotrophic tyrosine kinase receptor B signaling in the brain.

METHODS

Three different age of imprinting control region mice were exposed to cigarette smoke or filtered air for 10 consecutive days beginning on either gestational day 7 by maternal exposure, or postnatal days 2 or 21 by direct inhalation. A series of behavioral profiles and neurotrophins in brain were measured 24 hours after mice received acute restraint stress for 1 hour on postnatal day 59.

RESULTS

Cigarette smoke exposure in gestational day 7 and postnatal day 2 produced depression-like behaviors as evidenced by significantly increased immobility in both tail suspension and forced-swim test. Increased entry latencies, but not ambulation in the open field test, were also observed in the gestational day 7 and postnatal day 2 cigarette smoke exposure groups. Genetic analysis showed that gestational day 7 cigarette smoke exposure significantly altered mRNA level of brain-derived neurotrophic factor/tyrosine kinase receptor B in the hippocampus. However, behavioral profiles and brain-derived neurotrophic factor/tyrosine kinase receptor B signaling were not significantly changed in PND21 cigarette smoke exposure group compared with FA group.

CONCLUSIONS

These results suggest that a critical period of susceptibility to cigarette smoke exposure exists in the prenatal and early postnatal period, which results a downregulation in brain-derived neurotrophic factor/tyrosine kinase receptor B signaling in the hippocampus and enhances depression-like behaviors later in life.

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.

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.

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.

Invited commentary: Parental smoking as a risk factor for adult tobacco use: can maternal smoking during pregnancy be distinguished from the social environmental influence during childhood?

Parental smoking is known to have prenatal health effects on developing fetuses, and postnatal exposure to secondhand smoke causes adverse health effects during childhood and beyond. Further, there is solid evidence that parental smoking during childhood is a potent risk factor for smoking in offspring. In this issue of the Journal, Rydell et al. (Am J Epidemiol. 2014;179(12):1409-1417) add to a growing body of evidence showing that maternal smoking during pregnancy is statistically associated with the long-term risk of tobacco use in offspring. The data revealed a strong signal between maternal smoking during pregnancy and tobacco use in young adulthood, an association that was largely concentrated in snus use but not cigarette smoking. This new study adds to a growing body of epidemiologic evidence that consistently points toward maternal smoking during pregnancy being associated with an increased risk of offspring tobacco use in later life. There is also evidence from animal models indicating that fetal exposure to maternal nicotine use in utero can have a durable impact on the neural pathways that affect lifetime sensitivity to nicotine. This is an important research topic that continues to yield a consistent signal despite an array of inferential challenges.

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.

Early life exposure to cigarette smoke and depressive symptoms among women in midlife

INTRODUCTION

Active cigarette smoking has consistently been associated with depression, but little is known about the association between other cigarette smoke exposures, particularly in early life, and depression. We investigated whether exposures to maternal smoking during pregnancy (MSP) and childhood secondhand smoke (SHS) are associated with depressive symptoms in midlife.

METHODS

Pregnant mothers were enrolled and were provided data on maternal smoking and other parental characteristics. Female offspring were followed through age 7 years and again in midlife (age range = 38-44 years), when they provided data on smoking history, SHS across the life course, and current depressive symptoms using the Center for Epidemiological Studies Depression Scale (CES-D).

RESULTS

Participants exposed to MSP had a higher risk for depression (risk ratio [RR] = 1.83, 95% confidence interval [CI] = 1.08, 3.09) than those without MSP exposure. Relative to those with no MSP and no childhood SHS exposures, participants with MSP and childhood SHS had more than twice the risk of depressive symptoms (RR = 2.40, 95% CI = 1.07, 5.41). Further adjustment for adult factors, particularly current smoking, substantially reduced these associations (e.g., MSP vs. no MSP exposure: RR = 1.36 [95% CI = 0.75, 2.45]).

