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

Effects of prenatal exposure to cigarettes on anthropometrics, energy intake, energy expenditure, and screen time in children

BACKGROUND

Maternal prenatal smoking is associated with downstream childhood obesity. Although animal research suggests reduced resting energy expenditure (REE), decreased physical activity (PA), and increased energy intake as mechanisms, these relationships are unclear in humans. The objectives were to examine the association of prenatal maternal smoking with non-volitional energy expenditure (REE and the thermic effect of feeding [TEF]), child adiposity, energy intake, free-living PA (daily light PA (LPA), daily moderate-to-vigorous PA (MVPA), daily sedentary behavior (SB)), and screen time (television and computer/video game) in children.

METHODS

As part of a longitudinal study, 46 children (n = 27 controls and n = 19 smoking exposed) with mean age 7.6 ± 2 years were recruited. Body weight and composition (Bioelectrical Impedance), height (Stadiometer), waist circumference (cm; tape), BMI (kg/m²), REE (kcal/day; indirect calorimetry), PA (minutes; Accelerometry), screen time (hours; self-report) and ad libitum energy intake (lunch buffet; 7-day food log) were measured. Effects sizes were evaluated using Cohen's d.

RESULTS

Relative to controls, after controlling for age and family income, children who were exposed to cigarette smoke in utero exhibited greater waist circumference (p = 0.04, Cohen's d = 1.03), percent body fat (%BF; p = 0.02, Cohen's d = 0.97), and a trend for BMI (p = 0.05, Cohen's d = 0.86). Exposed children did not differ in REE (trend for lower: p = 0.1, Cohen's d = 0.42) or TEF but were shown to have significantly higher ad libitum energy intake (p = 0.02, Cohen's D = 0.70) from the palatable lunch buffet, but not from the out of laboratory 7-day energy intake (p = 0.8). Examining screen time behaviors, exposed children spent more time watching television during the week (p = 0.03, Cohen's D = 0.82), and overall television watching (p = 0.02, Cohen's D = 0.80); there were no group differences in any other screen time behaviors.

CONCLUSIONS

Children exposed to cigarette smoke in utero exhibit greater adiposity, and this exposure may have as contributing factors higher screen time, ad libitum energy intake, and a trend for reduced REE. The data suggest that lifestyle factors such as diet and screen time represent targets for obesity prevention in a high-risk population of young children exposed to prenatal cigarette smoke. Findings also highlight the need for smoking cessation programs to reduce downstream obesity in offspring.

Postnatal screening and care for non-medical risk factors by preventive child healthcare in deprived and non-deprived neighbourhoods

Background

Children born in families with non-medical risk factors, such as deprivation, have higher odds of preterm birth (< 37 weeks of gestation) or being born small for gestational age (birth weight < 10th percentile). In addition, growing up they are at risk for growth and developmental problems. Preventive Child Healthcare (PCHC) monitors growth and development of babies and children. Early identification of children at risk could result in early interventions to prevent growth and developmental problems in later life. Therefore, we aimed to assess current practices in postnatal risk screening and care for non-medical risk factors and the collaboration with other healthcare professionals, in both deprived and non-deprived neighbourhoods in the Netherlands.

Methods

Eight out of ten invited PCHC organisations, from different areas in the Netherlands, consented to participate in this study. A questionnaire was designed and digitally distributed to professionals working at these organisations, where 370 physicians and nurses were employed. Data was collected between June and September 2016. Descriptive statistics, chi square tests and t-tests were applied.

Results

Eighty-nine questionnaires were eligible for analyses. Twenty percent of the respondents were working in a deprived neighbourhood and 70.8% of the respondents were employed as nurse. Most of them performed screening for non-medical risk factors in at least 50% of their consultations. PCHC professionals working in deprived neighbourhoods encountered significantly more often families with non-medical risk factors and experienced significantly more communication problems than their colleagues working in non-deprived neighbourhoods. 48.2% of the respondents were satisfied with the current form of postnatal risk screening in their organisation, whereas 41.2% felt a need for a structured postnatal risk assessment. Intensified collaboration is preferred with district-teams, general practitioners and midwifes, concerning clients with non-medical risk factors.

Conclusion

This study shows that postnatal screening for non-medical risk factors is part of current PCHC practice, regardless the neighbourhood status they are deployed. PCHC professionals consider screening for non-medical risk factors as their responsibility. Consequently, they felt a need for a structured postnatal risk assessment and for an intensified collaboration with other healthcare professionals.

Electronic supplementary material

The online version of this article (10.1186/s12913-018-3243-2) contains supplementary material, which is available to authorized users.

Severe obesity in children 17 to 24 months of age: a cross-sectional study of TARGet Kids! and Better Outcomes Registry & Network (BORN) Ontario

OBJECTIVES

International data suggest the prevalence of severe obesity in young children may be increasing, yet no Canadian data are available. The objectives of this study were to examine definitions of severe obesity and to evaluate associated risk factors among young children in Ontario.

METHODS

A cross-sectional study was conducted in children 17 to 24 months of age using two Ontario data sources: TARGet Kids! (n = 3713) and BORN Ontario (n = 768). Body mass index z score (zBMI) definitions were adapted from the World Health Organization (WHO) (z score > 3) and the US Centers for Disease Control (CDC) (> 120% of the 95th percentile) and applied to define severe obesity in young children. Multinomial logistic regression was used to evaluate associations between demographic and pregnancy risk factors and zBMI categories.

RESULTS

A total of 1.1% (95% CI, 0.8-1.4) of children met the adapted WHO definition of severe obesity compared to 0.3% (95% CI, 0.2-0.6) using the CDC definition. Median neighbourhood household income (OR = 0.80, 95% CI, 0.69-0.93) and maternal pre-pregnancy BMI (OR = 1.08, 95% CI, 1.01-1.15) were associated with severe obesity in unadjusted analyses. After adjustment for potential confounders, the OR for the association between maternal pre-pregnancy BMI and severe obesity was 1.04 (95% CI, 0.94-1.15).

CONCLUSION

More than 1% of Ontario children met the adapted WHO definition of severe obesity in very early childhood. Modifiable risk factors were identified. Future studies are needed to understand the terminology, prevalence, and risk factors for severe obesity in young children across Canada.

Overview of air pollution and endocrine disorders

Over recent years, many environmental pollutant chemicals have been shown to possess the ability to interfere in the functioning of the endocrine system and have been termed endocrine disrupting chemicals (EDCs). These compounds exist in air as volatile or semi-volatile compounds in the gas phase or attached to particulate matter. They include components of plastics (phthalates, bisphenol A), components of consumer goods (parabens, triclosan, alkylphenols, fragrance compounds, organobromine flame retardants, fluorosurfactants), industrial chemicals (polychlorinated biphenyls), products of combustion (polychlorinated dibenzodioxins/furans, polyaromatic hydrocarbons), pesticides, herbicides, and some metals. This review summarizes current knowledge concerning the sources of EDCs in air, measurements of levels of EDCs in air, and the potential for adverse effects of EDCs in air on human endocrine health.

Barriers and facilitators to smoking cessation in pregnancy and in the post-partum period: The health care professionals' perspective

Objectives

Health care professionals and the health care environment play a central role in protecting pregnant and post‐partum women and their infants from smoking‐related harms. This study aimed to better understand the health professional's perspective on how interactions between women, health care professionals, and the environment influence how smoking is managed.

Design

Semi‐structured interviews and focus groups.

Methods

Data were from 48 health care staff involved in antenatal or post‐partum care at two UK sites, including midwives, obstetricians, health visitors, GPs, pharmacists, service commissioners, and Stop Smoking Service (SSS) advisors and managers. Thematic analysis was guided by a social–ecological framework (SEF).

Results

Themes were divided across three SEF levels and represented factors connected to the management of smoking in the health care context and the beliefs and behaviour of pregnant or post‐partum smokers. Organizational level: Service reconfigurations, ‘last resort’ nicotine replacement therapy prescribing policies, and non‐mandatory training were largely negative factors. There were mixed views on opt‐out referral pathways and positive views on carbon monoxide monitoring. Interpersonal level: Protection of client–professional relationships often inhibited frank discussions about smoking, and weak interservice relationships affected SSS referral motivation and quality. Individual level: Professionals felt community midwives had primary responsibility for managing smoking, although midwives felt underskilled doing this. Midwives’ perceived priority for addressing smoking was influenced by the demands from unrelated organizational initiatives.

