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

Maternal weight, smoking, and diabetes provided early predictors of longitudinal body mass index growth patterns in childhood

AIM

The aim of this study was to identify factors affecting overweight growth development using extended body mass index (BMI) data combined with birth and maternal records from Finnish national registries.

METHODS

The longitudinal data consist of growth measurements of 7372 from six birth cohorts in Finland: 1974 (n = 1109), 1981 (n = 983), 1991 (n = 607), 1994-1995 (n = 829), 2001 (n = 821), and 2003-2004 (n = 3023). Anthropometric data were collected from birth to age 15 years from the health records. Pregnancy health data were included for the four most recent birth cohorts (n = 2810). A statistical method called trajectory analysis was used to identify different BMI development trajectories. Factors associated with abnormal growth tracks were analysed using logistic regression models.

RESULTS

High pre-pregnancy BMI, gestational diabetes mellitus, maternal smoking, and greater gestational weight gain than the Institute of Medicine (United States) recommendations were associated with the overweight growth track. Two of the trajectories didn't seem to follow the normal growth pattern: overweight growth track appeared to lead to overweight, while low birth BMI track showed accelerating growth after the adiposity rebound point of BMI growth.

CONCLUSION

These findings suggest that maternal overweight before pregnancy, excessive gestational weight gain, gestational diabetes mellitus, and smoking could potentially be associated with the risk of obesity in children.

Understanding risk and causal mechanisms for developing obesity in infants and young children: A National Institutes of Health workshop

Obesity in children remains a major public health problem, with the current prevalence in youth ages 2-19 years estimated to be 19.7%. Despite progress in identifying risk factors, current models do not accurately predict development of obesity in early childhood. There is also substantial individual variability in response to a given intervention that is not well understood. On April 29-30, 2021, the National Institutes of Health convened a virtual workshop on "Understanding Risk and Causal Mechanisms for Developing Obesity in Infants and Young Children." The workshop brought together scientists from diverse disciplines to discuss (1) what is known regarding epidemiology and underlying biological and behavioral mechanisms for rapid weight gain and development of obesity and (2) what new approaches can improve risk prediction and gain novel insights into causes of obesity in early life. Participants identified gaps and opportunities for future research to advance understanding of risk and underlying mechanisms for development of obesity in early life. It was emphasized that future studies will require multi-disciplinary efforts across basic, behavioral, and clinical sciences. An exposome framework is needed to elucidate how behavioral, biological, and environmental risk factors interact. Use of novel statistical methods may provide greater insights into causal mechanisms.

Association of child weight with attendance at a healthy lifestyle service among women with obesity during pregnancy

Women with obesity during pregnancy are at increased risk of excessive gestational weight gain (GWG) and other maternal and infant adverse outcomes, which all potentially increase childhood obesity. This study explored infant weight outcomes for women with a body mass index (BMI) ≥ 35 kg/m² who were offered an antenatal healthy lifestyle service. A retrospective cohort study, including linking data from two separate health care Trusts, was undertaken. Data were collected from maternity records for women with a BMI ≥ 35 kg/m2 referred to an antenatal healthy lifestyle service from 2009 to 2015. The respective child's weight outcome data was additionally collected from health and National Child Measurement Programme records. Univariate logistic regression determined the odds of childhood overweight, obesity and severe obesity according to attendance at the antenatal healthy lifestyle service, GWG and sociodemographic characteristics. Factors significant (p < 0.05) within the univariate analysis were entered into multiple logistic regression models. Among women with a BMI ≥ 35 kg/m², 30.4% of their children were obese at school entry and 13.3% severely obese. Healthy lifestyle service attendance was not associated with childhood overweight or obesity at any point within the univariate analysis. At school age multiple regression analysis showed the odds of overweight and obesity increased with excessive GWG and the odds of obesity decreased with a parent in a professional occupation, additionally having a mother who smoked in pregnancy increased severe obesity. Women should be supported to optimise their BMI before pregnancy. Additionally, rather than exclusively focusing on changing an individual's behaviour, future interventions should consider external influences such as the woman's family, friends and sociodemographic background.

The role of fathers in child development from preconception to postnatal influences: Opportunities for the National Institutes of Health Environmental influences on Child Health Outcomes (ECHO) program

A growing body of literature highlights the important role of paternal health and socioemotional characteristics in child development, from preconception through adolescence. Much of this research addresses the indirect effects of fathers, for instance, their influence on maternal behaviors during the prenatal period or via the relationship with their partner. However, emerging evidence also recognizes the direct role of paternal health and behavior for child health and adjustment across development. This critical review presents evidence of biological and sociocultural influences of fathers on preconception, prenatal, and postnatal contributions to child development. The National Institutes of Health Environmental influences on Child Health Outcomes (ECHO) program incorporates in its central conceptualization the impact of fathers on family and child outcomes. This critical synthesis of the literature focuses on three specific child outcomes in the ECHO program: health outcomes (e.g., obesity), neurodevelopmental outcomes (e.g., emotional, behavioral, psychopathological development), and positive health. We highlight the unique insights gained from the literature to date and provide next steps for future studies on paternal influences.

The links between parental smoking and childhood obesity: data of the longitudinal study of Australian children

Childhood obesity is one of the most concerning public health issues globally and its implications in mortality and morbidity in adulthood are increasingly important. This study uses a unique dataset of Australian children aged 4-16 to examine the impact of parental smoking on childhood obesity. It confirms a significant link between parental smoking (stronger for mothers) and higher obesity risk in children, regardless of income, age, family size, or birth order. Importantly, we explore whether heightened preference for unhealthy foods can mediate the effect of parental smoking. Our findings suggest that increased consumption of unhealthy foods among children can be associated with parental smoking.

Maternal smoking during pregnancy increases the risk of gut microbiome-associated childhood overweight and obesity

Childhood obesity is linked to maternal smoking during pregnancy. Gut microbiota may partially mediate this association and could be potential targets for intervention; however, its role is understudied. We included 1,592 infants from the Canadian Healthy Infants Longitudinal Development Cohort. Data on environmental exposure and lifestyle factors were collected prenatally and throughout the first three years. Weight outcomes were measured at one and three years of age. Stool samples collected at 3 and 12 months were analyzed by sequencing the V4 region of 16S rRNA to profile microbial compositions and magnetic resonance spectroscopy to quantify the metabolites. We showed that quitting smoking during pregnancy did not lower the risk of offspring being overweight. However, exclusive breastfeeding until the third month of age may alleviate these risks. We also reported that maternal smoking during pregnancy significantly increased Firmicutes abundance and diversity. We further revealed that Firmicutes diversity mediates the elevated risk of childhood overweight and obesity linked to maternal prenatal smoking. This effect possibly occurs through excessive microbial butyrate production. These findings add to the evidence that women should quit smoking before their pregnancies to prevent microbiome-mediated childhood overweight and obesity risk, and indicate the potential obesogenic role of excessive butyrate production in early life.

