Dose response association of pregnancy cigarette smoke exposure, childhood stature, overweight and obesity

Physiological response during exercise is preserved in children exposed to a suboptimal gestational environment

OBJECTIVE

This study investigated whether exposure to suboptimal gestational factors (SGFs) alters mechanical efficiency (ME) and substrate oxidation during rest and exercise in children as a mechanism contributing to obesity.

METHODS

Data from the Quebec Adiposity and Lifestyle Investigation in Youth cohort were used. Children aged 8 to 10 years performed an incremental maximal cycling test with indirect calorimetry. Their ME was measured during submaximal and maximal effort. The substrate oxidation during rest and submaximal effort was also computed. ME and substrate oxidation results between children exposed to each SGF during pregnancy (gestational diabetes mellitus: n = 68; hypertensive disorders: n = 49; maternal smoking: n = 77) and nonexposed children (n = 370) were compared.

RESULTS

No difference was observed for ME during submaximal (F[3,540] = 0.46, p = 0.713) and maximal effort (F[3,545] = 0.86, p = 0.463) between exposed and nonexposed children. The percentage contributions of lipids and carbohydrates did not differ during rest (F[3,545] =1.68, p = 0.169) or submaximal exercise (F[3,544] = 0.31, p = 0.534) between exposed and nonexposed children.

CONCLUSIONS

Children exposed to investigated SGFs display a similar physiological response regarding ME and substrate oxidation during rest and exercise compared to nonexposed children. Future studies should confirm these novel results and continue investigating other research avenues to explain the higher risk of obesity in this population.

In utero smoking exposure induces changes to lung clearance index and modifies risk of wheeze in infants

BACKGROUND

Fetal exposure to tobacco smoking throughout pregnancy is associated with wheezing in infancy. We investigated the influence of in utero smoking exposure on lung ventilation homogeneity and the relationship between lung ventilation inhomogeneity at 7 weeks of age and wheezing in the first year of life.

METHODS

Maternal smoking was defined as self-reported smoking of tobacco or validated by exhaled (e)CO > 6 ppm. Lung function data from healthy infants (age 5-9 weeks) born to asthmatic mothers and parent-reported respiratory questionnaire data aged 12 months were collected in the Breathing for Life Trial (BLT) birth cohort. Tidal breathing analysis and SF6-based Multiple Breath Washout testing were performed in quiet sleep. Descriptive statistics and regression analysis were used to assess associations.

RESULTS

Data were collected on 423 participants. Infants born to women who self-reported smoking during pregnancy (n = 42) had higher lung clearance index (LCI) than those born to nonsmoking mothers (7.90 vs. 7.64; p = .030). Adjusted regression analyzes revealed interactions between self-reported smoking and LCI (RR: 1.98, 95% CI: 1.07-3.63, 0.028, for each unit increase in LCI) and between eCO > 6 ppm and LCI (RR: 2.25, 95% CI: 1.13-4.50, 0.022) for the risk of wheeze in the first year of life.

CONCLUSION

In utero tobacco smoke exposure induces lung ventilation inhomogeneities. Furthermore, an interaction between smoke exposure and lung ventilation inhomogeneities increases the risk of having a wheeze in the first year of life.

Maternal smoking during pregnancy links to childhood blood pressure through birth weight and body mass index: NHANES 1999-2018

Maternal smoking during pregnancy (MSDP) is associated with lower birth weight, childhood obesity, and elevated blood pressure (BP) in offspring. We aimed to examine whether birth weight and body mass index (BMI) mediate the effect of MSDP on BP in children. The study included 14,713 children aged 8 to 15 years from the National Health and Nutrition Examination Surveys from 1999 to 2018. General third-variable models were used to examine the mediating effects of birth weight and BMI on the association of MSDP with BP. A total of 1928 (13.1%) children were exposed to MSDP. MSDP was associated with reduced birth weight (p < 0.001), increased BMI (p < 0.001), and elevated systolic BP (p = 0.005). MSDP was not associated with systolic BP after adjustment for birth weight and BMI z-score (p = 0.875), with 95.0% of the effect of MSDP on BP mediated by birth weight (39.1%) and BMI (55.9%). In conclusion, lower birth weight and increased obesity measures mediate the adverse effects of MSDP on BP in children. These findings provide novel mechanistic insight into the adverse effect of MSDP on BP in children and have implications for preventing hypertension in later life.

Long-term adverse influence of smoking during pregnancy on height and body size of offspring at ten years old in the UK Biobank cohort

Background

To explore the long-term relationship between maternal smoking during pregnancy and early childhood growth in the UK Biobank cohort.

Methods

To estimate the effect of maternal smoking during pregnancy on offspring height and body size at ten years old, we performed binary logistic analyses and reported odds ratios (OR) as well as 95% confidence intervals (95%CIs). We also implemented the cross-contextual comparison study to examine whether such influence could be repeatedly observed among three different ethnicities in the UK Biobank cohort (n = 22,140 for White, n = 7094 for South Asian, and n = 5000 for Black). In particular, we conducted the sibling cohort study in White sibling cohort (n = 9953 for height and n = 7239 for body size) to control for unmeasured familial confounders.

Results

We discovered that children whose mothers smoked during pregnancy had greater risk of being shorter or plumper at age ten in the full UK Biobank White cohort, with 15.3% (95% CIs: 13.0%∼17.7%) higher risk for height and 32.4% (95%CIs: 29.5%∼35.4%) larger risk for body size. Similar associations were identified in the South Asian and Black ethnicities. These associations were robust and remained significant in the White sibling cohort (12.6% [95%CIs: 5.0%∼20.3%] for height and 36.1% [95%CIs: 26.3%∼45.9%] for body size) after controlling for family factors.

Conclusion

This study robustly confirms that maternal smoking during pregnancy can promote height deficit and obesity for offspring at ten years old. Our findings strongly encourage mothers to quit smoking during pregnancy for improving growth and development of offspring.

Investigating socioecological obesogenic factors in children with Autism Spectrum Disorder

Obesity-related information in children with Autism Spectrum Disorder (ASD) is limited, and research findings are contradictory. Thus, this study aimed to use a nationwide non-clinical sample to examine the association of sociological factors with overweight status in children with ASD and reveal the degree of differences in the risk factors for overweight in children with and without ASD. The data for this cross-sectional study, based on the modified ecological system theory model, were obtained from the 2019 National Survey of Children's Health. The weighted logistic regressions were performed to determine the factors associated with overweight status in children with ASD, controlling for demographics, physical activity-related behaviors, and family and environmental conditions. A total of 529 children were identified (mean age 13.78 years, 83.21% boys). Two-parent households, less healthy parents and households, households with smokers, poor sleep quality, and greater participation in organized activities were associated with a higher likelihood of overweight in children with ASD (all P < 0.05). The determinants of obesity among children with ASD go beyond the individual level; family and community support are important. Therefore, greater attention should be directed toward the families of children with ASD and community-level administrative policies to improve quality of life by preventing or reducing obesity in children with ASD.

