Smoking during pregnancy in relation to grandchild birth weight and BMI trajectories

Prenatal Exposure to Tobacco and Cannabis in Six Race/Ethnicity Groups during the First Three Years after Legalization of Cannabis for Recreational Use in California

There are known health concerns linked to prenatal tobacco and cannabis exposures. This study aims to objectively determine the level of exposure to tobacco and cannabis in pregnant individuals from six race/ethnicity groups (Black, Hispanic, Asian Indian, Native American, Vietnamese, and White) in the first three years following legalization of recreational marijuana use in 2018 in California. We used a cross-sectional sample of prenatal screening program participants (2018-2020) from southern and central California (N = 925). Exposures were estimated by a lab analysis of cotinine (tobacco) and 11-hydroxy-Δ9-tetrahydrocannabinol (OH-THC, cannabis) in banked serum. Disparities in tobacco exposure were evident, with Black subjects experiencing the highest smoking rate (16%) followed by Native American (10%) and White (8%) subjects, and ≤2% among Hispanic, Asian Indian, and Vietnamese subjects. Environmental tobacco exposure generally showed a similar pattern of exposure to tobacco smoking across race/ethnicity groups. Cannabis detection ranged from 5% among Hispanic subjects to 12% and 13% among White and Black subjects, respectively, and was higher among tobacco users and those exposed to environmental tobacco smoke than those with no cotinine detected. Tobacco and cannabis exposure were generally greatest in younger subjects and those with indices of a lower economic status; however, among Black subjects, cannabis exposure was greatest in older subjects and those with a higher socioeconomic status. Race/ethnicity, age, and socioeconomic factors can inform targeting of high-exposure groups for intervention.

Sex-specific effects of organophosphate ester exposure on child growth trajectories in the first two years

The connections between urinary organophosphate ester (OPE) metabolites and child growth have been identified in prior research, but there is currently a dearth of epidemiological evidence regarding the sex-specific impact of OPEs on child growth trajectories. This study enrolled 804 maternal–child pairs, and five OPE congeners were quantified in maternal serum during pregnancy. In this study, the impact of prenatal OPE exposure on child growth trajectories was assessed using linear mixed-effect models and a group-based trajectory model (GBTM), with consideration given to sex-specific effects. Fetuses were frequently exposed to OPEs in utero, and tris(2-butoxyethel) phosphate (TBEP) exhibited the highest concentration levels in maternal serum. Among male children, an increase of 2.72 ng/g lipid in TBEP concentration was associated with a 0.11-unit increase in head circumference-for-age z-score (HCAZ), and the effect was mainly concentrated at 1 and 2 months of age. Among female children, an increase of 2.72 ng/g lipid in tris(2-chloro-1-(chloromethyl) ethyl) phosphate (TDCPP) concentration was associated with a 0.15-unit increase in length-for-age z-score (LAZ) and a 0.14-unit increase in weight-for-age z-score (WAZ), and the effects were mainly concentrated at 9 months of age. For HCAZ trajectories, higher prenatal TBEP exposure was associated with higher odds for the fast growth group in male children. For the LAZ and WAZ trajectories, higher prenatal TDCPP exposure was associated with higher odds for the fast growth group in female children. The trajectory analysis approach provided insight into the complex associations between OPE exposure and child growth.

•Organophosphate ester (OPEs) were detected in serum samples of pregnant women, and tributyl phosphate (TBP) was the most frequently detected OPEs. •Prenatal exposure to TBP, tris(2-butoxyethyl) phosphate (TBEP), and tris(2-chloro-1-(chloromethyl) ethyl) phosphate (TDCPP) were positively associated with infant growth trajectories. •Female infants were more sensitive to OPE exposure than males.

