The impact of paternal alcohol, tobacco, caffeine use and physical activity on offspring mental health: a systematic review and meta-analysis

Paternal age, de novo mutations, and offspring health? New directions for an ageing problem

This Directions article examines the mechanisms by which a father's age impacts the health and wellbeing of his children. Such impacts are significant and include adverse birth outcomes, dominant genetic conditions, neuropsychiatric disorders, and a variety of congenital developmental defects. As well as age, a wide variety of environmental and lifestyle factors are also known to impact offspring health via changes mediated by the male germ line. This picture of a dynamic germ line responsive to a wide range of intrinsic and extrinsic factors contrasts with the results of trio studies indicating that the incidence of mutations in the male germ line is low and exhibits a linear, monotonic increase with paternal age (∼two new mutations per year). While the traditional explanation for this pattern of mutation has been the metronomic plod of replication errors, an alternative model pivots around the 'faulty male' hypothesis. According to this concept, the genetic integrity of the male germ line can be dynamically impacted by age and a variety of other factors, and it is the aberrant repair of such damage that drives mutagenesis. Fortunately, DNA proofreading during spermatogenesis is extremely effective and these mutant cells are either repaired or deleted by apoptosis/ferroptosis. There appear to be only two mechanisms by which mutant germ cells can escape this apoptotic fate: (i) if the germ cells acquire a mutation that by enhancing proliferation or suppressing apoptosis, permits their clonal expansion (selfish selection hypothesis) or (ii) if a genetically damaged spermatozoon manages to fertilize an oocyte, which then fixes the damage as a mutation (or epimutation) as a result of defective DNA repair (oocyte collusion hypothesis). Exploration of these proposed mechanisms should not only help us better understand the aetiology of paternal age effects but also inform potential avenues of remediation.

Challenges in using data on fathers/partners to study prenatal exposures and offspring health

Paternal exposures (and other non-maternal factors) around pregnancy could have important effects on offspring health. One challenge is that data on partners are usually from a subgroup of mothers with data, potentially introducing selection bias, limiting generalisability of findings. We aimed to investigate the potential for selection bias in studies using partner data.We characterise availability of data on father/partner and mother health behaviours (smoking, alcohol, caffeine and physical activity) around pregnancy from three UK cohort studies: the Avon Longitudinal Study of Parents and Children (ALSPAC), Born in Bradford and the Millennium Cohort Study. We assess the extent of sample selection by comparing characteristics of families where fathers/partners do and do not participate. Using the association of parental smoking during pregnancy and child birthweight as an example, we perform simulations to investigate the extent to which missing father/partner data may induce bias in analyses conducted only in families with participating fathers/partners.In all cohorts, father/partner data were less detailed and collected at fewer timepoints than mothers. Partners with a lower socio-economic position were less likely to participate. In simulations based on ALSPAC data, there was little evidence of selection bias in associations of maternal smoking with birthweight, and bias for father/partner smoking was relatively small. Missing partner data can induce selection bias. In our example analyses of the effect of parental smoking on offspring birthweight, the bias had a relatively small impact. In practice, the impact of selection bias will depend on both the analysis model and the selection mechanism.

Psychosocial and neurobiological aspects of the worldwide refugee crisis: From vulnerability to resilience

Anisman, H., Doubad, D., Asokumar, A. & Matheson, K. Psychosocial and neurobiological aspects of the worldwide refugee crisis: From vulnerability to resilience. NEUROSCI BIOBEHAV REV, XXXX. Immigration occurs between countries either to obtain employment, for family reunification or to escape violence and other life-threatening conditions. Refugees and asylum seekers are often obligated to overcome a uniquely challenging set of circumstances prior to and during migration. Settlement following immigration may pose yet another set of stressors related to acculturation to the host country, as well as financial insecurity, discrimination, language barriers, and social isolation. Here we discuss the multiple consequences of immigration experiences, focusing on the health disturbances that frequently develop in adults and children. Aside from the psychosocial influences, immigration-related challenges may cause hormonal, inflammatory immune, and microbiota changes that favor psychological and physical illnesses. Some biological alterations are subject to modification by epigenetic changes, which have implications for intergenerational trauma transmission, as might disruptions in parenting behaviors and family dysfunction. Despite the hardships experienced, many immigrants and their families exhibit positive psychological adjustment after resettlement. We provide information to diminish the impacts associated with immigration and offer strength-based approaches that may foster resilience.