Towards optimum smoking cessation interventions during pregnancy: a household model to explore cost-effectiveness

BACKGROUND AND AIMS

Previous economic evaluations of smoking cessation interventions for pregnant women are limited to single components, which do not in isolation offer sufficient potential impact to address smoking cessation targets. To inform the development of more appropriate complex interventions, we (1) describe the development of the Economics of Smoking in Pregnancy: Household (ESIP.H) model for estimating the life-time cost-effectiveness of smoking cessation interventions aimed at pregnant women and (2) use a hypothetical case study to demonstrate how ESIP.H can be used to identify the characteristics of optimum smoking cessation interventions.

METHODS

The hypothetical intervention was based on current evidence relating to component elements, including financial incentives, partner smoking, intensive behaviour change support, cigarettes consumption and duration of support to 12 months post-partum. ESIP.H was developed to assess the life-time health and cost impacts of multi-component interventions compared with standard National Health Service (NHS) care in England. ESIP.H considers cigarette consumption, partner smoking and some health conditions (e.g. obesity) that were not included in previous models. The Markov model's parameters were estimated based on published literature, expert judgement and evidence-based assumptions. The hypothetical intervention was evaluated from an NHS perspective.

RESULTS

The hypothetical intervention was associated with an incremental gain in quitters (mother and partner) at 12 months postpartum of 249 [95% confidence interval (CI) = 195-304] per 1000 pregnant smokers. Over the long-term, it had an incremental negative cost of £193 (CI = -£779 to 344) and it improved health, with a 0.50 (CI = 0.36-0.69) increase in quality-adjusted life years (QALYs) for mothers, partners and offspring, with a 100% probability of being cost-effective.

CONCLUSIONS

The Economics of Smoking in Pregnancy: Household model for estimating cost-effectiveness of smoking cessation interventions aimed at pregnant women found that a hypothetical smoking cessation intervention would greatly extend reach, reduce smoking and be cost-effective.

Associations between Second-Hand Tobacco Smoke Exposure and Cardiorespiratory Fitness, Physical Activity, and Respiratory Health in Children

BACKGROUND

Cardiorespiratory fitness (CRF) and physical activity (PA) are associated with a plethora of positive health effects. Many UK children fail to meet the recommended level of PA, with an observed decline in CRF levels over recent decades. Second-hand tobacco smoke (SHS) is responsible for a significant proportion of the worldwide burden of disease, but little is understood regarding the impact of SHS exposure on CRF and PA in children. The aim of this study was to test the associations between SHS exposure and CRF, PA, and respiratory health in children.

METHOD

Children (9-11 years) from UK primary schools in deprived areas participated (n = 104, 38 smoking households). Surveys determined household smoking, and exhaled carbon monoxide was used to indicate children's recent SHS exposure. CRF (VO_2peak) was assessed via maximal treadmill protocol using breath-by-breath analysis. Fractional exhaled nitric oxide and spirometry were utilised as indicators of respiratory health.

RESULTS

Linear regression models demonstrated that SHS exposure was negatively associated with allometrically scaled VO_2peak (B = -3.8, p = 0.030) but not PA or respiratory health.

CONCLUSION

The results indicate that SHS is detrimental to children's CRF; given that approximately one-third of children are regularly exposed to SHS, this important finding has implications for both public health and the sport and exercise sciences.

Effects of passive smoking on prenatal and infant development: Lessons from the past

This paper studies the effect of passive smoking on child development. We use data from a time when the adverse effects of smoking on health were not known and when tobacco was not an inferior good. This allows us to disentangle the effect on foetuses and infants of smoking from that of other indicators of social and economic conditions. We exploit a set of unique longitudinal historical datasets defined at a detailed level of geographical disaggregation, namely the 69 Italian provinces. The datasets record precise information on the per capita consumption of tobacco products, the heights of twenty-year old conscripts in the second half of the 19th century Italy, and other relevant controls. We find a strong negative effect of smoking in the period immediately before and after birth on the height at age 20. Results are robust to changes in specification and consistent across the height distribution.

The Triad Mother-Breast Milk-Infant as Predictor of Future Health: A Narrative Review

The benefits of human milk for both mother and infant are widely acknowledged. Human milk could represent a link between maternal and offspring health. The triad mother-breast milk-infant is an interconnected system in which maternal diet and lifestyle might have effects on infant's health outcome. This link could be in part explained by epigenetics, even if the underlining mechanisms have not been fully clarified yet. The aim of this paper is to update the association between maternal diet and human milk, pointing out how maternal diet and lifestyle could be associated with breast-milk composition, hence with offspring's health outcome.

Changes in parental smoking during pregnancy and risks of adverse birth outcomes and childhood overweight in Europe and North America: An individual participant data meta-analysis of 229,000 singleton births

BACKGROUND

Fetal smoke exposure is a common and key avoidable risk factor for birth complications and seems to influence later risk of overweight. It is unclear whether this increased risk is also present if mothers smoke during the first trimester only or reduce the number of cigarettes during pregnancy, or when only fathers smoke. We aimed to assess the associations of parental smoking during pregnancy, specifically of quitting or reducing smoking and maternal and paternal smoking combined, with preterm birth, small size for gestational age, and childhood overweight.

METHODS AND FINDINGS

We performed an individual participant data meta-analysis among 229,158 families from 28 pregnancy/birth cohorts from Europe and North America. All 28 cohorts had information on maternal smoking, and 16 also had information on paternal smoking. In total, 22 cohorts were population-based, with birth years ranging from 1991 to 2015. The mothers' median age was 30.0 years, and most mothers were medium or highly educated. We used multilevel binary logistic regression models adjusted for maternal and paternal sociodemographic and lifestyle-related characteristics. Compared with nonsmoking mothers, maternal first trimester smoking only was not associated with adverse birth outcomes but was associated with a higher risk of childhood overweight (odds ratio [OR] 1.17 [95% CI 1.02-1.35], P value = 0.030). Children from mothers who continued smoking during pregnancy had higher risks of preterm birth (OR 1.08 [95% CI 1.02-1.15], P value = 0.012), small size for gestational age (OR 2.15 [95% CI 2.07-2.23], P value < 0.001), and childhood overweight (OR 1.42 [95% CI 1.35-1.48], P value < 0.001). Mothers who reduced the number of cigarettes between the first and third trimester, without quitting, still had a higher risk of small size for gestational age. However, the corresponding risk estimates were smaller than for women who continued the same amount of cigarettes throughout pregnancy (OR 1.89 [95% CI 1.52-2.34] instead of OR 2.20 [95% CI 2.02-2.42] when reducing from 5-9 to ≤4 cigarettes/day; OR 2.79 [95% CI 2.39-3.25] and OR 1.93 [95% CI 1.46-2.57] instead of OR 2.95 [95% CI 2.75-3.15] when reducing from ≥10 to 5-9 and ≤4 cigarettes/day, respectively [P values < 0.001]). Reducing the number of cigarettes during pregnancy did not affect the risks of preterm birth and childhood overweight. Among nonsmoking mothers, paternal smoking was associated with childhood overweight (OR 1.21 [95% CI 1.16-1.27], P value < 0.001) but not with adverse birth outcomes. Limitations of this study include the self-report of parental smoking information and the possibility of residual confounding. As this study only included participants from Europe and North America, results need to be carefully interpreted regarding other populations.

