Maternal smoking during pregnancy and child overweight: systematic review and meta-analysis

Prenatal nicotine exposure affects cardiovascular function and growth of the developing fetus

AIM

Effects of nicotine on fetal hemodynamics are not well known, especially in the first trimester fetus. We investigated the acute and chronic effects of nicotine on hemodynamics in pregnant mice and their fetuses using ultrasound. Postnatal health status including growth and hemodynamics was also examined.

METHODS

To investigate the acute effects of nicotine on fetal hemodynamics, we injected nicotine 0.2 mg/kg subcutaneously into pregnant mice on gestational days (GD) 9.5, 11.5 and 13.5 and compared with saline-injected group. To determine the chronic effects of nicotine on fetal hemodynamics, we administered nicotine in drinking water (0.1 mg/mL) to pregnant mice from GD 6.5 until they gave birth and compared hemodynamics with water-administered mice.

RESULTS

Regarding the acute effects of nicotine, we found no intergroup difference in maternal hemodynamics; however, fetal blood flow through the dorsal aorta, carotid artery and umbilical artery tended to decrease, particularly on GD 11.5. Regarding the chronic effects of nicotine, we observed no intergroup difference in maternal body weight changes and hemodynamics; however, blood flow to all fetal organs tended to be lower in the nicotine water group than in the water group with significant difference on GD 13.5. The offspring of the nicotine water group had significantly low birth weights and continued to have low body weight until 9 weeks of age. In addition, these offspring developed postnatal cardiac hypertrophy.

CONCLUSION

Nicotine adversely affects fetal hemodynamics acutely and chronically in early pregnancy, potentially leading to fetal tissue hypoxia, intrauterine growth restriction and adverse postnatal health effects.

Influence of Second-Hand Smoke and Prenatal Tobacco Smoke Exposure on Biomarkers, Genetics and Physiological Processes in Children-An Overview in Research Insights of the Last Few Years

Children are commonly exposed to second-hand smoke (SHS) in the domestic environment or inside vehicles of smokers. Unfortunately, prenatal tobacco smoke (PTS) exposure is still common, too. SHS is hazardous to the health of smokers and non-smokers, but especially to that of children. SHS and PTS increase the risk for children to develop cancers and can trigger or worsen asthma and allergies, modulate the immune status, and is harmful to lung, heart and blood vessels. Smoking during pregnancy can cause pregnancy complications and poor birth outcomes as well as changes in the development of the foetus. Lately, some of the molecular and genetic mechanisms that cause adverse health effects in children have been identified. In this review, some of the current insights are discussed. In this regard, it has been found in children that SHS and PTS exposure is associated with changes in levels of enzymes, hormones, and expression of genes, micro RNAs, and proteins. PTS and SHS exposure are major elicitors of mechanisms of oxidative stress. Genetic predisposition can compound the health effects of PTS and SHS exposure. Epigenetic effects might influence in utero gene expression and disease susceptibility. Hence, the limitation of domestic and public exposure to SHS as well as PTS exposure has to be in the focus of policymakers and the public in order to save the health of children at an early age. Global substantial smoke-free policies, health communication campaigns, and behavioural interventions are useful and should be mandatory.

Using methylome data to inform exposome-health association studies: An application to the identification of environmental drivers of child body mass index

BACKGROUND

The exposome is defined as encompassing all environmental exposures one undergoes from conception onwards. Challenges of the application of this concept to environmental-health association studies include a possibly high false-positive rate.

OBJECTIVES

We aimed to reduce the dimension of the exposome using information from DNA methylation as a way to more efficiently characterize the relation between exposome and child body mass index (BMI).

METHODS

Among 1,173 mother-child pairs from HELIX cohort, 216 exposures ("whole exposome") were characterized. BMI and DNA methylation from immune cells of peripheral blood were assessed in children at age 6-10 years. A priori reduction of the methylome to preselect BMI-relevant CpGs was performed using biological pathways. We then implemented a tailored Meet-in-the-Middle approach to identify from these CpGs candidate mediators in the exposome-BMI association, using univariate linear regression models corrected for multiple testing: this allowed to point out exposures most likely to be associated with BMI ("reduced exposome"). Associations of this reduced exposome with BMI were finally tested. The approach was compared to an agnostic exposome-wide association study (ExWAS) ignoring the methylome.

RESULTS

Among the 2284 preselected CpGs (0.6% of the assessed CpGs), 62 were associated with BMI. Four factors (3 postnatal and 1 prenatal) of the exposome were associated with at least one of these CpGs, among which postnatal blood level of copper and PFOS were directly associated with BMI, with respectively positive and negative estimated effects. The agnostic ExWAS identified 18 additional postnatal exposures, including many persistent pollutants, generally unexpectedly associated with decreased BMI.

DISCUSSION

Our approach incorporating a priori information identified fewer significant associations than an agnostic approach. We hypothesize that this smaller number corresponds to a higher specificity (and possibly lower sensitivity), compared to the agnostic approach. Indeed, the latter cannot distinguish causal relations from reverse causation, e.g. for persistent compounds stored in fat, whose circulating level is influenced by BMI.

Negative influence of maternal smoking during pregnancy on infant outcomes

BACKGROUND

According to the INPES 2014 health barometer, the prevalence of smoking in pregnant women in France is the highest in Europe : 17.8% of expectant mothers who smoke continue to do so during pregnancy. Several epidemiological studies have confirmed multiple risks for tobacco-exposed infants (low birth weight; digestive, respiratory, neurological, and psychological disorders; obesity; type 1 diabetes).

PURPOSE

This study compared a cohort of infants exposed to tobacco in utero (T+) with those unexposed (T-). Birth weight, diet, presence of colic (ROME III criteria) and regurgitations (Vandenplas scale) were specifically analyzed.

METHODS

This observational, cross-sectional, and multicenter survey was conducted in France by pediatricians and general practitioners from September 2016 to February 2017. Infants with a chronic pathology and those with parents under 18 years of age were excluded. The data were collected by the physician and by the mother through a self-administered questionnaire.

RESULTS

A total of 452 physicians recruited 759 T+ and 741 T- infants in the study. The mean birth weight of T+ infants was significantly lower (3.1±0.5 kg [WHO z-score -0.476±1.081]) than that of T- infants (3.3±0.5 kg [0.033±0.965]; P<0.001). At the time of leaving the maternity facility, 47.7% of T+ infants were breastfed by their mother compared with 70.1% of T- infants. The median reported duration of breastfeeding was 1 month vs. 2 months for T+ and T- infants, respectively. Colic was significantly more common in T+ than in T- infants: 25.6% vs. 12.3% according to the ROME III criteria, and 45.7% vs. 29.7% according to the doctor's opinion (P<0.001 for both). In the T+ group, cases of regurgitation (63.6% vs. 56.5%; P=0.005), respiratory disorder (6.3% vs. 2.4%, P<0.001), and bronchiolitis (6.5% vs. 3.0%; P=0.001) were also more frequent.

CONCLUSION

This study confirms that maternal smoking during pregnancy is associated with health risks; exposed infants had significantly more digestive/respiratory symptoms and lower birth weight than unexposed infants. Preventive and educational actions need to be further strengthened in the face of this public health problem.

Impact of parental smoking on adipokine profiles and cardiometabolic risk factors in Chinese children

BACKGROUND AND AIMS

The mechanisms by which passive smoking leads to cardiometabolic risks, and the tissues involved still require elucidation. We aimed to evaluate the association of parental smoking exposure (PSE) with the secretion of adipocyte-derived hormones and cardiometabolic risk factors in Chinese children.

METHODS

We included 3150 school children aged 6-18 years from the Beijing Child and Adolescent Metabolic Syndrome (BCAMS) study. Data on PSE and potential confounders were collected. Six adipokines related to insulin resistance and metabolic syndrome (MetS) were measured.

RESULTS

PSE was reported in nearly two-thirds of the children. After adjusting for covariates, including age, sex, pubertal stages, lifestyle factors, and family history, PSE was independently associated with increases of 39.2% in leptin and 3.9% in retinol binding protein-4 and decreases of 11.4% in fibroblast growth factor 21 and 4.6% in adiponectin levels (p < 0.05 for all), plus risks for central obesity (OR 1.59, 95% CI 1.33-1.90), elevated blood pressure (1.22, 1.02-1.46) and MetS (1.43, 1.11-1.85). However, the associations of PSE with hypertension and MetS were abolished when adjusted for adiposity parameters or the above-mentioned adipokine profiles.

CONCLUSIONS

PSE was associated with dysregulation of adipokine levels, which might mediate the development of MetS in early life.

The association between secondhand smoke exposure and growth outcomes of children: A systematic literature review

INTRODUCTION

The strong relation between maternal smoking and maternal secondhand smoke (SHS) exposure and the growth of newborn infants has been proven. However, the effect of SHS on growth outcomes of older children is not well defined. Through a systematic literature review, we sought to determine whether a relationship exists between SHS exposure and growth outcomes of children up to 8 years of age.