Maternal smoking during pregnancy and birthweight on the third generation: results from two birth cohort studies

The purpose of this research is to investigate whether grandmother's smoking during pregnancy reduces the grandchildren's birthweight and whether maternal smoking during pregnancy modified this association. We also evaluated the effect of duration and intensity of smoking. This study included data from three generations from two birth cohorts carried out in Pelotas, a southern Brazilian city: women enrolled in the perinatal study in the 1982 and 1993 cohorts (G1); daughters (G2) of those G1 mothers who were followed to adulthood; and first children (G3) born from G2 women. Information on maternal smoking during pregnancy was obtained from women (G1) shortly after delivery of the two cohorts and from G2 in the follow-up in adulthood of the 1993 cohort. Mothers (G2) reported G3 birthweight during the follow-up visit at adulthood. Multiple linear regression was used to obtain effect measures adjusted for confounders. The study included 1602 grandmothers (G1), mothers (G2), and grandchildren (G3). Prevalence of maternal (G1) smoking during pregnancy was 43% and mean G3 birthweight was 3118.9 g (SD: 608.8). Grandmother's smoking in the pregnancy was not associated with grandchild's birthweight. However, offspring of both G1 and G2 smokers had lower mean birthweight than those whose mother and grandmother did not smoke (adjusted β: - 223.05; 95% CI: - 415.16, - 32.76).

CONCLUSION

No significant association was observed between grandmother's smoking in the pregnancy and grandchild's birthweight. But it seems that grandmother's smoking in pregnancy has an effect on grandchild's birthweight when the mother also smoked in the pregnancy. .

WHAT IS KNOWN

• Most studies on the association of maternal tobacco smoking in pregnancy with offspring birthweight have been restricted to two generations, and an inverse association is well known.

WHAT IS NEW

• Besides to investigate whether grandmother's smoking during pregnancy reduces the grandchildren's birthweight, we examined whether this association varied according to maternal smoking during pregnancy.

Smoking During Pregnancy and Risk of Attention-deficit/Hyperactivity Disorder in the Third Generation

BACKGROUND

Animal experiments indicate that environmental factors, such as cigarette smoke, can have multigenerational effects through the germline. However, there are little data on multigenerational effects of smoking in humans. We examined the associations between grandmothers' smoking while pregnant and risk of attention-deficit/hyperactivity disorder (ADHD) in her grandchildren.

METHODS

Our study population included 53,653 Nurses' Health Study II (NHS-II) participants (generation 1 [G1]), their mothers (generation 0 [G0]), and their 120,467 live-born children (generation 2 [G2]). In secondary analyses, we used data from 23,844 mothers of the nurses who were participants in the Nurses' Mothers' Cohort Study (NMCS), a substudy of NHS-II.

RESULTS

The prevalence of G0 smoking during the pregnancy with the G1 nurse was 25%. ADHD was diagnosed in 9,049 (7.5%) of the grandchildren (G2). Grand-maternal smoking during pregnancy was associated with increased odds of ADHD among the grandchildren (adjusted odds ratio [aOR] = 1.2; 95% confidence interval [CI] = 1.1, 1.2), independent of G1 smoking during pregnancy. In the Nurses' Mothers' Cohort Study, odds of ADHD increased with increasing cigarettes smoked per day by the grandmother (1-14 cigarettes: aOR = 1.1; 95% CI = 1.0, 1.2; 15+: aOR = 1.2; 95% CI = 1.0, 1.3), compared with nonsmoking grandmothers.

CONCLUSIONS

Grandmother smoking during pregnancy is associated with an increased risk of ADHD among the grandchildren.

Association Between Periconceptional Weight of Maternal Grandmothers and Attention-Deficit/Hyperactivity Disorder in Grandchildren

IMPORTANCE

Neurodevelopmental disorders have been proposed to involve alterations to epigenetic regulation, and epigenetic effects may extend to germline cells to affect later generations. Weight status may affect DNA methylation, and maternal weight before and during pregnancy has been associated with offspring DNA methylation as well as attention-deficit/hyperactivity disorder (ADHD).

OBJECTIVE

To assess whether a woman's weight before and during pregnancy is associated with ADHD in her grandchild.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study analyzed data from 19 835 grandmother-mother dyads and 44 720 grandchildren in the Nurses' Health Study II (NHS-II) cohort (2001-2013), a population-based prospective cohort study. Cluster-weighted generalized estimating equations were modeled to estimate the association of grandmother's prepregnancy body mass index (BMI) and gestational weight gain with grandchild risk of ADHD. Data analyses were conducted from May 2018 to April 2021. Grandmothers reported their height and weight before, and weight gain during, their pregnancy with the NHS-II participants. Mothers self-reported height and weight prior to pregnancy. From those data, grandmother BMI and mother BMI were calculated as weight in kilograms divided by height in meters squared and categorized as underweight (<18.5), healthy/normal (18.5-24.9), overweight (25.0-29.9), or obese (≥30).

