Maternal smoking during pregnancy and anger temperament among adult offspring

Research Review: Developmental origins of depression - a systematic review and meta-analysis

BACKGROUND

Many observational studies have found a direct association between adverse in utero, perinatal and postnatal exposures and offspring's depression. These findings are consistent with the 'developmental origins of disease hypothesis'. But no review has comprehensively summarized the roles of these exposures. This review aims to systematically scrutinize the strength of associations between individual prenatal, perinatal, and postnatal exposures and subsequent depression in offspring.

METHODS

We conducted a systematic review and meta-analysis to synthesize the literature from the EMBASE, HealthStar, PsychoInfo, and Medline databases since their inception to September 1, 2019. English language articles on population-based prospective cohort studies examining the associations between in utero, perinatal, and postnatal exposures and offspring's depression were searched. Random-effects models were used to calculate pooled estimates, and heterogeneity and sensitivity tests were conducted to explore potential confounders in the relationships of depression and early-life factors. Qualitative analysis was also conducted.

RESULTS

Sixty-four prospective cohort studies with 28 exposures studied in the relationships to offspring's depression met inclusion criteria. The meta-analysis found 12 prenatal, perinatal, and postnatal characteristics were associated with an increased risk of depression in offspring: low birth weight, premature birth, small gestational age, maternal education, socioeconomic status, having younger parents (<20 years), having older parents (≥35 years), maternal smoking, paternal smoking, maternal stress, maternal anxiety, and prenatal depression. Heterogeneity and sensitivity tests supported the findings. By and large, study characteristics had no effects on conclusions. Qualitative analyses generally supported the findings of meta-analysis and reported on additional risk factors.

CONCLUSIONS

This review provides a robust and comprehensive overview of the lasting psychopathological effects of in utero, perinatal, and postnatal exposures. The findings highlight the need for clinical and public health interventions focusing on the identified risk factors. Large prospective cohort studies are warranted to investigate the combined effects of multiple co-existing early-life exposures.

Placental Gene Expression and Offspring Temperament Trajectories: Predicting Negative Affect in Early Childhood

Exposure to prenatal stress increases offspring risk for long-term neurobehavioral impairments and psychopathology, such as Attention Deficit Hyperactivity Disorder (ADHD). Epigenetic regulation of glucocorticoid pathway genes may be a potential underlying mechanism by which maternal conditions 'program' the fetal brain for downstream vulnerabilities. The present study aims to investigate whether mRNA expression of glucocorticoid pathway genes in the placenta predict offspring negative affect during early childhood (between 6 and 24 months). Participants include 318 mother-child dyads participating in a longitudinal birth cohort study. Placental mRNA expression of glucocorticoid pathway genes (HSD11B1, HSD11B2, NR3C1, NCOR2) were profiled and negative affect traits of the offspring were measured at 6, 12, 18, and 24 months. HSD11B1 mRNA expression significantly predicted negative affect (β = -.09, SE = .04; p = .036), and Distress to Limitations trajectories (β = -.13, SE = .06; p = .016). NCOR2 mRNA expression significantly predicted Distress to Limitations (β = .43, SE = .21; p = .047), and marginally predicted Sadness trajectories (β = .39, SE = .21; p = .068). HSD11B2 and NR3C1 did not predict trajectories of Negative Affect or subscale scores. Infant negative affect traits were assessed via maternal self-report, and deviated from linearity across follow-up. mRNA expression of glucocorticoid pathway genes in the placenta may be a potentially novel tool for early identification of infants at greater risk for elevated negative affect. Further study is needed to validate the utility of mRNA expression of glucocorticoid pathway genes in the placenta.

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.

Neurological Effects in the Offspring After Switching From Tobacco Cigarettes to E-Cigarettes During Pregnancy in a Mouse Model

Maternal smoking is currently a public health concern and has been associated with a number of complications in the offspring. E-cigarettes are gaining popularity as a “safer” alternative to tobacco cigarettes during pregnancy, however, there are a limited number of studies to suggest that it is actually “safe.” Balb/C female mice were exposed to ambient air (n = 8; Sham), or tobacco cigarette smoke (n = 8; SE) before gestation, during gestation and lactation. A third group was exposed to cigarette smoke before gestation followed by e-cigarette aerosols during gestation and lactation (n = 8; Switch). Male offspring (12-week old, n = 10–14/group) underwent behavioral assessments to investigate short-term memory, anxiety, and activity using the novel object recognition and elevated plus maze tests. Brains were collected at postnatal day (P)1, P20, and Week 13 for global DNA methylation, epigenetic gene expression, and neuronal cell counts. The offspring from mothers switching to e-cigarettes exhibited no change in exploration/activity but showed a decrease in global DNA methylation, Aurora Kinase (Aurk) A and AurkB gene expression and a reduction in neuronal cell numbers in the cornu ammonis 1 region of the dorsal hippocampus compared with the SE group. Continuous tobacco cigarette smoke exposure during pregnancy resulted in marked neurological deficits in the offspring. Switching to e-cigarettes during pregnancy reduced these neurological deficits compared with cigarette smoke exposure. However, neurological changes were still observed, so we therefore conclude that e-cigarette use during pregnancy is not advised.