METHODS

A systematic review was performed, including articles published between 2004–2019, related to SHS exposure (prenatal and postnatal) and children’s growth (weight, length/height, and head circumference). The relevant articles were identified from Science Direct, ProQuest, Sage Publication, Scopus, Wiley Online Library, CINAHL Plus with Full Text (via EBSCOhost) and Google search.

RESULTS

Seventeen articles were identified, of which three categories of growth measurements were extracted, comprising weight (weight, WAZ, WHZ, and BMI), height (height/length and HAZ) and head circumference. SHS exposure both pre or postnatally was inversely associated with weight (deficit in weight, risk of underweight, risk of wasting) and height (lower length and risk of stunting) and elevated BMI of children. Furthermore, prenatal SHS exposure was associated with a lower head circumference.

CONCLUSIONS

The current review identified that exposure to SHS may be associated with adverse growth outcomes in children. It is crucial that active smokers, specifically those who live with children or with a pregnant partner, are made aware of the potential effects of SHS exposure on non-smokers. Further assessment of the association between exposure to SHS and other growth outcomes in other age groups is needed.

Prenatal smoke effect on mouse offspring Igf1 promoter methylation from fetal stage to adulthood is organ and sex specific

Prenatal smoke exposure (PSE) is associated with reduced birth weight, impaired fetal development, and increased risk for diseases later in life. Changes in DNA methylation may be involved, as multiple large-scale epigenome-wide association studies showed that PSE is robustly associated with DNA methylation changes in blood among offspring in early life. Insulin-like growth factor-1 (IGF1) is important in growth, differentiation, and repair processes after injury. However, no studies investigated the organ-specific persistence of PSE-induced methylation change of Igf1 into adulthood. Based on our previous studies on the PSE effect on Igf1 promoter methylation in fetal and neonatal mouse offspring, we now have extended our studies to adulthood. Our data show that basal Igf1 promoter methylation generally increased in the lung but decreased in the liver (except for 2 persistent CpG sites in both organs) across three different developmental stages. PSE changed Igf1 promoter methylation in all three developmental stages, which was organ and sex specific. The PSE effect was less pronounced in adult offspring compared with the fetal and neonatal stages. In addition, the PSE effect in the adult stage was more pronounced in the lung compared with the liver. For most CpG sites, an inverse correlation was found for promoter methylation and mRNA expression when the data of all three stages were combined. This was more prominent in the liver. Our findings provide additional evidence for sex- and organ-dependent prenatal programming, which supports the developmental origins of health and disease (DOHaD) hypothesis.

Prenatal exposure to traffic and ambient air pollution and infant weight and adiposity: The Healthy Start study

BACKGROUND

Prenatal exposures to ambient air pollution and traffic have been associated with adverse birth outcomes, and may also lead to an increased risk of obesity. Obesity risk may be reflected in changes in body composition in infancy.

OBJECTIVE

To estimate associations between prenatal ambient air pollution and traffic exposure, and infant weight and adiposity in a Colorado-based prospective cohort study.

METHODS

Participants were 1125 mother-infant pairs with term births. Birth weight was recorded from medical records and body composition measures (fat mass, fat-free mass, and adiposity [percent fat mass]) were evaluated via air displacement plethysmography at birth (n = 951) and at ~5 months (n = 574). Maternal residential address was used to calculate distance to nearest roadway, traffic density, and ambient concentrations of fine particulate matter (PM2.5) and ozone (O3) via inverse-distance weighted interpolation of stationary monitoring data, averaged by trimester and throughout pregnancy. Adjusted linear regression models estimated associations between exposures and infant weight and body composition.

RESULTS

Participants were urban residents and diverse in race/ethnicity and socioeconomic status. Average ambient air pollutant concentrations were generally low; the median, interquartile range (IQR), and range of third trimester concentrations were 7.3 μg/m3 (IQR: 1.3, range: 3.3-12.7) for PM2.5 and 46.3 ppb (IQR: 18.4, range: 21.7-63.2) for 8-h maximum O3. Overall there were few associations between traffic and air pollution exposures and infant outcomes. Third trimester O3 was associated with greater adiposity at follow-up (2.2% per IQR, 95% CI 0.1, 4.3), and with greater rates of change in fat mass (1.8 g/day, 95% CI 0.5, 3.2) and adiposity (2.1%/100 days, 95% CI 0.4, 3.7) from birth to follow-up.

CONCLUSIONS

We found limited evidence of an association between prenatal traffic and ambient air pollution exposure and infant body composition. Suggestive associations between prenatal ozone exposure and early postnatal changes in body composition merit further investigation.

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.

Associations between maternal stress during pregnancy and offspring obesity risk later in life-A systematic literature review

Exposure to prenatal stress is linked to health consequences in the offspring. The objective of this systematic review was to synthesize and critically appraise primary human studies that have examined the association between prenatal exposure to psychosocial stress, or adverse life events, stress hormones, and later risk of developing obesity. We searched Medline, Embase, ScienceDirect, WorldCat, and OpenGrey up to January 2019 to identify relevant literature. We critically appraised the identified studies, assessed their quality, and summarized their findings. From a total of 5930 search results and references of studies that authors considered pertinent, we identified 15 relevant studies among which three were of high quality and the rest were medium-quality studies. We found direct association between exposure to stress in fetal life and different measures of obesity in the offspring in eight studies. The direct association was usually observed in studies that involved measurement of stress among mothers exposed to natural disasters. Due to lack of adequate and comparable data from the included studies, we did not conduct a meta-analysis. We concluded that there may be direct association between prenatal stress and later obesity, but further research with more comparable sources of stressors is recommended.

Maternal Tobacco Smoke Exposure Causes Sex-Divergent Changes in Placental Lipid Metabolism in the Rat

Maternal tobacco smoke exposure (MTS) affects fetal acquisition of long-chain polyunsaturated fatty acids (LCPUFA) and increases the risk of obesity and cardio-metabolic disease in the offspring. Alterations in fetal LCPUFA acquisition in maternal smoking are mediated by the placenta. The handling of LCPUFA by the placenta involves protein-mediated transfer and storage. Molecular mediators of placental LCPUFA handling include PPARγ and the fatty acid transport proteins. We previously demonstrated, in a rat model, that MTS results in programming of adult-onset obesity and metabolic disease in male, but not female, offspring. In this study, we test the hypothesis that in utero MTS exposure alters placental structure, placental LCPUFA handling, and fetal fatty acid levels, in a sex-divergent manner. We exposed pregnant rats to tobacco smoke from embryonic day 11 to term gestation. We measured placental and fetal fatty acid profiles, the systolic/diastolic ratio (SD ratio), placental histology, and expression of molecular mediators in the placenta. Our primary finding is that MTS alters fatty acid profiles in male, but not female fetuses and placenta, including increasing the ratio of omega-6 to omega-3 fatty acids. MTS also increased SD ratio in male, but not female placenta. In contrast, the expression of PPARγ and FATPs was upregulated in female, but not male placenta. We conclude that MTS causes sex-divergent changes in placental handling of LCPUFA in the rat. We speculate that our results demonstrate an adaptive response to MTS by the female placenta.

Rethinking the association between overweight/obesity and ADHD in children: a longitudinal and psychosocial perspective

OBJECTIVE

This study examines the association between attention-deficit/hyperactivity disorder (ADHD) and overweight/obesity in a large-scale longitudinal study of children, while controlling for a range of psychosocial factors.

METHOD

Data were obtained from Growing Up in Ireland, a nationally representative and longitudinal study of approximately 6500 children who were assessed at 9 and 13 years of age. Body mass index (BMI) was determined using measured height and weight, ADHD status was determined by parent reports of professional diagnoses and ADHD symptoms were measured using the Strengths and Difficulties Questionnaire (SDQ).

RESULTS

The associations between ADHD status, ADHD symptoms (SDQ) and BMI category at age 9 and 13 years were evaluated using logistic regression. Adjustments were made for child factors (sex, developmental coordination disorder, emotional symptoms, conduct problems, birth weight and exercise) and parental factors (socio-economic status, parental BMI, parental depression, and maternal smoking and alcohol use during pregnancy). Logistic regression indicated that ADHD status was not associated with BMI category at 9 or at 13 years of age, but children with ADHD at 9 years were significantly more likely to be overweight/obese at 13 years than those without ADHD. However, when other child and parental factors were adjusted for, ADHD status was no longer significantly associated with weight status. Female sex, low levels of exercise, overweight/obese parents and prenatal smoking during pregnancy consistently increased the odds of childhood overweight/obesity.

CONCLUSIONS

While ADHD and overweight/obesity co-occur in general populations, this relationship is largely explained by a variety of psychosocial factors.

Maternal smoking, genetic susceptibility, and birth-to-adulthood body weight

BACKGROUND

Maternal smoking (MS) is associated with low birthweight (BW) but adult obesity in offspring, however, it remains unknown whether it modifies offspring's genetic susceptibility to obesity on BW, adult body weight, and birth-to-adulthood body weight tracking pattern.