Prevalence and determinants of overweight and obesity among preschool-aged children from migrant and socioeconomically disadvantaged contexts in Montreal, Canada

Among migrant and socioeconomically disadvantaged preschool-aged children followed in social perinatal primary care services in Montreal, Canada, we estimated the prevalence of overweight/obesity and identified determinants of body mass index z-score (zBMI) at 4-5 years old. We conducted a retrospective cohort study using electronic medical records of 275 child-mother dyads followed from birth to 4-5 years. Anthropometric measures and established maternal, perinatal and child risk factors for childhood obesity were examined. Age- and sex-specific zBMI at 4-5-years were computed and categorized according to WHO standards. Linear regression with model averaging was used to identify early life factors associated with zBMI. At 4-5 years, children's weight status was classified as underweight (1.5%), normal weight (69.7%), at-risk-of-overweight (19.2%), overweight (6.9%), and obesity (2.7%). Primiparity (0.51, 95% CI 0.24; 0.78), higher birthweight (1.04, 95% CI 0.70; 1.37), accelerated weight gain in the first year of life (0.21, 95% CI 0.13; 0.31), and introduction to solid foods before 6 months (0.89, 95% CI 0.42; 1.36) were associated with a higher zBMI, while less than high school education (-0.50, 95% CI -0.95; -0.05) and higher gestational age (-0.14, 95% CI -0.21; -0.05) were associated with lower zBMI at 4-5 years. Overweight/obesity is prevalent among preschool-aged children from migrant and socioeconomically disadvantaged contexts and is associated with known risk factors. Future research is needed to better understand the role of social perinatal primary care services in promoting optimal weight gain among children living in contexts of vulnerability.

Study protocol of an economic evaluation embedded in the Midwives and Obstetricians Helping Mothers to Quit Smoking (MOHMQuit) trial

BACKGROUND

Tobacco smoking during pregnancy is the most important preventable risk factor for pregnancy complications and adverse birth outcomes and can have lifelong consequences for infants. Smoking during pregnancy is associated with higher healthcare costs related to birth complications and during childhood. Psychosocial interventions to support pregnant women to quit are effective, yet provision of smoking cessation support has been inconsistent. The Midwives and Obstetricians Helping Mothers to Quit Smoking (MOHMQuit) intervention provides systems change, and leadership and clinician elements, to support clinicians to help women stop smoking in pregnancy. There have been few long-term analyses conducted of the cost-effectiveness of smoking cessation interventions for pregnant women that target healthcare providers. This protocol describes the economic evaluation of the MOHMQuit trial, a pragmatic stepped-wedge cluster-randomised controlled implementation trial in nine public maternity services in New South Wales (NSW), Australia, to ascertain whether MOHMQuit is cost-effective in supporting clinicians to help women quit smoking in pregnancy compared to usual care.

METHODS

Two primary analyses will be carried out comparing MOHMQuit with usual care from an Australian health care system perspective: i) a within-trial cost-effectiveness analysis with results presented as the incremental cost per additional quitter; and ii) a lifetime cost-utility analysis using a published probabilistic decision analytic Markov model with results presented as incremental cost per quality-adjusted life-year (QALY) gained for mother and child. Patient-level data on resource use and outcomes will be used in the within-trial analysis and extrapolated and supplemented with national population statistics and published data from the literature for the lifetime analysis.

DISCUSSION

There is increasing demand for information on the cost-effectiveness of implementing healthcare interventions to provide policy makers with critical information for the best value for money within finite budgets. Economic evaluation of the MOHMQuit trial will provide essential, policy-relevant information for decision makers on the value of evidence-based implementation of support for healthcare providers delivering services for pregnant women.

TRIAL REGISTRATIONS

ACTRN12622000167763, registered 2 February 2022.

An insight into brown/beige adipose tissue whitening, a metabolic complication of obesity with the multifactorial origin

Brown adipose tissue (BAT), a thermoregulatory organ known to promote energy expenditure, has been extensively studied as a potential avenue to combat obesity. Although BAT is the opposite of white adipose tissue (WAT) which is responsible for energy storage, BAT shares thermogenic capacity with beige adipose tissue that emerges from WAT depots. This is unsurprising as both BAT and beige adipose tissue display a huge difference from WAT in terms of their secretory profile and physiological role. In obesity, the content of BAT and beige adipose tissue declines as these tissues acquire the WAT characteristics via the process called "whitening". This process has been rarely explored for its implication in obesity, whether it contributes to or exacerbates obesity. Emerging research has demonstrated that BAT/beige adipose tissue whitening is a sophisticated metabolic complication of obesity that is linked to multiple factors. The current review provides clarification on the influence of various factors such as diet, age, genetics, thermoneutrality, and chemical exposure on BAT/beige adipose tissue whitening. Moreover, the defects and mechanisms that underpin the whitening are described. Notably, the BAT/beige adipose tissue whitening can be marked by the accumulation of large unilocular lipid droplets, mitochondrial degeneration, and collapsed thermogenic capacity, by the virtue of mitochondrial dysfunction, devascularization, autophagy, and inflammation.

Early childhood exposure to maternal smoking and obesity: A nationwide longitudinal survey in Japan

Involuntary exposure to tobacco smoke is suspected to be one of the risks factors that are associated with obesity in children. The purpose of this study was to examine the relationship between early childhood exposure to tobacco smoke and the risk of obesity and overweight in Japan. This study utilized a nationwide, population-based longitudinal survey. The participants were restricted to 32 081 children who had available information on maternal smoking history as well as childhood height and weight. We conducted a binomial log-linear regression analysis with children of non-smoking mothers as the reference group. The children with mothers who were smokers had a higher risk of developing obesity or being overweight compared to the children with mothers who were nonsmokers. The risk ratios were 1.20 (95% confidence interval [CI]: 1.09-1.32) for overweight and 1.17 (95% CI: 0.95-1.44) for obesity. Early exposure to maternal smoking increases the risk of being overweight and having obesity during childhood. The increased risk is more pronounced among children with mothers, smoked heavily, or parents, who were smokers.

Pregnant and postnatal women's experiences of interacting with health care providers about their tobacco smoking: a qualitative systematic review

OBJECTIVE

The objective of this review was twofold: (i) to comprehensively identify the best available evidence about the experiences of women who smoked tobacco during pregnancy or postnatally (or both) concerning health care providers' interactions with them about their smoking, when such interactions occurred during contact for prenatal or postnatal health care in any health care setting; and (ii) to synthesize the research findings for recommendations to strengthen health care providers' interventions regarding smoking during pregnancy and smoking during the postnatal period.

INTRODUCTION

Maternal tobacco smoking during pregnancy and maternal tobacco smoking postnatally pose serious health risks for the woman, fetus, and offspring, whereas maternal smoking cessation has beneficial health effects. Given the importance of health care providers' interactions with pregnant and postnatal women for smoking cessation care, it is essential to understand women's experiences of such interactions.

INCLUSION CRITERIA

Studies considered for this review had qualitative research findings about the experiences of women who smoked tobacco during pregnancy or postnatally (or both) in relation to health care providers' interactions with them about their smoking.

METHODS

The review was conducted using the JBI approach to qualitative systematic reviews. Published studies were sought through 6 academic databases (eg, CINAHL, MEDLINE). Unpublished studies were searched in 6 gray literature sources (eg, ProQuest Dissertations and Theses, Google Scholar). Reference lists of retrieved records were also searched. The searches occurred in October and November 2020; no country, language, or date limits were applied. Study selection involved title and abstract screening, full-text examination, and critical appraisal of all studies that met the inclusion criteria for the review. Study characteristics and research findings were extracted from the included studies. Study selection and extraction of findings were conducted by two reviewers independently; differences between reviewers were resolved through consensus. The research findings were categorized, and the categories were aggregated into a set of synthesized findings. The synthesized finding were assigned confidence scores. The categories and finalized synthesized findings were agreed upon by all reviewers.

RESULTS

The 57 included studies varied in qualitative research designs and in methodological quality (from mostly low to high). There were approximately 1092 eligible participants, and 250 credible and unequivocal research findings. The research findings yielded 14 categories and 6 synthesized findings with low to very low confidence scores. Some women who smoked tobacco during pregnancy and some women who smoked tobacco postnatally lacked supportive interactions by health care providers regarding their smoking; other women experienced supportive interactions by health care providers. Women were adversely impacted when health care providers' interactions lacked supportiveness, and were beneficially impacted when interactions were supportive. Women varied in openness to health care providers' interactions regarding their smoking, from not being receptive to being accepting, and some women wanted meaningful health care provider interactions.

