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.

A Virtual Exercise Program throughout Pregnancy during the COVID-19 Pandemic Modifies Maternal Weight Gain, Smoking Habits and Birth Weight—Randomized Clinical Trial

The intrauterine environment is key to health from a short- and long-term perspective. Birth weight is an important indicator that may influence the fetal environment due to epigenetics. Considering physical inactivity, in parallel with higher levels of stress, affecting smoking patterns and the physical and emotional health of the pregnant population, maintaining the health of future generations is crucial. A randomized clinical trial (NCT04563065) was conducted. One-hundred and ninety-two healthy pregnant individuals were assigned to the intervention (IG) or control (CG) group. Overall, significant differences were found between groups when stratified by birth weight (χ2 (1) = 6.610; p = 0.037) with low birth weight and macrosomia found more often in the CG (4% vs. 14% and 3% vs. 9%, respectively) and higher admissions to the neonatal intensive care unit (χ2 (1) = 5.075; p = 0.024) in the CG (20/28.6%) compared to the IG (9/13.0). Smoking during pregnancy was also found more often in the CG (12/17.1%) compared to the IG (3/4.4%) (p = 0.016). A virtual program of supervised exercise throughout pregnancy during the ongoing pandemic could help to maintain adequate birth weights, modify maternal smoking habits, and lower admissions to the neonatal intensive care unit.

Effect of E-cigarettes aerosol exposure during lactation in rats: Hormonal and biochemical aspects

Electronic cigarettes (e-cigarettes) have been marketed as a less lethal substitute for smoking traditional cigarettes. This study aims to investigate the impact of e-cigarettes aerosol exposure on lactating dams and pups, whose dams were exposed. Lactating dams received fresh air (control) or e-cigarettes aerosol during lactation (day 4-21). Maternal exposure to e-cigarettes aerosol during lactation induced significant reduction (P < 0.0001) in the fat content of the milk and serum Leptin level (P < 0.005) compared to control dams. Furthermore, pups whose dams were exposed to e-cigarettes during lactation showed an increased level of glucose, thyroxine and decreased level of insulin. The exposure to e-cigarettes aerosol during lactation altered the composition of milk as well as the hormonal and biochemical profile in dams and pups. This result, if observed in women using e-cigarettes, suggests that e-cigarettes' use during lactation may have consequences on the milk production and hormonal and biochemical profile in breastfeeding mothers and nursing babies.

Association of grandmaternal smoking during pregnancy with DNA methylation of grandchildren: the Isle of Wight study

Background: To investigate the intergenerational effects of grandmaternal smoking during pregnancy (GMSDP) on the DNA methylation of grandchildren. Methods: Data from the Isle of Wight birth cohort with information regarding GMSDP and DNA methylation profiling at the birth of grandchildren (n = 161) were used. Differentially methylated CpG sites related to GMSDP were identified using testing-training screening, analysis of variance and multivariate analysis of covariance. The association between identified CpG sites and expression levels of neighboring genes was tested by linear regression. Results: Twenty-three CpG sites were differentially methylated in grandchildren because of GMSDP, and eight of these were associated with expression levels of 13 neighboring genes. Conclusion: GMSDP has an intergenerational effect on the DNA methylation profile of grandchildren independent of maternal smoking during pregnancy.

Investigating the Role of Childhood Adiposity in the Development of Adult Type 2 Diabetes in a 64-year Follow-up Cohort: An Application of the Parametric G-formula Within an Agent-based Simulation Study

BACKGROUND

The contribution of childhood obesity to adult type 2 diabetes (T2DM), not through adult adiposity, as well as the causal pathways through which childhood obesity increases adult T2DM risk are not well understood. This study investigated the contribution of childhood obesity to incident T2DM including pathways not through adult adiposity, and explored whether race modified this contribution.

METHODS

We used data from the Virtual Los Angeles Cohort, an agent-based longitudinal birth cohort composed of 98,230 simulated individuals born in 2009 and followed until age 65 years. We applied the parametric mediational g-formula to the causal mediation analysis investigating the impact of childhood obesity on the development of adult T2DM.

RESULTS

The marginal adjusted odds ratio (aOR) for the total effect of childhood obesity on adult T2DM was 1.37 (95% CI = 1.32, 1.46). Nearly all the effect of childhood obesity on adult T2DM was mostly attributable to pathways other than through adult obesity; the aOR for the pure direct effect was 1.36 (95% CI = 1.31, 1.41). In all racial subpopulations, a similar 3% of the total effect of childhood obesity on adult T2DM was attributable to its effect on adult obesity.

CONCLUSIONS

Childhood obesity remains a risk factor for adult T2DM separate from its effects on adult obesity. This study emphasizes the potential benefits of early interventions and illustrates that agent-based simulation models could serve as virtual laboratories for exploring mechanisms in obesity research.

Effect of maternal active smoking during pregnancy on the trajectory of childhood body mass index: A multilevel analysis using quartiles of birthweight

INTRODUCTION

Maternal active smoking during pregnancy is associated with childhood obesity; however, whether maternal active smoking affects childhood body mass index (BMI) according to birthweight has not been examined.

METHODS

The study participants were 1955 women and their single-born infants, born between 1 April 1991 and 31 March 2003, in Koshu City, Japan, for whom complete data for birthweight, pre-pregnancy maternal BMI and pregnancy smoking status were available. Maternal smoking status during pregnancy was recorded using a questionnaire at the time of pregnancy registration. Childhood BMI was estimated by the BMI z-score, established by the World Health Organisation. Birthweight quartiles were grouped by sex and parity (first vs second or higher). Multilevel analysis, including both the individual and time as different level variables by each birthweight quartile, was used to describe the trajectories of BMI z-scores for statistical analyses.

RESULTS

In every quartile group, although children born to smoking mothers were leaner at birth, their BMI z-score increased around the age of 3 years. These children were larger than children born to non-smoking mothers. Significant interactions between maternal active smoking during pregnancy and child’s age were seen in those in the first and second quartiles of birthweight. Moreover, rapid growth in infancy was observed in the second quartile of birthweight.

CONCLUSIONS

The effect of maternal active smoking during pregnancy on childhood growth was more apparent among children in the second quartile of birthweight.

The joint effect of maternal smoking during pregnancy and maternal pre-pregnancy overweight on infants' term birth weight

Background

It is well known that maternal smoking during pregnancy and maternal pre-pregnancy overweight have opposite effects on the infants’ birth weight. We report on the association of the combination between both risk factors and the infants’ birth weight.

Methods

We studied 3241 infants born at term in the PIAMA birth cohort. Maternal smoking during pregnancy and pre-pregnancy height and weight were self-reported. Multivariable regression analysis was performed to assess the associations between infants of mothers who only smoked during pregnancy, who only had pre-pregnancy overweight and who had both risk factors simultaneously, on term birth weight and the risk of being SGA or LGA.