METHODS

This study included 246,759 UK Biobank participants with information on MS, BW (kg), adult body weight and BMI (kg/m²). Individual polygenetic score (PGS) was created on the basis of 97 BMI-associated genetic loci. We calculated individual birth-to-adulthood percentile change, and body weight tracking patterns that combined BW levels (<2.5, 2.5-4.0, and ≥4.0 as low, normal and high BW [LBW, NBW, and HBW]) and adulthood obesity status (≥30 as obesity [OB] and <30 as non-obesity [NOB]), including LBW-to-OB, LBW-to-NOB, NBW-to-OB, NBW-to-NOB, HBW-to-OB, and HBW-to-NOB.

RESULTS

Participants exposed to MS had a 0.108 kg lower BW (95% CI, -0.114 to -0.102), a 1.418 kg higher adult body weight (95% CI, 1.291-1.545), and a 6.91 greater percentile increase of body weight from birth to adulthood (95% CI, 6.62-7.21), compared with those nonexposed (all P < 0.001). In comparison to participants of NBW-to-NOB, MS was associated with an approximately twofold higher risk of LBW-to-OB (odds ratio [OR] 1.98, 95% CI 1.87-2.10), and a reduced likelihood of HBW-to-NOB (0.85, 95% CI 0.82-0.88). The increases in BW, adult body weight, and birth-to-adulthood percentile change per increment of 10 BMI-PGS were 0.021 vs. 0.012, 2.50 vs. 2.11, and 4.03 vs. 3.55, respectively, for participants exposed vs. nonexposed to MS (all P_interaction < 0.05).

CONCLUSION

Our results indicate that exposure to MS is associated with an increased risk of transition from low BW-to-adulthood obesity, and reduced likelihood of change from high BW-to-normal adult body weight. MS may modify the relation of genetic susceptibility to obesity and body weight in offspring.

Influence of early-life risk factors on socioeconomic inequalities in weight gain

Background

Previous research has examined the role of early-life risk factors on childhood weight gain.The extent to which these factors drive socioeconomic differences in weight is unclear. We aimed to quantify the influence of early-life risk factors on the development of socioeconomic inequalities in children's body mass index (BMI) z-score at 10-11 years.

Methods

Overall, 2186 children from the Longitudinal Study of Australian Children were examined. Socioeconomic position (SEP) was measured as a continuous composite of parent's education, occupation and income. The Product of Coefficients mediation method was used to quantify the contribution of maternal smoking during pregnancy, gestational diabetes, prematurity, caesarean section, birthweight, not being breastfed, early introduction of solid food, maternal BMI and paternal BMI to the relationship between SEP and BMI z-score.

Results

Each increasing decile of SEP (higher SEP) was associated with a 0.05 unit lower (95% CI: -0.06, -0.03) BMI z-score at 10-11 years. In total, 83.5% of these differences in BMI z-score could be explained by socioeconomic differences in maternal smoking during pregnancy (26.9%), maternal BMI (39.6%) and paternal BMI (17.0%).

Conclusions

Interventions to reduce socioeconomic inequalities in excess weight gain during childhood should support the attainment of a healthy parental weight and prevent smoking during pregnancy.

The association between prenatal exposure to environmental tobacco smoke and childhood obesity: a systematic review

OBJECTIVE

The objective of the review was to determine if prenatal exposure to environmental tobacco smoke (ETS) increases the risk of obesity and overweight in children.

INTRODUCTION

Childhood obesity has reached epidemic proportions in many developed countries. This is of great concern as childhood obesity is associated with early onset of chronic diseases such as coronary artery disease, type II diabetes and hypertension in adulthood. Extensive research suggests a multifactorial etiology. These factors include genetic markers, individual lifestyle, social and environmental factors, particularly the interaction between these factors. Among environmental factors, prenatal exposure to ETS has been linked to increased rates of obesity and overweight in childhood.

INCLUSION CRITERIA

This review considered studies on children of women who were non-smokers and who reported exposure to ETS during pregnancy. The exposure of interest was exposure to ETS or second hand smoke during pregnancy, determined by either: i) self-reported maternal exposure; and/or ii) serum cotinine levels. Observational studies such as cohort studies, case control studies, retrospective studies and analytical cross-sectional studies were included. Outcomes of interest were weight, height and body mass index of children from birth up to 18 years.

METHODS

A three-step search strategy was used to search for published and unpublished studies in the English language. No search range (years) was set. Two reviewers assessed the studies for inclusion and methodological quality using the Joanna Briggs Institute System for the Unified Management, Assessment and Review of Information (JBI SUMARI) standardized appraisal instruments. Data was extracted by two people independently and entered into the JBI extraction tool. Extracted data was pooled in a statistical meta-analysis based on a random effects model.

RESULTS

Nineteen studies were included in the review. Eight of the studies were included in the final meta-analysis. Findings suggest that there was an association between prenatal exposure to ETS and childhood obesity (odds ratio [OR]: 1.905, CI: 1.23-2.94), and no association between ETS exposure and overweight (OR: 1.51, CI: 0.49-4.59). The high rates of heterogeneity between studies in both of the meta-analyses determined by the I statistic (97% and 99%, respectively) sanction caution in the interpretation and use of these findings.

CONCLUSIONS

Based on the evidence, childhood obesity is associated with exposure to prenatal ETS, however overweight does not appear to be associated with this type of exposure.

Are genes destiny? Exploring the role of intrauterine environment in moderating genetic influences on body mass

OBJECTIVES

Genes influence every aspect of human behavior, physiology, and health. Obesity, a major global public health concern, is no exception. However, relatively little is known about whether environmental factors moderate the effects of genetic influences on body mass. By incorporating molecular genetics and the fetal origins of obesity hypothesis into a gene-environment interaction framework, this study investigates how the effect of the obesity-associated gene (FTO) interacts with the effect of intrauterine environment to influence body mass during adulthood.

METHODS

This study uses data from the Wisconsin Longitudinal Study, and uses sibling comparisons that allow for quasi-experimental variation in both genetic and environmental factors.

RESULTS

This study found positive, but noisy, within-family estimates of the FTO-body mass index (BMI) association. The association between birth weight and adult BMI was robust to controlling for unobserved family background factors. More importantly, this study revealed that the association between having a risk allele of the FTO gene and BMI (and obesity status) is largely concentrated among individuals who were heavier at birth. This provides evidence of a gene-environment interaction on BMI (and the development of obesity).

CONCLUSIONS

Genes are not destiny and environmental factors may offset the effects of obesity-promoting genes. Public health efforts to counteract genetic effects on body mass may begin as early as in utero. Efforts to prevent higher birth weight may thus help reduce the risk of obesity later in life, by directly addressing the programming effects of the in utero environment and also indirectly moderating obesity-promoting genetic effects.

Experiences and cessation needs of Indigenous women who smoke during pregnancy: a systematic review of qualitative evidence

OBJECTIVES

The aim of this review was to identify and synthesize the best available evidence to address two questions: i) what is the experience of smoking during pregnancy for Indigenous women? and ii) what are the smoking cessation needs of Indigenous women who smoke during pregnancy?

INTRODUCTION

Smoking during pregnancy not only affects pregnant women's general health but also causes such serious problems as pre-term delivery, low birth weight, and sudden infant death. Rates of smoking during pregnancy are particularly high among Indigenous women. Learning about Indigenous women's experiences of smoking during pregnancy and associated smoking cessation needs is important to providing informed health care to them.

INCLUSION CRITERIA

The participants of interest were Indigenous women who smoked during a current or past pregnancy. The phenomena of interest were the experiences of smoking during pregnancy for Indigenous women and the smoking cessation needs of Indigenous women during pregnancy. The context was any community worldwide where pregnant Indigenous women live. Studies considered for this review were those in which qualitative data were gathered and analysed on the phenomena of interest, including mixed methods research.

METHODS

A comprehensive search was conducted for published studies in academic databases (i.e. PubMed, CINAHL, PsycINFO, Embase, Sociological Abstracts, SocINDEX, and Web of Science), unpublished studies in sources of gray literature (i.e. ProQuest Dissertations and Theses, OAIster, LILACS, MedNar, Google, Google Scholar, OpenGrey and relevant websites), and any additional studies in reference lists. Language and date limiters were not applied. The searches included all studies globally and were carried out on October 31, 2016. Studies that met the inclusion criteria were assessed for methodological quality by two reviewers independently, using the criteria of the Joanna Briggs Institute (JBI) Critical Appraisal Checklist for Qualitative Research. Descriptive details of each study accepted for this review were extracted in accordance with the elements of the JBI Data Extraction Form for Qualitative Research. The research findings that were relevant to the phenomena of interest and had participant voice were extracted from each included study and synthesized using the JBI meta-aggregative approach. The synthesized findings were assigned confidence scores in accordance with the JBI ConQual approach.

RESULTS

Thirteen studies were included in this review following careful consideration of the methodological quality of each study. The studies yielded a total of 116 research findings, which were grouped into 19 categories and then aggregated to form five synthesized findings. Confidence in the findings was determined to be low to very low (see ConQual Summary of Findings).