CONCLUSIONS

Although confidence in the synthesized findings is low to very low, the evidence indicates that supportive health care provider interactions may facilitate positive smoking behavior change in pregnancy and postnatally. It is recommended that health care providers implement accepted clinical practice guidelines with women who smoke prenatally or postnatally, using an approach that is person-centered, emotionally supportive, engaging (eg, understanding), and non-authoritarian.

SYSTEMATIC REVIEW REGISTRATION NUMBER

PROSPERO CRD42020178866.

The bidirectional association between wheezing and obesity during adolescence and the beginning of adulthood in the 1993 birth cohort, Pelotas, Brazil

Objective: To analyze the bidirectional association between wheezing and obesity during adolescence and the beginning of adulthood in a cohort in southern Brazil. Methods: This prospective longitudinal study used data from the 1993 birth cohort in Pelotas, Brazil. The following outcome variables were measured at 22 years of age: self-reported wheezing during the last 12 months and obesity (BMI = 30 kg/m2). The following exposure variables were measured at ages 11, 15, and 18: self-reported wheezing (no wheezing or symptom presentation in 1, 2, or 3 follow-ups) and obesity (non-obese or obese in 1, 2, or 3 follow-ups). Crude and adjusted logistical regression stratified by sex were used in the analyses. The reference category was defined as participants who presented no wheezing or obesity. Results: A total of 3,461 participants had data on wheezing and 3,383 on BMI. At 22 years of age, the prevalence of wheezing was 10.1% (95%CI: 9.1; 11.2), and obesity, 16.2% (95%CI: 15.0; 17.6). In females, the presence of wheezing in two follow-ups revealed a 2.22-fold (95%CI: 1.36; 3.61) greater chance of developing obesity at 22 years of age. Meanwhile, the presence of obesity in two follow-ups resulted in a 2.03-fold (95%IC: 1.05; 3.92) greater chance of wheezing at 22 years of age. No associations were found between wheezing and obesity in males. Conclusions: The obtained data suggest a possible positive bidirectional association between wheezing and obesity, with greater odds ratios in the wheezing to obesity direction in females and in the category of occurrence of exposure in two follow-ups.

Body mass index trajectories from childhood concerning emotional states in young adulthood: Tehran Lipid and Glucose Study

This study aimed to identify body mass index (BMI) trajectories from childhood and their relationships with depression, anxiety, and stress symptoms in young adulthood. A total of 687 children aged 4-18 years were recruited from the Tehran Lipid and Glucose Study. Throughout 18 years of follow-up, BMI was measured every 3 years for a maximum of 6 data points. Participants completed the depression, anxiety, and stress scale in their young adulthood (aged 22-36). The group-based trajectory modelling was applied to identify BMI patterns. The logistic regression model was used to assess the association between BMI trajectories and depression, anxiety, and stress symptoms in adulthood. Two BMI trajectories were identified from childhood to young adulthood: healthy weight (HW = 69.6%) and persistent increasing overweight/obesity (PIO = 30.4%). After adjusting for potential confounders, compared with the HW group, men in the PIO group were more likely to experience higher stress levels (OR: 1.62, 95% CI: 0.99-2.63; p = 0.05). No significant association was observed between the PIO trajectory and depression and anxiety among both sexes and stress symptoms in females. Our results highlight that developing overweight and obesity from childhood may be related to increased stress in males.

Validity of Scottish predictors of child obesity (age 12) for risk screening in mid-childhood: a secondary analysis of prospective cohort study data-with sensitivity analyses for settings without various routinely collected predictor variables

OBJECTIVE

To analyse the Growing Up in Scotland cohort for predictors of obesity at age 12, present at school entry (age 5-6).

METHODS

The initial model included literature-based risk factors likely to be routinely collected in high-income countries (HICs), as well as "Adverse/Protective Childhood Experiences (ACEs/PCEs)". Missing data were handled by Multiple Chained Equations. Variable-reduction was performed using multivariable logistic regression with backwards and forwards stepwise elimination, followed by internal validation by bootstrapping. Optimal sensitivity/specificity cut-offs for the most parsimonious and accurate models in two situations (optimum available data, and routinely available data in Scotland) were examined for their referral burden, and Positive and Negative Predictive Values.

RESULTS

Data for 2787 children with full outcome data (obesity prevalence 18.3% at age 12) were used to develop the models. The final "Optimum Data" model included six predictors of obesity: maternal body mass index, indoor smoking, equivalized income quintile, child's sex, child's BMI at age 5-6, and ACEs. After internal validation, the area under the receiver operating characteristic curve was 0.855 (95% CI 0.852-0.859). A cut-off based on Youden's J statistic for the Optimum Data model yielded a specificity of 77.6% and sensitivity of 76.3%. 37.0% of screened children were "Total Screen Positives" (and thus would constitute the "referral burden".) A "Scottish Data" model, without equivalized income quintile and ACEs as a predictor, and instead using Scottish Index of Multiple Deprivation quintile and "age at introduction of solid foods," was slightly less sensitive (76.2%) but slightly more specific (79.2%), leading to a smaller referral burden (30.8%).

CONCLUSION

Universally collected, machine readable and linkable data at age 5-6 predict reasonably well children who will be obese by age 12. However, the Scottish treatment system is unable to cope with the resultant referral burden and other criteria for screening would have to be met.

Foetal tobacco and cannabis exposure, body fat and cardio-metabolic health in childhood

BACKGROUND

Foetal tobacco and cannabis exposure may have persistent cardio-metabolic consequences in the offspring.

OBJECTIVE

We examined the associations of maternal and paternal tobacco and cannabis use during pregnancy with offspring body fat and cardio-metabolic outcomes.

METHODS

In a population-based prospective cohort study among 4792 mothers, fathers, and children, we assessed parental substance use by questionnaires. Childhood outcomes included body mass index (BMI), body fat, blood pressure, and lipid, glucose and insulin concentrations at 10 years.

RESULTS

Children exposed to maternal tobacco use during pregnancy had a higher android/gynoid fat mass ratio (difference 0.22 SDS, 95% confidence interval [CI]: 0.13, 0.30), fat mass index (difference 0.20 SDS, 95% CI: 0.12, 0.28), triglyceride concentrations (difference 0.15 SDS, 95% CI: 0.04, 0.26), and a higher risk of overweight (odds ratio [OR] 1.35, 95% CI: 1.07, 1.71), compared to non-exposed. Children exposed to maternal cannabis during pregnancy had a higher BMI (difference 0.26 SDS, 95% CI: 0.08, 0.44), android/gynoid fat mass ratio (difference 0.21 SDS, 95% CI: 0.04, 0.39), and fat-free mass index (difference 0.24 SDS, 95% CI: 0.06, 0.41), compared to non-exposed. The associations for paternal substance use with child cardio-metabolic health outcomes were similar as those for maternal use.

CONCLUSIONS

Similar associations for maternal and paternal substance use during pregnancy suggest that these findings may be explained by shared family-based social and lifestyle factors, rather than by direct foetal programming.