MAIN OUTCOMES AND MEASURES

Cases of ADHD identified by maternal report of having a child with a diagnosis of ADHD.

RESULTS

In total, 19 835 grandmothers (97.6% White race/ethnicity; 2113 [10.7%] prepregnancy underweight and 1391 [7.0%] prepregnancy overweight or obese) were included in this cohort study. Of 44 720 grandchildren, 3593 (8%) received a diagnosis of ADHD. Higher odds of ADHD among grandchildren were found for those whose grandmother was underweight compared with healthy weight prior to pregnancy with the NHS-II participant (adjusted odds ratio, 1.25; 95% CI, 1.10-1.42). By contrast, grandmother gestational weight gain was not significantly associated with risk of grandchild ADHD (adjusted odds ratio for <20 lbs [9.1 kg], 1.06; 95% CI, 0.96-1.16; adjusted odds ratio for >29 lbs [13.2 kg], 1.01; 95% CI, 0.91-1.13). Mother prepregnancy BMI showed an association with ADHD among offspring, with a stronger association detected for obese status (adjusted odds ratio, 1.27; 95% CI, 1.07-1.49) than for overweight status (adjusted odds ratio, 1.13; 95% CI, 1.02-1.26) compared with normal weight as a reference group. The positive association between grandmother prepregnancy underweight and ADHD risk among the grandchildren remained unchanged after further adjustment for potential mediators, including maternal prepregnancy BMI.

CONCLUSIONS AND RELEVANCE

The results of this cohort study indicate that grandmother underweight prior to pregnancy is associated with an increased risk of ADHD among grandchildren, independent of grandmother gestational weight gain and independent of maternal prepregnancy weight status.

Exploring the evidence for epigenetic regulation of environmental influences on child health across generations

Environmental exposures, psychosocial stressors and nutrition are all potentially important influences that may impact health outcomes directly or via interactions with the genome or epigenome over generations. While there have been clear successes in large-scale human genetic studies in recent decades, there is still a substantial amount of missing heritability to be elucidated for complex childhood disorders. Mounting evidence, primarily in animals, suggests environmental exposures may generate or perpetuate altered health outcomes across one or more generations. One putative mechanism for these environmental health effects is via altered epigenetic regulation. This review highlights the current epidemiologic literature and supporting animal studies that describe intergenerational and transgenerational health effects of environmental exposures. Both maternal and paternal exposures and transmission patterns are considered, with attention paid to the attendant ethical, legal and social implications.

Effect of Grandmaternal Smoking on Body Size and Proportions at Birth

Many long-term adverse effects of smoking during pregnancy are known. Increasingly, adverse effects in the grandchild after grandmaternal smoking during pregnancy are reported. We explored this in a birth cohort of 24,000 grandmother–mother–child triads identified from the Finnish Medical Birth Register in 1991–2016. Multiple logistic regression was used to analyze the association between any smoking during pregnancy by both grandmother and mother, or only grandmother or mother on adverse birth outcomes. No smoking by neither grandmother nor mother was used as the reference. As endpoints, preterm birth, low birth weight, small for gestational age (birth weight, birth length, head circumference), and body proportionality (low ponderal index, high brain-to-body ratio, high head-to-length ratio) were included. Smoking by both grandmother and mother was consistently associated with higher risks than smoking only by the mother. Birth length and weight were especially sensitive to (grand)maternal smoking. In conclusion, the combined effect of grandmaternal and maternal smoking is associated with higher risks than only maternal smoking.

Young-Onset Carcinogenesis - The Potential Impact of Perinatal and Early Life Metabolic Influences on the Epigenome

The last decade has witnessed a significant rise in cancers in young adults. This spectrum of solid organ cancers occurring in individuals under the age of 40 years (some reports extending the age-group to <50 years) in whom aetiology of cancer cannot be traced back to pre-existing familial cancer syndromes, is referred to as termed young-, or early- onset cancers. The underlying causes for young-onset carcinogenesis have remained speculative. We recently proposed a hypothesis to explain the causation of this entity. We propose that the risk for young-onset cancer begins in the perinatal period as a result of the exposure of the foetus to stressors, including maternal malnutrition, smoking or alcohol, with the consequent epigenomic events triggered to help the foetus cope/adapt. Exposure to the same stressors, early in the life of that individual, facilitates a re-activation of these ‘responses designed to be protective’ but ultimately resulting in a loss of regulation at a metabolic and/or genetic level culminating in the evolution of the neoplastic process. In this manuscript, we will provide a rationale for this hypothesis and present evidence to further support it by clarifying the pathways involved, including elucidating a role for Acetyl-CoA and its effect on the epigenome. We present strategies and experimental models that can be used to test the hypothesis. We believe that a concerted effort by experts in different, but complementary fields, such as epidemiology, genetics, and epigenetics united towards the common goal of deciphering the underlying cause for young-onset cancers is the urgent need. Such efforts might serve to prove, or disprove, the presented hypothesis. However, the more important aim is to develop strategies to reverse the disturbing trend of the rise in young-onset cancers.