Conclusions

Opportunities to improve clinical support for pregnant smokers exist at organizational, interservice, and health care professional levels. Interactions between levels reflect the importance of simultaneously addressing different level‐specific barriers to smoking cessation in pregnancy.

Factors associated with body mass index in children and adolescents: An international cross-sectional study

BACKGROUND

The increasing prevalence of overweight and obesity in childhood has implications for their future health. There are many potential contributors to overweight and obesity in childhood. The aim was to investigate the association between postulated risk factors and body mass index (BMI) in children and adolescents.

METHODS

Secondary analysis of data from a multi-centre, multi-country, cross-sectional study (ISAAC Phase Three). Parents/guardians of children aged 6-7 years completed a questionnaire about their child's current height and weight, and the postulated risk factors. Adolescents aged 13-14 years reported their own height and weight and answered questions about the postulated risk factors. A general linear mixed model was used to determine the association between BMI and the postulated risk factors. Imputation was used if there were missing responses for 3 or fewer explanatory variables.

RESULTS

65,721 children (27 centres, 15 countries) and 189,282 adolescents (70 centres, 35 countries) were included in the final analyses. Many statistically significant associations were identified, although for most variables the effect sizes were small. In children birth weight (for each kg increase in birth weight the BMI increased by +0.43 kg/m2, p<0.001), television viewing (5+ hours/day +0.33 kg/m2 vs. <1 hour/day, p<0.001), fast food (≥3 times/week +0.16 kg/m2 vs. never, p<0.001) vigorous physical activity (3+ hours/week 0.071 kg/m2 vs. never, p = 0.023) and maternal smoking in the first year of life (+0.13 kg/m2, p<0.001) were associated with a higher BMI in the adjusted model. Nut consumption (≥3 times/week -0.11 kg/m2 vs. never, p = 0.002) was associated with a lower BMI. Early life exposures (antibiotics, paracetamol and breast feeding) were also associated with BMI. For adolescents statistically significant associations with BMI and were seen with maternal smoking (+0.25 kg/m2, p<0.001), television viewing (5+ hours/day +0.23 kg/m2 vs. <1 hour/day, p<0.001), fast food (≥3 times/week -0.19 kg/m2 vs. never, p<0.001), vigorous physical activity (3+ hours/week 0.047 kg/m2 vs. never, p<0.001) and nuts (≥3 times/week -0.22 kg/m2 vs. never, p<0.001).

CONCLUSIONS

Although several early life exposures were associated with small differences in BMI, most effect sizes were small. Larger effect sizes were seen with current maternal smoking, television viewing (both with higher BMI) and frequent nut consumption (lower BMI) in both children and adolescents, suggesting that current behaviours are more important than early exposures. Although many variables may influence BMI in childhood, the putative factors studied are not of sufficient magnitude to support major public health interventions.

Neonatal tobacco smoke reduces thermogenesis capacity in brown adipose tissue in adult rats

Maternal smoking is a risk factor for progeny obesity. We have previously shown, in a rat model of neonatal tobacco smoke exposure, a mild increase in food intake and a considerable increase in visceral adiposity in the adult offspring. Males also had secondary hyperthyroidism, while females had only higher T4. Since brown adipose tissue (BAT) hypofunction is related to obesity, here we tested the hypothesis that higher levels of thyroid hormones are not functional in BAT, suggesting a lower metabolic rate. We evaluated autonomic nerve activity in BAT and its function in adult rats that were exposed to tobacco smoke during lactation. At birth, litters were adjusted to 3 male and 3 female pups/litter. From postnatal day (PND) 3 to 21, Wistar lactating rats and their pups were divided into SE group, smoke-exposed in a cigarette smoking machine (4 times/day) and C group, exposed to filtered air. Offspring were sacrificed at PND180. Adult SE rats of both genders had lower interscapular BAT autonomic nervous system activity, with higher BAT mass but no change in morphology. BAT UCP1 and CPT1a protein levels were decreased in the SE groups of both genders. Male SE rats had lower β3-AR, TRα1, and TRβ1 expression while females showed lower PGC1α expression. BAT Dio2 mRNA and hypothalamic POMC and MC4R levels were similar between groups. Hypothalamic pAMPK level was higher in SE males and lower in SE females. Thus, neonatal cigarette smoke exposure induces lower BAT thermogenic capacity, which can be obesogenic at adulthood.

Impact of the Social and Natural Environment on Preschool-Age Children Weight

Background: The complex impact of environmental and social factors on preschool children being overweight/obese is unclear. We examined the associations between the levels of green space exposure and the risk of being overweight/obese for 4–6 year-old children and assessed the impact of maternal education on these associations. Methods: This cross-sectional study included 1489 mother-child pairs living in Kaunas, Lithuania, in 2012–2013. We assessed children overweight/obesity by standardized questionnaires using international body mass index cut-off points, and the level of greenness exposures by satellite-derived normalized difference vegetation index (NDVI) of each child’s home and by the distance to a nearest city park. The maternal education was used as the SES indicator. We used logistic regression models to investigate the strength of the associations. Results: Children from families with poorer maternal education, pathological mother-child relations and smoking mothers, and living in areas with less greenness exposure (NDVI-100 m), had significantly higher odds ratios of being overweight/obese. Lower maternal education and distance to a city park modified the effect of greenness cover level exposure on the risk of children being overweight/obese. Conclusions: Higher greenness exposure in the residential settings has beneficial effects on children’s physical development. The green spaces exposures for psychosocial stress management is recommended as a measure to prevent overweight/obesity among children.

Lifestyle of women before pregnancy and the risk of offspring obesity during childhood through early adulthood

BACKGROUND

In women, adhering to an overall healthy lifestyle is associated with a dramatically reduced risk of cardio-metabolic disorders. Whether such a healthy lifestyle exerts an intergenerational effects on child health deserves examination.

METHODS

We included 5701 children (9-14 years old at baseline) of the Growing Up Today Study 2, and their mothers, who are participants in the Nurses' Health Study II. Pre-pregnancy healthy lifestyle was defined as a normal body mass index, no smoking, physical activity ≥150 min/week, and diet in the top 40% of the Alternative Healthy Eating Index-2010. Obesity during childhood and adolescence was defined using the International Obesity Task Force age- and sex-specific cutoffs. Multivariable log-binominal regression models with generalized estimating equations were used to evaluate the association of pre-pregnancy healthy lifestyle and offspring obesity.

RESULTS

We identified 520 (9.1%) offspring who became obese during follow-up. A healthy body weight of mothers and no smoking before pregnancy was significantly associated with a lower risk of obesity among offspring: the relative risks [RRs; 95% confidence intervals (CIs)] were 0.37 (0.31-0.43) and 0.64 (0.49-0.84), respectively. Eating a healthy diet and regular moderate-to-vigorous physical activities were inversely related to offspring obesity risk, but these relations were not statistically significant. Compared to children of mothers who did not meet any low-risk lifestyle factors, offspring of women who adhered to all four healthy lifestyle factors had 75% lower risk of obesity (RR: 0.25, 95% CI: 0.14-0.43).

CONCLUSION

Adherence to an overall healthy lifestyle before pregnancy is strongly associated with a low risk of offspring obesity in childhood, adolescence, and early adulthood. These findings highlight the importance of an overall healthy lifestyle before pregnancy as a potential strategy to prevent obesity in future generations.

Smoking during pregnancy. Results of the cross-sectional KiGGS Wave 2 study and trends

Maternal smoking during pregnancy poses a significant risk to the development of unborn children. Data from KiGGS Wave 2 shows that 10.9% of mothers of 0 to 6 year-old children smoked during pregnancy. Mothers who were under 25 when giving birth smoked about two to three times more often than older mothers. Furthermore, there is a distinct social gradient in maternal smoking: a higher socioeconomic status is associated with a lower proportion of children with a mother who smoked during pregnancy. A comparison with data from the KiGGS baseline study shows that the proportion of mothers who smoked during pregnancy fell from to 19.9% to 10.9% between the two study periods. Thus, the KiGGS results are in line with those from the perinatal survey, which also found that the proportion of pregnant women who smoke has declined significantly since the mid-1990s.