Smoking during pregnancy is associated with child overweight independent of maternal pre-pregnancy BMI and genetic predisposition to adiposity

High maternal body mass index (BMI) and smoking during pregnancy are risk factors for child overweight. Maternal smoking tends to reduce her BMI and the association of smoking with child overweight may be confounded by or interacting with maternal genetic predisposition to adiposity. In the Danish National Birth Cohort, we investigated whether smoking during pregnancy is associated with child BMI/overweight independent of pre-pregnancy BMI and maternal genetic predisposition to adiposity estimated as total, transmitted and non-transmitted genetic risk scores (GRSs) based on 941 common genetic variants associated with BMI. Smoking during pregnancy was associated with higher child BMI and higher odds of child overweight in a dose–response relationship. The odds ratio (95% CI) for smoking 11 + cigarettes in third trimester versus no smoking was 2.42 (1.30; 4.50), irrespective of maternal BMI and maternal GRSs (total, transmitted or non-transmitted). There were no statistically significant interactions between maternal GRSs and smoking (all p-values for interactions > 0.05). In conclusion, in this study, smoking during pregnancy exhibits a dose–response association with increased child BMI/overweight, independent of maternal pre-pregnancy BMI, maternal transmitted, and non-transmitted genetic predisposition to adiposity. Avoidance of smoking during pregnancy may help prevent childhood obesity irrespective of the mother–child genetic predisposition.

Perinatal socio-behavioral and obstetric predictors of metabolically healthy and unhealthy obesity in adult offspring

OBJECTIVE

The purpose of this study was to investigate whether obstetric and perinatal socio-behavioral characteristics at the time of pregnancy predict obesity phenotypes of adult offspring.

METHODS

The Jerusalem Perinatal Study was conducted among 17,003 deliveries during 1974 to 1976. Follow-up studies were conducted during 2007 to 2009 and 2017 to 2019 among 1,440 offspring undergoing examinations. Offspring were classified into four phenotypes according to obesity and metabolic status: metabolically healthy normal weight (MHNW, reference group), unhealthy normal weight, healthy obesity (MHO), and unhealthy obesity (MUO). Regression models were carried out to identify perinatal predictors for risk phenotypes at age 30 to 35 years, emphasizing the differentiation between socio-behavioral and obstetric features.

RESULTS

A total of 15.7% of participants were classified as MUO, and 5.4% were classified as MHO. Low socioeconomic status was associated with both obesity phenotypes (e.g., odds ratio [OR]_MHO/MHNW = 2.98, p < 0.001). High socioeconomic status was associated with MUO (OR_MUO/MHNW = 1.93, p = 0.002). Maternal low education was also associated with both obesity phenotypes (OR_MUO/MHNW = 2.46, p < 0.001, OR_MHO/MHNW = 2.45, p = 0.005). Participants with MUO were more likely to have a smoking father (OR_MUO/MHNW = 1.48, p = 0.021).

CONCLUSIONS

Perinatal socio-behavioral characteristics are associated with adult obesity phenotypes. The findings point to possible mechanisms underlying the development of obesity in young adults and, thus, contribute toward identifying high-risk groups that would mostly benefit from obesity risk-reduction interventions.

Maternal Urinary Cotinine Concentrations During Pregnancy Predict Infant BMI Trajectory After Birth: Analysis of 89617 Mother-Infant Pairs in the Japan Environment and Children's Study

BACKGROUND

Clinical or epidemiological conclusions remain undecided on the direct effects of active and second-hand smoking during pregnancy on childhood obesity. Urinary cotinine (UC) concentration, an accurate and quantitative marker for smoking, may elucidate the dose-dependent relationship between smoking during pregnancy and childhood obesity. To analyze the relationship between UC concentration and smoking questionnaire (SQ) classes for active and second-hand smoking in pregnant mothers and trajectory of infant Kaup index (body mass index: BMI).

METHODS

This multicenter prospective cohort study was conducted using a list-wise complete set of 35829 among 89617 mother-infant singleton pairs, recruited between 2011 and 2014, in the Japan Environment and Children's Study (JECS). Pairs were categorized according to UC levels (1 to 4 classes) or SQ (0 to 4 classes).

RESULTS

Maternal BMI at delivery was the highest in UC class 4 (highest). Maternal and paternal education of ≥16 years and annual household income were lowest in UC class 4. Infant BMI was lower at birth, but trends in BMI and ΔBMI were higher from six to 36 months step-wise in the UC classes. The above tendency was observed in the list-wise complete dataset but was emphasized after multiple imputations and corrections of cofounders. UC concentration in five SQ classes largely fluctuated, and the relationship between SQ classes and trends in BMI and ΔBMI was not statistically significant.

CONCLUSION

Infants from high UC mothers had a low BMI at birth, increasing from six to 36 months of age. UC concentrations, but not smoking questionnaire classes, predict infant BMI trajectory, suggesting that active and second-hand smoking affect child obesity in a dose-dependent manner.

Childhood exposure to parental smoking and life-course overweight and central obesity

OBJECTIVE

To evaluate the association between childhood parental smoking exposure and the risk of overweight/obesity from childhood to adulthood.

METHODS

This study leverages the data from two longitudinal population based cohort studies, the Cardiovascular Risk in Young Finns Study between years 1980-2011/2012 (YFS; N = 2,303; baseline age 3-18 years) and the Special Turku Coronary Risk Factor Intervention Project between years 1989-2009/2010 (STRIP; N = 632; baseline age 7 months). Weight, height and waist circumference were measured from childhood to adulthood. Overweight/obesity was defined as body mass index ≥25 kg/m2 in adults and using the Cole criteria in children. Central obesity was defined as waist circumference > 100/90 cm in men/women and as a waist-to-height ratio > 0.50 in children. Statistical analyses were adjusted for age, sex, socioeconomic status, smoking, birth weight, parental ages, diet and physical activity.

RESULTS

Childhood parental smoking exposure was associated with increased risk for life-course overweight/obesity (YFS: RR1.13, 95%CI 1.02-1.24; STRIP: RR1.57, 95%CI 1.10-2.26) and central obesity (YFS: RR1.18, 95%CI 1.01-1.38; STRIP: RR1.45, 95%CI 0.98-2.15).

CONCLUSIONS

Childhood exposure to parental smoking is associated with increased risk of overweight/obesity over the life-course. KEY MESSAGES Exposure to parental smoking in childhood was associated with increased risk of overweight/obesity, central obesity and adiposity measured by skinfold thickness from childhood to adulthood.

Influence of Maternal Active and Secondhand Smoking during Pregnancy on Childhood Obesity at 3 Years of Age: A Nested Case-Control Study from the Japan Environment and Children's Study (JECS)

Maternal smoking during pregnancy is a risk factor for childhood obesity; however, the combined effect of secondhand smoking during pregnancy on children in the early years is unclear. We examined the effects of maternal active and secondhand smoking during pregnancy on childhood obesity in a large population-based cohort. A nested case–control study originating from the Japan Environment and Children’s Study was performed. The maternal smoking status was collected via self-administered questionnaires during mid/late pregnancy. Obesity in children was determined based on BMI measured at 3 years of age. In total, 4875 cases and 19,491 controls were included in the analyses. Conditional logistic regression models with a significance level of 5% (two-tailed test) were used to test the association. The proportion of mothers who continued smoking and who were exposed to secondhand smoking daily during pregnancy were 3.9% and 13.0% in cases and 2.9% and 10.8% in controls, respectively. Continuous maternal smoking was associated with increased odds of obesity compared to those who never smoked or quit smoking before the pregnancy (adjusted odds ratio, 1.39; 95% confidence interval, 1.01–1.92). The odds increased further when combined with secondhand smoking. The promotion of non-smoking among family members, in public and workplace could benefit pregnant women and offspring.

Indigenous Women's Experiences of Smoking and Quitting Smoking in Pregnancy: A Phenomenological Study

BACKGROUND

Maternal smoking during pregnancy (MSDP) is an important public health concern because of potential adverse health effects to the woman, fetus, and child after birth. Prevalence rates are high among groups with socioeconomic disadvantage, including Indigenous women.

PURPOSE

This study was conducted to understand experiences of MSDP for Indigenous women.

METHODS

The study was conducted using phenomenology. Data were collected through interviews with 15 pregnant and postnatal Indigenous women who had smoked during pregnancy. The data were analyzed for themes using phenomenological methods.