CONCLUSIONS

We observed that as compared to nonsmoking during pregnancy, quitting smoking in the first trimester is associated with the same risk of preterm birth and small size for gestational age, but with a higher risk of childhood overweight. Reducing the number of cigarettes, without quitting, has limited beneficial effects. Paternal smoking seems to be associated, independently of maternal smoking, with the risk of childhood overweight. Population strategies should focus on parental smoking prevention before or at the start, rather than during, pregnancy.

Conditional and unconditional genome-wide association study reveal complicate genetic architecture of human body weight and impacts of smoking

To reveal the impacts of smoking on genetic architecture of human body weight, we conducted a genome-wide association study on 5,336 subjects in four ethnic populations from MESA (The Multi-Ethnic Study of Atherosclerosis) data. A full genetic model was applied to association mapping for analyzing genetic effects of additive, dominance, epistasis, and their ethnicity-specific effects. Both the unconditional model (base) and conditional model including smoking as a cofactor were investigated. There were 10 SNPs involved in 96 significant genetic effects detected by the base model, which accounted for a high heritability (61.78%). Gene ontology analysis revealed that a number of genetic factors are related to the metabolic pathway of benzopyrene, a main compound in cigarettes. Smoking may play important roles in genetic effects of dominance, dominance-related epistasis, and gene-ethnicity interactions on human body weight. Gene effect prediction shows that the genetic effects of smoking cessation on body weight vary from different populations.

High Maternal Circulating Cotinine During Pregnancy is Associated With Persistently Shorter Stature From Birth to Five Years in an Asian Cohort

BACKGROUND

Self-reported maternal active smoking has been associated with reduced offspring birth length and shorter stature in early and late childhood.

OBJECTIVE

To use circulating cotinine as an objective biomarker to investigate the association between smoking and environmental tobacco smoke (ETS) exposure in pregnancy and longitudinal measures of offspring length/height from birth to 60 months.

METHODS

In 969 maternal-offspring dyads from the GUSTO cohort, maternal plasma cotinine at 26-28 weeks' gestation was measured by LC/MS/MS and categorized into four groups: Group 1: cotinine <0.17 ng/mL (the assay's detection limit) and no ETS exposure; Group 2: cotinine <0.17 ng/mL but self-reported ETS; Group 3: cotinine 0.17-13.99 ng/mL (ETS or light smoking); Group 4: cotinine ≥14 ng/mL (active smoking).

RESULTS

Adjusting for infant sex, gestational age at birth, ethnicity, maternal age, education, parity, BMI, and height, Group 4 offspring were shorter at birth [z-score β = -0.42 SD units (SDs) (95% CI = -0.77 to -0.06)] than Group 1 offspring. Group 4 offspring continued to be shorter at older ages, with similar effect sizes at 3 months [-0.57 SDs (-0.95 to -0.20)], 36 months [-0.53 SDs (-0.92 to -0.15)], 48 months [-0.43 SDs (-0.81 to -0.04)], and 60 months [-0.57 SDs (-0.96 to -0.17)]. Associations were particularly marked in boys. No significant differences in stature were observed in Groups 2 or 3 compared with Group 1.

CONCLUSIONS

This Asian longitudinal study associated high prenatal cotinine with persistently shorter stature in offspring from birth and into early childhood, whilst low prenatal cotinine levels and ETS exposure showed no such association.

IMPLICATIONS

Little is known about the long-term effects of prenatal tobacco exposure on offspring stature in Asia where passive smoking is common. This study has used an objective biomarker to reveal that the association of prenatal tobacco exposure with offspring length/height mainly occurs at a high maternal cotinine level of greater than 14 ng/mL in pregnancy, consistent with active smoking, but no significant associations were found with lower cotinine levels, consistent with passive smoking. Encouraging women to quit smoking prior to or during pregnancy may avert the long-term negative impact on their child's height despite appreciable prenatal ETS exposure.

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

OBJECTIVE

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

INTRODUCTION

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

INCLUSION CRITERIA

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

Effect of Prenatal Docosahexaenoic Acid Supplementation on Blood Pressure in Children With Overweight Condition or Obesity: A Secondary Analysis of a Randomized Clinical Trial

IMPORTANCE

The blood pressure-lowering property of docosahexaenoic acid (DHA) in children and adults is known, and an observational study from the Netherlands has linked higher intrauterine DHA exposure to lower childhood blood pressure. However, the association of prenatal intake of DHA supplement with childhood blood pressure has not been evaluated in randomized clinical trials.

OBJECTIVE

To determine the effect of DHA supplementation during pregnancy on childhood blood pressure.

DESIGN, SETTING, AND PARTICIPANTS

This prespecified secondary analysis of the Kansas University DHA Outcome Study (KUDOS), a phase 3, double-blind, randomized, placebo-controlled clinical trial was conducted at several local hospitals in the Kansas City, Kansas, metropolitan area. Pregnant women (n = 350) were enrolled in the KUDOS trial between January 10, 2006, and November 17, 2009, and were followed up until their children were 18 months of age. During pregnancy, the women received either 3 capsules per day of placebo or 600 mg per day of DHA from a mean (SD) of 14.5 (3.7) weeks' (all before 20 weeks) gestation until birth. The parents of 190 children consented to additional follow-up of their children until 6 years, which ended April 29, 2016. Study personnel involved in testing were blind to the randomization until all children had completed the trial. Data analysis was performed from May 23, 2017, to July 10, 2018.

INTERVENTIONS

Pregnant women were assigned to either 600 mg per day of DHA or a placebo that was half soy and half corn oil. Both placebo and DHA were provided in 3 capsules per day.

MAIN OUTCOMES AND MEASURES

Childhood blood pressure was a planned secondary outcome of a study powered to measure cognitive development. The hypothesis was that DHA would lower blood pressure prior to data analysis. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured at 4, 4.5, 5, 5.5, and 6 years and were analyzed for possible covariates using mixed models to generate a final model.

RESULTS

In total, 171 children (88 [51.5%] female) were included in this analysis. Of these children, 89 (52.0%) were randomized to the DHA group and 82 (47.9%) to the placebo group. A statistically significant interaction was found between treatment (placebo or DHA) and child weight status (5-year body mass index ≤85th or >85th percentile) for both SBP and DBP. Children who were overweight or obese whose mothers received placebo during pregnancy had higher SBP and DBP compared with children who were overweight or obese whose mothers received DHA (mean [SE] SBP, 104.28 [1.37] mm Hg vs 100.34 [1.02] mm Hg; DBP, 64.7 [1.23] mm Hg vs 59.76 [0.91] mm Hg). No differences in the SBP and DBP were found between children who were overweight or obese whose mothers received DHA and children who were not overweight or obese. In the mixed model analysis, the child's age at blood pressure measurement and the maternal prepregnancy body mass index were the only other statistically significant variables (child age, SBP: F = 7.385; P = .001; DBP: F = 7.39; P = .001; prepregnancy BMI, SBP: r = 0.284; P = .001; DBP: r = 0.216; P = .01).