Maternal smoking during pregnancy and offspring overweight: is there a dose-response relationship? An individual patient data meta-analysis

BACKGROUND/OBJECTIVES

A number of meta-analyses suggest an association between any maternal smoking in pregnancy and offspring overweight obesity. Whether there is a dose-response relationship across number of cigarettes and whether this differs by sex remains unclear.

SUBJECT/METHODS

Studies reporting number of cigarettes smoked during pregnancy and offspring BMI published up to May 2015 were searched. An individual patient data meta-analysis of association between the number of cigarettes smoked during pregnancy and offspring overweight (defined according to the International Obesity Task Force reference) was computed using a generalized additive mixed model with non-linear effects and adjustment for confounders (maternal weight status, breastfeeding, and maternal education) and stratification for sex.

RESULTS

Of 26 identified studies, 16 authors provided data on a total of 238,340 mother-child-pairs. A linear positive association was observed between the number of cigarettes smoked and offspring overweight for up to 15 cigarettes per day with an OR increase per cigarette of 1.03, 95% CI = [1.02-1.03]. The OR flattened with higher cigarette use. Associations were similar in males and females. Sensitivity analyses supported these results.

CONCLUSIONS

A linear dose-response relationship of maternal smoking was observed in the range of 1-15 cigarettes per day equally in boys and girls with no further risk increase for doses above 15 cigarettes.

Cardio-metabolic and socio-environmental correlates of waist-to-height ratio in German primary schoolchildren: a cross-sectional exploration

BACKGROUND

Controversial messages of childhood obesity emerge: Levelling off in terms of body mass index (BMI) is foiled by increases in abdominal obesity. Waist-to-height ratio (WHtR) may be used as a screening tool for abdominal obesity in children. The aim of this study was to investigate clinical and socio-environmental correlates of abdominal obesity in primary schoolchildren.

METHODS

Cross-sectional data from 753 children participating in baseline assessments of the outcome evaluation of a school-based prevention program were analysed. Abdominal obesity was defined as WHtR ≥0.5. According to German age and sex-specific BMI-percentiles, overweight (>90th percentile) and obesity (>97th percentile) were determined. Anthropometric and sonographic measurements, blood pressure and blood samples were taken by clinical staff in a standardized manner. Socio-environmental and lifestyle data were assessed via parental questionnaires. Differences between abdominally obese children and others, and correlations of WHtR with clinical data were tested. Socio-environmental correlates of abdominal obesity were explored in a logistic regression analysis.

RESULTS

At the time of the examination children were 7.57 ± 0.42 years old. Abdominal obesity was observed in 132 (17.5%) children. According to BMI-percentiles, 22.9% of these children were obese, 38.2% overweight, and 38.2% normal weight. Affected children more often used screen media and less often participated in club sports. Abdominal obesity was associated with higher blood pressure, lower HDL- and higher LDL-cholesterol. WHtR significantly correlated with intra-abdominal fat thickness (IAF). The logistic regression model revealed migration background (odds ratio (OR) 2.12, 95% confidence interval (CI) [1.41, 3.19]), smoking during pregnancy (OR 2.30, 95% CI [1.37, 3.86]), parental obesity (OR 1.95, 95% CI [1.22, 3.10]) and higher educational level (OR 0.64, 95% CI [0.42, 0.98]) to be significantly associated with abdominal obesity in children.

CONCLUSION

WHtR correlates strongly with IAF. Abdominal obesity in primary schoolchildren is associated with cardio-metabolic risk factors and also occurs in otherwise normal weight children. Against the background of rising numbers of abdominal obesity in children, targeted preventive measures are long overdue. The focus of such measures should be used on children with migration background and involve parents, especially those who are obese and those with lower educational levels.

Prediction of Adulthood Obesity Using Genetic and Childhood Clinical Risk Factors in the Cardiovascular Risk in Young Finns Study

BACKGROUND

Obesity is a known risk factor for cardiovascular disease. Early prediction of obesity is essential for prevention. The aim of this study is to assess the use of childhood clinical factors and the genetic risk factors in predicting adulthood obesity using machine learning methods.

METHODS AND RESULTS

A total of 2262 participants from the Cardiovascular Risk in YFS (Young Finns Study) were followed up from childhood (age 3-18 years) to adulthood for 31 years. The data were divided into training (n=1625) and validation (n=637) set. The effect of known genetic risk factors (97 single-nucleotide polymorphisms) was investigated as a weighted genetic risk score of all 97 single-nucleotide polymorphisms (WGRS97) or a subset of 19 most significant single-nucleotide polymorphisms (WGRS19) using boosting machine learning technique. WGRS97 and WGRS19 were validated using external data (n=369) from BHS (Bogalusa Heart Study). WGRS19 improved the accuracy of predicting adulthood obesity in training (area under the curve [AUC=0.787 versus AUC=0.744, P<0.0001) and validation data (AUC=0.769 versus AUC=0.747, P=0.026). WGRS97 improved the accuracy in training (AUC=0.782 versus AUC=0.744, P<0.0001) but not in validation data (AUC=0.749 versus AUC=0.747, P=0.785). Higher WGRS19 associated with higher body mass index at 9 years and WGRS97 at 6 years. Replication in BHS confirmed our findings that WGRS19 and WGRS97 are associated with body mass index.

CONCLUSIONS

WGRS19 improves prediction of adulthood obesity. Predictive accuracy is highest among young children (3-6 years), whereas among older children (9-18 years) the risk can be identified using childhood clinical factors. The model is helpful in screening children with high risk of developing obesity.

Chemical and non-chemical stressors affecting childhood obesity: a systematic scoping review

Childhood obesity in the United States has doubled over the last three decades and currently affects 17% of children and adolescents. While much research has focused on individual behaviors impacting obesity, little research has emphasized the complex interactions of numerous chemical and non-chemical stressors found in a child's environment and how these interactions affect a child's health and well-being. The objectives of this systematic scoping review were to (1) identify potential chemical stressors in the context of non-chemical stressors that impact childhood obesity; and, (2) summarize our observations for chemical and non-chemical stressors in regards to child-specific environments within a community setting. A review was conducted to identify chemical and non-chemical stressors related to childhood obesity for the childhood life stages ranging from prenatal to adolescence. Stressors were identified and grouped into domains: individual behaviors, family/household behaviors, community stressors, and chemical exposures. Stressors were related to the child and the child's everyday environments and used to characterize child health and well-being. This review suggests that the interactions of chemical and non-chemical stressors are important for understanding a child's overall health and well-being. By considering these relationships, the exposure science research community can better design and implement strategies to reduce childhood obesity.

Ancestral perinatal obesogen exposure results in a transgenerational thrifty phenotype in mice

Ancestral environmental exposures to non-mutagenic agents can exert effects in unexposed descendants. This transgenerational inheritance has significant implications for understanding disease etiology. Here we show that exposure of F0 mice to the obesogen tributyltin (TBT) throughout pregnancy and lactation predisposes unexposed F4 male descendants to obesity when dietary fat is increased. Analyses of body fat, plasma hormone levels, and visceral white adipose tissue DNA methylome and transcriptome collectively indicate that the F4 obesity is consistent with a leptin resistant, thrifty phenotype. Ancestral TBT exposure induces global changes in DNA methylation and altered expression of metabolism-relevant genes. Analysis of chromatin accessibility in F3 and F4 sperm reveals significant differences between control and TBT groups and significant similarities between F3 and F4 TBT groups that overlap with areas of differential methylation in F4 adipose tissue. Our data suggest that ancestral TBT exposure induces changes in chromatin organization transmissible through meiosis and mitosis.

Early life exposure to endocrine disrupting chemicals has been linked to increased adiposity during adulthood. Here Chamorro-García et al. show that ancestral exposure to the obesogen tributyltin causes obesity in untreated F4 generation male descendants by inducing heritable changes in genome architecture that promote a thrifty phenotype.

Paternal Acculturation and Maternal Health Behaviors: Influence of Father's Ethnicity and Place of Birth

OBJECTIVES

Studies show disparities in maternal health behaviors according to acculturation, but whether paternal factors influence these patterns is unknown. We assessed the relationships between fathers' ethnicity and place of birth with maternal smoking during pregnancy and breastfeeding initiation overall and for 30 major ethnic groups.