RESULTS

The women's narratives revealed four experiences: quitting smoking during pregnancy to protect the unborn baby from harm; quitting smoking during pregnancy because of personal adverse health effects; cutting down smoking during pregnancy and feeling remorse for not quitting; and keeping on smoking during pregnancy and not planning to try to quit. The women's experiences also indicated several impediments to quitting smoking.

CONCLUSIONS

There is need for health care policy to ensure adequate smoking cessation services and support for Indigenous women who smoke in pregnancy. Health care professionals should provide individualized interventions that take into account the challenges to quitting that pregnant women experience and that are in accordance with clinical practice guidelines for MSDP.

Associations of prenatal metabolomics profiles with early childhood growth trajectories and obesity risk in African Americans: the CANDLE study

OBJECTIVE

Prenatal metabolomics profiles, providing measures of in utero nutritional and environmental exposures, may improve the prediction of childhood outcomes. We aimed to identify prenatal plasma metabolites associated with early childhood body mass index (BMI) trajectories and overweight/obesity risk in offspring.

METHODS

This study included 450 African American mother-child pairs from the Conditions Affecting Neurocognitive Development and Learning in Early Childhood Study. An untargeted metabolomics analysis was performed on the mothers' plasma samples collected during the second trimester. The children's BMI-z-score trajectories from birth to age 4 [rising-high- (9.8%), moderate- (68.2%), and low-BMI (22.0%)] and overweight/obesity status at age 4 were the main outcomes. The least absolute shrinkage and selection operator (LASSO) was used to select the prenatal metabolites associated with childhood outcomes.

RESULTS

The mothers were 24.5 years old on average at recruitment, 76.4% having education less than 12 years and 80.0% with Medicaid or Medicare. In LASSO, seven and five prenatal metabolites were associated with the BMI-z-score trajectories and overweight/obese at age 4, respectively. These metabolites are mainly from/relevant to the pathways of steroid biosynthesis, amino acid metabolism, vitamin B complex, and xenobiotics metabolism (e.g., caffeine and nicotine). The odds ratios (95% CI) associated with a one SD increase in the prenatal metabolite risk scores (MRSs) constructed from the LASSO-selected metabolites were 2.97 (1.95-4.54) and 2.03 (1.54-2.67) for children being in the rising-high-BMI trajectory group and overweight/obesity at age 4, respectively. The MRSs significantly improved the risk prediction for childhood outcomes beyond traditional prenatal risk factors. The increase (95% CI) in the area under the receiver operating characteristic curves were 0.10 (0.03-0.18) and 0.07 (0.02-0.12) for the rising-high-BMI trajectory (P = 0.005) and overweight/obesity at age 4 (P = 0.007), respectively.

CONCLUSIONS

Prenatal metabolomics profiles advanced prediction of early childhood growth trajectories and obesity risk in offspring.

Air Pollution Neurotoxicity in the Adult Brain: Emerging Concepts from Experimental Findings

Epidemiological studies are associating elevated exposure to air pollution with increased risk of Alzheimer's disease and other neurodegenerative disorders. In effect, air pollution accelerates many aging conditions that promote cognitive declines of aging. The underlying mechanisms and scale of effects remain largely unknown due to its chemical and physical complexity. Moreover, individual responses to air pollution are shaped by an intricate interface of pollutant mixture with the biological features of the exposed individual such as age, sex, genetic background, underlying diseases, and nutrition, but also other environmental factors including exposure to cigarette smoke. Resolving this complex manifold requires more detailed environmental and lifestyle data on diverse populations, and a systematic experimental approach. Our review aims to summarize the modest existing literature on experimental studies on air pollution neurotoxicity for adult rodents and identify key gaps and emerging challenges as we go forward. It is timely for experimental biologists to critically understand prior findings and develop innovative approaches to this urgent global problem. We hope to increase recognition of the importance of air pollution on brain aging by our colleagues in the neurosciences and in biomedical gerontology, and to support the immediate translation of the findings into public health guidelines for the regulation of remedial environmental factors that accelerate aging processes.

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

Background

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

Methods

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

Results

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

Conclusions

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

Health outcomes of smoking during pregnancy and the postpartum period: an umbrella review

BACKGROUND

Smoking during pregnancy (SDP) and the postpartum period has serious health outcomes for the mother and infant. Although some systematic reviews have shown the impact of maternal SDP on particular conditions, a systematic review examining the overall health outcomes has not been published. Hence, this paper aimed to conduct an umbrella review on this issue.

METHODS

A systematic review of systematic reviews (umbrella review) was conducted according to a protocol submitted to PROSPERO ( CRD42018086350 ). CINAHL, EMBASE, MEDLINE, PsycINFO, Web of Science, CRD Database and HMIC databases were searched to include all studies published in English by 31 December 2017, except those focusing exclusively on low-income countries. Two researchers conducted the study selection and quality assessment independently.

RESULTS

The review included 64 studies analysing the relationship between maternal SDP and 46 health conditions. The highest increase in risks was found for sudden infant death syndrome, asthma, stillbirth, low birth weight and obesity amongst infants. The impact of SDP was associated with the number of cigarettes consumed. According to the causal link analysis, five mother-related and ten infant-related conditions had a causal link with SDP. In addition, some studies reported protective impacts of SDP on pre-eclampsia, hyperemesis gravidarum and skin defects on infants. The review identified important gaps in the literature regarding the dose-response association, exposure window, postnatal smoking.

CONCLUSIONS

The review shows that maternal SDP is not only associated with short-term health conditions (e.g. preterm birth, oral clefts) but also some which can have life-long detrimental impacts (e.g. obesity, intellectual impairment).

IMPLICATIONS

This umbrella review provides a comprehensive analysis of the overall health impacts of SDP. The study findings indicate that while estimating health and cost outcomes of SDP, long-term health impacts should be considered as well as short-term effects since studies not including the long-term outcomes would underestimate the magnitude of the issue. Also, interventions for pregnant women who smoke should consider the impact of reducing smoking due to health benefits on mothers and infants, and not solely cessation.

The fetal origins of disease: a prospective cohort study on the association of preeclampsia and childhood obesity

Cardiovascular diseases are the main cause of mortality worldwide, and childhood excess weight/obesity are strong correlators of accumulated risk in later life. A relationship between maternal preeclampsia and offspring's childhood obesity is recognized, but most studies fail to control for strong confounders. Our goal is to analyze the association between preeclampsia and childhood excess weight/obesity, after accounting for important confounders. We recruited 5133 women with singleton pregnancies during admission for delivery. Sixty-seven pregnancies were complicated by preeclampsia. Maternal and children outcomes were assessed at 10 years of age. We analyzed the association between preeclampsia and childhood excess weight/obesity by fitting a linear regression model (using offspring body mass index (BMI) z-score at 10 years of age) and a logistic regression model (using excess weight/obesity status). We then controlled both models for known confounders, namely maternal prepregnancy BMI, parity, and smoking during pregnancy. At 10 years of age, offspring of preeclamptic mothers had a higher BMI z-score and were more likely classified as overweight/obese, but these differences were not statistically significant. After controlling for maternal prepregnancy BMI, parity, and smoking during pregnancy, there was a high magnitude change in the beta coefficient of preeclampsia in the linear (0.175; -0.014) and the logistic regression models (1.48; 1.23) suggesting that the association between preeclampsia and childhood excess weigh/obesity is significantly confounded by these variables. These confounders also showed a significant association with childhood obesity. This finding suggests that in utero exposure to preeclampsia seems to have less impact in childhood obesity than the previously described confounders.