Results

Of 3241 infants, 421 infants (13%) were born to smoking, non-overweight mothers, 514 (15.8%) to non-smoking, overweight mothers, 129 (4%) to smoking and overweight mothers and 2177 (67%) to non-smoking, non-overweight mothers (reference group). Infants of mothers who smoked and also had pre-pregnancy overweight had similar term birth weight (− 26.6 g, 95%CI: − 113.0, 59.8), SGA risk (OR = 1.06, 95%CI: 0.56, 2.04), and LGA risk (OR = 1.09, 95%CI: 0.61, 1.96) as the reference group.

Conclusions

Our findings suggested that the effects of maternal smoking during pregnancy and maternal pre-pregnancy overweight on infants’ birth weight cancel each other out. Therefore, birth weight may not be a good indicator of an infant’s health status in perinatal practice because it may mask potential health risks due to these maternal risk factors when both present together.

Maternal smoking early in pregnancy is associated with increased risk of short stature and obesity in adult daughters

We assessed anthropometry in 22,421 adult daughters in association with their mothers’ tobacco smoking early in pregnancy (at their first antenatal visit) in Sweden, particularly their risk of short stature and obesity. Adult daughters were grouped by maternal smoking levels during pregnancy: Non-smokers (58.5%), Light smokers (24.1%; smoked 1–9 cigarettes/day), and Heavier smokers (17.4%; smoked ≥10 cigarettes/day). Anthropometry was recorded on the adult daughters at approximately 26.0 years of age. Obesity was defined as BMI ≥30 kg/m², and short stature as height more than two standard deviations below the population mean. Daughters whose mothers were Light and Heavier smokers in early pregnancy were 0.8 cm and 1.0 cm shorter, 2.3 kg and 2.6 kg heavier, and had BMI 0.84 kg/m² and 1.15 kg/m² greater, respectively, than daughters of Non-smokers. The adjusted relative risk of short stature was 55% higher in women born to smokers, irrespectively of smoking levels. Maternal smoking had a dose-dependent association with obesity risk, with offspring of Heavier smokers 61% and of Light smokers 37% more likely to be obese than the daughters of Non-smokers. In conclusion, maternal smoking in pregnancy was associated with an increased risk of short stature and obesity in their adult daughters.

Obesity and Socioeconomic Disparities: Rethinking Causes and Perinatal Care

Obesity affects more than 35% of women aged 20 to 39 years in the United States. This article summarizes recent research that reconceptualizes obesity as adipose disease associated with smoking; socio-economic disparities in employment, education, healthcare access, food quality, and availability; and environmental toxins, ultimately altering microbiomes and epigenetics. Individual prenatal care of women with obesity includes early testing for diabetes, counseling on epigenetic diets, advice supporting weight gain within national guidelines, and vigilance for signs of hypertensive disorders of pregnancy. Intrapartum care includes mechanical cervical ripening measures, patience with prolonged labor, and uterotonic medication readiness in the event of postpartum hemorrhage. Postpartum care includes thrombus risk amelioration through early ambulation, use of compression stockings, and anticoagulation. Delays in lactogenesis II can be offset by measures to support early breastfeeding. Sociopolitical action by nurses at national, state, and community levels to reduce population disparities in racism, education, and employment; reduce pollution from obesogenic chemicals; and improve food quality and distribution policies is likely to have the broadest impact in future obesity reductions and prevention.

Greater susceptibility of girls to airborne Benzo[a]pyrene for obesity-associated childhood asthma

BACKGROUND

Sexually dimorphic risk of obesity-associated asthma is posited to accelerate around puberty. Yet, the role of air pollution on the lean and obese asthmatic children has never been examined.

OBJECTIVE

To compare whether a unit exposure to airborne benzo[a]pyrene (B[a]P) is associated with altered risks of asthma across the overweight/obese (OV/OB) control, lean asthmatic, and OV/OB asthmatic children, respectively, compared to the lean controls, before and after adjusting for oxidant stress markers (i.e. 15‑F2t‑IsoP, 8‑oxo‑dG, and Carbonyl).

METHODS

Asthmatic and healthy control children, recruited from polluted urban and rural areas, were matched to ambient concentration of B[a]P. A unit increase in B[a]P and multinomial logistic regression on OV/OB control, lean asthmatic, and OV/OB asthma were compared across the sex- and age-groups.

RESULTS

The median B[a]P was associated with a linear increase among the female children, according to OV/OB and asthma, respectively, and together, compared to the lean control girls (p = 0.001). While B[a]P was associated with positive relationship with 15‑F2t‑IsoP level among the OV/OB boys, the same exposure-outcome association was inverse among the OV/OB girls. One natural log-unit increase in ambient B[a]P was associated with 10.5-times greater odds (95% CI, 2.6-39.6; p = 0.001) the adolescent OV/OB boys, compared to the unit odds among the lean controls. In contrast, the adolescent OV/OB girls were associated with highest adjusted odds of the asthma (aOR = 15.4; 95% CI, 2.9-29.1; p < 0.001) compared to the lean control girls. An adjustment for 15‑F2t‑IsoP, and Carbonyls was associated with greater odds of asthma per unit exposure for the adolescent OV/OB girls (aOR = 16.2; 95% CI, 1.4-181.8; p = 0.024).

CONCLUSIONS

B[a]P exposure was associated with a leap in the odds of asthma among the OV/OB adolescents, particularly the girls, after adjusting for 15‑F2t‑IsoP and Carbonyls.

Altered reward sensitivity in female offspring of cocaine-exposed fathers

Recent rodent studies have demonstrated that parental cocaine exposure can influence offspring behavior, supporting the idea that environmental insults can impact subsequent generations. However, studies on the effects of paternal cocaine exposure are limited and multiple inconsistencies exist. In the current study, we behaviorally characterize the effects of paternal cocaine exposure in a C57BL/6J intergenerational mouse model. Male sires were administered cocaine hydrochloride (20mg/kg) or saline (0.01mL/g) once a day for 75days, and bred with drug naïve females twenty-four hours after the final injection. Offspring, separated by sex, were tested in a battery of behaviors. We found that paternal cocaine exposure altered sensitivity to the rewarding and stimulant effects of psychostimulants and natural reward (sucrose) in female offspring; female cocaine-sired offspring showed blunted cocaine preference using cocaine conditioned place preference (CPP) at a low dose (5mg/kg), but displayed similar preference at a higher dose (10mg/kg) compared to saline-sired controls. Additionally, cocaine-sired female offspring exhibited higher psychomotor sensitivity to cocaine (10mg/kg) and amphetamine (2mg/kg) and consumed more sucrose. Cocaine-sired males exhibited increased psychomotor effects of cocaine and amphetamine. Male offspring also displayed an anxiety-like phenotype. No effect of paternal cocaine exposure was observed on depressive-like, learning and memory or social behavior in male or female offspring. Collectively, our findings show that paternal, chronic cocaine exposure induces intergenerational behavioral effects in male and female offspring with greatest impact on sensitivity to psychostimulants and sucrose in females.

