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

Prospective associations of parental smoking, alcohol use, marital status, maternal satisfaction, and parental and childhood body mass index at 6.5 years with later problematic eating attitudes

BACKGROUND

Few studies have prospectively investigated whether early-life exposures are associated with pre-adolescent eating attitudes.

OBJECTIVE

The objective of this study is to prospectively investigate associations of parental smoking, alcohol use, marital status, measures of maternal satisfaction, self-reported parental body mass index (BMI) and clinically measured childhood BMI, assessed between birth and 6.5 years, with problematic eating attitudes at 11.5 years.

METHODS

Observational cohort analysis nested within the Promotion of Breastfeeding Intervention Trial, a cluster-randomised trial conducted in 31 maternity hospitals and affiliated polyclinics in Belarus. Our primary outcome was a Children's Eating Attitudes Test (ChEAT) score 22.5 (85th percentile), an indicator of problematic eating attitudes. We employed multivariable mixed logistic regression models, which allow inference at the individual level. We also performed instrumental variable (IV) analysis using parents' BMIs as instruments for the child's BMI, to assess whether associations could be explained by residual confounding or reverse causation.

SUBJECTS

Of the 17 046 infants enrolled between 1996 and 1997 across Belarus, 13 751 (80.7%) completed the ChEAT test at 11.5 years.

RESULTS

In fully adjusted models, overweight children at age 6.5 years had a 2.14-fold (95% confidence interval (CI): 1.82, 2.52) increased odds of having ChEAT scores 85th percentile at age 11.5 years, and those who were obese had a 3.89-fold (95% CI: 2.95, 5.14) increased odds compared with normal-weight children. Children of mothers or fathers who were themselves overweight or obese were more likely to score 85th percentile (P for trend 0.001). IV analysis was consistent with a child's BMI causally affecting future eating attitudes. There was little evidence that parental smoking, alcohol use, or marital status or maternal satisfaction were associated with eating attitudes.

CONCLUSION

In our large, prospective cohort in Belarus, both parental and childhood overweight and obesity at 6.5 years were associated with pre-adolescent problematic eating attitudes 5 years later.

The obesogen tributyltin

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

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

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

Fetal and neonatal exposure to nicotine leads to augmented hepatic and circulating triglycerides in adult male offspring due to increased expression of fatty acid synthase

While nicotine replacement therapy is assumed to be a safer alternative to smoking during pregnancy, the long-term consequences for the offspring remain elusive. Animal studies now suggest that maternal nicotine exposure during perinatal life leads to a wide range of adverse outcomes for the offspring including increased adiposity. The focus of this study was to investigate if nicotine exposure during pregnancy and lactation leads to alterations in hepatic triglyceride synthesis. Female Wistar rats were randomly assigned to receive daily subcutaneous injections of saline (vehicle) or nicotine bitartrate (1mg/kg/day) for two weeks prior to mating until weaning. At postnatal day 180 (PND 180), nicotine exposed offspring exhibited significantly elevated levels of circulating and hepatic triglycerides in the male offspring. This was concomitant with increased expression of fatty acid synthase (FAS), the critical hepatic enzyme in de novo triglyceride synthesis. Given that FAS is regulated by the nuclear receptor Liver X receptor (LXRα), we measured LXRα expression in both control and nicotine-exposed offspring. Nicotine exposure during pregnancy and lactation led to an increase in hepatic LXRα protein expression and enriched binding to the putative LXRE element on the FAS promoter in PND 180 male offspring. This was also associated with significantly enhanced acetylation of histone H3 [K9,14] surrounding the FAS promoter, a hallmark of chromatin activation. Collectively, these findings suggest that nicotine exposure during pregnancy and lactation leads to an increase in circulating and hepatic triglycerides long-term via changes in the transcriptional and epigenetic regulation of the hepatic lipogenic pathway.

Maternal and newborn health profile in a first nations community in Canada

OBJECTIVES

We sought to characterize maternal health profiles and birth outcomes among First Nations people living in Southern Ontario.

METHODS

We performed a retrospective chart review of all 453 women from the Six Nations Reserve, Ontario, who were pregnant between 2005 and 2010. Maternal health behaviours, past medical history, physical measurements, birth outcomes, and newborn characteristics were abstracted. Key maternal and newborn characteristics were compared with those of a cohort of non-First Nations women recruited from nearby Hamilton, Ontario.

