Maternal smoking during pregnancy and risks to depression and anxiety in offspring: An observational study and genome-wide gene-environment interaction analysis in UK biobank cohort

The impact of maternal smoking during pregnancy and the age of smoking initiation on incident dementia: A prospective cohort study

INTRODUCTION

The impact of early-life tobacco exposure on dementia has remained unknown.

METHODS

Using the UK Biobank, the associations of maternal smoking during pregnancy (MSDP) and age of smoking initiation (ASI) with the onset time of all-cause dementia were estimated with accelerated failure time models. The effects of MSDP and ASI on brain structure and their genetic correlation to Alzheimer's disease (AD) were analyzed. A Mendelian randomization (MR) analysis was conducted.

RESULTS

The time ratios for smokers starting in childhood, adolescence, and adulthood (vs never smokers) were 0.87 (0.76 to 0.99), 0.92 (0.88 to 0.96), and 0.95 (0.89 to 1.01). MSDP and smoking in adolescence altered many brain regions, including the hippocampus. In genetic analysis, MSDP was genetically and causally linked to AD, and a younger ASI was genetically correlated to a higher AD risk.

DISCUSSION

Early-life smoking accelerated dementia onset and was genetically correlated to AD. MSDP demonstrated genetic and causal linkage to AD risks.

HIGHLIGHTS

Unlike the commonly used Cox proportional hazards model, this article uses a parametric survival analysis method - the accelerated failure model - to explore the relationship between exposure to onset time. It can be used as an alternative method when the proportional hazards assumption is not met. Genetic analyses including genetic correlation study and MR analysis and brain structure analyses were conducted to support our findings and explore the potential mechanisms. The study reveals the relationship between different smoking initiation periods and the onset time of dementia and shows that earlier smoking exposure has a more significant impact on dementia. It emphasizes the importance of preventing early smoking. In the future, more research focusing on the relationship between early exposure and dementia is called for to provide more detailed prevention measures for dementia that cover all age groups.

Mediating Effect of Tobacco Dependence on the Association Between Maternal Smoking During Pregnancy and Chronic Obstructive Pulmonary Disease: Case-Control Study

BACKGROUND

Maternal smoking during pregnancy (MSDP) is a known risk factor for offspring developing chronic obstructive pulmonary disease (COPD), but the underlying mechanism remains unclear.

OBJECTIVE

This study aimed to explore whether the increased COPD risk associated with MSDP could be attributed to tobacco dependence (TD).

METHODS

This case-control study used data from the nationwide cross-sectional China Pulmonary Health study, with controls matched for age, sex, and smoking status. TD was defined as smoking within 30 minutes of waking, and the severity of TD was assessed using the Fagerstrom Test for Nicotine Dependence. COPD was diagnosed when the ratio of forced expiratory volume in 1 second to forced vital capacity was <0.7 in a postbronchodilator pulmonary function test according to the 2017 Global Initiative for Chronic Obstructive Lung Disease criteria. Logistic regression was used to examine the correlation between MSDP and COPD, adjusting for age, sex, BMI, educational attainment, place of residence, ethnic background, occupation, childhood passive smoking, residential fine particulate matter, history of childhood pneumonia or bronchitis, average annual household income, and medical history (coronary heart disease, hypertension, and diabetes). Mediation analysis examined TD as a potential mediator in the link between MSDP and COPD risk. The significance of the indirect effect was assessed through 1000 iterations of the "bootstrap" method.

RESULTS

The study included 5943 participants (2991 with COPD and 2952 controls). Mothers of the COPD group had higher pregnancy smoking rates (COPD: n=305, 10.20%; controls: n=211, 7.10%; P<.001). TD was more prevalent in the COPD group (COPD: n=582, 40.40%; controls: n=478, 33.90%; P<.001). After adjusting for covariates, MSDP had a significant effect on COPD (β=.097; P<.001). There was an association between MSDP and TD (β=.074; P<.001) as well as between TD and COPD (β=.048; P=.007). Mediation analysis of TD in the MSDP-COPD association showed significant direct and indirect effects (direct: β=.094; P<.001 and indirect: β=.004; P=.03). The indirect effect remains present in the smoking population (direct: β=.120; P<.001 and indirect: β=.002; P=.03).

CONCLUSIONS

This study highlighted the potential association between MSDP and the risk of COPD in offspring, revealing the mediating role of TD in this association. These findings contribute to a deeper understanding of the impact of prenatal tobacco exposure on lung health, laying the groundwork for the development of relevant prevention and treatment strategies.