Cohort Profile: The Saguenay Youth Study (SYS)

The Saguenay Youth Study (SYS) is a two-generational study of adolescents and their parents (n = 1029 adolescents and 962 parents) aimed at investigating the aetiology, early stages and trans-generational trajectories of common cardiometabolic and brain diseases. The ultimate goal of this study is to identify effective means for increasing healthy life expectancy. The cohort was recruited from the genetic founder population of the Saguenay Lac St Jean region of Quebec, Canada. The participants underwent extensive (15-h) phenotyping, including an hour-long recording of beat-by-beat blood pressure, magnetic resonance imaging of the brain and abdomen, and serum lipidomic profiling with LC-ESI-MS. All participants have been genome-wide genotyped (with ∼ 8 M imputed single nucleotide polymorphisms) and a subset of them (144 adolescents and their 288 parents) has been genome-wide epityped (whole blood DNA, Infinium HumanMethylation450K BeadChip). These assessments are complemented by a detailed evaluation of each participant in a number of domains, including cognition, mental health and substance use, diet, physical activity and sleep, and family environment. The data collection took place during 2003-12 in adolescents (full) and their parents (partial), and during 2012-15 in parents (full). All data are available upon request.

Utility and applicability of the "Childhood Obesity Risk Evaluation" (CORE)-index in predicting obesity in childhood and adolescence in Greece from early life: the "National Action Plan for Public Health"

Early identification of infants being at high risk to become obese at their later childhood or adolescence can be of vital importance in any obesity prevention initiative. The aim of the present study was to examine the utility and applicability of the "Childhood Obesity Risk Evaluation (CORE)" index as a screening tool for the early prediction of obesity in childhood and adolescence. Anthropometric, socio-demographic data were collected cross-sectionally and retrospectively from a representative sample of 5946 children, and adolescents and were combined for calculating the CORE-index score. Logistic regression analyses were performed to examine the associations of the CORE-index score with obesity by gender and age group, and cut-off point analysis was also applied to identify the optimal value of the CORE-index score that differentiates obese from non-obese children. Mean CORE-index score in the total sample was 3.06 (sd 1.92) units (range 0-11 units). Each unit increase in the CORE-index score was found to be associated with a 30 % (95 % C.I. 1.24-1.36) increased likelihood for obesity in childhood or adolescence, while the optimal cut-off value of the CORE-index score that predicted obesity with the highest possible sensitivity and specificity was found to be 3.5.

CONCLUSION

The present study supports the utility and applicability of the CORE-index as a screening tool for the early identification of infants that are potentially at a higher risk for becoming obese at their childhood and adolescence. This tool could be routinely used by health professionals to identify infants at high risk and provide appropriate counselling to their parents and caregivers so as to maximize the effectiveness of early obesity prevention initiatives. What is known? • Childhood obesity has reached epidemic proportions worldwide. • Certain perinatal and socio-demographic indices that were previously identified as correlates of childhood obesity in children were combined to develop the CORE-index, a screening tool that estimates obesity risk in 9-13 year-old children. What is new? • The utility and applicability of the CORE-index as screening tool can be extended to the age range of 6-15 years. • The CORE-index is a cost-effective screening tool that can assist health professionals in initiating obesity preventive measures from early life.

Epigenomic and metabolic responses of hypothalamic POMC neurons to gestational nicotine exposure in adult offspring

Background

Epidemiological and animal studies have reported that prenatal nicotine exposure (PNE) leads to obesity and type-2 diabetes in offspring. Central leptin-melanocortin signaling via hypothalamic arcuate proopiomelanocortin (POMC) neurons is crucial for the regulation of energy and glucose balance. Furthermore, hypothalamic POMC neurons were recently found to mediate the anorectic effects of nicotine through activation of acetylcholine receptors. Here, we hypothesized that PNE impairs leptin-melanocortinergic regulation of energy balance in first-generation offspring by altering expression of long non-coding RNAs (lncRNAs) putatively regulating development and/or function of hypothalamic POMC neurons.

Methods

C57BL/6J females were exposed ad libitum to nicotine through drinking water and crossed with C57BL/6J males. Nicotine exposure was sustained during pregnancy and discontinued at parturition. Offspring development was monitored from birth into adulthood. From the age of 8 weeks, central leptin-melanocortin signaling, diabetes, and obesity susceptibility were assessed in male offspring fed a low-fat or high-fat diet for 16 weeks. Nicotine-exposed and non-exposed C57BL/6J females were also crossed with C57BL/6J males expressing the enhanced green fluorescent protein specifically in POMC neurons. Transgenic male offspring were subjected to laser microdissections and RNA sequencing (RNA-seq) analysis of POMC neurons for determination of nicotine-induced gene expression changes and regulatory lncRNA/protein-coding gene interactions.

Results

Contrary to expectation based on previous studies, PNE did not impair but rather enhanced leptin-melanocortinergic regulation of energy and glucose balance via POMC neurons in offspring. RNA-seq of laser microdissected POMC neurons revealed only one consistent change, upregulation of Gm15851, a lncRNA of yet unidentified function, in nicotine-exposed offspring. RNA-seq further suggested 82 cis-regulatory lncRNA/protein-coding gene interactions, 19 of which involved coding genes regulating neural development and/or function, and revealed expression of several previously unidentified metabolic, neuroendocrine, and neurodevelopment pathways in POMC neurons.

Conclusions

PNE does not result in obesity and type 2 diabetes but instead enhances leptin-melanocortinergic feeding and body weight regulation via POMC neurons in adult offspring. PNE leads to selective upregulation of Gm15851, a lncRNA, in adult offspring POMC neurons. POMC neurons express several lncRNAs and pathways possibly regulating POMC neuronal development and/or function.

Electronic supplementary material

The online version of this article (doi:10.1186/s13073-016-0348-2) contains supplementary material, which is available to authorized users.

Systematic review and meta-analysis of the association between maternal smoking in pregnancy and childhood overweight and obesity

BACKGROUND

By 2020, it is predicted that 60 million children worldwide will be overweight. Maternal smoking in pregnancy has been suggested as a contributing factor. Our objective was to systematically review studies on this, thereby expanding the evidence base for this association.

METHODS

Systematic review with meta-analysis, Prospero Registration number CRD42012002859. We searched PubMed, Embase, Global Health, Web of Science and the Grey literature. We included prevalence, cohort and cross-sectional studies involving full-term, singleton pregnancies. Published and unpublished studies through to 1 January 2015 in all languages, demonstrating an objective overweight outcome up until 18 years of age and data presented as an OR, were included. Quality assessment was undertaken using an adaption of the Newcastle-Ottawa scale. Statistical analysis was performed using Review Manager V.5.3.