MATERIALS AND METHODS

Data were from the Standard Certificate of Live Births on 1,053,096 births in Massachusetts between 1996 through 2010. We examined the concordance of maternal and paternal ethnicity and place of birth across three categories (United States-born white, United States-born Other ethnicity, and foreign-born), and then in relation to maternal smoking during pregnancy and breastfeeding initiation. Multivariable models adjusted for maternal age, marital status, education, plurality, parity, prenatal care, delivery source of payment, and year of birth.

RESULTS

United States-born white mothers were less likely to smoke during pregnancy (adjusted odds ratio [AOR] 0.66; 95% confidence interval [CI]: 0.60, 0.73) and more likely to initiate breastfeeding (AOR 1.56; 95% CI: 1.46, 1.66) if their partners were foreign-born. In contrast, foreign-born mothers whose partners were United States-born of Other ethnicity or United States-born white had a 1.65-5.12 higher odds of smoking during pregnancy and were 26%-41% less likely (AORs 0.59-0.74) to initiate breastfeeding than if their partners were also foreign-born. Results were consistent across most racial/ethnic groups.

CONCLUSIONS

Our findings offer new insight into the social pathways by which acculturation impacts maternal health behaviors and add to growing evidence that fathers are valuable to maternal health. Future efforts to understand how acculturation results in poorer maternal health behaviors should account for paternal influences.

Changes in Smoking Rates Among Pregnant Women and the General Female Population in Australia, Finland, Norway, and Sweden

Introduction:

Smoking rates have dropped substantially in most developed countries in recent decades. This general trend has, however, not always been evident among women—particularly younger women. Smoking habits do, however, often change in connection with pregnancy and the aim of this study is to determine whether smoking during pregnancy follows general trends in smoking rates in the general female population in four countries with active anti-tobacco policies and decreasing population smoking rates.

Methods:

Changes in rates of persistent smoking, that is, smoking in late pregnancy or daily smoking among all women of childbearing age were described according to age groups. Data were retrieved from the Australian Household Drug Surveys during 2000–2013 and from registries and surveys in Finland, Norway, and Sweden between 1995 and 2014.

Results:

In general, persistent smoking has decreased and late-pregnancy smoking rates are lower than daily smoking rates among all women. However, younger women are more likely to be persistent smokers regardless of pregnancy status. In Norway and Finland, persistent smoking was most common among young pregnant women and in Sweden there was an increased polarization between age groups. In Australia, a steady decrease in smoking rates appears to have stalled in younger pregnant women.

Conclusion:

Although smoking has declined substantially in recent decades, there are groups lagging behind this general trend. Young pregnant women are of particular concern in this respect. The possibility that these findings reflect the changing characteristics of younger pregnant women is discussed.

Implications:

This study puts recent trends in maternal smoking into a broader context by relating developments to changes in smoking rates among women in general. By using similar data from four countries we were able to follow changes in smoking rates “within” groups of women within the four countries without being limited by methodological problems related to cross-country or inter-group comparisons. We were above all able to show that aggregate data disclose the strong age gradient in maternal smoking habits.

Gestational diabetes and offspring birth size at elevated environmental pollutant exposures

BACKGROUND

Gestational diabetes mellitus (GDM) is associated with increased availability of glucose and macronutrients in fetal circulation and macrosomia. Therefore, the role of GDM in the association between metabolism-disrupting chemicals and birth size deserves attention.

OBJECTIVE

We examined whether GDM may mediate or modify the associations between maternal environmental pollutant exposures and offspring birth size measures.

METHODS

We analyzed 604 Faroese pregnant women and their offsprings born in 1997-2000. Maternal pregnancy serum concentrations of organochlorine compounds (OCs: polychlorinated biphenyl (PCB) congeners and dichlorodiphenyldichloroethylene (DDE)), and five perfluoroalkyl substances (PFASs), and hair and cord blood mercury concentrations were measured. We used regression (single-pollutants) and structural equation models (SEMs) (multiple-pollutant analyses using latent constructs of OCs, PFASs and mercury) to estimate the associations with GDM and birth size measures, accounting for mediation and/or effect modification by GDM.

RESULTS

Serum-DDE and hair-mercury concentrations were associated with GDM (adjusted OR per concentration doubling: 1.29; 95% CI: 0.94, 1.77 for DDE, and 0.79; 95% CI: 0.62, 0.99 for mercury), but in multiple pollutant-adjusted SEMs only a positive association between OC exposure and GDM remained significant (change in GDM odds per OC doubling: 0.45; 95% CI: 0.05, 0.86). PCB and overall OC exposure were positively associated with head circumference (SEM; mean change per OC doubling: 0.13cm; 95% CI, 0.01. 0.25). Overall PFAS exposure was inversely associated with birth weight (SEM; mean change per PFAS doubling: -169g; 95% CI: -359, 21), and for many single-PFASs we found a pattern of inverse associations with birth weight and head circumference in boys, and positive or null associations in girls. None of the environmental pollutants was associated with offspring length. GDM neither modified nor mediated the associations with birth size measures.

CONCLUSIONS

We found associations with GDM and offspring birth size to be specific to the environmental pollutant or pollutant group. Associations with birth size measures appear to be independent of GDM occurrence.

Do E-cigarettes induce weight changes and increase cardiometabolic risk? A signal for the future

The prevalence of non-cigarette tobacco use in electronic cigarettes, also called vaping, is rapidly increasing, especially in adolescents and young adults, due to attractive marketing techniques promoting them as healthier alternatives to conventional tobacco cigarettes. Although smoking is associated with weight loss, it increases insulin resistance and attributes to other features of the metabolic syndrome, increasing the cardiometabolic risk profile. Whether vaping has the same deleterious effects on metabolic parameters as regular cigarette smoke has not yet been studied thoroughly in humans. However, animal model experiments attribute comparable effects of e-cigarette smoking, even without nicotine exposure, on weight and metabolic parameters as compared to smoking cigarettes. In this review paper, we want to give an overview of published data on the effects on weight and cardiometabolic parameters of e-cigarette use and formulate some mechanistic hypotheses.

Adipose Tissue as a Site of Toxin Accumulation

We examine the role of adipose tissue, typically considered an energy storage site, as a potential site of toxicant accumulation. Although the production of most persistent organic pollutants (POPs) was banned years ago, these toxicants persist in the environment due to their resistance to biodegradation and widespread distribution in various environmental forms (e.g., vapor, sediment, and water). As a result, human exposure to these toxicants is inevitable. Largely due to their lipophilicity, POPs bioaccumulate in adipose tissue, resulting in greater body burdens of these environmental toxicants with obesity. POPs of major concern include polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins and furans (PCDDs/PCDFs), and polybrominated biphenyls and diphenyl ethers (PBBs/PBDEs), among other organic compounds. In this review, we (i) highlight the physical characteristics of toxicants that enable them to partition into and remain stored in adipose tissue, (ii) discuss the specific mechanisms of action by which these toxicants act to influence adipocyte function, and (iii) review associations between POP exposures and the development of obesity and diabetes. An area of controversy relates to the relative potential beneficial versus hazardous health effects of toxicant sequestration in adipose tissue. © 2017 American Physiological Society. Compr Physiol 7:1085-1135, 2017.

Differences in Body Mass Index between Siblings Who Are Discordant for Exposure to Antenatal Maternal Smoking

BACKGROUND

Maternal smoking during pregnancy is associated with increased childhood body mass index (BMI), but the relationship may be due to confounding by maternal factors. This study tested the hypothesis that siblings born to mothers who begin to smoke between pregnancies will have higher BMI than older unexposed siblings.

METHODS

Maternal details from the Aberdeen Maternity and Neonatal Databank were linked to the Study of Trends in Obesity in North East Scotland which holds offspring BMI at 5 years of age. Change in maternal smoking status between pregnancies was linked to offspring BMI and also to the difference in BMI between siblings.

RESULTS

Maternal smoking status in successive pregnancies was linked to child BMI at age 5 years in 6581 mother-child pairs of whom 718 included sibling pars. Children whose mothers had quit, started smoking or smoked in consecutive pregnancies had higher BMI compared with those not exposed to maternal smoking. Siblings born after onset of maternal smoking had higher mean BMI z score (0.19, 95% confidence interval (CI) 0.01, 0.36) compared with unexposed older siblings. Mean BMI z score was also higher by mean of 0.10 (95% CI 0.01, 0.20) in younger sibling compared with older siblings born to mothers who smoked in both pregnancies. BMI z score was not significantly different between siblings whose mothers quit between pregnancies.