CONCLUSION

There is a small body of research evidence on Indigenous women's experiences of smoking during pregnancy and their smoking cessation needs. Confidence in the synthesized findings is constrained due to methodological limitations in many of the primary studies included in this review, along with mixed credibility of the research findings from across primary studies.

Mediation by Placental DNA Methylation of the Association of Prenatal Maternal Smoking and Birth Weight

Prenatal maternal smoking is a risk factor for lower birth weight. We performed epigenome-wide association analyses of placental DNA methylation (DNAm) at 720,077 cytosine-phosphate-guanine (CpG) sites and prenatal maternal smoking among 441 mother-infant pairs (2010-2014) and evaluated whether DNAm mediates the association between smoking and birth weight using mediation analysis. Mean birth weight was 3,443 (standard deviation, 423) g, and 38 mothers (8.6%) reported smoking at a mean of 9.4 weeks of gestation. Prenatal maternal smoking was associated with a 175-g lower birth weight (95% confidence interval (CI): -305.5, -44.8) and with differential DNAm of 71 CpGs in placenta, robust to latent-factor adjustment reflecting cell types (Bonferroni-adjusted P < 6.94 × 10-8). Of the 71 CpG sites, 7 mediated the association between prenatal smoking and birth weight (on MDS2, PBX1, CYP1A2, VPRBP, WBP1L, CD28, and CDK6 genes), and prenatal smoking × DNAm interactions on birth weight were observed for 5 CpG sites. The strongest mediator, cg22638236, was annotated to the PBX1 gene body involved in skeletal patterning and programming, with a mediated effect of 301-g lower birth weight (95% CI: -543, -86) among smokers but no mediated effect for nonsmokers (β = -38 g; 95% CI: -88, 9). Prenatal maternal smoking might interact with placental DNAm at specific loci, mediating the association with lower infant birth weight.

Weight gain, feeding and eating in the first year of life of babies of smoking and non-smoking mothers

Babies of mothers who smoke during pregnancy tend to be born underweight but are at risk for pediatric obesity. Maternal feeding practices, maternal disordered eating, and child temperament were assessed as potential mediators of early weight gain in babies of smoking and non-smoking mothers. The BMIs of babies of 88 smoking and 107 non-smoking mothers were recorded at birth and reported one year later. Mothers self-reported on disordered eating and child feeding practices, and on their infants' temperament. Babies of smoking mothers had lower BMI at birth but not at age one. For babies of non-smoking but not for those of smoking mothers, BMI at birth predicted BMI at age one. Smoking mothers' disordered eating and pressure for children to eat predicted their babies' BMI at age one. In the non-smoking group only, there were significant correlations between babies' temperamental difficulties and babies' BMI at age one. In contrast to non-smoking mothers, smoking mothers tend to pressure their babies to eat, and not to feed them in response to their distress. This interim picture may provide insight into the transition of the children of smoking mothers from underweight newborns to children classified as overweight.

Hypothalamic Neuropeptides Expression and Hypothalamic Inflammation in Adult Rats that Were Exposed to Tobacco Smoke during Breastfeeding: Sex-Related Differences

The hypothalamus controls food intake and energy expenditure. In rats, maternal exposure to nicotine during breastfeeding alters the hypothalamic circuitry of the adult offspring, resulting in leptin resistance, neuropeptides changes and gliosis. Tobacco smoke exposure during lactation causes greater adiposity, hyperphagia and hyperleptinemia in the adult progeny. To understand the central mechanisms underlying the obese phenotype of adult rats that were directly and indirectly exposed to cigarette smoke during lactation, we investigated leptin signaling, orexigenic and anorexigenic neuropeptides expression, as well as astrocyte and microglia markers in hypothalamus. From postnatal day (PND) 3 to 21, Wistar lactating rat dams and their pups were divided into two groups: SE, smoke-exposed in a cigarette-smoking machine (four times/day); Crtl, exposed to filtered air. Offspring of both sexes were euthanized at PND180. The leptin pathway was not altered in SE animals from both sexes. SE males showed increased NPY (arcuate nucleus, ARC), CRH (paraventricular nucleus, PVN), as well as higher GFAP fiber density (ARC and PVN) and IL6 protein content. TRH (PVN) immunohistochemistry was reduced. SE females had lower CART-positive cells (ARC) and lower α-MSH immunostaining intensity (PVN and lateral hypothalamus), with no change of GFAP or IL-6. The protein contents of CX3CR1 (marker of activated microglia) and α7nAChR (anti-inflammatory marker) were not altered in both SE males and females. Neonatal cigarette smoke is deleterious to the hypothalamic circuitry, inducing changes in energy homeostasis favoring hyperphagia and decreased energy expenditure at adulthood in both sexes; however sex-dependent mechanisms were observed.

Smoking and pregnancy: Epigenetics and developmental origins of the metabolic syndrome

Maternal smoking causes lower birth weight, birth defects, and other adverse pregnancy outcomes. Epidemiological evidence over the past four decades has grown stronger and the adverse outcomes attributed to maternal smoking and secondhand smoke exposure have expanded. This review presents findings of latent and persistent metabolic effects in offspring of smoking mothers like those observed in studies of maternal undernutrition during pregnancy. The phenotype of offspring of smoking mothers is like that associated with maternal undernutrition. Born smaller than offspring of nonsmokers, these children have increased risk of being overweight or obese later. Plausible mechanisms include in utero hypoxia, nicotine-induced reductions in uteroplacental blood flow, placental toxicity, or toxic growth restriction from the many toxicants in tobacco smoke. Studies have reported increased risk of insulin resistance, type 2 diabetes and hypertension although the evidence here is weaker than for overweight/obesity. Altered DNA methylation has been consistently documented in smoking mothers' offspring, and these epigenetic alterations are extensive and postnatally durable. A causal link between altered DNA methylation and the phenotypic changes observed in offspring remains to be firmly established, yet the association is strong, and mediation analyses suggest a causal link. Studies examining expression patterns of affected genes during childhood development and associated health outcomes should be instructive in this regard. The adverse effects of exposure to tobacco smoke during pregnancy now clearly include permanent metabolic derangements in offspring that can adversely affect life-long health.

Infancy weight gain, parental socioeconomic position, and childhood overweight and obesity: a Danish register-based cohort study

BACKGROUND

Rapid infant weight gain (RIWG) is a very strong predictor of childhood overweight and obesity (COO). Socioeconomic position (SEP) is also related to the risk of COO and parents of different SEP may differ in their reaction to accelerated infant weight gain. Together this could lead to differences in how weight gain and COO risk relate across SEP. This study aimed to analyse possible interaction of SEP and RIWG on COO risk.

METHODS

A register-based longitudinal cohort study followed 19,894 healthy, term infants, born in Denmark between December 2011 and May 2015. Logistic regression models were used to estimate odds ratios (OR) of COO risk at 2 years (22-26 months) of age with 95% confidence intervals (95% CI) for categories of infancy weight gain based on changes in weight-for-age z-scores between 0 and 8-10 months of age (slow (<- 0.67), mean (- 0.67-0.67), rapid (> 0.67-1.34) and very rapid (> 1.34)). Possible multiplicative and additive interaction of SEP (based on household income and maternal education) on the relationship between infancy weight gain and COO were analysed.

RESULTS

In total, 19.1 and 15.1% experienced rapid or very rapid weight gain, respectively, and 1497 (7.5%) children were classified with COO at follow-up. These prevalences were higher in those with lower levels of SEP. Adjusted OR for COO were 3.09 (95% CI [2.66-3.59]) and 7.58 (95% CI [6.51-8.83]) for rapid and very rapid weight gain, respectively, when household income was included in the model. Results were similar in the model including maternal education. No signs of interactions were detected on a multiplicative scale. Weak signs of additive interaction were present, but these values did not reach significance.

CONCLUSION

Both rapid and very rapid weight gain were associated with substantially higher risks of COO but these associations were not modified by SEP. This indicates that promotion of healthy weight gain should take place in all population groups irrespective of their SEP.

Maternal smoking during pregnancy and offspring utilisation of health care services: A population-based cohort study

BACKGROUND

Maternal smoking during pregnancy (MSDP) has been associated with a wide range of adverse effects on offspring health, such as low birthweight, behavioural disorders, and asthma. The number of women that smoke during pregnancy in Denmark is still high, making it relevant to study the long-term health outcomes in offspring exposed to maternal smoking in utero.

OBJECTIVE

We investigated whether exposure to MSDP is associated with more frequent use of health care services during the first 10 years of life.

METHODS

This population-based cohort study included participants enrolled in the Danish National Birth Cohort between 1996 and 2003. Data on MSDP were obtained from two telephone interviews during pregnancy and one interview after pregnancy. The primary outcome was contacts to the health care system. From Danish national registries, we obtained information on number and type of contacts to the general practitioner (GP), and information on the specific types of services provided. Further, we obtained information on hospital admissions, and redemption of prescribed medicine. We fitted negative binomial regression models and Cox proportional hazards regression models to estimate associations. All analyses were adjusted for socio-economic status, birth year, and various maternal factors.