CONCLUSIONS

Early life exposure to cigarette smoke is associated with increased risk for depression in midlife, with the association largely mediated by active smoking. These findings support a role for early life cigarette exposures in shaping smoking and depression risks in later life, and they provide some support for the direction of smoke exposure influence on depression.

Prenatal cigarette smoke exposure causes hyperactivity and aggressive behavior: role of altered catecholamines and BDNF

Smoking during pregnancy is associated with a variety of untoward effects on the offspring. However, recent epidemiological studies have brought into question whether the association between neurobehavioral deficits and maternal smoking is causal. We utilized an animal model of maternal smoking to determine the effects of prenatal cigarette smoke (CS) exposure on neurobehavioral development. Pregnant mice were exposed to either filtered air or mainstream CS from gestation day (GD) 4 to parturition for 4h/d and 5d/wk, with each exposure producing maternal plasma concentration of cotinine equivalent to smoking <1 pack of cigarettes per day (25ng/ml plasma cotinine level). Pups were weaned at postnatal day (PND) 21 and behavior was assessed at 4weeks of age and again at 4-6months of age. Male, but not female, offspring of CS-exposed dams demonstrated a significant increase in locomotor activity during adolescence and adulthood that was ameliorated by methylphenidate treatment. Additionally, male offspring exhibited increased aggression, as evidenced by decreased latency to attack and number of attacks in a resident-intruder task. These behavioral abnormalities were accompanied by a significant decrease in striatal and cortical dopamine and serotonin and a significant reduction in brain-derived neurotrophic factor (BDNF) mRNA and protein. Taken in concert, these data demonstrate that prenatal exposure to CS produces behavioral alterations in mice that are similar to those observed in epidemiological studies linking maternal smoking to neurodevelopmental disorders. Further, these data also suggest a role for monaminergic and BDNF alterations in these effects.

Epigenetic programing of depression during gestation

Gestational factors play a role in the development of several neuropsychiatric disorders including schizophrenia and autism. In utero conditions influence future mental health through epigenetic mechanisms, which alter gene expression without affecting DNA coding sequence. Environmental factors account for at least 60% of the risk for developing major depression, and earlier onset of depressive illness has been observed over the past decades. I speculate that gestational factors may play a greater role in programing depression than previously recognized. Here, I examine recent evidence for a role for gestational factors in programing mood disorders, and how epigenetic mechanisms mediate this effect.

Happiness and depression in adolescence after maternal smoking during pregnancy: birth cohort study

Background

Prenatal cigarette smoke exposure may have adverse psychological effects on offspring. The objective was to assess the association between parental smoking during pregnancy and offspring happiness at age 18, as well as depression.

Methodology

Participants were part of a birth cohort study in Pelotas, Brazil (5,249 participants). Happiness was measured by the SubjectiveHappinessScale, a Likert-like scale with four questions generating a score from 1 to 7, with ≥ 6 indicating "happiness". Depression was measured using the Mini International Psychiatric Interview.

​Results

About one third of mothers reported having smoked during pregnancy and 4.6% reported smoking 20 or more cigarettes a day. The prevalence of happiness was 32.2% (95% CI 30.8; 33.7), depression 6.8% (95% CI 6.1; 7.6), and simultaneous happiness and depression less than 1%. The prevalence of offspring happiness decreased as smoking in pregnancy increased, even after control for confounding variables, showing an OR = 0.79 [95% CI 0.55; 1.13]. The opposite happened to depression; the prevalence of offspring depression increased as smoking in pregnancy increased (<20 cigarettes/day OR = 1.38 [95% CI 1.03; 1.84] and ≥20 cigarettes/day OR = 2.11[95% CI 1.31; 3.40]. Smoking by the partner was associated with decreased offspring happiness after adjustment for confounders, but did no show association with offspring depression.

Conclusions

Offspring were less likely to be happy and more likely to be depressed if their mother smoked during pregnancy, and less likely to be happy if their father smoked during mother’s pregnancy. Although we can not affirm that this is a “causal pathway”, public policies to reduce smoking in pregnancy could improve the health of the offspring in the short and long term.