FINDINGS

The meta-analysis included 39 studies of 236 687 children from Europe, Australia, North America and South America and Asia. Maternal smoking in pregnancy ranged from 5.5% to 38.7%, with the prevalence of overweight from 6.3% to 32.1% and obesity from 2.6% to 17%. Pooled adjusted ORs demonstrated an elevated odds of maternal smoking in pregnancy for childhood overweight (OR 1.37, 95% CI 1.28 to 1.46, I₂ 45%) and childhood obesity (OR 1.55, 95% CI 1.40 to 1.73, I₂ 24%).

INTERPRETATION

Our results demonstrate an association between maternal prenatal smoking and childhood overweight. This contributes to the growing evidence for the aetiology of childhood overweight, providing important information for policymakers and health professionals alike in planning cessation programmes or antismoking interventions for pregnant female smokers.

The effects of nicotine on human fetal development

Maternal smoking during pregnancy continues to represent a major public health concern. Nicotine is extremely harmful to the developing fetus through many different mechanisms, and the harms increase with later gestational age at exposure. Pregnancies complicated by maternal nicotine use are more likely to have significant adverse outcomes. Nicotine-exposed children tend to have several health problems throughout their lives, including impaired function of the endocrine, reproductive, respiratory, cardiovascular, and neurologic systems. Poor academic performance and significant behavioral disruptions are also common, including ADHD, aggressive behaviors, and future substance abuse. To diminish the adverse effects from cigarette smoking, some women are turning to electronic cigarettes, a new trend that is increasing in popularity worldwide. They are largely perceived as being safer to use in pregnancy than traditional cigarettes, although there is not adequate evidence to support this claim. At this time, electronic cigarette use during pregnancy cannot be recommended. Birth Defects Research (Part C) 108:181-192, 2016. © 2016 Wiley Periodicals, Inc.

Association Between Age and Obesity Over Time

BACKGROUND AND OBJECTIVES

A decline in the prevalence of obesity among 2- to 5-year-olds in the United States was recently reported. This decline may be due to changes in the population composition of children over time or may be a consequence of changes in how strongly individual- or family-level factors are linked to childhood obesity. We applied regression decomposition techniques to identify the sources of the decline.

METHODS

We used data from the 2003-2004 and 2011-2012 NHANES restricted to 2- to 5-year-old children and Blinder-Oaxaca regression decomposition techniques to partition the decline in early childhood obesity into 2 components: changes resulting from (1) how demographic, economic, and health characteristics of children have changed over this period (ie, changes in population composition) and (2) changes in how these demographic, economic, and health factors are associated with obesity (ie, changes in associations).

RESULTS

The obesity rate was lower in 2011-2012 than it was in 2003-2004 mainly because obesity was strongly and positively associated with age in 2003-2004 (ie, older children were more likely to be obese than younger children) but not in 2011-2012 (ie, older children were not more likely to be obese than younger children).

CONCLUSIONS

If the weaker association between age and obesity we observed for this cohort of 2- to 5-year-old children in 2011-2012 persists for subsequent cohorts of young children, the obesity rate for young children will remain at or near the lower rate seen in 2011-2012.

Combined early and adult life risk factor associations for mid-life obesity in a prospective birth cohort: assessing potential public health impact

OBJECTIVE

The combined effect of life-course influences on obesity development and thus their potential public health impact is unclear. We evaluated combined associations and predicted probabilities for early and adult life risk factors with central and general obesity in mid-adulthood.

SETTING

1958 British birth cohort.

PARTICIPANTS

4629 males and 4670 females with data on waist circumference.

OUTCOME MEASURES

45 year obesity measured via waist circumference, waist-hip ratio (WHR) and BMI.

RESULTS

At 45 years, approximately a third of the population were centrally obese and a quarter were generally obese. Three factors (parental overweight, maternal smoking during pregnancy and adult inactivity) were consistently associated with central and general obesity. Predicted probabilities for waist obesity increased from those with none to all three risk factors (0.15-0.33 in men; 0.19-0.39 in women (ptrend<0.001)), with a similar trend for general obesity. Additional factors (adult smoking, low fibre and heavy alcohol consumption) were associated with WHR obesity, although varying by gender. Prevalence of risk factors was higher in manual than non-manual groups: for example, in men 38% versus 25%, respectively, had ≥2 risk factors for waist and general obesity.

CONCLUSIONS

Early-life and adult factors that are amenable to change are highly prevalent and accumulate in association with central and general obesity in mid-adulthood. The increase in probabilities for mid-adult obesity associated with cumulative levels of risk factors suggests the potential for public health impact.

Maternal Smoking and Metabolic Health Biomarkers in Newborns

Background

Maternal smoking has been associated with elevated risk of type 2 diabetes among the offspring in adulthood. The mechanisms underlying this fetal “programming” effect remain unclear. The present study sought to explore whether maternal smoking affects metabolic health biomarkers in fetuses/newborns.

Methods

In a prospective singleton pregnancy cohort (n = 248), we compared metabolic health biomarkers in the newborns of smoking and non-smoking mothers. Outcomes included cord plasma insulin, proinsulin, insulin-like growth factor I (IGF-I), IGF-II, leptin and adiponectin concentrations, glucose-to-insulin ratio (an indicator of insulin sensitivity) and proinsulin-to-insulin ratio (an indicator of β-cell function).

Results

Independent of maternal (glucose tolerance, age, ethnicity, parity, education, body mass index, alcohol use) and infant (sex, gestational age, birth weight z score, mode of delivery, cord blood glucose concentration) characteristics, the newborns of smoking mothers had lower IGF-I concentrations (mean: 6.7 vs. 8.4 nmol/L, adjusted p = 0.006), and marginally higher proinsulin-to-insulin ratios (0.94 vs. 0.72, adjusted p = 0.06) than the newborns of non-smoking mothers. Cord plasma insulin, proinsulin, IGF-II, leptin and adiponectin concentrations and glucose-to-insulin ratios were similar in the newborns of smoking and non-smoking mothers.

Conclusions

Maternal smoking was associated with decreased fetal IGF-I levels, and borderline lower fetal β-cell function. Larger cohort studies are required to confirm the latter finding. The preliminary findings prompt the hypothesis that these early life metabolic changes may be involved in the impact of maternal smoking on future risk of metabolic syndrome related disorders in the offspring.