Environmental Risk Factors and Health: An Umbrella Review of Meta-Analyses

Background: Environmental health is a growing area of knowledge, continually increasing and updating the body of evidence linking the environment to human health. Aim: This study summarizes the epidemiological evidence on environmental risk factors from meta-analyses through an umbrella review. Methods: An umbrella review was conducted on meta-analyses of cohort, case-control, case-crossover, and time-series studies that evaluated the associations between environmental risk factors and health outcomes defined as incidence, prevalence, and mortality. The specific search strategy was designed in PubMed using free text and Medical Subject Headings (MeSH) terms related to risk factors, environment, health outcomes, observational studies, and meta-analysis. The search was limited to English, Spanish, and French published articles and studies on humans. The search was conducted on September 20, 2020. Risk factors were defined as any attribute, characteristic, or exposure of an individual that increases the likelihood of developing a disease or death. The environment was defined as the external elements and conditions that surround, influence, and affect a human organism or population’s life and development. The environment definition included the physical environment such as nature, built environment, or pollution, but not the social environment. We excluded occupational exposures, microorganisms, water, sanitation and hygiene (WASH), behavioral risk factors, and no-natural disasters. Results: This umbrella review found 197 associations among 69 environmental exposures and 83 diseases and death causes reported in 103 publications. The environmental factors found in this review were air pollution, environmental tobacco smoke, heavy metals, chemicals, ambient temperature, noise, radiation, and urban residential surroundings. Among these, we identified 65 environmental exposures defined as risk factors and 4 environmental protective factors. In terms of study design, 57 included cohort and/or case-control studies, and 46 included time-series and/or case-crossover studies. In terms of the study population, 21 included children, and the rest included adult population and both sexes. In this review, the largest body of evidence was found in air pollution (91 associations among 14 air pollution definitions and 34 diseases and mortality diagnoses), followed by environmental tobacco smoke with 24 associations. Chemicals (including pesticides) were the third larger group of environmental exposures found among the meta-analyses included, with 19 associations. Conclusion: Environmental exposures are an important health determinant. This review provides an overview of an evolving research area and should be used as a complementary tool to understand the connections between the environment and human health. The evidence presented by this review should help to design public health interventions and the implementation of health in all policies approach aiming to improve populational health.

Maternal nicotine exposure impairs brown adipose tissue via AMPK-SIRT1-PGC-1α signals in male offspring

AIMS

Maternal nicotine exposure during pregnancy and lactation is associated with obesity in offspring. Brown adipose tissue (BAT) is correlated with energy metabolism and obesity. In this study, we explored the mechanism of maternal nicotine exposure on BAT changes in male offspring.

MAIN METHODS

Pregnant rats were randomly assigned to nicotine (1.0 mg/kg twice per day, subcutaneous administration) or control groups. In vitro, C3H10T1/2 cells were induced to differentiate into mature brown adipocytes, and 0-50 μM nicotine was given to C3H10T1/2 cells during the differentiation process.

KEY FINDINGS

Nicotine-exposed males had white-like adipocytes and abnormal mitochondria structure in iBAT at 26 weeks. The expression of mitochondrial genes, UCP1 and AMPK-SIRT1-PGC-1α pathway were downregulated in the nicotine group at 26 weeks rather than 4 weeks. In vitro, 50 μM nicotine decreased the expression of mitochondrial genes, UCP1 and AMPK-SIRT1-PGC-1α pathway in brown adipocytes.

SIGNIFICANCE

Maternal nicotine exposure showed the "programming" effect on the decreased brown-like phenotype in BAT of adult male offspring via downregulating AMPK-SIRT1-PGC-1α pathway. This impairment of BAT may be a potential mechanism of nicotine-induced obesity in male offspring.

Parents' smoking onset before conception as related to body mass index and fat mass in adult offspring: Findings from the RHINESSA generation study

Emerging evidence suggests that parents' preconception exposures may influence offspring health. We aimed to investigate maternal and paternal smoking onset in specific time windows in relation to offspring body mass index (BMI) and fat mass index (FMI). We investigated fathers (n = 2111) and mothers (n = 2569) aged 39-65 years, of the population based RHINE and ECRHS studies, and their offspring aged 18-49 years (n = 6487, mean age 29.6 years) who participated in the RHINESSA study. BMI was calculated from self-reported height and weight, and FMI was estimated from bioelectrical impedance measures in a subsample. Associations with parental smoking were analysed with generalized linear regression adjusting for parental education and clustering by study centre and family. Interactions between offspring sex were analysed, as was mediation by parental pack years, parental BMI, offspring smoking and offspring birthweight. Fathers' smoking onset before conception of the offspring (onset ≥15 years) was associated with higher BMI in the offspring when adult (β 0.551, 95%CI: 0.174-0.929, p = 0.004). Mothers' preconception and postnatal smoking onset was associated with higher offspring BMI (onset <15 years: β1.161, 95%CI 0.378-1.944; onset ≥15 years: β0.720, 95%CI 0.293-1.147; onset after offspring birth: β2.257, 95%CI 1.220-3.294). However, mediation analysis indicated that these effects were fully mediated by parents' postnatal pack years, and partially mediated by parents' BMI and offspring smoking. Regarding FMI, sons of smoking fathers also had higher fat mass (onset <15 years β1.604, 95%CI 0.269-2.939; onset ≥15 years β2.590, 95%CI 0.544-4.636; and onset after birth β2.736, 95%CI 0.621-4.851). There was no association between maternal smoking and offspring fat mass. We found that parents' smoking before conception was associated with higher BMI in offspring when they reached adulthood, but that these effects were mediated through parents' pack years, suggesting that cumulative smoking exposure during offspring's childhood may elicit long lasting effects on offspring BMI.

[In Utero Exposure to Maternal Smoking: Impact on the Child from Birth to Adulthood - CNGOF-SFT Expert Report and Guidelines for Smoking Management during Pregnancy]

INTRODUCTION

Smoking during pregnancy leads to fetal passive smoking. It is associated with several obstetrical complications and is a major modifiable factor of maternal and fetal morbidity. Long-term consequences also exist but are less well known to health professionals and in the general population.

METHODS

Consultation of the Medline® database.

RESULTS

Maternal smoking during pregnancy is associated in the offspring with sudden infant death syndrome (NP2), impaired lung function (NP2), lower respiratory infections and asthma (NP2), overweight and obesity (NP2), cancers (NP3), risk of tobacco use, nicotine dependence and early smoking initiation (NP2). Unadjusted analyses show associations between in utero tobacco exposure and cognitive deficits (NP3), impaired school performance (NP3) and behavioral disorders in children (NP2), which are in a large part explained by environmental factors. There is a cross-generational effect of smoking during pregnancy. For example, an increased risk of asthma is observed in the grandchildren of smoking women (NP4). The respective roles of ante- and post-natal smoking remain difficult to assess.

CONCLUSION

These results highlight the importance of prevention measures against tobacco use in the general population, as well as screening measures and support for smoking cessation before or at the beginning of the pregnancy.

Prospective associations between parental substance use and youth highly processed food intake in the Fragile Families and Child Wellbeing Study

BACKGROUND

Given growing evidence of overlap in characteristics of addictive substances and highly processed foods (e.g., ice cream), transdiagnostic approaches may be appropriate. Prior work indicates youth with parents who use addictive substances are at risk for greater substance use. The current study tested hypotheses that parental substance use behaviors would prospectively predict greater youth highly processed food intake [but not minimally processed food intake (e.g., fruit)].

METHODS

The Fragile Families and Child Wellbeing Study was a longitudinal birth cohort study of youth (N = 4,898) born in large U.S. cities in 1998-2000. The current study was an archival data analysis using parental substance use data collected at youth birth and when youth were age 3, and youth diet data collected when youth were ages 5, 9, and 15.

