Is the intergenerational transmission of smoking from mother to child mediated by children's behavior problems?

Epigenetic modification impacting brain functions: Effects of physical activity, micronutrients, caffeine, toxins, and addictive substances

Changes in gene expression are involved in many brain functions. Epigenetic processes modulate gene expression by histone modification and DNA methylation or RNA-mediated processes, which is important for brain function. Consequently, epigenetic changes are also a part of brain diseases such as mental illness and addiction. Understanding the role of different factors on the brain epigenome may help us understand the function of the brain. This review discussed the effects of caffeine, lipids, addictive substances, physical activity, and pollutants on the epigenetic changes in the brain and their modulatory effects on brain function.

The Understanding of Maternal Smoking among Women who were Smoking or had Quit Smoking during Pregnancy

BACKGROUND

Maternal tobacco smoking during pregnancy is associated with adverse health effects for the woman, fetus, and child, including such serious effects as preterm birth, low birth weight, stillbirth, and neonatal and sudden infant death. Smoking cessation during pregnancy reduces health risks.

PURPOSE

In order to support pregnant women to quit smoking, it is essential to know determinants of quitting smoking in pregnancy. The purpose of this research was to examine women's understanding of maternal smoking, in terms of their beliefs, in relation to quitting smoking during pregnancy.

METHODS

The study was a cross-sectional survey with anonymous questionnaires. The sample consisted of 161 pregnant and postnatal women who were continuing or had continued to smoke during pregnancy or had quit smoking during pregnancy. Logistic regression was used to determine the impact of women's understanding of maternal smoking on quitting smoking in pregnancy.

RESULTS

A large majority of the women had low to moderate understanding of maternal smoking. Those with higher levels of understanding were more likely to quit smoking during pregnancy than were those with a low level of understanding. Not having children prior to the current pregnancy or childbirth also increased the likelihood of quitting smoking during pregnancy while being without a partner combined with having a longer duration of smoking decreased the likelihood of quitting smoking during pregnancy.

CONCLUSION

As a modifiable factor, pregnant women's understanding of maternal smoking can be readily targeted with informational interventions in an effort to help them quit smoking.

Pregnant and postnatal women's experiences of interacting with health care providers about their tobacco smoking: a qualitative systematic review

OBJECTIVE

The objective of this review was twofold: (i) to comprehensively identify the best available evidence about the experiences of women who smoked tobacco during pregnancy or postnatally (or both) concerning health care providers' interactions with them about their smoking, when such interactions occurred during contact for prenatal or postnatal health care in any health care setting; and (ii) to synthesize the research findings for recommendations to strengthen health care providers' interventions regarding smoking during pregnancy and smoking during the postnatal period.

INTRODUCTION

Maternal tobacco smoking during pregnancy and maternal tobacco smoking postnatally pose serious health risks for the woman, fetus, and offspring, whereas maternal smoking cessation has beneficial health effects. Given the importance of health care providers' interactions with pregnant and postnatal women for smoking cessation care, it is essential to understand women's experiences of such interactions.

INCLUSION CRITERIA

Studies considered for this review had qualitative research findings about the experiences of women who smoked tobacco during pregnancy or postnatally (or both) in relation to health care providers' interactions with them about their smoking.

METHODS

The review was conducted using the JBI approach to qualitative systematic reviews. Published studies were sought through 6 academic databases (eg, CINAHL, MEDLINE). Unpublished studies were searched in 6 gray literature sources (eg, ProQuest Dissertations and Theses, Google Scholar). Reference lists of retrieved records were also searched. The searches occurred in October and November 2020; no country, language, or date limits were applied. Study selection involved title and abstract screening, full-text examination, and critical appraisal of all studies that met the inclusion criteria for the review. Study characteristics and research findings were extracted from the included studies. Study selection and extraction of findings were conducted by two reviewers independently; differences between reviewers were resolved through consensus. The research findings were categorized, and the categories were aggregated into a set of synthesized findings. The synthesized finding were assigned confidence scores. The categories and finalized synthesized findings were agreed upon by all reviewers.

RESULTS

The 57 included studies varied in qualitative research designs and in methodological quality (from mostly low to high). There were approximately 1092 eligible participants, and 250 credible and unequivocal research findings. The research findings yielded 14 categories and 6 synthesized findings with low to very low confidence scores. Some women who smoked tobacco during pregnancy and some women who smoked tobacco postnatally lacked supportive interactions by health care providers regarding their smoking; other women experienced supportive interactions by health care providers. Women were adversely impacted when health care providers' interactions lacked supportiveness, and were beneficially impacted when interactions were supportive. Women varied in openness to health care providers' interactions regarding their smoking, from not being receptive to being accepting, and some women wanted meaningful health care provider interactions.