Early-life exposure to substance abuse and risk of type 2 diabetes in adulthood

Type 2 diabetes (T2D) is a chronic non-communicable disease that is driven by insulin resistance as a result of increasing obesity and decreasing activity levels that occur with increasing age. This disease generally develops after the age of 40, but it is now increasingly diagnosed in children and young adults. Increasing evidence, however, suggests that T2D can originate during early development. It has been repeatedly found that malnutrition during the gestational period can result in intrauterine growth restriction and low birth weight, which in combination with postnatal catch-up growth may subsequently lead to the development of T2D. There is ample evidence that T2D may also be programmed by maternal substance abuse (the harmful use of psychoactive substances such as illicit drugs or alcohol) during pregnancy and/or lactation. The research activity in this field is currently mainly focused on the childhood health problems following prenatal exposures to substance abuse. The delayed programming effects on adult-onset disorders, including metabolic syndrome and T2D, however, have been reported only rarely. This review provides animal and human evidence that early-life exposure to substance abuse, including alcohol, nicotine, and cocaine, may program not only childhood health outcomes but also life-long metabolic health status, including risk of T2D and related conditions.

Maternal lifestyle characteristics during pregnancy, and the risk of obesity in the offspring: a study of 5,125 children

BACKGROUND

To investigate the association between gestational weight gain, maternal age and lifestyle habits (e.g., physical activity, smoking, and alcohol consumption) during pregnancy, with Body Mass Index of the offspring at the age of 8.

METHODS

Α random sample of 5,125 children was extracted from a national database and matched with their mothers. With the use of a standardised questionnaire, telephone interviews were carried out for the collection of information like: maternal age at pregnancy, gestational weight gain (GWG), exercise levels, smoking and alcohol consumption. The Body Mass Index (BMI) status of the offspring at the age of 8 was calculated from data retrieved from the national database (e.g., height and weight).

RESULTS

The odds for being overweight/obese at the age of 8 for 1 kg GWG, for smoking, and for mild exercise during pregnancy compared to sedentary was 1.01 (95%CI: 1.00, 1.02), 1.23 (95%CI: 1.03, 1.47) and 0.77 (95%CI: 0.65, 0.91), respectively. Further analysis revealed that offspring of women who exceeded the Institute of Medicine (IOM) maternal weight gain recommendations were at an increased risk of obesity (OR: 1.45; 95%CI, 1.26, 1.67) compared with offspring of women with GWG within the recommended range. Maternal age and alcohol consumption were not associated with the outcome (p > 0.05).

CONCLUSION

GWG, physical activity and smoking status during pregnancy were significantly associated with obesity for the offspring at the age of 8. Health care professionals should strongly advise women to not smoke and to perform moderate exercise during pregnancy to prevent obesity in the offspring in later life.

Associations between the prenatal environment and cardiovascular risk factors in adolescent girls: Internalizing and externalizing behavior symptoms as mediators

This longitudinal study examines links among adolescent internalizing and externalizing symptoms, the prenatal environment (e.g., nicotine exposure) and pre/perinatal maternal health, and cardiovascular risk factors. Girls (N=262) ages 11-17 reported internalizing and externalizing behaviors and mothers reported about the prenatal environment and maternal health during and 3 months post-pregnancy. Adolescent cardiovascular risk included adiposity, smoking, blood pressure, and salivary C-reactive protein. Internalizing symptoms mediated relations between prenatal exposures/maternal health and adiposity; externalizing symptoms mediated relations between prenatal exposures and adolescent smoking. Healthcare providers who attend to internalizing and externalizing symptoms in girls may ultimately influence cardiovascular health, especially among those with pre/perinatal risk factors.

Do all roads lead to Rome? The role of neuro-immune interactions before birth in the programming of offspring obesity

The functions of the nervous system can be powerfully modulated by the immune system. Although traditionally considered to be quite separate, neuro-immune interactions are increasingly recognized as critical for both normal and pathological nervous system function in the adult. However, a growing body of information supports a critical role for neuro-immune interactions before birth, particularly in the prenatal programming of later-life neurobehavioral disease risk. This review will focus on maternal obesity, as it represents an environment of pathological immune system function during pregnancy that elevates offspring neurobehavioral disease risk. We will first delineate the normal role of the immune system during pregnancy, including the role of the placenta as both a barrier and relayer of inflammatory information between the maternal and fetal environments. This will be followed by the current exciting findings of how immuno-modulatory molecules may elevate offspring risk of neurobehavioral disease by altering brain development and, consequently, later life function. Finally, by drawing parallels with pregnancy complications other than obesity, we will suggest that aberrant immune activation, irrespective of its origin, may lead to neuro-immune interactions that otherwise would not exist in the developing brain. These interactions could conceivably derail normal brain development and/or later life function, and thereby elevate risk for obesity and other neurobehavioral disorders later in the offspring's life.

Childhood growth trajectories according to combinations of pregestational weight status and maternal smoking during pregnancy: a multilevel analysis

Pregestational weight status and maternal smoking during pregnancy are significantly associated with fetal and childhood growth. However, few studies have examined associations between childhood growth and combinations of these factors using multilevel analysis. This study aimed to describe differences in childhood growth trajectories according to these combinations, using data from a prospective cohort study in Japan. The study participants were 1,973 women and their singletons, who were born between April 1, 1991 and March 31, 2003. Children were categorized according to whether they were born to normal-weight, nonsmoking mothers (NN); normal-weight, smoking mothers (NS); underweight, nonsmoking mothers (UN); underweight, smoking mothers (US); overweight, nonsmoking mothers (ON); or overweight, smoking mothers (OS). Birth weight and anthropometric data were collected from 1,965 children at birth (99.6%), 1,655 aged 3 (83.9%), 1,527 aged 5 (77.4%), 1,497 aged 7–8 (75.9%), and 1,501 aged 9–10 (76.1%). Multilevel analysis examining both individual and age as different level variables according to sex was used to describe the trajectories of body mass index z scores for statistical analyses. Although children of the OS group were the leanest at birth, their body mass indices had increased rapidly by 3 years of age. Moreover, body mass index was also likely to increase in boys in the NS and ON groups. A different trend was observed in girls. Body mass index decreased from 5 years of age in girls in the US group. There were no remarkable differences in body mass index trajectories between children in the other groups. In conclusion, childhood growth trajectories differed according to combinations of pregestational weight status and maternal smoking during pregnancy. Further, there were sex-related differences in the associations between childhood growth and factor combinations.

Saguenay Youth Study: a multi-generational approach to studying virtual trajectories of the brain and cardio-metabolic health

This paper provides an overview of the Saguenay Youth Study (SYS) and its parental arm. The overarching goal of this effort is to develop trans-generational models of developmental cascades contributing to the emergence of common chronic disorders, such as depression, addictions, dementia and cardio-metabolic diseases. Over the past 10 years, we have acquired detailed brain and cardio-metabolic phenotypes, and genome-wide genotypes, in 1029 adolescents recruited in a population with a known genetic founder effect. At present, we are extending this dataset to acquire comparable phenotypes and genotypes in the biological parents of these individuals. After providing conceptual background for this work (transactions across time, systems and organs), we describe briefly the tools employed in the adolescent arm of this cohort and highlight some of the initial accomplishments. We then outline in detail the phenotyping protocol used to acquire comparable data in the parents.