RESULTS

Over and above the influence of covariates including family income, prenatal maternal illicit drug use significantly predicted 0.34, 0.23, and 1.32 servings increase in youth sugary food/beverage intake at ages 5, 9, and 15, respectively, and 0.25 servings increase in youth snack foods or chips intake at age 9. Prenatal maternal illicit drug use did not significantly predict youth fruit and vegetable intake at any age. Less consistent and weaker significant prospective associations emerged between postnatal maternal substance use and youth diet, and between paternal substance use and youth diet.

CONCLUSIONS

Prenatal exposure to illicit drugs may present transdiagnostic risk for greater youth highly processed food intake and substance use. Future causal and mechanistic research is warranted.

The Dynamic Relationship Between Asthma and Obesity in Schoolchildren

Asthma and obesity are among the most prevalent chronic health conditions in children. Although there has been compelling evidence of co-occurrence of asthma and obesity, it is uncertain whether asthma contributes to the development of obesity or obesity contributes to the onset of asthma or both. In this study, we used a joint transition modeling approach with cross-lagged structure to understand how asthma and obesity influence each other dynamically over time. Subjects for this study included 5,193 kindergarten and first-grade students enrolled from 13 communities in 2002-2003 in the Southern California Children's Health Study, with up to 10 years of follow-up. We found that nonobese children with diagnosed asthma at a study visit were at 37% higher odds of becoming obese by the next annual visit compared with children without asthma (odds ratio = 1.38; 95% credible interval: 1.12, 1.71). However, the presence of obesity at the current visit was not statistically significantly associated with asthma onset in the next visit (odds ratio = 1.25; 95% credible interval: 0.94, 1.62). In conclusion, childhood asthma appears to drive an increase in the onset of obesity among schoolchildren, while the onset of obesity does not necessarily imply the future onset of asthma, at least in the short term.

Prenatal air pollution exposure and growth and cardio-metabolic risk in preschoolers

OBJECTIVES

We investigated the association between outdoor air pollutants exposure in the first trimester of pregnancy, and growth and cardio-metabolic risk at four years of age, and evaluated the mediating role of birth weight.

METHODS

We included mother-child pairs (N = 1,724) from the Spanish INMA birth cohort established in 2003-2008. First trimester of pregnancy nitrogen dioxide (NO₂) and fine particles (PM_2.5) exposure levels were estimated. Height, weight, waist circumference, blood pressure, and lipids were measured at four years of age. Body mass index (BMI) trajectories from birth to four years were identified.

RESULTS

Increased PM_2.5 exposure in the first trimester of pregnancy was associated with decreased z-scores of weight (zWeight) and BMI (zBMI) (zWeight change per interquartile range increase in PM_2.5 exposure = -0.12; 95% CI: -0.23, -0.01; zBMI change = -0.12; 95% CI: -0.23, -0.01). Higher NO₂ and PM_2.5 exposure was associated to a reduced risk of being in a trajectory with accelerated BMI gain, compared to children with the average trajectory. Birth weight partially mediated the association between PM_2.5 and zWeight and zBMI. PM_2.5 and NO₂ were not associated with the other cardio-metabolic risk factors.

CONCLUSIONS

This comprehensive study of many growth and cardio-metabolic risk related outcomes suggests that air pollution exposure during pregnancy may be associated with delays in physical growth in the early years after birth. These findings imply that pregnancy exposure to air pollutants has a lasting effect on growth after birth and require follow-up at later child ages.

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.

THE EXPOSOME IN HUMAN EVOLUTION: FROM DUST TO DIESEL

Global exposures to air pollution and cigarette smoke are novel in human evolutionary history and are associated with about 16 million premature deaths per year. We investigate the history of the human exposome for relationships between novel environmental toxins and genetic changes during human evolution in six phases. Phase I: With increased walking on savannas, early human ancestors inhaled crustal dust, fecal aerosols, and spores; carrion scavenging introduced new infectious pathogens. Phase II: Domestic fire exposed early Homo to novel toxins from smoke and cooking. Phases III and IV: Neolithic to preindustrial Homo sapiens incurred infectious pathogens from domestic animals and dense communities with limited sanitation. Phase V: Industrialization introduced novel toxins from fossil fuels, industrial chemicals, and tobacco at the same time infectious pathogens were diminishing. Thereby, pathogen-driven causes of mortality were replaced by chronic diseases driven by sterile inflammogens, exogenous and endogenous. Phase VI: Considers future health during global warming with increased air pollution and infections. We hypothesize that adaptation to some ancient toxins persists in genetic variations associated with inflammation and longevity.

Maternal nicotine dependence is associated with longitudinal increases in child obesogenic eating behaviors

BACKGROUND

Meta-analysis shows that parental cigarette smoking is associated with child obesity.

OBJECTIVES

This study tested for associations between severity of maternal nicotine dependence and longitudinal changes in child eating behavior in archival data analysis.

METHODS

Maternal nicotine dependence was assessed with the Fagerstrom Test for Nicotine Dependence. Child eating behavior was assessed with the Child Eating Behavior Questionnaire when children were ages 4, 6, 8, and 10.

RESULTS

Over and above the influence of child age, child biological sex, and family income-to-needs ratio, more severe maternal nicotine dependence was associated with greater increases in child Food Responsiveness (γ = 0.07, SE_γ  = 0.03, P = .014, 95% CI [0.01, 0.13]) and Emotional Overeating (γ = 0.06, SE_γ  = 0.03, P = .024, 95% CI [0.01, 0.11]) across 6 years.

CONCLUSIONS

Maternal nicotine dependence may be a transdiagnostic risk factor that identifies children at risk for reward-driven, obesogenic eating behavior.

Blood Pressure and Heart Rate Variability in Preschool Children Exposed to Smokeless Tobacco in Fetal Life

Background

Maternal smoking during pregnancy has been associated with higher blood pressure and autonomic imbalance in the offspring. However, it has been difficult to determine the selective prenatal and postnatal contributions as children frequently have been exposed to smoking both before and after birth. The specific role of nicotine is also unclear. We aimed to determine whether exclusive prenatal exposure to nicotine from maternal use of smokeless tobacco (Swedish snus) in pregnancy was associated with blood pressure and autonomic heart rate control in their children.

Methods and Results

We measured oscillometric blood pressures in forty 5‐ to 6‐year‐old children with snus exposure in fetal life (n=21) and in tobacco‐free controls (n=19). Taking the child′s age and height into account, snus‐exposed children had 4.2 (95% CI, 0.2–8.1) mm Hg higher systolic blood pressure than controls (P=0.038). The corresponding sex‐, age‐, and height‐standardized systolic blood pressure centiles were 61 and 46 (95% CI of the difference, 2–28) (P=0.029). Heart rate variability was tested in 30 of the children. The spectral heart rate variability variable low‐frequency/high‐frequency ratio was higher (median, 0.69; interquartile range, 0.45–1.21) in snus‐exposed children than in controls (median, 0.21; interquartile range, 0.32–0.57; P=0.034).

Conclusions

Prenatal snus exposure was associated with higher systolic blood pressure and altered heart rate variability at 6 years of age. These findings may indicate adverse prenatal programming of nicotine, but implications for cardiovascular health in later life remain to be studied. Meanwhile, women should be recommended to abstain from all types of tobacco and nicotine products during pregnancy.

See Editorial Watanabe and Parikh

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.

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.

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.

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.

What exposures in early life are risk factors for childhood obesity?