Proxy gene-by-environment Mendelian randomization study confirms a causal effect of maternal smoking on offspring birthweight, but little evidence of long-term influences on offspring health

Background

A lack of genetic data across generations makes transgenerational Mendelian randomization (MR) difficult. We used UK Biobank and a novel proxy gene-by-environment MR to investigate effects of maternal smoking heaviness in pregnancy on offspring health, using participants’ (generation one: G1) genotype (rs16969968 in CHRNA5) as a proxy for their mothers’ (G0) genotype.

Methods

We validated this approach by replicating an established effect of maternal smoking heaviness on offspring birthweight. Then we applied this approach to explore effects of maternal (G0) smoking heaviness on offspring (G1) later life outcomes and on birthweight of G1 women’s children (G2).

Results

Each additional smoking-increasing allele in offspring (G1) was associated with a 0.018 [95% confidence interval (CI): -0.026, -0.009] kg lower G1 birthweight in maternal (G0) smoking stratum, but no meaningful effect (-0.002 kg; 95% CI: -0.008, 0.003) in maternal non-smoking stratum (interaction P-value = 0.004). The differences in associations of rs16969968 with grandchild’s (G2) birthweight between grandmothers (G0) who did, versus did not, smoke were heterogeneous (interaction P-value = 0.042) among mothers (G1) who did (-0.020 kg/allele; 95% CI: -0.044, 0.003), versus did not (0.007 kg/allele; 95% CI: -0.005, 0.020), smoke in pregnancy.

Conclusions

Our study demonstrated how offspring genotype can be used to proxy for the mother’s genotype in gene-by-environment MR. We confirmed the causal effect of maternal (G0) smoking on offspring (G1) birthweight, but found little evidence of an effect on G1 longer-term health outcomes. For grandchild’s (G2) birthweight, the effect of grandmother’s (G0) smoking heaviness in pregnancy may be modulated by maternal (G1) smoking status in pregnancy.

Grand-maternal lifestyle during pregnancy and body mass index in adolescence and young adulthood: an intergenerational cohort study

To examine associations of healthy lifestyle during pregnancy with body mass index (BMI) and risk of overweight or obesity of grandchildren during adolescence and young adulthood. Our study population included 14,001 grandmother–mother–child triads comprised of participants of two ongoing prospective cohort studies of related individuals. We used self-reported grand-maternal gestational weight gain, diet, physical activity, and smoking during pregnancy to create a lifestyle score ranged from 0 to 12, with a higher score indicating healthier lifestyle. Grandchild BMI was self-assessed in follow-up questionnaires. Compared with individuals whose grandmothers had the least healthy lifestyle during pregnancy, individuals whose grandmothers had the most healthy lifestyle had 0.17 (95% CI 0.01, 0.33; P for trend = 0.05) kg/m² lower BMI and 7% (95% CI 2%, 12%; P for trend = 0.001) lower risk of overweight or obesity during adolescence and young adulthood. The inverse associations between grand-maternal lifestyle and BMI in grandchildren were mainly mediated by maternal pre-pregnancy BMI (mediation effect: 64%; P value = 0.001). Overall, maternal BMI, along with maternal socioeconomic status and lifestyle factors in the second and third generations accounted for all of the inter-generational association (mediation effect: 99%; P value < 0.001). The inverse associations of grand-maternal lifestyle with BMI of offspring were not modified by grand-maternal pre-pregnancy BMI, grandchild age, or grandchild gender. Grandchildren of women who had the healthiest lifestyles during pregnancy defined by no excess gestational weight gain, no smoking, a healthy diet and being physically active, were less likely to be overweight or obese in adolescence and early adulthood.