Transgenerational effects of obesogens and the obesity epidemic

In the last three decades there has been a dramatic, worldwide increase in the incidence of obesity, particularly in Western societies. This trend has required a significant economic investment to treat obesity-related disorders such as type 2 diabetes, cardiovascular disease, and non-alcoholic fatty liver disease. There is an urgent need to understand the factors that contribute to this increase in obesity in order to find new tools that will improve quality of life in affected individuals and to avoid the propagation of obesity to future generations. Endocrine disrupting chemicals have become an important piece of the obesity epidemic puzzle but little is known about the mechanism underlying their effects. In this commentary, we highlight recent work showing that the consequences of ancestral exposure to obesogenic chemicals results in the transmission of obesity-related phenotypes through at least three generations.

Transgenerational inheritance of prenatal obesogen exposure

Obesity and metabolic syndrome diseases have exploded into an epidemic of global proportions. The generally accepted cause of obesity is overconsumption of calorie-dense food and diminished physical activity (the calories in-calories out model). However, emerging evidence demonstrates that environmental factors can predispose exposed individuals to gain weight, irrespective of diet and exercise. The environmental obesogen model proposes that chemical exposure during critical stages in development can influence subsequent adipogenesis, lipid balance and obesity. Obesogens are chemicals that inappropriately stimulate adipogenesis and fat storage. Numerous obesogens have been identified in recent years and some of these have been shown to act through the peroxisome proliferator activated receptor gamma, the master regulator of adipogenesis. Others act through as yet unidentified pathways. Notably, some of these obesogens elicit transgenerational effects on a variety of health endpoints, including obesity in offspring after exposure of pregnant F0 females. Thus, prenatal exposure to xenobiotic compounds can have lasting, potentially permanent effects on the offspring of exposed animals. Transgenerational effects of chemical exposure raise the stakes in the debate about whether and how endocrine disrupting chemicals should be regulated.

Independent and joint effects of prenatal maternal smoking and maternal exposure to second-hand smoke on the development of adolescent obesity: a longitudinal study

AIM

To examine associations of prenatal maternal smoking and second-hand smoke (SHS) exposure with the development of adolescent obesity.

METHODS

Longitudinal data (1991-2007) from National Institute of Child Health and Human Development Study of Early Child Care and Youth Development involving mothers that smoked and or exposed to SHS during the year before birth were analysed. Adolescent obesity in ages 12.0-15.9 years was defined as a BMI ≥ 95th percentile. Generalised estimating equations (GEE) were used for the analyses.

RESULTS

Obesity was more prevalent among adolescents whose mothers smoked or had SHS exposure than those that did not smoke or exposed to SHS. After adjusting for maternal and child factors, GEE models showed that odds of adolescent obesity increased with prenatal maternal smoking (OR = 1.57, 95% CI = 1.03-2.39) and SHS exposure (OR = 1.53, 95% CI = 1.04-2.27). The odds for obesity increased more than two times among adolescents exposed to both maternal smoking and SHS (OR = 2.10, 95% CI = 1.24, 3.56) compared with those without exposure. Additionally, not breastfeeding, maternal obesity, and longer screen viewing hours per day were associated with increased odds of obesity.

CONCLUSIONS

There is possibly a long-term joint effect of prenatal maternal smoke (smoking and SHS) exposure on obesity among adolescent offspring, and the effect is independent of birthweight. These findings suggest that adolescent obesity could possibly be curtailed with the development and promotion of smoking cessation programmes for families during the year before birth.

Risk of childhood overweight after exposure to tobacco smoking in prenatal and early postnatal life

OBJECTIVE

To investigate the association between exposure to mothers smoking during prenatal and early postnatal life and risk of overweight at age 7 years, while taking birth weight into account.

METHODS

From the Danish National Birth Cohort a total of 32,747 families were identified with available information on maternal smoking status in child's pre- and postnatal life and child's birth weight, and weight and height at age 7 years. Outcome was overweight according to the International Obesity Task Force gender and age specific body mass index. Smoking exposure was categorized into four groups: no exposure (n = 25,076); exposure only during pregnancy (n = 3,343); exposure only postnatally (n = 140); and exposure during pregnancy and postnatally (n = 4,188). Risk of overweight according to smoking status as well as dose-response relationships were estimated by crude and adjusted odds ratios using logistic regression models.

RESULTS

Exposure to smoking only during pregnancy, or both during pregnancy and postnatally were both significantly associated with overweight at 7 years of age (OR: 1.31, 95% CI: 1.15-1.48, and OR: 1.76, 95% CI: 1.58-1.97, respectively). Analyses excluding children with low birth weight (<2,500 gram) revealed similar results. A significant prenatal dose-response relationship was found. Per one additional cigarette smoked per day an increase in risk of overweight was observed (OR: 1.02, 95% CI: 1.01-1.03). When adjusting for quantity of smoking during pregnancy, prolonged exposure after birth further increased the risk of later overweight in the children (OR 1.28, 95% CI:1.09-1.50) compared with exposure only in the prenatal period.

CONCLUSIONS

Mother's perinatal smoking increased child's OR of overweight at age 7 years irrespective of birth weight, and with higher OR if exposed both during pregnancy and in early postnatal life. Clear dose-response relationships were observed, which emphasizes the need for prevention of any tobacco exposure of infants.

Obesity and asthma: the role of environmental pollutants

Air pollution is a well-known risk for lung diseases, including asthma. Growing evidences suggesting air pollution as a novel risk factor for the development of obesity. Several Epidemiological studies have ascertained an association between various ambient and indoor air pollutants and obesity by medium of endocrine disruptive chemicals that can disrupt the normal development and homeostatic controls over adipogenesis and energy balance and induce obesity. Several obesity-induced mechanisms have been proposed that increases this vulnerability of obese individuals to harmful effects of air pollution rendering them more susceptible to developing air-pollution driven incident asthma or worsening of already existing asthma.

Exposure to maternal smoking during fetal life affects food preferences in adulthood independent of the effects of intrauterine growth restriction

Experimental animal studies have shown that nicotine exposure during gestation alters the expression of fetal hypothalamic neuropeptides involved in the control of appetite. We aimed to determine whether the exposure to maternal smoking during gestation in humans is associated with an altered feeding behavior of the adult offspring. A longitudinal prospective cohort study was conducted including all births from Ribeirão Preto (São Paulo, Brazil) between 1978 and 1979. At 24 years of age, a representative random sample was re-evaluated and divided into groups exposed (n = 424) or not (n = 1586) to maternal smoking during gestation. Feeding behavior was analyzed using a food frequency questionnaire. Covariance analysis was used for continuous data and the χ 2 test for categorical data. Results were adjusted for birth weight ratio, body mass index, gender, physical activity and smoking, as well as maternal and subjects' schooling. Individuals exposed to maternal smoking during gestation ate more carbohydrates than proteins (as per the carbohydrate-to-protein ratio) than non-exposed individuals. There were no differences in the consumption of the macronutrients themselves. We propose that this adverse fetal life event programs the individual's physiology and metabolism persistently, leading to an altered feeding behavior that could contribute to the development of chronic diseases in the long term.