CONCLUSIONS

In utero exposure to maternal smoking during pregnancy may increase the likelihood of increased BMI in childhood.

Maternal protein intake in pregnancy and offspring metabolic health at age 9-16 y: results from a Danish cohort of gestational diabetes mellitus pregnancies and controls

Background: Recent years have seen strong tendencies toward high-protein diets. However, the implications of higher protein intake, especially during developmentally sensitive periods, are poorly understood. Conversely, evidence on the long-term developmental consequences of low protein intake in free-living populations remains limited.Objective: We examined the association of protein intake in pregnancy with offspring metabolic health at age 9-16 y in a longitudinal cohort that oversampled pregnancies with gestational diabetes mellitus (GDM).Design: Six hundred eight women with an index pregnancy affected by gestational diabetes mellitus and 626 controls enrolled in the Danish National Birth Cohort were used for the analysis. Protein (total, animal, vegetable) intake was assessed by using a food-frequency questionnaire in gestational week 25. The offspring underwent a clinical examination including fasting blood samples and a dual-energy X-ray absorptiometry scan (subset of 650) from which metabolic outcomes were derived. Multivariable analyses were conducted applying a 1:1 substitution of carbohydrates for protein.Results: The mean ± SD protein intake in pregnancy was 93 ± 15 g/d (16% ± 3% of energy) in GDM-exposed women and 90 ± 14 g/d (16% ± 2% of energy) in control women. There were overall no associations between maternal protein intake and offspring fasting insulin and homeostasis model assessment of insulin resistance (HOMA-IR). We found that maternal total protein intake was associated with a tendency for a higher abdominal fat mass percentage (quartile 4 compared with quartile 1: 0.40 SD; 95% CI: -0.03, 0.83 SD; P = 0.07) in GDM-exposed offspring and a tendency for a higher total fat mass percentage among male offspring (quartile 4 compared with quartile 1: 0.33 SD; 95% CI: -0.01, 0.66 SD; P = 0.06), but a small sample size may have compromised the precision of the effect estimates. GDM-exposed offspring of mothers with a protein intake in the lowest decile (≤12.5% of energy compared with >12.5% of energy) had lower fasting insulin (ratio of geometric means: 0.82; 95% CI: 0.68, 0.99; P = 0.04) and a tendency toward lower HOMA-IR (ratio of geometric means: 0.82; 95% CI: 0.66, 1.02; P = 0.07), but there was no evidence of associations with body composition. Male offspring seemed to derive a similar benefit from a maternal low protein intake as did GDM-exposed offspring.Conclusions: Overall, our results provide little support for an association of maternal protein intake in pregnancy with measures of offspring metabolic health. Further studies in larger cohorts are needed to determine whether low maternal protein intake in pregnancy may improve glucose homeostasis in GDM-exposed and male offspring.

Psychosocial stress and obesity among children residing in Kaunas City

INTRODUCTION

An unfavorable psychosocial environment has been associated with an increased prevalence of obesity among children. However, the available evidence on the association of low socioeconomic status and parent-child relationships with childhood obesity is scarce. The aim of our study was to conduct a simultaneous evaluation of the risks associated with pathological mother-child relationships, education level, and overweight/obesity among 4-6 year-old children.

METHODS

This cross-sectional study included 1489 mother-child pairs living in Kaunas city, Lithuania. The Parenting Stress Index was measured using the Parent-Child Dysfunctional Interaction subscale. Children's overweight/obesity was defined as the body mass index ≥18kg/m². Logistic regression models as well as crude and adjusted odds ratios (OR) and their 95% confidence intervals (CI) were used to indicate the strength of the associations between childhood overweight/obesity, maternal education level, and psychosocial stress.

RESULTS

The percentage of children with overweight/obesity rose with an increasing Parenting Stress Index score. The percentage of children with overweight/obesity in the group of parents with better education and normal mother-child relations was 6.0%, while in the group of less educated parents and pathological mother-child relations, this percentage reached 13.9%. The stratified multivariable model showed that, with reference to the group of better educated parents and normal mother-child relations, lower education level and pathological mother-child relations were statistically significant risk factors for overweight/obesity in 4-6 year-old children, increasing the OR of overweight/obesity (aOR: 2.43; 95% CI: 1.31-4.51). Pathological mother-child relations and maternal smoking mediated the effect of low maternal education level on children's BMI z-scores.

CONCLUSION

Pathological mother-child relations, lower parental education levels, and smoking may be predictors of children's overweight/obesity. Measures oriented towards health behavior and psychosocial stress management should be encouraged among parents in order to decrease the risk of overweight/obesity in their children.

Examining the role of unmeasured confounding in mediation analysis with genetic and genomic applications

Background

In mediation analysis if unmeasured confounding is present, the estimates for the direct and mediated effects may be over or under estimated. Most methods for the sensitivity analysis of unmeasured confounding in mediation have focused on the mediator-outcome relationship.

Results

The Umediation R package enables the user to simulate unmeasured confounding of the exposure-mediator, exposure-outcome, and mediator-outcome relationships in order to see how the results of the mediation analysis would change in the presence of unmeasured confounding. We apply the Umediation package to the Genetic Epidemiology of Chronic Obstructive Pulmonary Disease (COPDGene) study to examine the role of unmeasured confounding due to population stratification on the effect of a single nucleotide polymorphism (SNP) in the CHRNA5/3/B4 locus on pulmonary function decline as mediated by cigarette smoking.

Conclusions

Umediation is a flexible R package that examines the role of unmeasured confounding in mediation analysis allowing for normally distributed or Bernoulli distributed exposures, outcomes, mediators, measured confounders, and unmeasured confounders. Umediation also accommodates multiple measured confounders, multiple unmeasured confounders, and allows for a mediator-exposure interaction on the outcome. Umediation is available as an R package at https://github.com/SharonLutz/Umediation A tutorial on how to install and use the Umediation package is available in the Additional file 1.

Electronic supplementary material

The online version of this article (doi:10.1186/s12859-017-1749-y) contains supplementary material, which is available to authorized users.

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

Background

Maternal smoking has been linked to lower birth weight and higher risk of childhood obesity. However, it is unknown whether grand-maternal smoking during pregnancy is associated with grandchildren birth weight and body mass index (BMI) trajectories.

Methods

We investigated associations of smoking during pregnancy with birth weight, risks of overweight and BMI trajectories among 46,858 mother-child dyads and 6,583 grandmother-mother-child triads of three cohort studies of related individuals. Smoking during pregnancy was reported by mothers, and anthropometric data were provided by participants in each cohort.

Results

Compared to grandchildren of non-smoking women, grandchildren of women who smoked more than 14 cigarettes per day throughout pregnancy were 70 g (95% CI: 12, 129 g; P for trend = 0.01) heavier at birth, and 18% (95% CI: 4%, 34%; P for trend = 0.01) more likely to become overweight. The mean BMI of grandchildren of women who smoked during pregnancy was 0.45 kg/m² (95% CI: 0.14, 0.75 kg/m²; P for trend = 0.006) higher through adolescence and young adulthood than that of grandchildren of non-smoking mothers.

Conclusions

Grandmothers’ smoking during pregnancy was associated with higher birth weight, higher risk of overweight, and higher BMI through adolescence and young adulthood.

Tobacco Exposure and Conditional Weight-for-Length Gain by 2 Years of Age

Objective

To prospectively examine dose-response and timing effects of prenatal (PTE) and postnatal tobacco exposure on obesity risk assessed by conditional weight-for-length gain (CWFLG), by 2 years of age. CWFLG over the first 2 years of life was examined for 117 PTE and 57 nonexposed children. Repeated assessments of PTE were conducted beginning in the first trimester of pregnancy, using multiple methods. PTE or postnatal exposure status was not predictive of CWFLG. However, there was a dose-response association and an association with fetal exposure ascertained by infant meconium positive for nicotine and metabolites. PTE is related to restricted growth at birth, yet associated with accelerated CWFLG by 2 years of age, a measure that controls for birthweight differences. Results highlight the importance of examining dose-response and timing of exposure associations, along with the importance of obesity risk-reduction interventions within the first 2 years of life among PTE children.