The 3G Multigenerational Cohort of Nova Scotian women and their mothers and offspring

BACKGROUND

The negative impact of exposures such as maternal obesity, excessive gestational weight gain, and hypertension in pregnancy on the health of the next generation has been well studied. Evidence from animal studies suggests that the effects of in utero exposures may persist into the second generation, but the epidemiological literature on the influence of pregnancy-related exposures across three generations in humans is sparse.

OBJECTIVES

This cohort was established to investigate associations between antenatal and perinatal exposures and health outcomes in women and their offspring.

POPULATION

The cohort includes women who were born and subsequently had their own pregnancies in the Canadian province of Nova Scotia from 1980 onward.

DESIGN

Intergenerational linkage of data in the Nova Scotia Atlee Perinatal Database was used to establish a population-based dynamic retrospective cohort.

METHODS

The cohort has prospectively collected information on sociodemographics, maternal health and health behaviours, pregnancy health and complications, and obstetrical and neonatal outcomes for two generations of women and their offspring.

PRELIMINARY RESULTS

As of October 2018, the 3G cohort included 14 978 grandmothers (born 1939-1986), 16 766 mothers or cohort women (born 1981-2003), and 28 638 children (born 1996-2018). The cohort women were generally younger than Nova Scotian women born after 1980, and as a result, characteristics associated with pregnancy at a younger age were more frequently seen in the cohort women; sampling weights will be created to account for this design effect. The cohort will be updated annually to capture future deliveries to women who are already in the cohort and women who become eligible for inclusion when they deliver their first child.

CONCLUSIONS

The 3G Multigenerational Cohort is a population-based cohort of women and their mothers and offspring, spanning a time period of 38 years, and provides the opportunity to study inter- and transgenerational associations across the maternal line.

Maternal Birth Weight and BMI Mediate the Transgenerational Effect of Grandmaternal BMI on Grandchild's Birth Weight

OBJECTIVE

The aims of this study are to examine the potential association between grandmaternal BMI and grandchild's birth weight (BW) and whether maternal BW and BMI mediate this association.

METHODS

Data of 209 grandmother-mother pairs and 355 grandchildren from the Isle of Wight birth cohort in the UK were analyzed using path analysis.

RESULTS

An indirect effect of grandmaternal BMI on increasing grandchild's BW was mediated by maternal BW and BMI at age 18 years (indirect effects: β = 2.3 g/unit increase in grandmaternal BMI via maternal BW and β = 4.4 g via maternal BMI; P = 0.04). These two mediating effects of maternal BW and BMI confounded one another. Grandmaternal smoking during pregnancy had an indirect effect on decreasing grandchild's BW, dependent on maternal smoking during pregnancy and BW (indirect effects: β = -36.1 g compared with nonsmoking grandmothers via maternal smoking during pregnancy and β = -27.2 g via maternal BW; P = 0.005). Neither direct effect between grandmaternal BMI and grandchild's BW nor that between grandmaternal smoking during pregnancy and grandchild's BW was statistically significant.

CONCLUSIONS

Larger grandmaternal BMI indirectly increased grandchild's BW via maternal BW and BMI. Grandmaternal smoking during pregnancy indirectly reduced grandchild's BW via maternal smoking during pregnancy and BW.

The role of environmental exposures and the epigenome in health and disease

The genetic material of every organism exists within the context of regulatory networks that govern gene expression, collectively called the epigenome. Epigenetics has taken center stage in the study of diseases such as cancer and diabetes, but its integration into the field of environmental health is still emerging. As the Environmental Mutagenesis and Genomics Society (EMGS) celebrates its 50th Anniversary this year, we have come together to review and summarize the seminal advances in the field of environmental epigenomics. Specifically, we focus on the role epigenetics may play in multigenerational and transgenerational transmission of environmentally induced health effects. We also summarize state of the art techniques for evaluating the epigenome, environmental epigenetic analysis, and the emerging field of epigenome editing. Finally, we evaluate transposon epigenetics as they relate to environmental exposures and explore the role of noncoding RNA as biomarkers of environmental exposures. Although the field has advanced over the past several decades, including being recognized by EMGS with its own Special Interest Group, recently renamed Epigenomics, we are excited about the opportunities for environmental epigenetic science in the next 50 years. Environ. Mol. Mutagen. 61:176-192, 2020. © 2019 Wiley Periodicals, Inc.