Trajectory of Adolescent Obesity: Exploring the Impact of Prenatal to Childhood Experiences

This study examined longitudinal associations of prenatal exposures as well as childhood familial experiences with obesity status from ages 10 to 18. Hierarchical generalized linear modeling (HGLM) was applied to examine 5,156 adolescents from the child sample of the 1979 National Longitudinal Survey of Youth (NLSY79). Higher maternal weight, maternal smoking during pregnancy, lower maternal education, and lack of infant breastfeeding were contributors to elevated adolescent obesity risk in early adolescence. However, maternal age, high birth weight of child, and maternal annual income exhibited long-lasting impact on obesity risk over time throughout adolescence. Additionally, childhood familial experiences were significantly related to risk of adolescent obesity. Appropriate use of family rules in the home and parental engagement in children's daily activities lowered adolescent obesity risk, but excessive television viewing heightened adolescent obesity risk. Implementation of consistent family rules and parental engagement may benefit adolescents at risk for obesity.

Parental smoking and childhood obesity: higher effect estimates for maternal smoking in pregnancy compared with paternal smoking--a meta-analysis

BACKGROUND

Some studies reported similar effect estimates for the impact of maternal smoking in pregnancy and paternal smoking on childhood obesity, whereas others suggested higher effects for maternal smoking. We performed a meta-analysis to compare the effect of in utero exposure to maternal smoking and that of paternal or household smoking exposure in utero or after birth with mutual adjustment.

METHODS

Meta-analysis of observational studies identified in MEDLINE, EMBASE and Web of Knowledge published in 1900-2013. Study inclusion criterion was assessment of the association of maternal smoking during pregnancy and paternal or household smoking (anyone living in the household who smokes) at any time with childhood overweight and obesity. The analyses were based on all studies with mutually adjusted effect estimates for maternal and paternal/household smoking applying a random-effects model.

RESULTS

Data for 109,838 mother/child pairs were reported in 12 studies. The pooled odds ratios (ORs) for overweight 1.33 [95% confidence interval (CI) 1.23;1.44] (n=6, I2=0.00%) and obesity 1.60 (95% CI 1.37;1.88) (n=4, I2=32.47%) for maternal smoking during pregnancy were higher than for paternal smoking: 1.07 (95% CI 1.00;1.16) (n=6, I2=41.34%) and 1.23 (95% CI 1.10;1.38) (n=4, I2=14.61%), respectively. Similar estimates with widely overlapping confidence limits were found for maternal smoking during pregnancy and childhood overweight and obesity: 1.35 (95% CI 1.20;1.51) (n=3, I2=0.00%) and 1.28 (95% CI 1.07;1.54) (n=3, I2=0.00%) compared with household smoking 1.22 (95% CI 1.06;1.39) (n=3, I2=72.14%) and 1.31 (95% CI 1.15;1.50)] (n=3, I2=0.00%).

CONCLUSIONS

Higher effect estimates for maternal smoking in pregnancy compared with paternal smoking in mutually adjusted models may suggest a direct intrauterine effect.

The impact of tobacco smoke exposure on wheezing and overweight in 4-6-year-old children

Aim. To investigate the association between maternal smoking during pregnancy, second-hand tobacco smoke (STS) exposure, education level, and preschool children's wheezing and overweight. Methods. This cohort study used data of the KANC cohort—1,489 4–6-year-old children from Kaunas city, Lithuania. Multivariate logistic regression was employed to study the influence of prenatal and postnatal STS exposure on the prevalence of wheezing and overweight, controlling for potential confounders. Results. Children exposed to maternal smoking during pregnancy had a slightly increased prevalence of wheezing and overweight. Postnatal exposure to STS was associated with a statistically significantly increased risk of wheezing and overweight in children born to mothers with lower education levels (OR 2.12; 95% CI 1.04–4.35 and 3.57; 95% CI 1.76–7.21, accordingly). Conclusions. The present study findings suggest that both maternal smoking during pregnancy and STS increase the risk of childhood wheezing and overweight, whereas lower maternal education might have a synergetic effect. Targeted interventions must to take this into account and address household smoking.

Exposure to neurotoxicants and the development of attention deficit hyperactivity disorder and its related behaviors in childhood

The purpose of this manuscript is to review the literature to determine evidence of associations between exposure to prenatal and postnatal environmental agents and the development of attention deficit hyperactivity disorder (ADHD) and related behaviors. A review of published research literature was conducted on associations between exposures to prenatal and postnatal cigarette smoke, prenatal exposure to alcohol, cocaine, and heroin, childhood exposure to lead, and prenatal exposure to organophosphate pesticides and outcomes of ADHD or behaviors related to ADHD. Review of the literature in these areas provides some evidence of associations between each of the exposures and ADHD-related behaviors, with the strongest evidence from prenatal cigarette and alcohol exposure and postnatal lead exposure. However, research on each exposure also produced evidence of weaknesses in these hypothesized links due to imprecise research methodologies and issues of confounding and inaccurate covariate adjustment. More rigorous studies are needed to provide definitive evidence of associations between each of these prenatal or postnatal exposures and the development of ADHD or symptoms of ADHD. Future studies need to clarify the underlying mechanisms between these exposures and the increased risk for ADHD and associated behaviors. More research is also needed utilizing study designs that include genetic information, as ADHD is highly heritable and there appear to be some protective mechanisms offered by certain genetic characteristics as evidenced in gene by environmental studies. Finally, while studies focusing on individual drugs and chemicals are an important first step, we cannot ignore the fact that children are exposed to combinations of drugs and chemicals, which can interact in complex ways with each other, as well as with the child's genetic makeup and psychosocial environment to influence ADHD risk.

Parental smoking during pregnancy and offspring cardio-metabolic risk factors at ages 17 and 32

OBJECTIVE

To examine the association of maternal and/or paternal smoking during pregnancy with offspring cardio-metabolic risk (CMR) factors at adolescence and early adulthood, taking into account socio-demographic, medical and lifestyle characteristics of parents and offspring, as well as offspring common genetic variation.

METHODS

We used a population-based cohort of all 17 003 births in Jerusalem during 1974-76, with available archival data on parental and birth characteristics. Measurements at age 17 were assessed at military induction examinations for 11 530 offspring. 1440 offspring from the original 1974-1976 birth cohort were sampled using a stratified sampling approach, and were interviewed and examined at age 32. Parental smoking during pregnancy (i.e. maternal, paternal and any parent) was primarily defined dichotomously (any number of cigarettes smoked daily by mother or father during pregnancy vs. non-smokers). Additionally, smoking was assessed by quantity of cigarettes smoked daily. Linear regression models were used to evaluate the associations of parental smoking during pregnancy with various offspring CMR factors, after controlling for potential confounders and for genetic variation in candidate genes.