CONCLUSIONS AND RELEVANCE

Maternal docosahexaenoic acid intake during pregnancy appeared to mitigate the association between childhood overweight condition or obesity and blood pressure.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02487771.

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

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

Maternal smoking during pregnancy and early development of overweight and growth deficit in children: an analysis of survival

Abstract Objectives: to evaluate the association between smoking during pregnancy and nutritional status. Methods: cohort study with a sample of 460 children in the baseline. The children were assessed four times, being measured for weight and length to be converted in indexes length forage (L/A) and body mass index forage (BMI/A) in Z-score. The time until occurrence of growth deficit and overweight was calculated in days and compared to maternal smoking during pregnancy. To assess the association between smoking during pregnancy and the outcomes, a Hazard Ratio by Cox regression was obtained, adjusting by confounding variables selected from Directed Acyclic Graphs (DAG). Results: the time until occurrence of growth deficit and overweight was lower in children whose mothers smoked during pregnancy. Smoking during pregnancy was a risk factor for length deficit (HR = 2.84; CI95% = 1.42 to 5.70) and for overweight (HR = 1.96; CI95% = 1, 09 to 3.53), even after the adjustment. Conclusions: maternal smoking was a changeable factor associated with anthropometric outcomes, which demonstrates the need for actions to combat smoking during pregnancy in order to prevent early nutritional deviations.

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.

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.

The impact of pre and perinatal lifestyle factors on child long term health and social outcomes: a systematic review

To understand the full extent of the impact of a trial, it is important to consider the long-term consequences of outcomes beyond the trial follow-up period, especially for early year's interventions. A systematic review of the literature associated with the long-term consequences of four key outcomes from the Building Blocks trial, specifically, low birth weight, smoking during pregnancy, interval to subsequent pregnancy and A&E attendance or inpatient admission was conducted. These factors were guided by the funders, the Department of Health, as being of particular interest in the UK context. Relevant studies were identified from a number of sources including large databases, reference checking and citation searching. The search yielded 3665 papers, 43 of which were considered appropriate for inclusion. Of these, 29 were relating to smoking during pregnancy, 13 to low birth weight, 0 to A&E attendances during early childhood and 1 to short (< 2 years) interval to subsequent pregnancy. Consistent associations were found between maternal smoking during pregnancy and the effects this has on children's health, educational attainment and likelihood of engaging in problem behaviour and criminal activity in later life. Low birth weight was also found to impact on children's long-term health and cognitive development. Subsequent pregnancies within two years of the previous birth were linked with increased likelihood of pre-term birth and neonatal death. Only minimal evidence was identified regarding the consequences of a short interval to second pregnancy and of child A&E and outpatient attendances. Given that these outcomes have been identified by the UK Department of Health as of particular interest for UK benefit, investment of research in these areas is recommended to establish a clearer picture of both short and long-term consequences.

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.

Effect of diet and maternal education on allergies among preschool children: A case-control study

INTRODUCTION

The prevalence of asthma and allergy has increased among children. This increase in prevalence might be related to dietary patterns.

AIMS

The present epidemiological study investigated the relationship between the consumption of fruit, vegetables, nuts, meat and fish, and the prevalence of wheeze, asthma, and eczema among preschool children.

METHODS

This nested case-control study included 1489 children aged 4-6 years and residing in Kaunas city, Lithuania. The subjects were recruited to the KANC newborn cohort study during 2007-2009. Parents' responses to questionnaires were used to collect information on allergic diseases, diet, and other variables. The association between dietary patterns and children's allergic diseases were tested by using logistic regressions, after adjustment for maternal education level, smoking during pregnancy, parental asthma, children's sex, parity, and antibiotic usage during the first year of life.

RESULTS

In this study, 83.3% of all children consumed fresh fruit and/or vegetables at least three times per week. A significantly lower adjusted odds ratio (aOR) of wheeze was found among children who ate fruit than among those who did not (aOR: 0.48; 95% CI: 0.22-0.96). The consumption of nuts was also associated with a lower 61% risk of eczema among 4-6 years old children.

CONCLUSION

The results indicated a beneficial effect of a frequent consumption of fresh fruit and nuts on the prevalence of allergies among children. These results might have important implications for children's health.

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.

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.

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.

Parental smoking during pregnancy shortens offspring's legs

One of the most severe detrimental environmental factors acting during pregnancy is foetal smoke exposure. The aim of this study was to assess the effect of maternal, paternal and parental smoking during pregnancy on relative leg length in 7- to 10-year-old children. The research conducted in the years 2001-2002 included 978 term-born children, 348 boys and 630 girls, at the age of 7-10 years. Information concerning the birth weight of a child was obtained from the health records of the women. Information about the mother's and the father's smoking habits during pregnancy and about the mothers' education level was obtained from a questionnaire. The influence of parental smoking on relative leg length, controlled for age, sex, birth weight and the mother's education, as a proxy measure of socioeconomic status, and controlled for an interaction between sex and birth weight, was assessed by an analysis of covariance, where relative leg length was the dependent variable, smoking and sex were the independent variables, and birth weight as well as the mother's education were the covariates. Three separate analyses were run for the three models of smoking habits during pregnancy: the mother's smoking, the father's smoking and both parents' smoking. Only both parents' smoking showed a significant effect on relative leg length of offspring. It is probable that foetal hypoxia caused by carbon monoxide contained in smoke decelerated the growth of the long bones of foetuses.

The relationship between facial morphology, body measurements and socio-economic factors

Background and aim: The effect of socio-economic factors (living conditions) and parental smoking habits on development of facial morphology and body measurements was studied on a longitudinal Czech sample of 25 girls and 25 boys.

Subjects and methods: A set of studied digitalized photographs taken from 0.5 to 18 years in intervals of 6 months originated in the Brno Longitudinal Study. Facial shape changes of sub-adult participants were described using a configuration of 27 landmarks and further studied by using methods of geometric morphometric and multivariate statistics. In order to localize growth-related shape changes within the face, the studied region was divided into upper, middle and lower facial units and analyzed separately.

Results and conclusion: The results show that in the course of ontogenesis there is a strong correlation between facial shape change and body measurements, height included (r=0.10 and r=0.24 in boys and in girls, respectively). The pubertal spurt of the facial shape change rate was revealed at 10.5 years in girls and at 11.5 years in boys. The earlier onset of the pubertal rate increase in facial shape changes in boys was associated with records of poor living conditions. In addition, the mother’s smoking habits were linked to a noticeable facial shape change.