Influence of substance use on male reproductive health and offspring outcomes

The prevalence of substance use globally is rising and is highest among men of reproductive age. In Africa, and South and Central America, cannabis use disorder is most prevalent and in Eastern and South-Eastern Europe, Central America, Canada and the USA, opioid use disorder predominates. Substance use might be contributing to the ongoing global decline in male fertility, and emerging evidence has linked paternal substance use with short-term and long-term adverse effects on offspring development and outcomes. This trend is concerning given that substance use is increasing, including during the COVID-19 pandemic. Preclinical studies have shown that male preconception substance use can influence offspring brain development and neurobehaviour through epigenetic mechanisms. Additionally, human studies investigating paternal health behaviours during the prenatal period suggest that paternal tobacco, opioid, cannabis and alcohol use is associated with reduced offspring mental health, in particular hyperactivity and attention-deficit hyperactivity disorder. The potential effects of paternal substance use are areas in which to focus public health efforts and health-care provider counselling of couples or individuals interested in conceiving.

The "Bad Father": Paternal Role in Biology of Pregnancy and in Birth Outcome

Pregnancy is generally studied as a biological interaction between a mother and a fetus; however, the father, with his characteristics, lifestyle, genetics, and living environment, is by no means unrelated to the outcome of pregnancy. The half of the fetal genetic heritage of paternal derivation can be decisive in cases of inherited chromosomal disorders, and can be the result of de novo genetic alterations. In addition to the strictly pathological aspects, paternal genetics may transmit thrombophilic traits that affect the implantation and vascular construction of the feto-placental unit, lead to placenta-mediated diseases such as pre-eclampsia and fetal growth retardation, and contribute to the multifactorial genesis of preterm delivery. Biological aspects of immunological tolerance to paternal antigens also appear to be crucial for these pathologies. Finally, this review describes the biological findings by which the environment, exposure to pathogens, lifestyle, and nutritional style of the father affect fetal pathophysiological and epigenetic definition.

The associations of secondhand smoke exposure with neurodevelopmental disorders and critical time window identification: A systematic review and meta-analysis

BACKGROUND

Secondhand smoke (SHS) exposure was harmful for brain development. However, the association between SHS exposure and NDDs diagnosis were unclear.

OBJECTIVES

To evaluate associations between SHS exposure and NDDs diagnosis, identify critical time windows, and summarize the strength of evidence.

METHODS

To investigate the associations of SHS exposure and the development of NDDs, we searched Ovid, EMBASE, Web of Science, Cochrane Library, and PubMed for all the relevant studies up to 31 March 2023. The risk estimates and standardized mean differences (SMD) for the individuals with any NDDs who were exposed to SHS exposure compared with those unexposed or low-exposed.

RESULTS

The results showed that a total of 31,098 citations were identified, of which 54 studies were included. We identified significant associations between SHS exposure and the risks of NDDs including specific types of NDDs like attention deficit hyperactivity disorder (ADHD) and learning disabilities (LD) despite the observed heterogeneity for NDDs and ADHD. We also observed a significant association between cotinine exposure and ADHD. However, inconsistent ratings between the two quality-of-evidence methods for all the meta-analyses indicated the current evidence of the associations and the potential exposure window remained inconclusive.

DISCUSSION

Our findings suggested that SHS exposure was associated with a higher risk of developing ADHD and LD, with inconclusive quality-of-evidence. In addition, period-specific associations remained unclear based on current evidence.

Maternal and paternal licit and illicit drug use, smoking and drinking and autism spectrum disorder

The aim of this study was to investigate the association between maternal and paternal licit and illicit drug use, smoking and drinking and autism spectrum disorder (ASD). We conducted a case-control study with children and adolescents diagnosed with ASD and neurotypical individuals. The data were collected using a semi-structured questionnaire administered during interviews with the children's mothers or guardians. The following variables were analyzed: child sex and age; maternal and parental age; use of medicines before and during pregnancy; classes of medicines used during pregnancy; maternal and paternal smoking; maternal and paternal drinking; maternal and paternal illicit drug use. The data were analyzed using logistic regression and crude and adjusted odds ratios (OR). After adjustment, the results showed an association between maternal use of antipyretics/pain killers during pregnancy (OR = 2.26; 95%CI 1.29-3.95; p < 0.040) and ASD. No association was found between maternal and paternal smoking, drinking and illicit drug use before and during pregnancy and ASD. The findings suggest that the development of ASD is influenced by environmental factors.