Individual and Joint Effects of Early-Life Ambient Exposure and Maternal Prepregnancy Obesity on Childhood Overweight or Obesity

BACKGROUND

Although previous studies suggest that exposure to traffic-related pollution during childhood increases the risk of childhood overweight or obesity (COWO), the role of early life exposure to fine particulate matter (aerodynamic diameter <2.5 μm; PM_2.5) and its joint effect with the mother’s prepregnancy body mass index (MPBMI) on COWO remain unclear.

OBJECTIVES

The present study was conducted to examine the individual and joint effects of ambient PM_2.5 exposures and MPBMI on the risk of COWO.

METHODS

We estimated exposures to ambient PM_2.5in utero and during the first 2 y of life (F2YL), using data from the U.S. Environmental Protection Agency’s (EPA’s) Air Quality System matched to residential address, in 1,446 mother–infant pairs who were recruited at birth from 1998 and followed up prospectively through 2012 at the Boston Medical Center in Massachusetts. We quantified the individual and joint effects of PM_2.5 exposure with MPBMI on COWO, defined as the child’s age- and sex-specific BMI z-score ≥85th percentile at the last well-child care visit between 2 and 9 y of age. Additivity was assessed by estimating the reduced excess risk due to interaction.

RESULTS

Comparing the highest and lowest quartiles of PM_2.5, the adjusted relative risks (RRs) [95% confidence intervals (CIs)] of COWO were 1.3 (95% CI: 1.1, 1.5), 1.2 (95% CI: 1.0, 1.4), 1.2 (95% CI: 1.0, 1.4), 1.3 (95% CI: 1.1, 1.6), 1.3 (95% CI: 1.1, 1.5) and 1.3 (1.1, 1.5) during preconception; the first, second, and third trimesters; the entire period of pregnancy; and F2YL, respectively. Spline regression showed a dose–response relationship between PM_2.5 levels and COWO after a threshold near the median exposure (10.46 μg/m³–10.89 μg/m³). Compared with their counterparts, children of obese mothers exposed to high levels of PM_2.5 had the highest risk of COWO [RR≥2.0, relative excess risk due to interaction (RERI) not significant].

CONCLUSIONS

In the present study, we observed that early life exposure to PM_2.5 may play an important role in the early life origins of COWO and may increase the risk of COWO in children of mothers who were overweight or obese before pregnancy beyond the risk that can be attributed to MPBMI alone. Our findings emphasize the clinical and public health policy relevance of early life PM_2.5 exposure. https://doi.org/10.1289/EHP261

A Systematic Review on the Effects of Polycyclic Aromatic Hydrocarbons on Cardiometabolic Impairment

Background:

Various epidemiological studies have shown that exposure to environmental pollutants including polycyclic aromatic hydrocarbons (PAHs) might increase the risk of cardiovascular diseases (CVDs) and their risk factors. This study aims to systematically review the association of PAH exposure with metabolic impairment.

Methods:

Data were collected by searching for relevant studies in international databases using the following keywords: “polycyclic aromatic hydrocarbon” + “cardiovascular disease,” PAH + CVD, polycyclic aromatic hydrocarbon and “air pollutant” + “CVD,” and the desired data were extracted and included in the study according to the systematic review process.

Results:

From the 14 articles included in the present systematic review, eight articles were conducted on the relationship between PAH and CVDs, four articles were conducted to examine the association of PAH exposure with blood pressure (BP), and two articles investigated the link between PAH and obesity.

Conclusions:

Most studies included in this systematic review reported a significant positive association of PAH exposure with increased risk of CVDs and its major risk factors including elevated BP and obesity. These findings should be confirmed by longitudinal studies with long-term follow-up.

Applying Precision Public Health to Prevent Preterm Birth

Preterm birth (PTB) is one of the major health-care challenges of our time. Being born too early is associated with major risks to the child with potential for serious consequences in terms of life-long disability and health-care costs. Discovering how to prevent PTB needs to be one of our greatest priorities. Recent advances have provided hope that a percentage of cases known to be related to risk factors may be amenable to prevention; but the majority of cases remain of unknown cause, and there is little chance of prevention. Applying the principle of precision public health may offer opportunities previously unavailable. Presented in this article are ideas that may improve our abilities in the fields of studying the effects of migration and of populations in transition, public health programs, tobacco control, routine measurement of length of the cervix in mid-pregnancy by ultrasound imaging, prevention of non-medically indicated late PTB, identification of pregnant women for whom treatment of vaginal infection may be of benefit, and screening by genetics and other “omics.” Opening new research in these fields, and viewing these clinical problems through a prism of precision public health, may produce benefits that will affect the lives of large numbers of people.

Somatic growth in the first six months of life of infants exposed to maternal smoking in pregnancy

Background

Some studies suggest a relationship between maternal smoking during pregnancy and not only intrauterine fetal growth restriction or low birth weight, but also with changes in the postnatal growth and development. The objective of the present study was to investigate the effects of smoking during pregnancy on infants growth in the first 6 months of life compared with a control group and a group with idiopathic intrauterine growth restriction.

Methods

Longitudinal observational study using a convenience sample of newborns divided into three groups: infants of smoking mothers (tobacco), with idiopathic intrauterine growth restriction (IUGR) and a control group. The sample was selected from two hospitals in Porto Alegre, located in southern Brazil, between 2011 and 2015. Newborns were evaluated at birth, 7 and 15 days, and in the first, third, and sixth month. Anthropometric measures were weight, length and head circumference. The growth indicators used were expressed as z-scores. The analyses were performed using the generalized estimating equation method.

Results

The sample included 273 mother/newborn pairs: 86 tobacco group, 34 IUGR group, and 153 control group. In terms of weight at birth, all groups differed significantly (p < 0.001). The birth length of tobacco and control groups were similar, but the IUGR group was lower than both (p < 0.001). We found no differences in growth trajectory between tobacco and control group, but there were differences in the growth of the IUGR group when compared with the other groups. At 6 months of age, all groups had similar anthropometric measurements.

Conclusion

Intrauterine growth restriction had major impact on the growth trajectory of the infants studied, regardless of other factors, such as smoking and diet.

Metabolism disrupting chemicals and metabolic disorders

The recent epidemics of metabolic diseases, obesity, type 2 diabetes(T2D), liver lipid disorders and metabolic syndrome have largely been attributed to genetic background and changes in diet, exercise and aging. However, there is now considerable evidence that other environmental factors may contribute to the rapid increase in the incidence of these metabolic diseases. This review will examine changes to the incidence of obesity, T2D and non-alcoholic fatty liver disease (NAFLD), the contribution of genetics to these disorders and describe the role of the endocrine system in these metabolic disorders. It will then specifically focus on the role of endocrine disrupting chemicals (EDCs) in the etiology of obesity, T2D and NAFLD while finally integrating the information on EDCs on multiple metabolic disorders that could lead to metabolic syndrome. We will specifically examine evidence linking EDC exposures during critical periods of development with metabolic diseases that manifest later in life and across generations.

Early-life exposure to EDCs: role in childhood obesity and neurodevelopment

Endocrine-disrupting chemicals (EDCs) might increase the risk of childhood diseases by disrupting hormone-mediated processes that are critical for growth and development during gestation, infancy and childhood. The fetus, infant and child might have enhanced sensitivity to environmental stressors such as EDCs due to their rapid development and increased exposure to some EDCs as a consequence of development-specific behaviour, anatomy and physiology. In this Review, I discuss epidemiological studies examining the relationship between early-life exposure to bisphenol A (BPA), phthalates, triclosan and perfluoroalkyl substances (PFAS) with childhood neurobehavioural disorders and obesity. The available epidemiological evidence suggest that prenatal exposure to several of these ubiquitous EDCs is associated with adverse neurobehaviour (BPA and phthalates) and excess adiposity or increased risk of obesity and/or overweight (PFAS). Quantifying the effects of EDC mixtures, improving EDC exposure assessment, reducing bias from confounding, identifying periods of heightened vulnerability and elucidating the presence and nature of sexually dimorphic EDC effects would enable stronger inferences to be made from epidemiological studies than currently possible. Ultimately, improved estimates of the causal effects of EDC exposures on child health could help identify susceptible subpopulations and lead to public health interventions to reduce these exposures.

Endocrine Disruptors and Obesity

PURPOSE OF REVIEW

The purpose of this review was to summarise current evidence that some environmental chemicals may be able to interfere in the endocrine regulation of energy metabolism and adipose tissue structure.