Developmental cigarette smoke exposure II: Kidney proteome profile alterations in 6 month old adult offspring

Cigarette smoke exposure (CSE) during gestation and early development suppresses the growth trajectory in offspring. In prior studies utilizing a mouse model of 'active' developmental CSE (GD1-PD21), low birth weight induced by CSE persisted throughout the neonatal period and was present at the cessation of exposure at weaning with proportionally smaller kidney mass that was accompanied by impairment of carbohydrate metabolism. In the present study, littermates of those characterized in the prior study were maintained until 6 months of age at which time the impact of developmental CSE on the abundance of proteins associated with cellular metabolism in the kidney was examined. Kidney protein abundances were examined by 2D-SDS-PAGE based proteome profiling with statistical analysis by Partial Least Squares-Discriminant Analysis. Key findings of this study include a persistence of impact of developmental CSE past the original exposure period on the nucleic acid and carbohydrate metabolism networks and oxidant scavenging pathways.

Obesity and colorectal cancer: molecular features of adipose tissue

The huge part of population in developed countries is overweight or obese. Obesity is often determined by body mass index (BMI) but new accurate methods and ratios have recently appeared to measure body fat or fat located in the intestines. Early diagnosis of obesity is crucial since it is considered an increasing colorectal cancer risk factor. On the one hand, colorectal cancer has been strongly associated with lifestyle factors. A diet rich in red and processed meats may increase colorectal cancer risk; however, high-fiber diets (grains, cereals and fruits) have been associated with a decreased risk of colorectal cancer. Other life-style factors associated with obesity that also increase colorectal cancer risk are physical inactivity, smoking and high alcohol intake. Cutting-edge studies reported that high-risk transformation ability of adipose tissue is due to production of different pro-inflammatory cytokines like IL-8, IL-6 or IL-2 and other enzymes like lactate dehydrogenase (LDH) and tumour necrosis factor alpha (TNFα). Furthermore, oxidative stress produces fatty-acid peroxidation whose metabolites possess very high toxicities and mutagenic properties. 4-hydroxy-2-nonenal (4-HNE) is an active compounds that upregulates prostaglandin E2 which is directly associated with high proliferative colorectal cancer. Moreover, 4-HNE deregulates cell proliferation, cell survival, differentiation, autophagy, senescence, apoptosis and necrosis via mitogen-activated protein kinase (MAPK), phosphoinositide 3-kinase (PIK3CA)—AKT and protein kinase C pathways. Other product of lipid peroxidation is malondialdehyde (MDA) being able to regulate insulin through WNT-pathway as well as having demonstrated its mutagenic capability. Accumulation of point mutation enables genomic evolution of colorectal cancer described in the model of Fearon and Vogelstein. In this review, we will summarize different determination methods and techniques to assess a truthfully diagnosis and we will explain some of the capabilities that performs adipocytes as the largest endocrine organ.

Short and long term health effects of parental tobacco smoking during pregnancy and lactation: a descriptive review

A great deal of attention has been focused on adverse effects of tobacco smoking on conception, pregnancy, fetal, and child health. The aim of this paper is to discuss the current evidence regarding short and long-term health effects on child health of parental smoking during pregnancy and lactation and the potential underlying mechanisms. Studies were searched on MEDLINE(®) and Cochrane database inserting, individually and using the Boolean ANDs and ORs, 'pregnancy', 'human lactation', 'fetal growth', 'metabolic outcomes', 'obesity', 'cardiovascular outcomes', 'blood pressure', 'brain development', 'respiratory outcomes', 'maternal or paternal or parental tobacco smoking', 'nicotine'. Publications coming from the reference list of studies were also considered from MEDLINE. All sources were retrieved between 2015-01-03 and 2015-31-05. There is overall consistency in literature about negative effects of fetal and postnatal exposure to parental tobacco smoking on several outcomes: preterm birth, fetal growth restriction, low birth weight, sudden infant death syndrome, neurodevelopmental and behavioral problems, obesity, hypertension, type 2 diabetes, impaired lung function, asthma and wheezing. While maternal smoking during pregnancy plays a major role on adverse postnatal outcomes, it may also cumulate negatively with smoking during lactation and with second-hand smoking exposure. Although this review was not strictly designed as a systematic review and the PRISMA Statement was not fully applied it may benefit the reader with a promptly and friendly readable update of the matter. This review strengthens the need to plan population health policies aimed to implement educational programs to hopefully minimize tobacco smoke exposure during pregnancy and lactation.

Effect of the exposure to maternal smoking during pregnancy and childhood on the body mass index until adolescence

OBJECTIVE

Investigate the effect of exposure to smoking during pregnancy and early childhood on changes in the body mass index (BMI) from birth to adolescence.

METHODS

A population-based cohort of children (0-5 years old) from Cuiabá, Midwest Brazil, was assessed in 1999-2000 (n = 2,405). Between 2009 and 2011, the cohort was re-evaluated. Information about birth weight was obtained from medical records, and exposure to smoking during pregnancy and childhood was assessed at the first interview. Linear mixed effects models were used to estimate the association between exposure to maternal smoking during pregnancy and preschool age, and the body mass index of children at birth, childhood and adolescence.

RESULTS

Only 11.3% of the mothers reported smoking during pregnancy, but most of them (78.2%) also smoked during early childhood. Among mothers who smoked only during pregnancy (n = 59), 97.7% had smoked only in the first trimester. The changes in body mass index at birth and in childhood were similar for children exposed and those not exposed to maternal smoking. However, from childhood to adolescence the rate of change in the body mass index was higher among those exposed only during pregnancy than among those who were not exposed.

CONCLUSIONS

Exposure to smoking only during pregnancy, especially in the first trimester, seems to affect changes in the body mass index until adolescence, supporting guidelines that recommend women of childbearing age to stop smoking.

Long chain polyunsaturated fatty acid supplementation in infancy increases length- and weight-for-age but not BMI to 6 years when controlling for effects of maternal smoking

Long chain polyunsaturated fatty acids (LCPUFA) are added to infant formula but their effect on long-term growth of children is under studied. We evaluated the effects of feeding LCPUFA-supplemented formula (n = 54) compared to control formula (n = 15) throughout infancy on growth from birth-6 years. Growth was described using separate models developed with the MIXED procedure of SAS(®) that included maternal smoking history and gender. Compared to children fed control formula, children who consumed LCPUFA supplemented formula had higher length-/stature-/and weight-for-age percentiles but not body mass index (BMI) percentile from birth to 6 years. Maternal smoking predicted lower stature (2-6 years), higher weight-for-length (birth-18 months) and BMI percentile (2-6 years) independent of LCPUFA effects. Gender interacted with the effect of LCPUFA on stature, and the relationship between smoking and BMI, with a larger effect for boys. Energy intake did not explain growth differences. A relatively small control sample is a limitation.