RESULTS

The average age of women in the study cohort was 25.1 ± 6.2 (mean ± SD) years, and 75.8% were multiparous. The mean pre-pregnancy BMI was 28.3 ± 6.6 kg/m(2), and the average weight gain in pregnancy was 14.9 ± 8.3 kg. Mean weight gain during pregnancy was inversely associated with pre-pregnancy BMI, and 57.1% of women gained more than the recommended weight. The prevalence of type 2 diabetes or gestational diabetes was 4.7%, hypertension was present before or during pregnancy in 5.6%, and 35% used tobacco during pregnancy. The mean gestational age at delivery was 39.5 ± 1.7 weeks and the mean crude birth weight was 3619 ± 557 g. The main determinants of newborn weight included sex of the newborn, pre-pregnancy BMI, and weight gain during pregnancy. Compared with a contemporary cohort of 622 non-First Nations mothers and newborns, First Nations mothers were, on average, younger (25.1 vs. 32.1 years; P < 0.001), had a higher mean pre-pregnancy BMI (28.3 vs. 26.8 kg/m(2); P < 0.001), and were more likely to use tobacco during pregnancy (35.0% vs. 14.4%; P < 0.001). First Nations newborns had significantly higher mean birth weight (+176 grams) and length (+2.3 cm) than non-First Nations newborns.

CONCLUSION

First Nations mothers from the Six Nations Reserve tended to have a high pre-pregnancy BMI, tended to gain more than the recommended weight during pregnancy, and commonly used tobacco during pregnancy. Programs to prevent overweight/obesity and excess weight gain during pregnancy and to minimize smoking are required among women of child-bearing age in this community.

Effect of maternal smoking cessation before and during early pregnancy on fetal and childhood growth

Background

Maternal smoking during pregnancy is a major cause of intrauterine growth restriction and childhood obesity, but only a few studies have examined the association of smoking cessation before and during pregnancy with fetal and childhood growth. We examined this association in a prospective cohort study in Japan.

Methods

Our study included children born between 1991 and 2006 and their mothers. Using a questionnaire, maternal smoking status was recorded at pregnancy. The anthropometric data of the children were collected during a medical check-up at age 3 years. Multiple linear and logistic regression models were used for data analysis stratified by sex.

Results

In total, 2663 mothers reported their smoking status during early pregnancy, and data were collected from 2230 (83.7%) children at age 3 years. Maternal smoking during pregnancy was associated with a significant reduction in birth weight (approximately 120–150 g). Body mass index at age 3 years was significantly higher among boys born to smoking mothers than among boys born to nonsmoking mothers. Maternal smoking during pregnancy was associated with overweight at age 3 years among boys (adjusted odds ratio, 2.4; 95% CI, 1.03–5.4). However, among women who stopped smoking in early pregnancy, there was no increase in the risks of a small for gestational age birth or childhood overweight at age 3 years.

Conclusions

Children born to mothers who stopped smoking before or during early pregnancy had appropriate fetal and childhood growth.

Placental DNA methylation alterations associated with maternal tobacco smoking at the RUNX3 gene are also associated with gestational age

AIMS

The developmental origins of health and disease hypothesis states that later-life disease may be influenced by the quality of the in utero environment. Environmental toxicants can have detrimental effects on fetal development, potentially through effects on placental development and function. Maternal smoking during pregnancy is associated with low birth weight, preterm birth and other complications, and exposure to cigarette smoke in utero has been linked to gross pathologic and molecular changes to the placenta, including differential DNA methylation in placental tissue. The aim of this study was to investigate the relationship between maternal smoking during pregnancy, methylation changes in the placenta and gestational age.

MATERIALS & METHODS

We used Illumina(®)'s (CA, USA) Human Methylation27 BeadChip technology platform to investigate the methylation status of 21,551 autosomal, non-SNP-associated CpG loci in DNA extracted from 206 human placentas and examined loci whose variation in methylation was associated with maternal smoking during pregnancy.

RESULTS

We found that methylation patterns of a number of loci within the RUNX3 gene were significantly associated with smoking during pregnancy, and one of these loci was associated with decreased gestational age (p = 0.04).

CONCLUSION

Our findings, demonstrating maternal smoking-induced changes in DNA methylation at specific loci, suggest a mechanism by which in utero tobacco smoke exposure could exert its detrimental effects upon the health of the fetus.

The imperative to prevent and treat childhood obesity: why the world cannot afford to wait

In the past 20 years, the prevalence of obesity in the United States increased almost 50% among adults and by 300% in children. Today, 9.7% of all U.S. infants up to 2 years old have abnormally high weight-for-recumbent length; 25% of children under age 5 are either overweight or obese; and 17% of adolescents are obese. Ethnic disparities in the rates of obesity are also large and apparent in childhood. Further, 44% of obese adolescents have metabolic syndrome. Obese children tend to become obese adults; thus, in a decade, young adults will likely have much higher risks of chronic disease, which has tremendous implications for the healthcare system. However, early childhood may be the best time to prevent obesity. Teachers' healthy eating choices are positively associated with changes in body mass index percentiles for children, for example. In addition, 8 million children attend afterschool programs, which can successfully promote health and wellness and successfully treat obesity. This childhood epidemic of obesity and its health-related consequences in adolescents should be a clinical and public health priority. However, this major public health problem cannot be managed solely in clinical settings. Rather, public health strategies must be integrated into home and family, school and community-based settings.