RECENT FINDINGS

Recent findings demonstrate that such endocrine-disrupting chemicals, termed "obesogens", can promote adipogenesis and cause weight gain. This includes compounds to which the human population is exposed in daily life through their use in pesticides/herbicides, industrial and household products, plastics, detergents, flame retardants and as ingredients in personal care products. Animal models and epidemiological studies have shown that an especially sensitive time for exposure is in utero or the neonatal period. In summarising the actions of obesogens, it is noteworthy that as their structures are mainly lipophilic, their ability to increase fat deposition has the added consequence of increasing the capacity for their own retention. This has the potential for a vicious spiral not only of increasing obesity but also increasing the retention of other lipophilic pollutant chemicals with an even broader range of adverse actions. This might offer an explanation as to why obesity is an underlying risk factor for so many diseases including cancer.

Effect of Exclusive Breastfeeding Among Overweight and Obese Mothers on Infant Weight-for-Length Percentile at 1 Year

BACKGROUND

Breastfeeding is associated with decreased risk of childhood obesity. However, there is a strong correlation between maternal weight status and childhood obesity, and it is unclear whether or not breastfeeding among overweight mothers could mitigate this risk. Our goal was to examine whether or not exclusive breastfeeding (compared to formula feeding) among overweight and obese mothers is associated with lower weight-for-length (W/L) percentile at 1 year.

MATERIALS AND METHODS

Data from the Infant Feeding Practices II study were used. Infants who were preterm or underweight at 1 year, and mothers who were underweight before pregnancy, were excluded from analysis. There was a significant interaction between exclusive breastfeeding for 4 months and maternal prepregnancy weight status (normal weight, overweight, obese) on infant W/L percentile at 1 year. Stratified linear mixed-effects growth modeling controlling for covariates was created to test the relationship between exclusive breastfeeding and infant W/L percentile within each maternal weight category.

RESULTS

A total of 915 subjects met inclusion criteria. Normal weight and obese mothers who exclusively breastfed for 4 months had infants with a smaller rate of increase in W/L percentile during the first year compared with those who used formula. Infants of overweight and obese mothers who exclusively breastfed for 4 months had lower W/L percentile at 1 year than those who used formula.

CONCLUSIONS

Exclusive breastfeeding for 4 months among normal weight and obese mothers resulted in less increase in W/L percentiles in the first year. Obese mothers often have a difficult time initiating and maintaining breastfeeding. Concerted efforts are needed to support this population with breastfeeding.

Early Life Characteristics Associated with Appetite-Related Eating Behaviors in 7-Year-Old Children

OBJECTIVE

To assess early life characteristics associated with appetite-related eating behaviors in 7-year-old children.

STUDY DESIGN

The participants are children from the population-based birth cohort Generation XXI. Data on sociodemographics, health, and lifestyles and anthropometrics were collected at birth, and 4- and 7-year-old evaluations. A Portuguese version of the Children's Eating Behavior Questionnaire was completed by mothers (n = 3562 children) with children aged 7 years old. A 2-factor solution was identified: factor 1-appetite restraint and factor 2-appetite disinhibition. Associations were estimated through generalized linear models adjusted for maternal age, education, body mass index (BMI) before birth, family structure, number of siblings, and child's sex (β regression coefficients and 95% CIs).

RESULTS

Higher appetite restraint at 7 years old was associated with higher maternal age and educational level, families with both parents (1- vs 2-parent: β = -0.074, 95% CI -0.140, -0.007) and no siblings (≥2 vs 0: β = -0.152, 95% CI -0.224, -0.081), and more sedentary lifestyles at 4 years old. It was also associated with lower child and maternal BMI and waist circumference at 4 years old. In contrast, higher appetite disinhibition was associated with lower maternal educational background, having a 1-parent family, more sedentary behaviors (≥120 vs <120 min/d of media: β = 0.055, 95% CI 0.018, 0.093), and higher BMI and waist circumference at 4 years old.

CONCLUSIONS

Higher maternal age and education, and a family with both parents at 4 years old seem to influence higher appetite restraint, but less appetite disinhibition at 7 years old. More sedentary lifestyles at 4 years old were associated with higher appetite restraint and appetite disinhibition scores later in childhood. These results can be useful for the development of prevention guidelines and educational strategies aimed at improving healthy eating behaviors.

Association between body mass index percentile trajectories in infancy and adiposity in childhood and early adulthood

OBJECTIVE

To identify distinct body mass index (BMI) percentile trajectories during early childhood and examine adiposity levels in childhood and early adulthood according to the BMI percentile trajectories.

METHODS

Iowa Fluoride Study cohort parents (n = 1,093) reported their child's anthropometric data on average six times between ages 0 and 23 months. A subset of the cohort underwent DXA scans at approximately age 8 years (n = 495) and again at approximately age 19 years (n = 314). Group-based trajectory analysis was conducted to identify distinct BMI percentile trajectories from ages 0 to 23 months. Sex-specific age-adjusted linear regression analyses were conducted to compare fat mass index in childhood and early adulthood among subgroups that follow the distinct BMI percentile patterns.

RESULTS

Four BMI percentile patterns were identified: consistently low (group 1: 9.8%), increase in the second year (group 2: 33.7%), increase in the first year (group 3: 23.9%), and consistently high (group 4: 32.6%). Compared with group 2 females, groups 3 and 4 females had higher fat mass index in childhood and early adulthood (P < 0.05). However, no significant difference was found in males.

CONCLUSIONS

Females who experience a steep increase of BMI percentile in the first year of life, as opposed to a steep increase in the second year of life, may have higher body fat later in life, but this was not found in males.

Maternal smoking during pregnancy and rapid weight gain from birth to early infancy

Background

Although several studies have focused on the association between maternal smoking during pregnancy and rapid weight gain (RWG) during infancy, the dose-response relationship has not yet been confirmed, and very few studies have included Asian populations. Using a record-linkage method, we examined the association between maternal smoking during pregnancy and RWG in infants at around 4 months of age to clarify the dose-response relationship.

Methods

Two databases were used: maternal check-ups during pregnancy and early infancy check-ups (between April 1, 2013 and March 31, 2014 in Okinawa, Japan) were linked via IDs and provided to us after unlinkable anonymizing. For 10,433 subjects (5229 boys and 5204 girls), we calculated the change in infants' weight z-score by subtracting the z-score of their birth weight from their weight at early infancy check-ups. Smoking exposure was categorized into five groups. We used Poisson regression to examine the association of maternal smoking during pregnancy with RWG in early infancy.

Results

Overall, 1524 (14.6%) were ex-smoker and 511 (4.9%) were current smoker. Compared with the reference category of non-smokers, the adjusted risk ratio of RWG was 1.18 (95% confidence interval [CI], 1.06–1.32) for ex-smokers, 1.18 (95% CI, 0.93–1.50) for those who smoked 1–5 cigarettes per day, 1.57 (95% CI, 1.24–2.00) for those who smoked 6–10 cigarettes per day, and 2.13 (95% CI, 1.51–3.01) for those who smoked ≥11 cigarettes per day. There was a clear dose-response relationship.

Conclusion

Our study suggests that maternal smoking during pregnancy is associated in a dose-dependent manner with increased risk of RWG in early infancy.

•

Maternal smoking in pregnancy is associated with Rapid Weight Gain in early infancy.

•

The association of maternal smoking with rapid weight gain was dose-dependent.

•

This study was based on a large population-based dataset in Japan.

Smoking in pregnancy, adolescent mental health and cognitive performance in young adult offspring: results from a matched sample within a Finnish cohort

BACKGROUND

The association between prenatal exposure to maternal cigarette smoking (PEMCS) and adult cognition is debated, including if there are differences according to sex. We aimed to determine if there are associations between PEMCS and cognition in early adulthood in men and women and examine if observed associations were mediated by adolescent mental health factors that are associated with cognition, namely psychotic-like experiences (PLEs), inattention and hyperactivity, and other externalizing behaviors.

METHODS

Participants were 471 individuals drawn from the general population-based Northern Finland 1986 Birth Cohort (NFBC 1986) followed up from pregnancy and birth to early adulthood; individuals with PEMCS were matched with those without PEMCS by socioeconomic and demographic factors. Cognitive performance in adulthood was assessed with a range of tests and their association with PEMCS was measured by sex using hierarchical linear regression, unadjusted and then controlling for potential confounders, mediators and moderators, including adolescent mental health factors.