RESULTS

We studied 83,905 liveborn singletons and found that offspring exposed to maternal smoking in utero had more contacts to the GP in the first 10 years of life with an incidence rate ratio of 1.05, 95% confidence interval [CI] 1.04, 1.06. A higher rate of admission to hospital in 9 out of 20 categories was found, as was a higher rate of being prescribed psychoanaleptics (hazard ratio [HR] 1.41, 95% CI 1.25, 1.60), drugs for obstructive pulmonary disease (HR 1.14, 95% CI 1.14, 1.20), and antibiotics (HR 1.03, 95% CI 1.01, 1.05).

CONCLUSIONS

We found that offspring exposed to MSDP had a higher use of health care services than unexposed offspring.

From conception to infancy - early risk factors for childhood obesity

Maternal lifestyle during pregnancy, as well as early nutrition and the environment infants are raised in, are considered relevant factors for the prevention of childhood obesity. Several models are available for the prediction of childhood overweight and obesity, yet most have not been externally validated. Moreover, the factors considered in the models differ among studies as the outcomes manifest after birth and depend on maturation processes that vary between individuals. The current Review examines and interprets data on the early determinants of childhood obesity to provide relevant strategies for daily clinical work. We evaluate a selection of prenatal and postnatal factors associated with child adiposity. Actions to be considered for preventing childhood obesity include the promotion of healthy maternal nutrition and weight status at reproductive age and during pregnancy, as well as careful monitoring of infant growth to detect early excessive weight gain. Paediatricians and other health-care professionals should provide scientifically validated, individual nutritional advice to families to counteract excessive adiposity in children. Based on systematic reviews, original papers and scientific reports, we provide information to help with setting up public health strategies to prevent overweight and obesity in childhood.

Impact of maternal smoking on the infant gut microbiota and its association with child overweight: a scoping review

BACKGROUND

Childhood obesity is a growing public health concern with evidence demonstrating that while infant exposure to maternal smoking is linked to low birth weight at birth, there is a rapid catch up in weight and increased risk of obesity in later life. This scoping review aims to synthesize up-to-date evidence on the impact of maternal smoking on the infant gut microbiota and its association with child overweight.

METHODS

We conducted a PRISMA-compliant scoping review. Primary population-based cohort studies published between 1900 and April 2018 were included. Relevant publications were retrieved from seven databases: PubMed, Medline, Embase, Scopus, Biosis, Cochrane library, and Web of Science Core Collection.

RESULTS

A total of three prospective cohort studies were included which utilized high-throughput 16S rRNA gene sequencing to assess the gut microbiota and included a total of 1277 infant/neonatal participants. Neonates exposed to environmental smoke had a higher relative abundance of Ruminococcus and Akkermansia. Infants exposed to environmental smoke during pregnancy or postnatally were found to have increased gut bacterial richness, particularly Firmicutes at 3 months of age, while 6-month-old infants born to smoking mothers had an increased abundance of Bacteroides and Staphylococcus. Elevated Firmicutes richness at 3 months of age was associated with elevated odds of child overweight and obesity at 1 and 3 years of age.

CONCLUSION

The limited evidence to date warrants further large scale, longitudinal studies to explore the impact of maternal smoking and environmental tobacco smoke on the infant gut microbiome and its relation to child overweight.

Adherence to a healthy eating index from pre-school to school age and its associations with sociodemographic and early life factors

Childhood is considered an important period for the development of healthy eating behaviours. This study aimed to evaluate the influence of early life factors and sociodemographic characteristics, including early diet quality, on diet quality at 7 years. The sample includes 5013 children evaluated at the ages of 4 and 7 years from the Portuguese birth cohort Generation XXI with complete information on FFQ. A healthy eating index was developed at both ages to assess adherence to the WHO's dietary recommendations, including eight food groups. Consumption quartiles were obtained for each group at 4 years and assigned a score between 1 and 4. A higher score represents a higher adherence to a better diet (range: 8 to 32). The associations between early life factors and sociodemographic characteristics and the score of the healthy eating index at 7 years were evaluated through linear regression models. The healthy eating index had an average score of 21⋅4 ± 3⋅53 (range: 12 to 32) at 4 years and 20⋅3 ± 3⋅36 (range: 11 to 31) at 7 years. After adjustment for confounders, a positive association was found between the healthy eating index at 4 and 7 years (β = 0⋅384, 95 % CI 0⋅356, 0⋅441). Maternal years of education (β = 0⋅094, 95 % CI 0⋅071, 0⋅116) and dietary score (β = 0⋅182, 95 % CI 0⋅155, 0⋅209) were positively associated with increasing dietary quality from 4 to 7 years. A healthier diet at preschool age, higher maternal education and a healthier diet increase the likelihood of maintaining a high healthy eating index score at school age.

Maternal smoking during pregnancy and offspring body composition in adulthood: Results from two birth cohort studies

OBJECTIVE

To evaluate the association of maternal smoking during pregnancy with offspring body composition in adulthood and explore the causality of this association.

DESIGN

Birth cohort.

SETTING

Population-based study in Pelotas, Brazil.

PARTICIPANTS

All newborn infants in the city's hospitals were enrolled in 1982 and 1993. At a mean age of 30.2 and 22.6 years, the 1982 and 1993 cohorts, respectively, followed the subjects and 7222 subjects were evaluated.

PRIMARY OUTCOME MEASURES

Body mass index (BMI), fat mass index, android to gynoid fat ratio, waist circumference, waist to height ratio, lean mass index and height.

RESULTS

Prevalence of maternal smoking during pregnancy was 35.1% and 32.6%, in 1982 and 1993 cohorts, respectively. Offspring of smoking mothers showed higher mean BMI (β: 0.84; 95% CI: 0.55 to 1.12 kg/m²), fat mass index (β: 0.44; 95% CI: 0.23 to 0.64 kg/m²), android to gynoid fat ratio (β: 0.016; 95% CI: 0.010 to 0.023), waist circumference (β: 1.74; 95% CI: 1.15 to 2.33 cm), waist to height ratio (β: 0.013; 95% CI: 0.010 to 0.017) and lean mass index (β: 0.33; 95% CI: 0.24 to 0.42 kg/m²), whereas height was lower (β: -0.95; -1.26 to -0.65). Weight gain in the first 2 years captured most of the association of maternal smoking with BMI (96.2%), waist circumference (86.1%) and fat mass index (71.7%).

CONCLUSIONS

Maternal smoking in pregnancy was associated with offspring body composition measures in adulthood.

Insulin Resistance in Children

Insulin resistance (IR) is a pathological condition strongly associated with obesity. However, corticosteroids or growth hormone therapy and genetic diseases may affect insulin sensitivity lifelong. In obese children and adolescents of any age there is an evident association between IR and an increased prevalence of type 2 diabetes (T2D) and other elements contributing to the metabolic syndrome, leading to a higher cardiovascular risk. Therefore, early diagnosis and interventions in the attempt to prevent T2D when glycemia values are still normal is fundamental. The gold standard technique used to evaluate IR is the hyperinsulinemic euglycemic clamp, however it is costly and difficult to perform in clinical and research sets. Therefore, several surrogate markers have been proposed. Although the treatment of insulin resistance in children is firstly targeted to lifestyle interventions, in selected cases the integration of a pharmacological intervention might be taken into consideration. The aim of this review is to present the current knowledge on IR in children, starting with an outline of the recent evidences about the congenital forms of deficiency in insulin functioning and therefore focusing on the physiopathology of IR, its appropriate measurement, consequences, treatment options and prevention strategies.

Examining Associations between Perinatal and Postnatal Risk Factors for Childhood Obesity Using Sibling Comparisons

Background: One of the major criticisms of observational studies examining risk factors for childhood obesity is unmeasured confounding. We examined the associations between breastfeeding initiation, cesarean delivery, prenatal smoking, and gestational diabetes mellitus (GDM) with childhood obesity using both a traditional observational approach and a sibling-pair design with family fixed effects. Methods: We used data from the Linked the Collecting Electronic Nutrition Trajectory Data Using e-Records of Youth (CENTURY) Study, a clinical database created through the linkage of well-child visits with children's birth certificates, with obesity measured at 2 (N = 55,058) and 5 (N = 43,894) years of age. We conducted three sets of regression models: (1) full sample to examine the adjusted association between each risk factor and obesity with clustering by family; (2) rerun only among siblings with clustering by family; and (3) fixed effects analysis among siblings. Results: Across risk factors, 30%-39% of children had siblings. In the full sample, breastfeeding initiation was associated with a lower BMI z-score, while cesarean delivery and smoking during pregnancy were associated with a higher BMI z-score. Effect sizes were consistent in models with siblings only. However, in the fixed effects models, the coefficients attenuated and were no longer significant for each of these risk factors. We found no association between GDM and child BMI z-score in any of the models. Results were consistent for childhood obesity as a dichotomous measure and at 5 years of age. Conclusions: Our findings suggest that unmeasured genetic, environmental, and familial factors are likely confounding associations between breastfeeding, cesarean delivery, prenatal smoking, and GDM with childhood obesity in observational studies.