Gestational diabetes predicts the risk of childhood overweight and abdominal circumference independent of maternal obesity

AIM

Gestational diabetes mellitus is believed to be a risk factor for childhood overweight/obesity. We aimed to assess whether this association is either a reflection or independent of confounding by maternal BMI.

METHODS

Data from 7355 mother-child dyads of the German Perinatal Prevention of Obesity cohort with full anthropometric information on mothers and children, gestational diabetes and confounding factors were obtained at school entry health examination. We calculated crude and adjusted logistic regression models for the association of gestational diabetes and childhood overweight/obesity and abdominal adiposity defined by age- and sex-specific percentiles for BMI and waist circumference.

RESULTS

Among all children (mean age 5.8 years), 8.1% were overweight, 2.6% were obese and 15.5% had abdominal adiposity. The prevalence of overweight (obesity) was 21% (8.2%) in children of mothers with gestational diabetes and 10.4% (2.4%) in children of healthy mothers. Analyses with adjustment for maternal BMI and other potential confounders yielded an odds ratio of 1.81 (95% CI 1.23-2.65) and 2.80 (95% CI 1.58-4.99) for the impact of gestational diabetes on childhood overweight and obesity, respectively. Similar results were obtained for the risk of childhood abdominal adiposity (odds ratio 1.64, 95% CI 1.16-2.33) by maternal gestational diabetes.

CONCLUSIONS

The postulated increased risk of overweight and abdominal adiposity in offspring of mothers with gestational diabetes cannot be explained by maternal BMI alone and may be stronger for childhood obesity than for overweight.

Diversified microbiota of meconium is affected by maternal diabetes status

OBJECTIVES

This study was aimed to assess the diversity of the meconium microbiome and determine if the bacterial community is affected by maternal diabetes status.

METHODS

The first intestinal discharge (meconium) was collected from 23 newborns stratified by maternal diabetes status: 4 mothers had pre-gestational type 2 diabetes mellitus (DM) including one mother with dizygotic twins, 5 developed gestational diabetes mellitus (GDM) and 13 had no diabetes. The meconium microbiome was profiled using multi-barcode 16S rRNA sequencing followed by taxonomic assignment and diversity analysis.

RESULTS

All meconium samples were not sterile and contained diversified microbiota. Compared with adult feces, the meconium showed a lower species diversity, higher sample-to-sample variation, and enrichment of Proteobacteria and reduction of Bacteroidetes. Among the meconium samples, the taxonomy analyses suggested that the overall bacterial content significantly differed by maternal diabetes status, with the microbiome of the DM group showing higher alpha-diversity than that of no-diabetes or GDM groups. No global difference was found between babies delivered vaginally versus via Cesarean-section. Regression analysis showed that the most robust predictor for the meconium microbiota composition was the maternal diabetes status that preceded pregnancy. Specifically, Bacteroidetes (phyla) and Parabacteriodes (genus) were enriched in the meconium in the DM group compared to the no-diabetes group.

CONCLUSIONS

Our study provides evidence that meconium contains diversified microbiota and is not affected by the mode of delivery. It also suggests that the meconium microbiome of infants born to mothers with DM is enriched for the same bacterial taxa as those reported in the fecal microbiome of adult DM patients.

Association between nicotine replacement therapy use in pregnancy and smoking cessation

BACKGROUND

There is an urgent need to find better ways of helping pregnant smokers to stop. Randomized controlled trials (RCTs) have not detected an effect of nicotine replacement therapy (NRT) for smoking cessation in pregnancy. This may be because of inadequate dosing because of faster nicotine metabolism in this group. In England, many pregnant smokers use single form and combination NRT (patch plus a faster acting form). This correlational study examined whether the latter is associated with higher quit rates.

METHODS

Routinely collected data from 3880 pregnant smokers attempting to stop in one of 44 Stop Smoking Services in England. The outcome measure was 4-week quit rates, verified by expired-air carbon monoxide level<10 ppm. Outcome was compared between those not using medication versus using single form NRT (patch or one of the faster acting forms), or combination NRT. Potential confounders were intervention setting (specialist clinic, home visit, primary care, other), intervention type (one-to-one, group, drop-in, other), months pregnant, age, ethnicity and occupational group in multi-level logistic regressions.

RESULTS

After adjustment, combination NRT was associated with higher odds of quitting compared with no medication (OR=1.93, 95% CI=1.13-3.29, p=0.016), whereas single NRT showed no benefit (OR=1.06, 95% CI=0.60-1.86, p=0.84).