Inflammation and Nutritional Science for Programs/Policies and Interpretation of Research Evidence (INSPIRE)

An increasing recognition has emerged of the complexities of the global health agenda—specifically, the collision of infections and noncommunicable diseases and the dual burden of over- and undernutrition. Of particular practical concern are both 1) the need for a better understanding of the bidirectional relations between nutritional status and the development and function of the immune and inflammatory response and 2) the specific impact of the inflammatory response on the selection, use, and interpretation of nutrient biomarkers. The goal of the Inflammation and Nutritional Science for Programs/Policies and Interpretation of Research Evidence (INSPIRE) is to provide guidance for those users represented by the global food and nutrition enterprise. These include researchers (bench and clinical), clinicians providing care/treatment, those developing and evaluating programs/interventions at scale, and those responsible for generating evidence-based policy. The INSPIRE process included convening 5 thematic working groups (WGs) charged with developing summary reports around the following issues: 1) basic overview of the interactions between nutrition, immune function, and the inflammatory response; 2) examination of the evidence regarding the impact of nutrition on immune function and inflammation; 3) evaluation of the impact of inflammation and clinical conditions (acute and chronic) on nutrition; 4) examination of existing and potential new approaches to account for the impact of inflammation on biomarker interpretation and use; and 5) the presentation of new approaches to the study of these relations. Each WG was tasked with synthesizing a summary of the evidence for each of these topics and delineating the remaining gaps in our knowledge. This review consists of a summary of the INSPIRE workshop and the WG deliberations.

Endocrine disruptive compounds and cardio-metabolic risk factors in children

The endocrine disrupting chemicals (EDC) are exogenous chemicals that can disrupt hormonal signaling system. EDCs are ubiquitous in our environment and many EDC are detectable in humans. With the increasing obesity prevalence in children it is imperative to explore the role of EDC as obesogens. This review summarizes recent epidemiological evidence regarding impact of these EDC on weight gain and metabolic outcomes in children. The EDCs include pharmaceuticals, pesticides, industrial by-products, and cigarette smoke. Current evidence suggests a link between early life exposure to some industrial by-products, synthetic hormones and cigarette smoke with weight gain. However, there is inconclusive evidence of an association between exposure to fungicides, dioxin, phytoestrogens, flame retardants, heavy metals and childhood obesity.

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

AIM

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

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

Prenatal exposure to environmental contaminants and body composition at age 7-9 years

The study aim was to investigate the association between prenatal exposure to endocrine disrupting chemicals (EDCs) and the body composition of 7 to 9 year old Flemish children. The subjects were 114 Flemish children (50% boys) that took part in the first Flemish Environment and Health Study (2002-2006). Cadmium, PCBs, dioxins, p,p'-DDE and HCB were analysed in cord blood/plasma. When the child reached 7-9 years, height, weight, waist circumference and skinfolds were measured. Significant associations between prenatal exposure to EDCs and indicators of body composition were only found in girls. After adjustment for confounders and covariates, a significant negative association was found in girls between prenatal cadmium exposure and weight, BMI and waist circumference (indicator of abdominal fat) and the sum of four skinfolds (indicator of subcutaneous fat). In contrast, a significant positive association (after adjustment for confounders/covariates) was found between prenatal p,p'-DDE exposure and waist circumference as well as waist/height ratio in girls (indicators of abdominal fat). No significant associations were found for prenatal PCBs, dioxins and HCB exposure after adjustment for confounders/covariates. This study suggests a positive association between prenatal p,p'-DDE exposure and indicators of abdominal fat and a negative association between prenatal cadmium exposure and indicators of both abdominal as well as subcutaneous fat in girls between 7 and 9 years old.

Differences in BMI z-scores between offspring of smoking and nonsmoking mothers: a longitudinal study of German children from birth through 14 years of age

BACKGROUND

Children of mothers who smoked during pregnancy have a lower birth weight but have a higher chance to become overweight during childhood.

OBJECTIVES

We followed children longitudinally to assess the age when higher body mass index (BMI) z-scores became evident in the children of mothers who smoked during pregnancy, and to evaluate the trajectory of changes until adolescence.

METHODS

We pooled data from two German cohort studies that included repeated anthropometric measurements until 14 years of age and information on smoking during pregnancy and other risk factors for overweight. We used longitudinal quantile regression to estimate age- and sex-specific associations between maternal smoking and the 10th, 25th, 50th, 75th, and 90th quantiles of the BMI z-score distribution in study participants from birth through 14 years of age, adjusted for potential confounders. We used additive mixed models to estimate associations with mean BMI z-scores.

RESULTS

Mean and median (50th quantile) BMI z-scores at birth were smaller in the children of mothers who smoked during pregnancy compared with children of nonsmoking mothers, but BMI z-scores were significantly associated with maternal smoking beginning at the age of 4-5 years, and differences increased over time. For example, the difference in the median BMI z-score between the daughters of smokers versus nonsmokers was 0.12 (95% CI: 0.01, 0.21) at 5 years, and 0.30 (95% CI: 0.08, 0.39) at 14 years of age. For lower BMI z-score quantiles, the association with smoking was more pronounced in girls, whereas in boys the association was more pronounced for higher BMI z-score quantiles.

CONCLUSIONS

A clear difference in BMI z-score (mean and median) between children of smoking and nonsmoking mothers emerged at 4-5 years of age. The shape and size of age-specific effect estimates for maternal smoking during pregnancy varied by age and sex across the BMI z-score distribution.

Effect of tobacco smoke exposure during pregnancy and preschool age on growth from birth to adolescence: a cohort study

BACKGROUND

There is strong evidence of an association between maternal smoking during pregnancy and restriction of intrauterine growth, but the effects of this exposure on postnatal linear growth are not well defined. Furthermore, few studies have investigated the role of tobacco smoke exposure also after pregnancy on linear growth until adolescence. In this study we investigated the effect of maternal smoking exposure during pregnancy and preschool age on linear growth from birth to adolescence.

METHODS

We evaluated a cohort of children born between 1994 and 1999 in Cuiabá, Brazil, who attended primary health clinics for vaccination between the years 1999 and 2000 (at preschool age) and followed-up after approximately ten years. Individuals were located in public and private schools throughout the country using the national school census. Height/length was measured, and length at birth was collected at maternity departments. Stature in childhood and adolescence was assessed using the height-for-age index sex-specific expressed as z-score from curves published by the World Health Organization. Linear mixed effects models were used to estimate the association between exposure to maternal smoking, during pregnancy and preschool age, and height of children assessed at birth, preschool and school age, adjusted for age of the children.

RESULTS

We evaluated 2405 children in 1999-2000, length at birth was obtained from 2394 (99.5%), and 1716 at follow-up (71.4% of baseline), 50.7% of the adolescents were male. The z-score of height-for-age was lower among adolescents exposed to maternal smoking both during pregnancy and childhood (p < 0.01). Adjusting for age, sex, maternal height, maternal schooling, socioeconomic position at preschool age, and breastfeeding, children exposed to maternal smoking both during pregnancy and preschool age showed persistent lower height-for-age since birth to adolescence (coefficient: -0.32, p < 0.001) compared to non-exposed. Paternal smoking at preschool age was not associated with growth after adjustment for confounders.

CONCLUSION

Exposure to maternal smoking not only during pregnancy, but also at early childhood, showed long-term negative effect on height of children until adolescence.

Maternal smoking during pregnancy and childhood overweight and fat distribution: the KOALA Birth Cohort Study

What is already known about this subject There is an association between maternal smoking during pregnancy and higher body mass index (BMI) and overweight in childhood. What this study adds The association between maternal smoking during pregnancy and childhood overweight develops with age, starting with a lower birth weight, followed by weight catch-up in the first year after birth, finally leading to overweight at school age. Children of mothers who had smoked during pregnancy had a higher risk of exceeding the 85th percentile of BMI, waist circumference and total skinfold thickness at school age.