Prenatal influences on temperament development: The role of environmental epigenetics

This review summarizes current knowledge and outlines future directions relevant to questions concerning environmental epigenetics and the processes that contribute to temperament development. Links between prenatal adversity, epigenetic programming, and early manifestations of temperament are important in their own right, also informing our understanding of biological foundations for social-emotional development. In addition, infant temperament attributes represent key etiological factors in the onset of developmental psychopathology, and studies elucidating their prenatal foundations expand our understanding of developmental origins of health and disease. Prenatal adversity can take many forms, and this overview is focused on the environmental effects of stress, toxicants, substance use/psychotropic medication, and nutrition. Dysregulation associated with attention-deficit/hyperactivity-disruptive disorders was noted in the context of maternal substance use and toxicant exposures during gestation, as well as stress. Although these links can be made based on the existing literature, currently few studies directly connect environmental influences, epigenetic programming, and changes in brain development/behavior. The chain of events starting with environmental inputs and resulting in alterations to gene expression, physiology, and behavior of the organism is driven by epigenetics. Epigenetics provides the molecular mechanism of how environmental factors impact development and subsequent health and disease, including early brain and temperament development.

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.

Prenatal risk factors for depression: a critical review of the evidence and potential mechanisms

Exposure to adverse experiences in early life increases the risk of depression during adulthood. Recent findings have highlighted that exposure of a fetus to an adverse intrauterine environment may also have implications for later offspring depression. This review considers the status of the evidence for these associations and the potential mechanisms underlying prenatal developmental risks for later depression, addressing the challenging possibility that environmental predisposition to depression may begin before birth.

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.

An interaction of a NR3C1 polymorphism and antenatal solar activity impacts both hippocampus volume and neuroticism in adulthood

The investigation of the interaction of genes and environment in the context of mental health and personality yields important new insights for a better understanding of human nature. Both antenatal and postnatal environmental factors have been considered as potential modulators of genetic activity. Antenatally, especially smoking or alcohol drinking habits of the mother dramatically influence the health of the child during pregnancy and even later on in life. In the present study we would like to introduce a more "distant" factor that is not under the control of the becoming mother but that nevertheless plays a potential role for the health of the unborn child later on in adulthood. Here, we retrospectively investigate the influence of solar activity (while the child is still in the uterus of the becoming mother) on brain structure (with a focus on hippocampus and amygdala volume) and personality in adulthood. We observe an interaction of a genetic variant (rs41423247) of the glucocorticoid receptor gene (NR3C1) and solar activity in the first trimester after conception on both hippocampal volume and the personality trait neuroticism in adulthood in N = 254 participants. The NR3C1 gene is the focus of interest, because of its influence on the hypothalamic-pituitary-adrenal (HPA) axis and negative emotionality. Carriers of the CC variant of rs41423247 grown in the womb under the influence of high sun radiation (high solar activity) show both the highest hippocampal volume in the left hemisphere and lowest neuroticism scores. The present findings should encourage researchers in psychology and psychiatry to include also environmental influences such as solar activity besides genetics to better understand the etiogenesis of psychiatric disorders.

The impact of smoking in adolescence on early adult anxiety symptoms and the relationship between infant vulnerability factors for anxiety and early adult anxiety symptoms: the TOPP Study

Cigarette smoking is increased in people with trait anxiety and anxiety disorders, however no longitudinal data exist illuminating whether smoking in adolescence can influence the developmental trajectory of anxiety symptoms from early vulnerability in infancy to adult anxiety expression. Using The Tracing Opportunities and Problems in Childhood and Adolescence (TOPP) Study, a community-based cohort of children and adolescents from Norway who were observed from the age of 18 months to age 18-19 years, we explored the relationship between adolescent smoking, early vulnerability for anxiety in infancy (e.g. shyness, internalizing behaviors, emotional temperaments) and reported early adult anxiety. Structural equation modeling demonstrated that adolescent active smoking was positively associated with increased early adulthood anxiety (β = 0.17, p<0.05), after controlling for maternal education (proxy for socioeconomic status). Adolescent anxiety did not predict early adult smoking. Adolescent active smoking was a significant effect modifier in the relationship between some infant vulnerability factors and later anxiety; smoking during adolescence moderated the relationship between infant internalizing behaviors (total sample: active smokers: β = 0.85, p<0.01, non-active smokers: ns) and highly emotional temperament (total sample: active smokers: β = 0.55, p<0.01,non-active smokers: ns), but not shyness, and anxiety in early adulthood. The results support a model where smoking acts as an exogenous risk factor in the development of anxiety, and smoking may alter the developmental trajectory of anxiety from infant vulnerability to early adult anxiety symptom expression. Although alternative non-mutually exclusive models may explain these findings, the results suggest that adolescent smoking may be a risk factor for adult anxiety, potentially by influencing anxiety developmental trajectories. Given the known adverse health effects of cigarette smoking and significant health burden imposed by anxiety disorders, this study supports the importance of smoking prevention and cessation programs targeting children and adolescence.