Maternal caffeine consumption during pregnancy and offspring cord blood DNA methylation: an epigenome-wide association study meta-analysis

Background: Prenatal caffeine exposure may influence offspring health via DNA methylation, but no large studies have tested this. Materials & methods: Epigenome-wide association studies and differentially methylated regions in cord blood (450k or EPIC Illumina arrays) were meta-analyzed across six European cohorts (n = 3725). Differential methylation related to self-reported caffeine intake (mg/day) from coffee, tea and cola was compared with assess whether caffeine is driving effects. Results: One CpG site (cg19370043, PRRX1) was associated with caffeine and another (cg14591243, STAG1) with cola intake. A total of 12-22 differentially methylated regions were detected with limited overlap across caffeinated beverages. Conclusion: We found little evidence to support an intrauterine effect of caffeine on offspring DNA methylation. Statistical power limitations may have impacted our findings.

Paternal programming of fetoplacental and offspring metabolic disorders

The alarming increase in the prevalence of metabolic pathologies is of worldwide concern and has been linked not only to genetic factors but also to a large number of non-genetic factors. In recent years, there has been increasing interest in the study of the programming of metabolic diseases, such as type 2 diabetes mellitus (T2DM) and obesity, by paternal exposure, a paradigm termed "Paternal Origins of Health and Disease" (POHaD). This term derives from the better known "Developmental Origins of Health and Disease" (DOHaD), which focuses on the involvement of the maternal intrauterine environment and complications during pregnancy associated with the health and disease of the offspring. Studies on paternal programming have documented environmentally induced epigenetic modifications in the male germline and in seminal plasma, which lead to intergenerational and transgenerational phenotypes, evident already during fetoplacental development. Studies with animal models at both ends of the nutritional spectrum (undernutrition or overnutrition) have been performed to understand the possible mechanisms and signaling pathways leading to the programming of metabolic disorders by exploring epigenetic changes throughout the life of the offspring. The aim of this review was to address the evidence of the programming of fetoplacental developmental alterations and metabolic pathologies in the offspring of males with metabolic disorders and unhealthy exposures, highlighting the mechanisms involved in such programming and looking for paternal interventions to reduce negative health outcomes in the offspring.

The impact of exposure to tobacco smoking and maternal trauma in fetal life on risk of migraine

Introduction

Prenatal period is the key time in human development. Many prenatal factors are well-known and increase the risk of developing diseases' after birth. Few studies indicated the link between the prenatal period and the prevalence of migraine in childhood and adolescence so far. We decided to broaden current knowledge and investigate whether the prenatal factors influence the prevalence of migraine in adulthood. The objective of this study is to provide evidence of relationship between in utero environment and risk of migraine.

Methods

In total 266 females (136 in the migraine group, 130 in the control group) and 80 males (35 in the migraine group, 45 in the control group), aged 18-65 participated in the study. The quality of prenatal environment was characterized on the basis of mother's and father's education, tobacco smoke exposure, alcohol consumption, and traumatic event during pregnancy, which are considered as prenatal factors and affect on fetal development.

Results

Migraine occurrence in adulthood was significantly associated with maternal tobacco smoking during pregnancy (OR 3.42, 95% CI 1.54-7.61, p = 0.036) and traumatic event during pregnancy (OR 2.27, 95% CI 1.24-4.13, p = 0.020).

Discussion

Our study suggests that the fetal programming effect of tobacco smoking exposure and maternal trauma is not limited to prenatal life and is suggested as having a role in adulthood. Our findings support evidence that migraine adulthood can be partly influenced by early life conditions.

Developmental origins of health and disease: Impact of paternal nutrition and lifestyle

Most epidemiological and experimental studies have focused on maternal influences on offspring's health. The impact of maternal undernutrition, overnutrition, hypoxia, and stress is linked to adverse offspring outcomes across a range of systems including cardiometabolic, respiratory, endocrine, and reproduction among others. During the past decade, it has become evident that paternal environmental factors are also linked to the development of diseases in offspring. In this article, we aim to outline the current understanding of the impact of male health and environmental exposure on offspring development, health, and disease and explore the mechanisms underlying the paternal programming of offspring health. The available evidence suggests that poor paternal pre-conceptional nutrition and lifestyle, and advanced age can increase the risk of negative outcomes in offspring, via both direct (genetic/epigenetic) and indirect (maternal uterine environment) effects. Beginning at preconception, and during utero and the early life after birth, cells acquire an epigenetic memory of the early exposure which can be influential across the entire lifespan and program a child's health. Potentially not only mothers but also fathers should be advised that maintaining a healthy diet and lifestyle is important to improve offspring health as well as the parental health status. However, the evidence is mostly based on animal studies, and well-designed human studies are urgently needed to verify findings from animal data.