RESULTS

There were no associations between PEMCS and cognitive scores in females. In males, there were associations with vocabulary (beta = -0.444, 95% CI: -0.783, -0.104) and matrix reasoning (beta = -0.379, 95% CI: -0.711, -0.047).

CONCLUSIONS

While associations between PEMCS and cognition were limited, observed findings with measures of general intelligence in males contribute to suggestions of differences in response to PEMCS by sex. Furthermore, observed associations may be partly mediated by earlier inattention and hyperactivity. Findings add support to efforts aimed to eliminate smoking in pregnancy.

BMI Development and Early Adolescent Psychosocial Well-Being: UK Millennium Cohort Study

BACKGROUND AND OBJECTIVES

The underlying influences on different patterns of BMI development are not well understood, and psychosocial outcomes linked to BMI development have been little investigated. Objectives were to identify BMI developmental trajectories across the first decade of life, examine early life predictors of trajectory membership, and investigate whether being on a particular BMI trajectory is associated with markers of psychosocial well-being.

METHODS

We used latent class analysis to derive BMI trajectories by using data collected at ages 3, 5, 7, and 11 years on 16 936 participants from the Millennium Cohort Study. Regression models were used to estimate predictors of BMI trajectory membership and their psychosocial correlates.

RESULTS

Four trajectories were identified: 83.8% had an average "stable" nonoverweight BMI, 0.6% were in a "decreasing" group, 13.1% had "moderate increasing" BMIs, and 2.5% had "high increasing" BMIs. Predictors of "moderate" and "high" increasing group membership were smoking in pregnancy (odds ratios [ORs] = 1.17 and 1.97, respectively), maternal BMI (ORs = 1.10 and 1.14), skipping breakfast (ORs = 1.66 and 1.76), nonregular bedtimes (ORs = 1.22 and 1.55). Children in the "moderate" and "high" increasing groups had worse scores for emotional symptoms, peer problems, happiness, body satisfaction, and self-esteem, and those in the "high increasing" group were more likely to have tried alcohol and cigarettes.

CONCLUSIONS

Several potentially modifiable early life factors including smoking in pregnancy, skipping breakfast, and bedtime routines were important predictors of BMI development in the overweight and obese range, and high BMI growth was linked to worse psychosocial well-being.

Assessment of global DNA methylation in the first trimester fetal tissues exposed to maternal cigarette smoking

AIMS

Maternal cigarette smoking during pregnancy increases the risk of negative health consequences for the exposed child. Epigenetic mechanisms constitute a likely link between the prenatal exposure to maternal cigarette smoking and the increased risk in later life for diverse pathologies. Maternal smoking induces gene-specific DNA methylation alterations as well as global DNA hypermethylation in the term placentas and hypomethylation in the cord blood. Early pregnancy represents a developmental time where the fetal epigenome is remodeled and accordingly can be expected to be highly prone to exposures with an epigenetic impact. We have assessed the influence of maternal cigarette smoking during the first trimester for fetal global DNA methylation.

METHODS AND RESULTS

We analyzed the human fetal intestines and livers as well as the placentas from the first trimester pregnancies. Global DNA methylation levels were quantified with ELISA using a methylcytosine antibody as well as with the bisulfite pyrosequencing of surrogate markers for global methylation status, LINE-1, and AluYb8. We identified gender-specific differences in global DNA methylation levels, but no significant DNA methylation changes in exposure responses to the first trimester maternal cigarette smoking.

CONCLUSIONS

Acknowledging that only examining subsets of global DNA methylation markers and fetal sample availability represents possible limitations for the analyses, our presented results indicate that the first trimester maternal cigarette smoking is not manifested in immediate aberrations of fetal global DNA methylation.

Perinatal, sociodemographic and lifestyle correlates of increased total and visceral fat mass levels in schoolchildren in Greece: the Healthy Growth Study

Objective

To identify possibly independent associations of perinatal, sociodemographic and lifestyle factors with childhood total and visceral body fat.

Design

A representative sample of 2655 schoolchildren (9–13 years) participated in the Healthy Growth Study, a cross-sectional epidemiological study.

Setting

Seventy-seven primary schools in four large regions in Greece.

Subjects

A sample of 1228 children having full data on total and visceral fat mass levels, as well as on anthropometric, dietary, physical activity, physical examination, socio-economic and perinatal indices, was examined.

Results

Maternal (OR=3·03 and 1·77) and paternal obesity (OR=1·62 and 1·78), maternal smoking during pregnancy (OR=1·72 and 1·93) and rapid infant weight gain (OR=1·42 and 1·96) were significantly and positively associated with children’s increased total and visceral fat mass levels, respectively. Children’s television watching for >2 h/d (OR=1·40) and maternal pre-pregnancy obesity (OR=2·46) were associated with children’s increased total and visceral fat mass level, respectively. Furthermore, increased children’s physical activity (OR=0·66 and 0·47) were significantly and negatively associated with children’s total and visceral fat mass levels, respectively. Lastly, both father’s age >46 years (OR=0·57) and higher maternal educational level (OR=0·45) were associated with children’s increased total visceral fat mass level.

Conclusions

Parental sociodemographic characteristics, perinatal indices and pre-adolescent lifestyle behaviours were associated with children’s abnormal levels of total and visceral fat mass. Any future programme for childhood prevention either from the perinatal age or at late childhood should take these indices into consideration.

Sociodemographic correlates of smoking in pregnancy and antenatal-care attendance in Indigenous and non-Indigenous women in South Australia

Smoking in pregnancy is a key health issue in Australia, particularly among Indigenous women. However, few studies have examined the sociodemographic factors associated with smoking in pregnancy or the predictors of antenatal-care attendance among Indigenous and non-Indigenous Australian women who smoke. Data from the South Australian perinatal statistics collection of all births from 2000-2010 (n=197538) were analysed separately by Indigenous status to determine the sociodemographic factors associated with smoking in pregnancy and antenatal-care attendance by women who smoke. For Indigenous and non-Indigenous women, smoking in pregnancy was significantly independently associated with socioeconomic disadvantage, residing in regional or remote areas, increased parity, unemployment, being a public patient and attending fewer antenatal care visits. Smoking in pregnancy was associated with younger age and not being partnered only for non-Indigenous women. For Indigenous and non-Indigenous pregnant women who smoked, antenatal-care attendance was lower among women who were of younger age, higher parity, unemployed and not partnered. Differences in attendance within sociodemographic factors were greater for Indigenous women. Therefore, while sociodemographic correlates of smoking in pregnancy and antenatal-care attendance are largely similar for Indigenous and non-Indigenous women, tailored cessation and antenatal-care programs that reflect the differences in sociodemographic groups most at risk may be beneficial.

New Strategies to Prioritize Nutrition, Physical Activity, and Obesity Interventions

Interventions for obesity have not often been based on considerations that could predict their effectiveness. However, advances in research provide several new approaches that can inform priorities for public health interventions directed at nutrition, physical activity, and obesity. These approaches include estimation of the effect size, comparison of the calorie gap with the caloric deficit induced by the intervention, population reach and impact, cost and cost effectiveness of the intervention, time required to evaluate the effect of the intervention on weight change, and feasibility of the intervention. Incorporation of these considerations by policymakers and public health practitioners will help identify those interventions most likely to achieve changes in the prevalence of obesity.

Maternal Diet and Nutrient Requirements in Pregnancy and Breastfeeding. An Italian Consensus Document

The importance of lifestyle and dietary habits during pregnancy and breastfeeding, for health of mothers and their offspring, is widely supported by the most recent scientific literature. The consumption of a varied and balanced diet from the preconceptional period is essential to ensure both maternal well-being and pregnancy outcomes. However, the risk of inadequate intakes of specific micronutrients in pregnancy and lactation is high even in the most industrialized countries. This particularly applies to docosahexaenoic acid (DHA), iron, iodine, calcium, folic acid, and vitamin D, also in the Italian population. Moreover, the risk of not reaching the adequate nutrient supply is increased for selected groups of women of childbearing age: those following exclusion diets, underweight or overweight/obese, smokers, adolescents, mothers who have had multiple or close pregnancies, and those with previous unfavorable pregnancy outcomes.

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.