BACKGROUND

Maternal smoking during pregnancy is associated with childhood overweight, but the association with fat distribution is not clear.

OBJECTIVE

To explore the longitudinal association between smoking during pregnancy and childhood overweight and fat distribution.

METHODS

In the KOALA Birth Cohort Study, repeated questionnaires were administered to 2698 mother-child pairs, including questions on smoking at 14 and 34 weeks of pregnancy. Main outcomes were birth weight, weight gain in the first year, body mass index (BMI) z-scores and overweight (BMI ≥85th percentile) at 1, 2, 4-5 and 6-7 years (n = 1730) and waist circumference and four skinfold thicknesses measured at home visits at age 6-7 years in a subgroup (n = 418). We used multivariable linear and logistic regression, with generalized estimating equations (GEE) for repeated measurements.

RESULTS

Maternal smoking was associated with lower birth weight, higher weight gain in the first year and increasing overweight after infancy (change with age P = 0.02 in the GEE). Maternal smoking vs. non-smoking during pregnancy was associated with a higher risk of the child exceeding the 85th percentile of BMI (adjusted odds ratio [aOR] 3.72; 95% CI 1.33-10.4), waist circumference (aOR 2.65; 95% CI 1.06-6.59) and sum of skinfold thicknesses (aOR 4.45; 95% CI 1.63-12.2) at the age of 6-7 years.

CONCLUSIONS

Maternal smoking during pregnancy is associated with lower birth weight, weight catch-up and development of overweight into childhood.

Asthma in children in relation to pre-term birth and fetal growth restriction

To assess the impact of parental asthma on risk of pre-term birth (PTB) and intrauterine growth restriction, and their subsequent association with childhood asthma. Three sequential cross-sectional surveys were conducted in 1993 (3,746), 1998 (1,964) and 2006 (1,074) in the same 15 schools among 5-11 year old children in Merseyside using the same respiratory health questionnaire completed by parents (sample size in brackets). Between 1993 and 2006, prevalence of PTB varied between 12.4 and 15.2 %, and of small for gestational age (SGA or growth restricted) babies between 2.1 and 4.6 %, and maternal asthma prevalence between 8.1 and 13.4 %. For the combined surveys mothers with asthma were more likely to have a PTB than non-asthmatic mothers (OR 1.39, 95 % CI 1.10-1.95, p < 0.001), and in the 2006 survey were more likely to have an SGA baby. 40.9 % of PTBs of asthmatic mothers developed doctor diagnosed asthma compared to 34.3 % for term babies (adjusted OR 1.65, 1.34-2.04, p < 0.001). The corresponding estimates for the symptom triad of cough, wheeze and breathlessness were 19.4 and 17.6 % (adjusted OR 1.78, 0.79-3.98). Conversely SGA babies were less likely to develop doctor diagnosed asthma (adjusted OR 0.49, 0.27-0.90, p < 0.021), or the symptom triad of cough, wheeze and breathlessness (adjusted OR 0.22, 0.05-0.97, p < 0.043), whether or not the mother was asthmatic. Maternal asthma is an independent risk factor for PTB which predisposes to childhood asthma. Intrauterine growth restriction was protective against childhood asthma.

High cotinine levels are persistent during the first days of life in newborn second hand smokers

BACKGROUND

Despite the adverse effects of maternal smoking during pregnancy on the newborn's health are well-known, in the pediatric population, a high prevalence exists that is very much affected by second hand smoke (SHS). This study aims to investigate the impact of maternal smoking habits during pregnancy on cotinine levels in newborns during the first days of life. The high association between cotinine concentration in maternal and umbilical cord blood (UCB) has been previously reported, but the levels of blood cotinine that remain in infants born to smokers is unknown.

METHODS

Cotinine concentration was measured in UCB, in maternal and newborn peripheral blood. Data from UCB sample dyads of ninety mothers and from seventy-one newborns were analyzed.

RESULTS

Cotinine levels were significantly different among non-smokers (9.9 ± 5.9 ng/ml), moderate (67.3 ± 7.4 ng/ml), and heavy smokers (137.7 ± 19.5 ng/ml) (p<0.0001). Significant correlations were found between maternal and UCB cotinine (r=0.748; p<0.001), and between UCB and newborn plasma cotinine at 48 h after birth (r=0.541; p<0.001). The smokers exposed their infants to cotinine with a median of 31.7 ± 8.6 ng/ml (moderate) or 59.1 ± 13.3 ng/ml (heavy smokers) until at least, 48 h after birth. Reduced birth weight and length were significantly related with UCB cotinine levels.

CONCLUSIONS

A positive association between UCB and plasmatic cotinine in newborns was found. The high cotinine levels detected in newborns from smoker mothers indicates that their infants are subjected to elevated SHS from birth. These results can help to reinforce the awareness of the adverse effects of smoking during pregnancy.

Socio-demographic and lifestyle-related characteristics associated with self-reported any, daily and occasional smoking during pregnancy

Smoking during pregnancy is a risk factor for various adverse birth outcomes. In order to develop effective interventions, insight is needed into the characteristics associated with pregnant women who smoke. Unknown is whether these characteristics differ for women who smoke daily and women who smoke occasionally. Our study sample, drawn from the DELIVER study (Sept 2009-March 2011), consisted of 6107 pregnant women in primary care in the Netherlands who were up to 34 weeks pregnant. The associations of thirteen socio-demographic or lifestyle-related characteristics with 'any smoking', 'daily smoking' and 'occasional smoking' during pregnancy were tested using multiple binary logistic regression with general estimating equations (GEE). Characteristics most strongly associated with any smoking were low education (OR 10.3; 95% confidence interval (CI) 7.0-15.4), being of Turkish ethnicity (OR 3.9; 95%CI 2.3-6.7) and having no partner (OR 3.7; 95%CI 2.3-6.0). Women of Dutch ethnicity were three times more likely to smoke than those from Dutch-speaking Caribbean countries and non-religious women were much more likely to smoke than religious women. Low education was markedly more strongly associated with daily smoking than with occasional smoking (OR 20.3; 95%CI 13.2-31.3 versus OR 6.0; 95%CI 3.4-10.5). Daily smokers were more likely to be associated with other unfavorable lifestyle-related characteristics, such as not taking folic acid, being underweight, and having had an unplanned pregnancy. There is still much potential for health gain with respect to smoking during pregnancy in the Netherlands. Daily and occasional smokers appear to differ in characteristics, and therefore possibly require different interventions.

Developing prediction equations and a mobile phone application to identify infants at risk of obesity

Background

Advancements in knowledge of obesity aetiology and mobile phone technology have created the opportunity to develop an electronic tool to predict an infant’s risk of childhood obesity. The study aims were to develop and validate equations for the prediction of childhood obesity and integrate them into a mobile phone application (App).