The Long-Term Effects of Dietary Nutrient Intakes during the First 2 Years of Life in Healthy Infants from Developed Countries: An Umbrella Review

The role of both qualitative and quantitative early nutrient intakes on later health has been suggested for decades and supported by observational studies on humans, mainly preterm and low-birth-weight infants, and animal models. However, to date, no comprehensive review has been conducted to evaluate the full impact of nutritional variables on healthy full-term infants. This umbrella review considers meta-analyses and systematic reviews on the health effects of different nutritional exposures or interventions in the first 2 y of life of healthy full-term infants in developed countries. The systematic reviews and meta-analyses published by March 2018 in MEDLINE, EMBASE, and Cochrane Database of Systematic Reviews were included. The following outcomes were considered: growth and obesity, cardiovascular disease, neurodevelopment, allergy and autoimmunity, infections, and malignancy. Breastfeeding and complementary feeding were considered separately and analyzed by means of their differences in delivering heterogeneous food-related variables. The resulting data on the long-term effect of early nutritional differences in healthy full-term infants were found to be inconclusive. Only breastfeeding has a beneficial effect, which is nevertheless slight and limited to just a few outcome measures, whereas the type and duration required to be effective are still unclear. As regards the complementary feeding period, no clear effects of different dietary interventions emerge in terms of health outcomes. Available evidence on the health effects of differences in early nutrition in healthy full-term infants still remains largely inconclusive.

Metabolic programming in early life in humans

An association of low birth weight with an increased risk of adult cardiovascular disease and diabetes led to the developmental origins of health and disease (DOHaD) hypothesis, which proposes that undernutrition during early development permanently 'programmes' organ structure and metabolism, leading to vulnerability to later cardio-metabolic disease. High birth weight caused by maternal gestational diabetes is also associated with later diabetes, suggesting that fetal over-nutrition also has programming effects. Post-natal factors (excess weight gain/obesity, smoking, poor diets and physical inactivity) interact with fetal exposures to increase disease risk. Animal studies have shown permanent metabolic effects in offspring after alterations to maternal or early post-natal diets but evidence in humans is largely limited to observational and quasi-experimental situations such as maternal famine exposure. Randomized trials of maternal nutritional interventions during pregnancy have so far had limited follow-up of the offspring. Moreover, interventions usually started after the first trimester and therefore missed key peri-conceptional or early pregnancy events such as epigenetic changes, placentation and fetal organogenesis. Recent and ongoing trials intervening pre-conceptionally and powered for long-term offspring follow-up will address these issues. While current preventive strategies for cardio-metabolic disease focus on high-risk individuals in mid-life, DOHaD concepts offer a 'primordial' preventive strategy to reduce disease in future generations by improving fetal and infant development. This article is part of the theme issue 'Developing differences: early-life effects and evolutionary medicine'.

The relationship between parental locus of control and adolescent obesity: a longitudinal pre-birth cohort

OBJECTIVES

To investigate whether parental external locus of control (ELOC) measured in pregnancy is related to obesity in their adolescent offspring and whether the child's own ELOC measured at age 8 contributes. To determine whether associations are due to types of behaviour used by externally oriented participants.

SUBJECTS/METHODS

Longitudinal pre-birth cohort study (Avon Longitudinal Study of Parents & Children (ALSPAC)) set in south-west England. Families whose adolescent offspring had their fat mass measured using DXA scans at any of ages 9, 11, 13, 15 or 17 (range, n = 7329 at 9 to n = 4850 at 17). The primary outcome measures were mean fat mass, and obesity measured as ≥85th centile of fat mass at each age.

RESULTS

We found that parent and child externality was associated with greater fat mass [e.g., mean difference at age 15 associated with maternal ELOC was 1.70 kg (+1.17, +2.24), paternal ELOC 1.49 kg (+0.89, +2.09) and child's ELOC 1.50 kg (+0.93, +2.06) (P < 0.0001)]. Further analyses showed that factors associated with parent behaviour such as smoking in pregnancy, failure to breast feed, and early introduction of solids accounted for a third of the excess fat mass associated with maternal externality, whereas aspects of diet and energetic activity in later childhood were not. Further analyses demonstrated that the child's own ELOC only became independently important for adolescent obesity from age 13, whereas the mothers' and to a lesser extent the fathers' ELOC were associated at each age.

CONCLUSIONS

There is increased interest in determining factors that may be involved in the aetiology and maintenance of excessive weight in adolescents. We demonstrate that parental locus of control is a promising candidate. We suggest interventions to change parents' locus of control towards internality in pregnancy might have long-term preventative benefits on the likelihood of obesity in the offspring.

Associations of first trimester co-use of tobacco and Cannabis with prenatal immune response and psychosocial well-being

PURPOSE

This study aims to describe the association of first trimester co-use of tobacco and cannabis with maternal immune response and psychosocial well-being, relative to tobacco use only.

METHODS

A preliminary midpoint analysis included 138 pregnant women with biologically verified tobacco use, 38 of whom (28%) also tested positive for recent cannabis use. Maternal perceived stress (Perceived Stress Scale), depressive symptoms (Edinburgh Postnatal Depression Scale), and serum immune markers (IL-1β, IL-2, IL-6, IL-8, IL-10, TNFα, CRP, MMP8), were collected, although cytokine data were only available for 122 women.

RESULTS

Participant average age was 29.1 years, approximately half had a high school education or less, and half were unemployed. Compared to tobacco only users, co-users were more likely to be non-White, younger and more economically disadvantaged. In the adjusted linear regression models, TNF-α levels were significantly lower among co-users relative to tobacco only users, after adjusting for age, race/ethnicity, body mass index and tobacco use group (tobacco cigarettes, electronic nicotine delivery devices [ENDS] or both). TNF-α was the only immune marker found to be significant in this analysis. Measured stress levels (M = 5.9, SD = 3.3; potential range 0-16) and depression scores (M = 7.8, SD = 5.8; potential range 0-30) were low across all participants and did not differ as a function of co-use.

CONCLUSION

Preliminary results suggest women co-using during the first trimester exhibit decreased pro-inflammatory immune responsivity on one out of eight markers. Further research is needed to determine the impact of this immune modulation on fetal health outcomes and the unique contribution of cannabis.

Effect of maternal smoking in pregnancy and childhood on child and adolescent sleep outcomes to 21 years: a birth cohort study

BACKGROUND

The effects of prenatal maternal smoking have been studied extensively, however little research has examined the effects of prenatal exposure to maternal smoking on offspring sleep, particularly over several developmental periods. We examined the effects of prenatal maternal smoking and postnatal smoking from birth to 14 years, on offspring sleep at 6 months, 5, 14 and 21 years.

METHODS

This was a prospective, community-based birth cohort study involving 7223 women who delivered a singleton child in Brisbane, Australia between 1981 and 1983. Women were recruited at the first antenatal visit. Offspring sleep problems were reported by mothers at 6 months, 5 and 14 years, and by youth at 14 and 21 years. 3738 mothers prospectively reported their smoking status from pregnancy to 14 years postpartum. Youth snoring was reported by mothers at 14 years and by youth at 21 years. Multinomial logistic regression analyses were performed.

RESULTS AND DISCUSSION

Prenatal maternal smoking was independently associated with an increased risk of offspring adolescent parasomnias including walking and talking in sleep and nightmares, and an increased likelihood of being in the highest quintile for maternal and youth reported sleep problems at 14 years. Maternal postnatal smoking was associated with increased likelihood of offspring snoring at 14 years.

CONCLUSIONS

Exposure to maternal prenatal smoking has different effects on offspring sleep compared to exposure to postnatal smoking. Prenatal smoking exposure may be associated with changes in neurodevelopment whereas postnatal smoking is more likely to affect the respiratory system. These findings highlight the long lasting and potentially serious clinical effects of exposure to pre and postnatal maternal smoking on offspring, the mechanisms by which warrant further investigation.

Childhood obesity: increased risk for cardiometabolic disease and cancer in adulthood

Prevalence of childhood obesity has worldwide more than doubled since 1980. Underlying factors are complex and are far from completely understood. Strategies to prevent childhood obesity have mainly focused on behavioral intervention; and obesity therapy was mainly based on lifestyle modification to date. However, effects for both have been quite limited so far and no country has succeeded in fighting the obesity epidemy we are facing. Normalization of body weight before onset of puberty is crucial for several reasons: First, obese children and adolescents frequently stay obese until adulthood. Second, obesity during adolescence is significantly associated with increased risk for cardiovascular and metabolic disease such as type 2 diabetes in adulthood. And third, recent data have shown a strong association between higher body mass index (BMI) during adolescence and increased risk for several malignancies such as leukemia, Hodgkin's disease, colorectal cancer, breast cancer and others in adulthood. This review summarizes our current understanding of epidemiology, underlying factors, concomitant disease, as well as available intervention strategies and gives an overview of what has been reached so far and what measures should be undertaken to counteract the obesogenic environment.