CONCLUSIONS

Although confidence in the synthesized findings is low to very low, the evidence indicates that supportive health care provider interactions may facilitate positive smoking behavior change in pregnancy and postnatally. It is recommended that health care providers implement accepted clinical practice guidelines with women who smoke prenatally or postnatally, using an approach that is person-centered, emotionally supportive, engaging (eg, understanding), and non-authoritarian.

SYSTEMATIC REVIEW REGISTRATION NUMBER

PROSPERO CRD42020178866.

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.

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.

How much and why does the mum matter? Mechanisms explaining the intergenerational transmission of smoking

Offspring whose mother smokes during pregnancy have higher risk of smoking themselves. In this study, epigenetics, antisocial behaviours, and social learning were investigated as potential mechanisms of mother-to-child transmission of smoking among a population sample drawn from the Birth Cohort Study 1970. Findings on daughters showed that the direct epigenetic hypothesis was mediated by social learning mechanisms, suggesting that exposure to maternal smoking across childhood and adolescence strongly explained why the smoking habits of mother and daughter correlate. However, prenatal smoking effects on sons were only partially explained by observational learning of mother smoking habits. Our estimates provided evidence concerning the potential role also played by the child's persistent antisocial behaviours. These results were confirmed after controlling for early life circumstances and current socioeconomic conditions. Policy implications of the results are discussed.

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.

Elevated risk of nicotine dependence among sib-pairs discordant for maternal smoking during pregnancy: evidence from a 40-year longitudinal study

BACKGROUND

Compelling evidence links maternal smoking during pregnancy with elevated risk of nicotine dependence among the offspring. However, no study to date has examined the maternal smoking during pregnancy-nicotine dependence link among sibling-pairs discordant for maternal smoking during pregnancy. We tested two hypotheses that, if supported, suggest that the maternal smoking during pregnancy-nicotine dependence link may be physiologically mediated.

METHODS

Study participants were adult offspring of women enrolled in the Providence and Boston sites of the Collaborative Perinatal Project (1959-1966). Approximately 10% of these adult offspring (average age: 39.6 years) were enrolled in the New England Family Study (n = 1,783), a follow-up study that oversampled families with multiple siblings. Logistic regression models predicting maternal smoking during pregnancy risk on various prospectively collected smoking and marijuana use outcomes, including nicotine dependence, were fit using models that allowed between-mother effects of maternal smoking during pregnancy exposure to differ from within-mother effects. In the absence of significant effect heterogeneity, we calculated a combined estimate.

RESULTS

Maternal smoking during pregnancy predicted progression from weekly smoking to nicotine dependence (odds ratio = 1.4 [95% confidence interval = 1.2, 1.8]), but not weekly smoking or progression to marijuana dependence.

CONCLUSIONS

Current evidence from sibling-pairs discordant for maternal smoking during pregnancy is consistent with previous reports of a dose-response association between maternal smoking during pregnancy and nicotine dependence, as well as of up-regulation of nicotine receptors among animals exposed to maternal smoking during pregnancy. Together, they provide support for the existence of a physiologically mediated link between maternal smoking during pregnancy and nicotine dependence.

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.

Maternal drinking and risky sexual behavior in offspring

Teenage mothers are more likely to use drugs, and their children are more likely to use substances and become pregnant during adolescence. Teenage mothers' substance use may play a role in the intergenerational risk for adolescent pregnancy. Pregnant adolescents (12-18 years) were seen during pregnancy and postnatal years 6, 10, 14, and 16 (n = 332). Teenage mothers reported on substance use and family characteristics. The offspring reported substance use (starting at age 10) and sexual behavior (ages 14 and 16). Prenatal alcohol exposure was associated with offspring (a) having a risky first sex partner and (b) multiple sex partners in the past year. Heavy maternal drinking during childhood was associated with offspring reports of a risky first sex partner and early teenage pregnancy. Findings from this unique birth cohort have implications for alcohol prevention efforts with girls during and after a teenage pregnancy and interventions to prevent risky sex in high-risk youth.