Maternal smoking around birth and its influence on offspring allergic diseases: A mendelian randomization study

Objective

The influence of maternal smoking around birth (MSAB) on offspring allergic diseases, specifically childhood asthma (CA), allergic rhinitis (AR), allergic conjunctivitis (AC), and atopic dermatitis (AD) remains incompletely understood. We performed a rigorous mendelian randomization (MR) study to obtain the unconfounded association between MSAB and allergic diseases in offspring with and without adjustment for the effect of breastfeeding.

Methods

Utilizing publicly available information of MSAB, breastfeeding, CA, AR, AC, and AD from large-scale genome-wide association studies (GWAS), we performed a two-sample mendelian randomization (TSMR) analysis to assess the respective causal relationship of MSAB and breastfeeding to allergic diseases in offspring. To get a reliable conclusion, MR Egger regression, weighted median, and inverse variance weighted (IVW) were employed to estimate the causality, with IVW as the primary analysis. Multivariate MR (MVMR) analysis was used to assess the effect of MSAB on allergic diseases after adjusting for breastfeeding's impact. Sensitivity analysis was conducted using the Cochran Q test, MR-Egger, and leave-one-out approaches to ensure the reliability and stability of results.

Results

The TSMR analysis demonstrated MSAB increased the risks of CA (PIVW = 0.013, OR: 1.018, 95%CI: 1.004 to 1.033) and AD (PIVW = 0.006, OR: 8.293, 95%CI: 1.815 to 37.884) in offspring. Conversely, breastfeeding decreased the risk of CA (PIVW <0.001, OR: 0.946, 95%CI: 0.918 to 0.974). MSAB still increased the risks of CA (P = 0.0497, OR: 1.013, 95%CI: 1.000017 to 1.026) and AD (P = 0.003, OR: 13.800, 95%CI: 2.490 to 269.246) after adjusting for breastfeeding. We observed no strong indication of a negative causality between MSAB and AC and AR.

Conclusion

Our findings provided robust evidence of the adverse effects of MSAB on offspring. We emphasized the urgency of smoking cessation around birth and the importance of breastfeeding even in smoking mothers.

New insights into the physiology and pathophysiology of the atypical sodium leak channel NALCN

Cell excitability and its modulation by hormones and neurotransmitters involve the concerted action of a large repertoire of membrane proteins, especially ion channels. Unique complements of coexpressed ion channels are exquisitely balanced against each other in different excitable cell types, establishing distinct electrical properties that are tailored for diverse physiological contributions, and dysfunction of any component may induce a disease state. A crucial parameter controlling cell excitability is the resting membrane potential (RMP) set by extra- and intracellular concentrations of ions, mainly Na+, K+, and Cl-, and their passive permeation across the cell membrane through leak ion channels. Indeed, dysregulation of RMP causes significant effects on cellular excitability. This review describes the molecular and physiological properties of the Na+ leak channel NALCN, which associates with its accessory subunits UNC-79, UNC-80, and NLF-1/FAM155 to conduct depolarizing background Na+ currents in various excitable cell types, especially neurons. Studies of animal models clearly demonstrate that NALCN contributes to fundamental physiological processes in the nervous system including the control of respiratory rhythm, circadian rhythm, sleep, and locomotor behavior. Furthermore, dysfunction of NALCN and its subunits is associated with severe pathological states in humans. The critical involvement of NALCN in physiology is now well established, but its study has been hampered by the lack of specific drugs that can block or agonize NALCN currents in vitro and in vivo. Molecular tools and animal models are now available to accelerate our understanding of how NALCN contributes to key physiological functions and the development of novel therapies for NALCN channelopathies.

Healthy Lifestyle Beliefs Scale: Psychometric properties in Portuguese pregnant women

Healthy lifestyle during pregnancy influences the pregnant woman's and child's physical and mental health, impacting perinatal outcomes. Healthy lifestyle beliefs are predictors of lifestyle behaviors, requiring a valid and reliable instrument to assess them during prenatal care. The 16-item Healthy Lifestyle Belief Scale (HLBS) measures a person's beliefs about their ability to live a healthy lifestyle. This study aimed to examine the psychometric properties of a Portuguese version of the HLBS among pregnant women. A methodological study was developed in two phases: cross-cultural adaptation and evaluation of the psychometric properties of the Portuguese version in a nonprobability sample of 192 Portuguese pregnant women. The exploratory factor analysis suggested three subscales, which explained 53.8% of the total variance. Cronbach's α was 0.83 for the overall scale and for the subscales ranged between 0.71 and 0.81. The HLBS is a reliable and valid instrument to assist health professionals in assessing the ability of Portuguese pregnant women to adopt a healthy lifestyle. Assessing healthy lifestyle beliefs potentially contributes to the development of health behavior interventions in pregnant women and consequently improves perinatal outcomes through evidence-based practices.