Prenatal determinants of childhood obesity: a review of risk factors 1

Childhood obesity is a predictor of adult obesity and has its roots in the pre-pregnancy or pregnancy period. This review presents an overview of the prenatal risk factors for childhood obesity, which were categorized into 2 groups: biological risk factors (maternal pre-pregnancy body mass index, gestational weight gain, diabetes in pregnancy, and caesarean section), and environmental and behavioural risk factors (maternal smoking and exposure to obesogens, maternal dietary patterns, maternal intestinal microbiome and antibiotics exposure, and maternal psychosocial stress). Identifying modifiable predisposing prenatal factors for obesity will inform further development of inventions to prevent obesity over the life course, and future directions for research and intervention are discussed.

History of the Obesogen Field: Looking Back to Look Forward

The Obesogen field developed from two separate scientific research areas, endocrine disruptors and the Developmental Origins of Health and Disease (DOHaD). Endocrine Disrupting Chemicals (EDCs) are exogenous chemicals or mixtures of chemicals that interfere with the action of hormones. Exposure to EDCs during early development (DOHaD) has been shown to increase susceptibility to a variety of diseases including infertility, asthma, breast and prostate cancer, early puberty, susceptibility to infections, heart disease, autoimmune disease, and attention deficit hyperactivity disorder/learning disability. The effects of EDCs on obesity and fat cell development first gained attention around the turn of the twenty-first century. In 2002 Dr. Paula Baillie-Hamilton wrote the first review article focusing on environmental chemicals and obesity. She suggested that the obesity epidemic correlated with the increased production of chemicals after World War II. Baillie-Hamilton identified studies showing that exposures to a variety of chemicals led to weight gain. Shortly after that a commentary on an article showing that nonylphenol would increase fat cell differentiation in vitro noted the Baillie-Hamilton article and made the point that perhaps obesity was due in part to exposure to EDCs. In 2006 the field of DOHaD/EDCs and obesity made a giant leap forward when Dr. Bruce Blumberg published a paper showing that tributyltin could lead to weight gain in mice and coined the term obesogen for a chemical that caused weight gain and lead to obesity. In 2011, the NIEHS developed the first funding initiative focused on obesogens. In the following years there have been several workshops focused on obesogens. This paper describes these early days that lead to the obesogen hypotheses and the growth of the field for a decade, leading to its prominence today, and provides some insight into where the field is moving.

Maternal smoking during pregnancy and offspring body mass index and overweight: a systematic review and meta-analysis

Abstract: The present study aimed to conduct a systematic review and meta-analysis to evaluate the evidence on the association of maternal smoking during pregnancy with offspring body composition in childhood, adolescence and adulthood. MEDLINE, Web of Science and LILACS databases were searched. Reference lists were also screened. We included original studies, conducted in humans, that assessed the association of maternal smoking during pregnancy with offspring body mass index (BMI) and overweight in childhood, adolescence and adulthood, published through May 1st, 2018. A meta-analysis was used to estimate pooled effect sizes. The systematic review included 64 studies, of which 37 evaluated the association of maternal smoking during pregnancy with overweight, 13 with BMI, and 14 evaluated both outcomes. Of these 64 studies, 95 measures of effect were extracted and included in the meta-analysis. We verified that the quality of evidence across studies regarding maternal smoking in pregnancy and overweight and BMI of offspring to be moderate and low, respectively. Most studies (44 studies) were classified as moderate risk bias. Heterogeneity among studies included was high and, in the random-effects pooled analysis, maternal smoking during pregnancy increased the odds of offspring overweight (OR: 1.43, 95%CI: 1.35; 1.52) and mean difference of BMI (β: 0.31, 95%CI: 0.23; 0.39). In conclusion, offspring of mothers who smoked during pregnancy have higher odds of overweight and mean difference of BMI, and these associations persisted into adulthood.

Quit-smoking counselling in Dutch midwifery practices: Barriers to the implementation of national guidelines

OBJECTIVE

Although smoking during pregnancy can have severe health consequences for the (unborn) child, 9% of Dutch pregnant women smoke at any time during their pregnancy. Midwives in the Netherlands are a responsible party in the provision of quit-smoking counselling for pregnant women by means of the 7-step `V-MIS' intervention, but in practice the implementation appears to be suboptimal. The purpose of the present study was to assess the provision of quit-smoking counselling by midwives, and to clarify the nature and extent of any existing barriers and needs in the provision of quit-smoking counselling in Dutch midwifery settings.

METHODS

An online questionnaire to the target population of Dutch midwives (N ≈ 3150) was set out in the spring of 2016. The questionnaire included items on the provision of quit-smoking counselling for pregnant women, and on possible barriers and needs regarding the provision of this counselling. Descriptive statistics were used to analyse weighed data from 135 midwives representative for the Dutch setting in terms of age, function, and region.

RESULTS

Eighty-one percent of the midwives inquire about smoking profile (V-MIS step 1) but only 10% go through all the V-MIS counselling steps (i.e. up to discussing postnatal passive smoking and smoke free breastfeeding, step 7). Although 74% of the midwives regard it as their task to provide quit-smoking guidance to pregnant women, 77% perceive referral to a professional as a useful strategy (mostly to the GP; 74%). For 61% of the midwives, their clients' lack of motivation undermines the provision of quit-smoking counselling. Other hindering factors are the perceived lack of free brochures (54%), simple tools or gadgets (51%), and financial consequences for the midwife (37%) and/or the client (22%).

CONCLUSION

The smoking cessation intervention strategy currently imposed in Dutch midwifery practices (V-MIS) is being used by midwives, however its implementation may considerably benefit from strengthening skills in motivational interviewing techniques, provision of supporting materials, and structural embedding of GP referral. Based on the study's findings, practical recommendations are made to facilitate the provision of quit-smoking counselling in (international) midwifery settings.

The association between antibiotic use in infancy and childhood overweight or obesity: a systematic review and meta-analysis

PURPOSE

Antibiotic use is associated with alteration of the gut microbiome and metabolic activity. As childhood obesity is a predisposing factor for adult obesity, addressing childhood risk factors to weight gain in early life is important. This review aims to investigate the association between infant antibiotic exposure (aged < 24 months) and childhood obesity or overweight.

METHODS

Articles were retrieved from CINAHL, Cochrane CENTRAL, Embase and MEDLINE. Eligible articles investigated antibiotic use in exposed versus unexposed infants and measured childhood weight change. Data were synthesized narratively and meta-analysed where possible.

RESULTS

After title/abstract and full-text screening, 17 articles representing 15 unique studies were included for narrative synthesis. We found a small association between antibiotic exposure in infancy (<24 months) and childhood overweight or obesity. The strongest associations were observed in boys versus girls and children exposed to multiple antibiotic courses or broad-spectrum drugs. Meta-analysis of 12 sets of results comparing the earliest age of exposure to any antibiotic with overweight or obesity at the latest age of outcome found a pooled odds ratio of 1.05 (95% confidence interval: 1.00-1.11).

CONCLUSIONS

Antibiotic exposure in infants, aged < 24 months, was associated with a small increase in odds of childhood overweight or obesity in some subgroups of children.

Fish Intake in Pregnancy and Offspring Metabolic Parameters at Age 9⁻16-Does Gestational Diabetes Modify the Risk?

Oily fish, an important source of marine n-3 long-chain polyunsaturated fatty acids (LCPUFA), has shown to reduce cardiometabolic risk in adults. Whether maternal fish intake affects offspring metabolic health is less established, especially among high-risk pregnancies. We aimed to examine the association of fish intake in pregnancy with offspring metabolic health who were either exposed or unexposed to gestational diabetes mellitus (GDM). Our study included 1234 mother-offspring dyads (608 with a GDM index pregnancy and 626 control dyads) nested within the Danish National Birth Cohort, which is a prebirth cohort. Maternal seafood and marine n-3 LCPUFA consumption was quantified by a food frequency questionnaire (gestational week 25) and a sub-sample with interview data (weeks 12 and 30). The offspring were clinically examined at 9–16 years, including a Dual energy X-ray Absorptiometry (DXA) scan and a fasting blood sample. We calculated multivariable effect estimates and 95% confidence intervals (CI) for anthropometric, adiposity, and metabolic parameters. The median (IQR) intake of total seafood was 23(24) g/day. We found largely no association for total seafood and marine n-3 LCPUFA with offspring metabolic parameters in either group. Using interview data, GDM-exposed women reporting no fish in week 12 and 30 (versus intake >2 times/week) had offspring with a higher Body Mass Index (BMI) (ratio of geometric means (RGM): 1.28, 95% CI: 1.06, 1.55), waist circumference (RGM: 1.22, 95% CI: 1.05, 1.40), triglycerides (RGM: 1.77, 95% CI: 1.03, 3.03), and homeostatic model assessment of insulin resistance HOMA-IR (RGM: 2.16, 95% CI: 1.17, 3.97). We found no associations of n-3 LCPUFA and seafood intake with offspring metabolic outcomes. However, GDM-exposed women who consistently reported eating no fish had offspring with a poorer metabolic profile. Fish intake in pregnancy may mitigate some adverse effects of intrauterine hyperglycemia, however, these findings need replication in better powered studies.