RESULTS

Prevalence of exposure to parental smoking in-utero (i.e. smoking of any parent) was 53.2% and 48.4% among the 17 years old and 32 years old samples, respectively. At age 17, smoking of at least one parent during pregnancy was significantly associated with weight (B = 1.39), height (B = 0.59), BMI (B = 0.32) and pulse rate (B = -0.78) (p-values < 0.001). At age 32, parental smoking, adjusted for covariates, was associated with 2.22 kg higher mean offspring weight, 0.95 cm higher mean offspring height, 0.57 kg/m(2) higher BMI, and 1.46 cm higher waist-circumference (p-values ≤ 0.02). Similar results, reflecting a dose response, were observed when maternal and paternal smokings were assessed by number of cigarettes smoked daily.

CONCLUSIONS

This prospective study demonstrates a potential long-term adverse effect of parental smoking during pregnancy on offspring health and calls for increasing efforts to promote smoking cessation of both parents before pregnancy.

The obesogen tributyltin

The obesogen hypothesis postulates the role of environmental chemical pollutants that disrupt homeostatic controls and adaptive mechanisms to promote adipose-dependent weight gain leading to obesity and metabolic syndrome complications. One of the most direct molecular mechanisms for coupling environmental chemical exposures to perturbed physiology invokes pollutants mimicking endogenous endocrine hormones or bioactive dietary signaling metabolites that serve as nuclear receptor ligands. The organotin pollutant tributyltin can exert toxicity through multiple mechanisms but most recently has been shown to bind, activate, and mediate RXR-PPARγ transcriptional regulation central to lipid metabolism and adipocyte biology. Data in support of long-term obesogenic effects on whole body adipose tissue are also reported. Organotins represent an important model test system for evaluating the impact and epidemiological significance of chemical insults as contributing factors for obesity and human metabolic health.

Maternal smoking, breastfeeding, and risk of childhood overweight: findings from a national cohort

To examine the association between exposure to tobacco compounds in breast milk and risk of childhood overweight, we used historical data for a subset of 21,063 mother-child pairs in the US Collaborative Perinatal Project. Based on self-reports, mothers were classified as non-smokers, light (1-9 cigarettes/day), moderate (10-19), or heavy (20+) smokers. Feeding type (exclusive breastfeeding or bottle-feeding) was observed during nursery stay after birth. We stratified children by maternal smoking and feeding type, and then fit interaction terms to isolate exposure to tobacco compounds via breast milk from exposure in uterus and in ambient air after birth. Using measured weight and height, overweight at age 7 was defined as a body mass index ≥85th percentile by sex and age. Among exclusively bottle-fed children, adjusted odds ratios (ORs) of overweight at age 7 were 1.24 (95% confidence interval [CI], 1.12-1.38; vs. non-smoking) for light maternal smoking, 1.43 (95% CI, 1.25-1.63) for moderate maternal smoking, and 1.46 (95% CI, 1.28-1.66) for heavy maternal smoking. Among exclusively breastfed children, the corresponding ORs were 1.33 (95% CI, 0.96-1.84) for light, 1.86 (95% CI, 1.27-2.73) for moderate, and 2.22 (95% CI, 1.53-3.20) for heavy maternal smoking. There was a modest positive interaction between breastfeeding and heavy maternal smoking on overweight risk at age 7. Tobacco compounds via breast milk of smoking mothers (significantly for heavy smokers) appear to be associated with a modest elevation in childhood overweight risk at 7 years of age. More aggressive intervention is needed to help pregnant and breastfeeding women to quit smoking.

In utero exposure to benzo[a]pyrene increases adiposity and causes hepatic steatosis in female mice, and glutathione deficiency is protective

Polycyclic aromatic hydrocarbons (PAHs), including benzo[a]pyrene (BaP), are ubiquitous environmental pollutants found in tobacco smoke, air pollution, and grilled foods. Reactive metabolites and reactive oxygen species generated during PAH metabolism are detoxified by reactions involving glutathione (GSH). Early life exposures to tobacco smoke and air pollution have been linked to increased risk of obesity and metabolic syndrome. We investigated the independent and interactive effects of prenatal exposure to BaP and GSH deficiency due to deletion of the modifier subunit of glutamate cysteine ligase (Gclm), the rate-limiting enzyme in GSH synthesis, on adiposity and hepatic steatosis in adult female F1 offspring. We mated Gclm(+/-) dams with Gclm(+/-) males and treated the pregnant dams with 0, 2, or 10mg/kg/day BaP in sesame oil by oral gavage daily from gestational day 7 through 16. We analyzed metabolic endpoints in female Gclm(-/-) and Gclm(+/+) littermate F1 offspring. Prenatal BaP exposure significantly increased visceral adipose tissue weight, weight gain between 3 weeks and 7.5 months of age, hepatic lipid content measured by oil red O staining, and hepatic fatty acid beta-oxidation gene expression in Gclm(+/+), but not in Gclm(-/-), female offspring. Hepatic expression of lipid biosynthesis and antioxidant genes were decreased and increased, respectively, in Gclm(-/-) mice. Our results suggest that reported effects of pre- and peri-natal air pollution and tobacco smoke exposure on obesity may be mediated in part by PAHs. GSH deficiency is protective against the metabolic effects of prenatal BaP exposure.

Maternal smoking during pregnancy and daughters' risk of gestational diabetes and obesity

AIMS/HYPOTHESIS

The primary aim of the study was to investigate the risk of developing gestational diabetes in women who were exposed to tobacco smoke in utero. Secondary aims were to assess the risk of obesity and non-gestational diabetes.

METHODS

Data were retrieved from the Medical Birth Register of Sweden for women who were born in 1982 (when smoking data were first registered) or later and who had given birth to at least one child; 80,189 pregnancies were included. The associations between in utero smoking exposure (three categories: non-smokers, 1-9 cigarettes/day [moderately exposed] and >9 cigarettes/day [heavily exposed]) and subsequent gestational diabetes (n = 291), non-gestational diabetes (n = 280) and obesity (n = 7,300) were assessed.

RESULTS

The adjusted ORs (aORs) of gestational diabetes were increased among women who were moderately (1.62, 95% CI 1.24, 2.13) and heavily (1.52, 95% CI 1.12, 2.06) exposed. The corresponding aORs of obesity were 1.36 (95% CI 1.28, 1.44) and 1.58 (95% CI 1.48, 1.68), respectively. A reduced OR for non-gestational diabetes was seen in the offspring of heavy smokers (aOR 0.66, 95% CI 0.45, 0.96).

CONCLUSIONS/INTERPRETATION

Women exposed to smoking during fetal life were at higher risk of developing gestational diabetes and obesity.