Associations between health behaviours, fertility and reproductive outcomes: triangulation of evidence in the Norwegian Mother, Father and Child Cohort Study (MoBa)

BACKGROUND

Guidance to improve fertility includes reducing alcohol and caffeine consumption, achieving healthy weight-range and stopping smoking. Advice is informed by observational evidence, which is often biased by confounding.

METHODS

This study primarily used data from a pregnancy cohort, the Norwegian Mother, Father and Child Cohort Study. First, we conducted multivariable regression of health behaviours (alcohol and caffeine consumption, body-mass index (BMI), and smoking) on fertility outcomes (e.g. time to conception) and reproductive outcomes (e.g. age at first birth) (n = 84,075 females, 68,002 males), adjusting for birth year, education and attention-deficit and hyperactive-impulsive (ADHD) traits. Second, we used individual-level Mendelian randomisation (MR) to explore possible causal effects of health behaviours on fertility/reproductive outcomes (n = 63,376 females, 45,460 males). Finally, we performed summary-level MR for available outcomes in UK Biobank (n = 91,462-1,232,091) and controlled for education and ADHD liability using multivariable MR.

RESULTS

In multivariable regression analyses, higher BMI associated with fertility (longer time to conception, increased odds of infertility treatment and miscarriage), and smoking was associated with longer time to conception. In individual-level MR analyses, there was strong evidence for effects of smoking initiation and higher BMI on younger age at first birth, of higher BMI on increased time to conception, and weak evidence for effects of smoking initiation on increased time to conception. Age at first birth associations were replicated in summary-level MR analysis; however, effects attenuated using multivariable MR.

CONCLUSIONS

Smoking behaviour and BMI showed the most consistent associations for increased time to conception and a younger age at first birth. Given that age at first birth and time to conception are positively correlated, this suggests that the mechanisms for reproductive outcomes are distinct to the mechanisms acting on fertility outcomes. Multivariable MR suggested that effects on age at first birth might be explained by underlying liability to ADHD and education.

An epigenetic synopsis of parental substance use

The rate of substance use is rising, especially among reproductive-age individuals. Emerging evidence suggests that paternal pre-conception and maternal prenatal substance use may alter offspring epigenetic regulation (changes to gene expression without modifying DNA) and outcomes later in life, including neurodevelopment and mental health. However, relatively little is known due to the complexities and limitations of existing studies, making causal interpretations challenging. This review examines the contributions and influence of parental substance use on the gametes and potential transmissibility to the offspring's epigenome as possible areas to target public health warnings and healthcare provider counseling of individuals or couples in the pre-conception and prenatal periods to ultimately mitigate short- and long-term offspring morbidity and mortality.

Parental smoking and young adult offspring psychosis, depression and anxiety disorders and substance use disorder

Background

To study the associations between maternal smoking during pregnancy and paternal smoking before pregnancy and adult offspring psychiatric disorders.

Methods

Prospective general population cohort study in Northern Finland, with people from the Northern Finland Birth Cohort 1986: 7259 subjects (77% of the original sample). Data on parental smoking were collected from parents during pregnancy using questionnaires. Outcomes were offspring’s register-based diagnoses: any psychiatric disorder, any non-organic psychosis, mood disorder, anxiety disorder and substance use disorder (SUD) until the age of 29–30 years. Maternal smoking during pregnancy and paternal smoking before pregnancy were pooled to three-class variables: (i) none; (ii) 1–9 and (iii) ≥10 cigarettes/day. Information regarding both parents’ alcohol use during pregnancy and at offspring age 15–16 years, maternal education level, family structure, parental psychiatric diagnoses and offspring gender, smoking, intoxication frequency and illicit substance use at the age of 15–16 years were investigated as covariates.

Results

In the multivariable analyses, maternal smoking during pregnancy did not associate with the studied outcomes after adjusting for offspring smoking and other substance use at offspring age 15–16 years and parental psychiatric disorders. However, paternal smoking ≥10 cigarettes/day before pregnancy [hazard ratio (HR) = 5.5, 95% confidence interval (CI) 2.7–11.2, P < 0.001] and paternal psychiatric disorders (HR = 1.7, 95% CI 1.1–2.8, P = 0.028) associated with offspring SUD after adjustments.

Conclusions

Information across the offspring life course is essential in exploring the association between parental smoking and offspring psychiatric disorders. Paternal smoking before pregnancy and paternal psychiatric disorders may act as modifiers in elevating the risk of substance-use-related problems among offspring.