Prenatal nicotine exposure during pregnancy results in adverse neurodevelopmental alterations and neurobehavioral deficits

Maternal tobacco use and nicotine exposure during pregnancy have been associated with adverse birth outcomes in infants and can lead to preventable pregnancy complications. Exposure to nicotine and other compounds in tobacco and electronic cigarettes (e-cigarettes) has been shown to increases the risk of miscarriage, prematurity, stillbirth, low birth weight, perinatal morbidity, and sudden infant death syndrome (SIDS). Additionally, recent data provided by clinical and pre-clinical research demonstrates that nicotine exposure during pregnancy may heighten the risk for adverse neurodevelopmental disorders such as Attention-Deficit Hyperactivity (ADHD), anxiety, and depression along with altering the infants underlying brain circuitry, response to neurotransmitters, and brain volume. In the United States, one in 14 women (7.2%) reported to have smoked cigarettes during their pregnancy with the global prevalence of smoking during pregnancy estimated to be 1.7%. Approximately 1.1% of women in the United States also reported to have used e-cigarettes during the last 3 months of pregnancy. Due to the large percentage of women utilizing nicotine products during pregnancy in the United States and globally, this review seeks to centralize pre-clinical and clinical studies focused on the neurobehavioral and neurodevelopmental complications associated with prenatal nicotine exposure (PNE) such as alterations to the hypothalamic-pituitary-adrenal (HPA) axis and brain regions such as the prefrontal cortex (PFC), ventral tegmental area (VTA), nucleus accumbens (NA), hippocampus, and caudate as well as changes to nAChR and cholinergic receptor signaling, long-term drug seeking behavior following PNE, and other related developmental disorders. Current literature analyzing the association between PNE and the risk for offspring developing schizophrenia, attention-deficit hyperactivity disorder (ADHD), autism spectrum disorder (ASD), anxiety, and obesity will also be discussed.

Examining the biological mechanisms of human mental disorders resulting from gene-environment interdependence using novel functional genomic approaches

We explore how functional genomics approaches that integrate datasets from human and non-human model systems can improve our understanding of the effect of gene-environment interplay on the risk for mental disorders. We start by briefly defining the G-E paradigm and its challenges and then discuss the different levels of regulation of gene expression and the corresponding data existing in humans (genome wide genotyping, transcriptomics, DNA methylation, chromatin modifications, chromosome conformational changes, non-coding RNAs, proteomics and metabolomics), discussing novel approaches to the application of these data in the study of the origins of mental health. Finally, we discuss the multilevel integration of diverse types of data. Advance in the use of functional genomics in the context of a G-E perspective improves the detection of vulnerabilities, informing the development of preventive and therapeutic interventions.

Assessing the interaction effects of brain structure longitudinal changes and life environmental factors on depression and anxiety

Disrupted brain structures and several life environmental factors have been shown to influence depression and anxiety, but their interactions with anxiety and depression remain elusive. Genome-wide association study datasets of 15 brain structure longitudinal changes (N = 15,640) were obtained from the published study. Genotype and phenotype-related data of depression, anxiety, and life environmental factors (including smoking, alcohol drinking, coffee intake, maternal smoking, physical activity, vitamin D, insomnia, sleep duration, and family satisfaction) were collected from UK Biobank. We calculated the polygenic risk scores (PRS) of 15 brain structure changes and then conducted linear regression analyses to explore the interactions of brain structure changes and life environmental factors on depression and anxiety using 15 brain structure change-related PRS, life environmental factors and interactions of them as instrumental variables, and depression score or anxiety score as outcomes. Sex stratification in all analyses was performed to reveal sex-specific differences in the interactions. We found 14 shared interactions related to both depression and anxiety in total sample, such as alcohol drinking × cerebellum white matter 3 (WM; beta = -.003, p = .018 for depression; beta = -003, p = .008 for anxiety) and maternal smoking × nucleus accumbens 2 (beta = .088, p = .002 for depression; beta = .070, p = .008 for anxiety). We also observed sex-specific differences in the interactions, for instance, alcohol drinking × cerebellum WM 3 was negatively associated with depression and anxiety in males (beta = -.004, p = .020 for depression; beta = -.005, p = .002 for anxiety). Our study results reveal the important interactions between brain structure changes and several life environmental factors on depression and anxiety, which may help to explore the pathogenesis of depression and anxiety.