Parental smoking exposure and adolescent smoking trajectories

OBJECTIVE

In a multigenerational study of smoking risk, the objective was to investigate the intergenerational transmission of smoking by examining if exposure to parental smoking and nicotine dependence predicts prospective smoking trajectories among adolescent offspring.

METHODS

Adolescents (n = 406) ages 12 to 17 and a parent completed baseline interviews (2001-2004), and adolescents completed up to 2 follow-up interviews 1 and 5 years later. Baseline interviews gathered detailed information on parental smoking history, including timing and duration, current smoking, and nicotine dependence. Adolescent smoking and nicotine dependence were assessed at each time point. Latent Class Growth Analysis identified prospective smoking trajectory classes from adolescence into young adulthood. Logistic regression was used to examine relationships between parental smoking and adolescent smoking trajectories.

RESULTS

Four adolescent smoking trajectory classes were identified: early regular smokers (6%), early experimenters (23%), late experimenters (41%), and nonsmokers (30%). Adolescents with parents who were nicotine-dependent smokers at baseline were more likely to be early regular smokers (odds ratio 1.18, 95% confidence interval 1.05-1.33) and early experimenters (odds ratio 1.04, 95% confidence interval 1.04-1.25) with each additional year of previous exposure to parental smoking. Parents' current non-nicotine-dependent and former smoking were not associated with adolescent smoking trajectories.

CONCLUSIONS

Exposure to parental nicotine dependence is a critical factor influencing intergenerational transmission of smoking. Adolescents with nicotine-dependent parents are susceptible to more intense smoking patterns and this risk increases with longer duration of exposure. Research is needed to optimize interventions to help nicotine-dependent parents quit smoking early in their children's lifetime to reduce these risks.

Attention deficit/hyperactivity disorder symptoms and depression symptoms as mediators in the intergenerational transmission of smoking

BACKGROUND

Attention deficit/hyperactivity disorder and depression have been found to be comorbid with smoking behaviors, and all three behavioral syndromes have been shown to be familially transmitted. The present paper reports on the results of analyses testing whether child attention deficit/hyperactivity disorder and depression symptoms were mediators in the intergenerational transmission of cigarette smoking.

METHOD

Path analyses using bootstrapped mediation procedures were conducted on data from a community sample of 764 families (one or both parents and one adolescent offspring) from the Indiana University Smoking Survey. Parents reported on their smoking behaviors, ADHD, and depression and their child's ADHD, while offspring reported on their smoking behaviors and depression.

RESULTS

Although fathers' and mothers' smoking status, depression, and ADHD were not significantly correlated with boys' smoking initiation, there was a significant mediated (indirect) pathway from mothers' depression to boys' smoking initiation through boys' depression. Several parental variables were significantly correlated with smoking initiation in girls, and the pathways from mothers' smoking status, mothers' ADHD, and fathers' smoking status to girls' smoking initiation were significantly mediated by girls' ADHD.

CONCLUSIONS

For adolescent girls, the intergenerational transmission of ADHD appears to be important in understanding the intergenerational transmission of cigarette smoking. Sex differences in the intergenerational transmission of psychopathology as it leads to smoking initiation were also discussed.

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

We examined the long-term effects of prenatal cigarette smoke exposure (PCSE) on the behavior problems and smoking behavior of 22-year-old offspring. The mothers of these offspring were interviewed about their tobacco and other drug use during pregnancy at the fourth and seventh gestational months, and at delivery. Data on the offspring are from interviews at age 22 (n=608). Behavior problems were measured by the Adult Self-Report (ASR) with the following outcome scales: total behavior problems, externalizing, internalizing, attention, anxiety/depression, withdrawn, thought, intrusive, aggression, somatic and rule breaking behavioral problems. Young adult smoking behavior was measured using self-reported average daily cigarettes, and was validated with urine cotinine. Nicotine dependence was measured with the Fagerström Tobacco and Nicotine Dependence (FTND) scale. Regression analyses tested the relations between trimester-specific PCSE and young adult's behavioral problems and smoking behavior, adjusting for demographic and maternal psychological characteristics, and other prenatal substance exposures. Exposed young adults had significantly higher scores on the externalizing, internalizing, aggression, and somatic scales of the ASR. These young adults were also more likely to have a history of arrests. Young adults with PCSE also had a higher rate of smoking and nicotine dependence. Our previous findings of the relations between PCSE and aggressive behavior in early childhood and PCSE and smoking behavior in early adolescence extend into young adulthood.