A Narrative Review of Medical and Genetic Risk Factors among Children Age 5 and Younger with Severe Obesity

Severe obesity defined as an age- and gender-specific body mass index ≥120% of the 95th percentile in children younger than 5 years is well recognized as a significant challenge for prevention and treatment. This article provides an overview of the prevalence, classification of obesity severity, patterns of weight gain trajectory, medical and genetic risk factors, and comorbid disorders among young children with an emphasis on severe obesity. Studies suggest rapid weight gain trajectory in infancy, maternal smoking, maternal gestational diabetes, and genetic conditions are associated with an increased risk for severe obesity in early childhood. Among populations of young children with severe obesity seeking care, co-morbid conditions such as dyslipidemia and fatty liver disease are present and families report behavioral concerns and developmental delays. Children with severe obesity by age 5 represent a vulnerable population of children at high medical risk and need to be identified early and appropriately managed.

Maternal glycemic index and glycemic load in pregnancy and offspring metabolic health in childhood and adolescence-a cohort study of 68,471 mother-offspring dyads from the Danish National Birth Cohort

BACKGROUND

High glycemic index (GI) and glycemic load (GL) as indicators of carbohydrate quality and quantity have been found to increase risk of metabolic outcomes in adults. Whether carbohydrate quality may influence metabolic programming already in early life is unknown. We examined the association of maternal GI and GL with offspring body mass index (BMI) in the first 7 years of life among 68,471 mother-offspring dyads from the Danish National Birth Cohort (DNBC). In a sub-cohort of offspring with clinical data (n = 1234) that included 608 dyads exposed to gestational diabetes mellitus (GDM), we also examined the relation to metabolic health at 9-16 years.

METHODS

Maternal GI and GL were quantified using a mid-pregnancy food frequency questionnaire. We used birth weight and length to calculate offspring's ponderal index. Age- and sex-specific BMI z scores at 5 mo, 12 mo, and 7 y were standardized against WHO reference data. In the clinical cohort, we quantified body composition, HOMA-IR, and HOMA-B. We used multivariable mixed linear and Poisson regression to model the associations.

RESULTS

Median (IQR) of GI and GL were 83 (63-111) and 241 (180-333) g/day, respectively. We found that GI (Q4 vs. Q1:1.09, 95%CI: 1.03, 1.15) and GL (Q4 vs. Q1:1.10, 95%CI: 1.05, 1.16) modestly increased the relative risk of large-for gestational age (LGA). In the clinical sub-cohort, we observed a potential increase in offspring HOMA-IR, adiposity, and metabolic syndrome z score with higher maternal GI and GI. These associations were stronger among the GDM-exposed offspring, but the CI included the null value.

CONCLUSION

We found associations of GI and GL in pregnancy with offspring LGA. Potential long-term benefits to offspring exposed to GDM need to be confirmed in larger, well-powered studies.

Differences in maternal smoking across successive pregnancies - dose-dependent relation to BMI z-score in the offspring: an individual patient data (IPD) meta-analysis

INTRODUCTION

Uncontrolled family factors may bias the estimation of the association between maternal smoking during pregnancy and offspring body mass index (BMI). The objective was to assess if there is an association between maternal smoking during pregnancy and offspring BMI z-score independent of factors in the siblings' shared environment and if such association is linear.

METHODS

We performed an individual patient data meta-analysis using five studies providing sibling data (45,299 children from 14,231 families). In a multi-level model, separating within-family and between-family effects and with random intercept for families, we analysed the dose-response association between maternal number of cigarettes per day during pregnancy and offspring's BMI z-score using B-splines to allow for non-linear associations.

RESULTS

A linear within-family effect for number of cigarettes smoked in the range from 1 to 30 cigarettes per day on the offspring's BMI z-score was observed. Each additional cigarette per day between sibling pregnancies resulted in an increase in BMI z-score of 0.007 (95% CI [0.006, 0.009]). A between family-effect emerged only with doses ≥25 cigarettes per day.

CONCLUSIONS

The number of cigarettes mothers smoke per day during pregnancy is positively associated with offspring BMI z-score even among siblings, suggesting that the association is not entirely explained by confounding by family factors.

Early-Life Exposures and Risk of Diabetes Mellitus and Obesity

PURPOSE OF REVIEW

Type 2 diabetes is a growing concern worldwide with increasing incidence in youth. Development of preventive strategies in earlier stages of life is crucial. We aimed to examine epidemiological evidence of early-life exposures and their associations with childhood and later risk of obesity and diabetes, and to discuss potential mechanisms.

RECENT FINDINGS

Parental obesity and diabetes in the preconception period may influence offspring's obesity risk via epigenetic mechanisms influencing gametogenesis and early development that could have significant transgenerational effects. A more comprehensive understanding of these effects is needed to identify possible avenues for interventions in both fathers and mothers to be. In addition, current evidence suggests that growth and body weight trajectories in infancy and childhood are useful indicators of later obesity and type 2 diabetes. Moreover, the composition and variations in the microbiome in early life are associated with long-term health and could mediate associations between several early-life exposures and later risk of diseases. Altogether, the epidemiological evidence supports the need for preconception and early-life interventions to reduce the obesity and diabetes burden in later life.

Maternal smoking and low family income during pregnancy as predictors of the relationship between depression and adiposity in young adults

There is an increasing incidence of overweight/obesity and mental health disorders in young adults and the two conditions often coexist. We aimed to investigate the influence of antenatal and postnatal factors that may underlie this association with a focus on maternal prenatal smoking, socio-economic status and gender. Data from the Western Australian Pregnancy Cohort (Raine) Study (women enrolled 1989-1991) including 1056 offspring aged 20 years (cohort recalled 2010-2012) were analyzed (2015-2016) using multivariable models for associations between offspring depression scores (DASS-21 Depression-scale) and body mass index (BMI), adjusting for pregnancy and early life factors and offspring behaviours. There was a significant positive relationship between offspring depression-score and BMI independent of gender and other psychosocial covariates. There was a significant interaction between maternal prenatal smoking and depression-score (interaction coefficient=0.096; 95% CI: 0.006, 0.19, P=0.037), indicating the relationship between depression-score and BMI differed according to maternal prenatal smoking status. In offspring of maternal prenatal smokers, a positive association between BMI and depression-score (coefficient=0.133; 95% CI: 0.05, 0.21, P=0.001) equated to 1.1 kg/m2 increase in BMI for every 1standard deviation (8 units) increase in depression-score. Substituting low family income during pregnancy for maternal prenatal smoking in the interaction (interaction coefficient=0.091; 95% CI: 0.01, 0.17, P=0.027) showed a positive association between BMI and depression score only among offspring of mothers with a low family income during pregnancy (coefficient=0.118; 95% CI: 0.06, 0.18, P<0.001). There were no significant effects of gender on these associations. Whilst further studies are needed to determine whether these associations are supported in other populations, they suggest potentially important maternal behavioural and socio-economic factors that identify individuals vulnerable to the coexistence of obesity and depression in early adulthood.

Maternal smoking during pregnancy and cord blood DNA methylation: new insight on sex differences and effect modification by maternal folate levels

Maternal smoking during pregnancy may affect newborn DNA methylation (DNAm). However, little is known about how these associations vary by a newborn's sex and/or maternal nutrition. To fill in this research gap, we investigated epigenome-wide DNAm associations with maternal smoking during pregnancy in African American mother-newborn pairs. DNAm profiling in cord (n = 379) and maternal blood (n = 300) were performed using the Illumina HumanMethylation450 BeadChip array. We identified 12 CpG sites whose DNAm levels in cord blood were associated with maternal smoking, at a false discovery rate <5%. The identified associations in the GFI1 gene were more pronounced in male newborns than in females (P = 0.002 for maternal smoking × sex interaction at cg18146737). We further observed that maternal smoking and folate level may interactively affect cord blood DNAm level at cg05575921 in the AHRR gene (P = 5.0 × 10-4 for interaction): compared to newborns unexposed to maternal smoking and with a high maternal folate level (>19.2 nmol/L), the DNAm level was about 0.03 lower (P = 3.6 × 10-4) in exposed newborns with a high maternal folate level, but was 0.08 lower (P = 1.2 × 10-8) in exposed newborns with a low maternal folate level. Our data suggest that adequate maternal folate levels may partly counteract the impact of maternal smoking on DNAm. These findings may open new avenues of inquiry regarding sex differences in response to environmental insults and novel strategies to mitigate their intergenerational health effects through optimization of maternal nutrition.