Maternal smoking around birth may lower the protective effects of breastfeeding on anxiety, depression and neuroticism in adult offspring: a UK biobank study

We aim to explore the combined effects of the smoking and breastfeeding on offspring mental health outcomes. We used data from UK biobank (N = 342,846) to evaluate joint effect of breastfeeding and maternal smoke during pregnancy (MSDP) on seven adult offspring mental health outcomes (self-reported depression, depression score, self-reported anxiety, anxiety score, neuroticism score, self-harm, suicide). We stratified individuals to MSDP group and non-MSDP group as well as breastfeeding group and non-breastfeeding group. Multiple linear regression and logistic regressions analysis were performed between independent variables (MSDP or breastfeeding) and dependent variables separately (seven mental health outcomes) in each stratum. Effect estimates were expressed as β values and OR values. Sex, age, 10 principle components of population structure, smoking, alcohol use, and Townsend deprivation index were examined as covariates. At MSDP grouping level, coefficients (odds ratio [OR]) for association of breastfed as a baby with self-reported anxiety (category variable) were 0.87 (95%CI, (0.82-0.93), P = 1.74 × 10^-5) in the MSDP group and 0.83 (95%CI, (0.79-0.87), P = 2.76 × 10^-17) in the non-MSDP group. At breastfeeding grouping level, OR for association of MSDP and self-reported anxiety were 1.15 (95%CI, (1.10-1.20), P = 5.36 × 10^-11) in breastfeeding group and 1.12(95%CI, (1.06-1.20), P = 2.02 × 10^-4) in non-breastfeeding group. At MSDP grouping level, negatively associations were found for breastfeeding and anxiety score (continuable variable) in MSDP group (-0.04 SD change per SD change in MSDP, 95% CI, (- 0.06, - 0.02), P = 2.42 × 10^-3) and non-MSDP group (-0.06 SD change per SD change in MSDP, 95%CI, (- 0.07, - 0.04), P = 1.70 × 10^-11). At breastfeeding grouping level, positive association was found for MSDP and anxiety score in the breastfeeding group (0.07 SD change per SD change in MSDP, 95%CI, (0.06-0.09), P = 1.49 × 10^-20) and non-breastfeeding group (0.07 SD change per SD change in MSDP, 95%CI, (0.05-0.09), P = 7.19 × 10^-8). Compared with non-MSDP group, the protective effect (reflected by coefficients) of breastfeeding on anxiety in the MSDP decreased. Our preliminary study found MSDP may lower the protective effect of breastfeeding on the adult offspring anxiety, depression and neuroticism, providing useful recommendations for health care service via quitting smoking during pregnancy and encouraging prolonged breastfeeding.

Prenatal Alcohol Exposure and the Risk of Depression in Offspring: a Meta-Analysis

BACKGROUND

Prenatal alcohol exposure (PAE) has been related to poor consequences of mental health in offspring. However, it remains unknown whether maternal alcohol drinking during pregnancy is associated with depression in the offspring.

METHODS

A meta-analysis was performed accordingly. Relevant observational studies were identified from Medline, Embase, and Web of Science databases. A fixed-effect or a random-effect model was selected dependending on the between-study heterogeneity.

RESULTS

Eight cohort studies were included. The heterogeneity was not significant (I ² = 14%). A meta-analysis with a fixed-effect model showed that PAE was associated with a higher risk of depression in offspring (odds ratio (OR): 2.28, 95% confidence interval (CI): 1.61 to 3.25, p < 0.001). Subgroup analysis showed that moderate (OR: 1.74, 95% CI: 1.22 to 2.49, p=0.002, I ² = 0%) or heavy (OR: 2.41, 95% CI: 1.55 to 3.73, p < 0.001, I ² = 0%) maternal alcohol drinking in pregnancy was associated with depression in offspring, but not for those with low maternal alcohol drinking (OR: 1.18, 95% CI: 0.97 to 1.44, p=0.10, I ² = 0%). Further subgroup analyses according to study design, timing of PAE evaluation, age at depression diagnosis, and quality scores showed consistent results. Univariate metaregression showed a dose-response association between PAE and offspring depression (coefficient: 0.073, 95% CI: 0.019 to 0.127, p=0.014).

CONCLUSIONS

Current evidence suggests that PAE may be a risk factor of depression in offspring.