Methods and Findings

Anthropometry and childhood obesity risk data were obtained for 1868 UK-born White or South Asian infants in the Born in Bradford cohort. Logistic regression was used to develop prediction equations (at 6±1.5, 9±1.5 and 12±1.5 months) for risk of childhood obesity (BMI at 2 years >91^st centile and weight gain from 0–2 years >1 centile band) incorporating sex, birth weight, and weight gain as predictors. The discrimination accuracy of the equations was assessed by the area under the curve (AUC); internal validity by comparing area under the curve to those obtained in bootstrapped samples; and external validity by applying the equations to an external sample. An App was built to incorporate six final equations (two at each age, one of which included maternal BMI). The equations had good discrimination (AUCs 86–91%), with the addition of maternal BMI marginally improving prediction. The AUCs in the bootstrapped and external validation samples were similar to those obtained in the development sample. The App is user-friendly, requires a minimum amount of information, and provides a risk assessment of low, medium, or high accompanied by advice and website links to government recommendations.

Conclusions

Prediction equations for risk of childhood obesity have been developed and incorporated into a novel App, thereby providing proof of concept that childhood obesity prediction research can be integrated with advancements in technology.

Parental smoking during pregnancy and risk of overweight and obesity in the daughter

Objective

Emerging evidence suggests that prenatal exposures may affect long-term health outcomes. In utero exposure to smoking is associated with an increased risk of overweight and obesity in children and adolescents. However, few studies have examined how prenatal exposure to parental smoking influences risk of obesity in adulthood and whether these associations are independent of childhood and adolescent adiposity. The aim of the current study was to investigate whether prenatal exposure to parental smoking influences body size in adulthood and whether any association may be mediated by childhood and adolescent body size.

Methods

We investigated the association between parental smoking during pregnancy and risk of overweight and obesity in adulthood and at age 18, and adiposity during childhood among 35,370 participants in the Nurses’ Health Study II. Data on smoking during pregnancy and socioeconomic variables were provided by the mothers, and anthropometric data and adult risk factors were reported by participants.

Results

After adjustment for socioeconomic and behavioral variables, maternal smoking during pregnancy was associated with adiposity at ages 5–10, age 18, and during adulthood. For age 18 overweight the ORs (95% CIs) for 1–14, 15–24, and 25+cigarettes/day were 1.13 (1.18–1.50), 1.40 (1.20–1.64), and 1.15 (0.79–1.69) and for obesity were 1.41 (1.14–1.75), 1.69 (1.31–2.18), and 2.36 (1.44–3.86). The corresponding ORs (95% CIs) for obesity in adulthood were 1.26 (1.16–1.37), 1.46 (1.30–1.63), and 1.43 (1.10–1.86). Risk of adiposity was not increased among daughters whose mothers stopped smoking during the first trimester (OR [95% CI] for overweight (1.03 [95% CI 0.90–1.17] and obesity (1.12 [95% CI 0.97–1.30]). Women whose fathers smoked during pregnancy were also at increased risk of overweight and obesity in adulthood with covariate-adjusted ORs (95% CIs) for obesity of 1.19 (1.11–1.29) for 1–14 cigarettes/day, 1.27 (1.18–1.37) for 15–24 cigarettes/day, and 1.40 (1.27–1.54) for 25+ cigarettes/day compared to fathers who did not smoke (p_trend<0.0001). Paternal smoking during pregnancy was also associated with an increased risk of obesity at age 18 among those whose fathers smoked 15 or more cigarettes/day but was not associated with childhood body size.

Conclusions

Maternal smoking during pregnancy was associated in a dose-response manner with overweight and obesity in the daughter through adolescence and adult life. Smoking cessation during the first trimester appears to mitigate this excess risk.

Paternal smoking was also associated with risk of overweight and obesity of the adult daughter and this association persisted after adjustment for maternal smoking.

Early life risk factors of being overweight at 10 years of age: results of the German birth cohorts GINIplus and LISAplus

OBJECTIVE

To develop a prediction model that quantifies the risk of being overweight at 10 years of age.

SUBJECTS/METHODS

In total, 3121 participants from the GINIplus (German Infant Nutritional Intervention plus environmental and genetic influences on allergy development) and LISAplus (Influences of Lifestyle-Related Factors on the Immune System and the Development of Allergies in Childhood plus Air Pollution and Genetics) German birth cohorts were recruited. We predicted standardized body mass index (BMI) at 10 years of age using standardized BMIs from birth to 5 years. Parental education, family income and maternal smoking during pregnancy were considered as covariates. Linear and logistic regression models were used to evaluate the impact of risk factors on BMI and on being overweight at 10 years of age, respectively.

RESULTS

Birth weight, standardized BMI at 5 years (60-64 months) (β=0.77; 95% confidence interval (CI): 0.73-0.81) and maternal smoking during pregnancy were positively associated with standardized BMI at 10 years of age. Standardized BMI and overweight at 5 years were strongest predictors of being overweight at 10 years. Conversely, high parental education conferred a protective effect (β=-0.15; 95% CI: -0.29 to -0.01). Being overweight at 5 years (60-64 months) increased the risk of being overweight at 10 years of age with odds ratios above 10. Among children who were predicted to be overweight at 10 years, cross-validation results showed that 76.8% of female subjects and 68.1% of male subjects would be overweight at 10 years of age.

CONCLUSION

BMI and being overweight at 5 years of age are strong predictors of being overweight at 10 years of age. The effectiveness of targeted interventions in children who are overweight at 5 years of age should be explored.

Evaluation of the association between maternal smoking, childhood obesity, and metabolic disorders: a national toxicology program workshop review

BACKGROUND

An emerging literature suggests that environmental chemicals may play a role in the development of childhood obesity and metabolic disorders, especially when exposure occurs early in life.

OBJECTIVE

Here we assess the association between these health outcomes and exposure to maternal smoking during pregnancy as part of a broader effort to develop a research agenda to better understand the role of environmental chemicals as potential risk factors for obesity and metabolic disorders.

METHODS

PubMed was searched up to 8 March 2012 for epidemiological and experimental animal studies related to maternal smoking or nicotine exposure during pregnancy and childhood obesity or metabolic disorders at any age. A total of 101 studies-83 in humans and 18 in animals-were identified as the primary literature.

DISCUSSION

Current epidemiological data support a positive association between maternal smoking and increased risk of obesity or overweight in offspring. The data strongly suggest a causal relation, although the possibility that the association is attributable to unmeasured residual confounding cannot be completely ruled out. This conclusion is supported by findings from laboratory animals exposed to nicotine during development. The existing literature on human exposures does not support an association between maternal smoking during pregnancy and type 1 diabetes in offspring. Too few human studies have assessed outcomes related to type 2 diabetes or metabolic syndrome to reach conclusions based on patterns of findings. There may be a number of mechanistic pathways important for the development of aberrant metabolic outcomes following perinatal exposure to cigarette smoke, which remain largely unexplored.

CONCLUSIONS

From a toxicological perspective, the linkages between maternal smoking during pregnancy and childhood overweight/obesity provide proof-of-concept of how early-life exposure to an environmental toxicant can be a risk factor for childhood obesity.