Globally, estimates show that 41 million children younger than 5 years of age are affected by overweight and obesity. In many regions of the world, these prevalence rates have increased dramatically, especially in low- and middle-income countries, making childhood obesity a global policy issue. Recent data show that many children are already affected by overweight or obesity by the time they start school; hence, the examination of early exposures, with interventions around these exposures, is warranted. In this review, we outline the main modifiable exposures in early life that can lead to an increased risk of obesity. These exposures can be broadly categorised into parental factors such as obesity and gestational diabetes; dietary exposures in early life, including breastfeeding and complementary feeding and feeding behaviours; physical activity, sedentary behaviours and sleep; and environmental exposures such as maternal exposure to tobacco. We also identify research gaps and opportunities for further research.

Prenatal education of overweight or obese pregnant women to prevent childhood overweight (the ETOIG study): an open-label, randomized controlled trial

BACKGROUND

We aimed to evaluate whether pre and perinatal education of pregnant women would reduce childhood overweight.

METHODS

Four French centers included women at ≤21 gestational weeks (GWs) with body mass index (BMI) >25 kg/m² before pregnancy. Patients were randomized to a control group (routine care including at least one dietary visit) or an intervention group (2 individuals (26 and 30 GW) and 4 group sessions (21, 28, 35 GW, 2 months postpartum)) aimed at educating the future mother regarding infant and maternal nutrition. The primary objective was to reduce post-natal excessive weight gain in the infant from birth to 2 years (NCT00804765). This project was funded by a grant from the National Programme for Hospital Research (PHRC-2007 French Ministry of Health).

RESULTS

We included 275 women (BMI: 32.5 kg/m²). The rate of post-natal excessive weight gain was similar in the intervention (n = 132) and control (n = 136) groups by intention to treat (ITT: 59.1% vs 60.3% respectively, p = 0.84) in available data (AD, n = 206) and by per-protocol analysis (PP, n = 177). Two years after delivery, normalization of maternal BMI and number of infants with BMI < 19 kg/m² were not significantly different in the interventional group in ITT and in the control group. Although not significantly different in ITT, normalization of maternal BMI was more frequent in AD (n = 149: 12.9% vs 3.8%, p = 0.04) and 2-year-old infant BMIs were less likely to be >19 kg/m² in the intervention group in AD (n = 204: 0% vs 6.8%, p = 0.014) and PP (n = 176: 0% vs 6.4%, p = 0.03).

CONCLUSIONS

An education and nutritional counseling program for overweight women, starting after 3 months of gestation, did not significantly change post-natal excessive weight gain of infants or prevent overweight in mothers and children 2 years after delivery.

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.

Effect of maternal mental health improvement programs on obesity in pediatric populations: a protocol for a systematic review and meta-analysis

BACKGROUND

Childhood obesity has become a global epidemic irrespective of the socioeconomic status of a country or nation. Obesity increases the risk of various diseases in children, for example asthma, sleep apnea, bone and joint problems, type-2 diabetes, and heart problems. The existing literature informs us of the many factors associated with childhood obesity. Among these factors, maternal mental health has been found to be a strong predictor. Maternal mental health programs were implemented to address the issue of childhood obesity but with little or no improvement. It suggests systematically reviewing the literature to assess the contents of these programs and carrying out meta-analysis for the overall effect of these interventions.

METHODS

The studies included in this review will be experimental designs such as randomized controlled trials (RCTs) which provide information on interventions to improve maternal mental health and its effects on childhood obesity. We plan to search MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, PsycINFO, ERIC, CINAHL, ProQuest Dissertations and Theses Global, Scopus, and Web of Science with no restrictions as to language. Reference lists of the selected articles will also be searched for additional articles. The Cochrane EPOC Risk of Bias Tool will be used to assess the quality of studies. If the studies lend themselves to a statistical analysis, we will also carry out a meta-analysis.

DISCUSSION

This review will help determine the effect of maternal health improvement programs on childhood obesity. These findings, in turn, will guide the research community on the development of related programs in the future.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO: CRD42017072737 .

[Maternal smoking during pregnancy: A risk factor for respiratory disorders in children]

Maternal smoking during pregnancy (MSDP) is a well-established risk factor for negative pregnancy outcomes, but its negative effects on the health of the child after birth are less well known by both health professionals and the general public. Large cohort studies over the past 10 years have shown that MSDP is an independent risk factor for several childhood health problems such as e.g. obesity and smoking. A large number of recent studies and 3 meta-analyses demonstrate that MSDP is an independent risk factor of wheezing and asthma of the child exposed in utero to maternal smoking. MSDP is associated with epigenetic toxicities the currently most plausible hypothesis to explain the diversity of its postnatal negative effects. The eradication of MSDP could contribute to the reduction of health problems in the next generation, including the incidence of childhood respiratory disorders.

A critical review of assays for hazardous components of air pollution

Increased mortality and diverse morbidities are globally associated with exposure to ambient air pollution (AAP), cigarette smoke (CS), and household air pollution (HAP). The AAP-CS-HAP aerosols present heterogeneous particulate matter (PM) of diverse chemical and physical characteristics. Some epidemiological models have assumed the same health hazards by PM weight for AAP, CS, and HAP regardless of the composition. While others have recognized that biological activities and toxicity will vary with components, we focus particularly on oxidation because of its major role in assay outcomes. Our review of PM assays considers misinterpretations of some chemical measures used for oxidative activity. Overall, there is low consistency across chemical and cell-based assays for oxidative and inflammatory activity. We also note gaps in understanding how much airborne PM of various sizes enter cells and organs. For CS, the body burden per cigarette may be much below current assumptions. Synergies shown for health hazards of AAP and CS suggest crosstalk in detoxification pathways mediated by AHR, NF-κB, and Nrf2. These complex genomic and biochemical interactions frustrate resolution of the toxicity of specific AAP components. We propose further strategies based on targeted gene expression based on cell-type differences.

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.

Association between secondhand smoke exposure and early eruption of deciduous teeth: a cross-sectional study

INTRODUCTION

Secondhand smoke (SHS) exposure is a risk factor for early childhood caries. Here we examined the association between SHS exposure and early tooth eruption (ETE) to clarify the additional etiology of an increased chance of contact between the tooth’s surface and acid produced by fermenting oral bacteria.

METHODS

Data of 388 child–mother pairs who attended health checkups at public health centers were assessed for children aged ≥18 months. SHS exposure was reported as maternal smoking during pregnancy and household smoking after birth. Associations between SHS exposure and ETE (≥3 canines in the oral cavity) were tested using multivariable analyses of the dose-response relationship. Subgroup and sensitivity analyses were performed for birth-weight subgroups and SHS exposure variables, respectively.

RESULTS

ETE prevalence was 65.5%, 68.1%, and 76.9% in the no, medium-dose (ceased partway and sometimes), and highest-dose (every day) exposure groups, respectively, during pregnancy, and 61.5%, 75.0%, and 75.5%, respectively, after birth. The association between the highest dose exposure during pregnancy and ETE was not significant (OR=1.42, 95% CI: 0.34–5.96, p=0.631), whereas that between highest dose exposure after birth and ETE was significant (OR=2.13, 95% CI: 1.06–4.31, p=0.034); this association was distinct in the subgroup of children with smaller birth weights (<3000 g) (OR=3.19, 95% CI: 1.08–9.44, p=0.036). The dose-response relationship was consistently significant for exposure after birth (p<0.05). The sensitivity analysis that employed no SHS exposure, as a reference, revealed that exposure after birth but no exposure during pregnancy was significantly associated with ETE (OR=2.29, 95% CI: 1.19–4.40, p=0.013). However, the association between exposure during pregnancy and ETE was consistently non-significant (p>0.05).

CONCLUSIONS

When controlling for variables of birth weight and exposure type, SHS exposure after birth was independently associated with the early eruption of deciduous canines. Further studies are warranted to examine the trajectory of SHS exposure after birth, ETE, and early childhood caries incidence.

ABBREVIATIONS

ETE: Early tooth eruption, SHS: Secondhand smoke