CONCLUSIONS

Use of a combination of nicotine patch and a faster acting form may confer a benefit in terms of promoting smoking cessation during pregnancy. While this conclusion is based on correlational data, it lends support to continuing this treatment option pending confirmation by an RCT.

Maternal smoking during pregnancy and fetal biometry: the INMA Mother and Child Cohort Study

In utero tobacco exposure has been associated with fetal growth restriction, but uncertainty remains about critical windows of exposure and specific effects on body segments. In the present study, we aimed to examine the association of maternal smoking with fetal biometry in different stages of pregnancy. The study population comprised 2,478 fetuses from a Spanish birth cohort study that was established between 2003 and 2008. Biparietal diameter, femur length, abdominal circumference, and estimated fetal weight were evaluated at 12, 20, and 34 weeks of gestation. Fetal size and growth were assessed by standard deviation scores adjusted by maternal and fetal characteristics. Maternal smoking was assessed using questionnaire and a sample of urinary cotinine at week 32 of gestation. Associations were estimated using multiple regression analysis. Smokers at week 12 of gestation showed decreased fetal growth as reflected by all growth parameters at 20-34 weeks, leading to a reduced fetal size at week 34. The reduction was greatest in femur length, at -9.4% (95% confidence interval -13.4, -5.4) and least in abdominal circumference, at -4.4% (95% CI: -8.7, -0.1). Fetuses of smokers who quit smoking before week 12 showed reduced growth only in femur length (-5.5; 95% CI: -10.1, -0.9). Dose-response curves for smoking versus fetal growth parameters (abscissa: log2 cotinine) were linear for biparietal diameter and femur length.

Prenatal Exposure to Maternal Cigarette Smoke and Offspring Risk of Excess Weight Is Independent of Both Birth Weight and Catch-Up Growth

Prenatal exposure to maternal cigarette smoke (PEMCS) is one of the most common insults to the developing fetus and has consistently emerged as an important risk factor for excess weight in the offspring. However, no consensus exists on the mechanism of action or duration of impact. This study seeks to further examine the role of PEMCS on overweight status of children up to age 10. Mother and child pairs (n=1183) were analysed from the Québec Longitudinal Study of Child Development (QLSCD) (1998–2010). Multivariable logistic regression models were used to control for confounders and assess mediation. PEMCS was associated with overweight status at age 10 (OR: 1.70; 95% CI: 1.20–2.43) after adjustment for early life exposures and childhood behaviours. This relationship remained robust after adjustment for birth weight and catch-up growth. Other significant predictors included APGAR score, mother’s immigrant and weight status, family type and child energy intake. The elevated risk of excess weight among the offspring of smoking mothers was not accounted for by other known determinants, and PEMCS appears to play a role independent of birth weight and catch-up growth. Our research suggests that young mothers may be an important audience for targeting preventive strategies.

Tobacco or healthy children: the two cannot co-exist

Tobacco exposure increases mortality and morbidity of the fetus, the child, the adolescent, and their children in turn. Nearly half the children in the world are exposed. Smoking is not merely personal choice or personal responsibility; those subtle phrases undermine those who have no choice in the matter. Tobacco control must take a multi-pronged attack. Smoking cessation by adults in childbearing years must take center stage of these efforts, because it is the only way to ensure a smoke-free environment for children. Smoke-free parents provide a role model for smoke-free young people, and erode the image of smoking as a desirable adult behavior to emulate. Pediatricians and pediatric pulmonologists have a key role to play here. This goal will reduce morbidity and mortality among adults and children. Legislation regarding taxation, environments, tobacco constituents, product placement and display, packaging, and media education are all key to this core goal. Smoke-free policy must be protected from attack based on trade agreements. Research is needed into more effective ways to attract and help people give up smoking, and into educating and re-deploying tobacco industry workers in emerging and developed countries.

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.

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

AIMS/HYPOTHESIS

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

METHODS

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

RESULTS

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

CONCLUSIONS/INTERPRETATION

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

Reducing racial/ethnic disparities in childhood obesity: the role of early life risk factors

IMPORTANCE Many early life risk factors for childhood obesity are more prevalent among blacks and Hispanics than among whites and may explain the higher prevalence of obesity among racial/ethnic minority children. OBJECTIVE To examine the extent to which racial/ethnic disparities in adiposity and overweight are explained by differences in risk factors during pregnancy (gestational diabetes and depression), infancy (rapid infant weight gain, feeding other than exclusive breastfeeding, and early introduction of solid foods), and early childhood (sleeping <12 h/d, presence of a television set in the room where the child sleeps, and any intake of sugar-sweetened beverages or fast food). DESIGN Prospective prebirth cohort study. SETTING Multisite group practice in Massachusetts. PARTICIPANTS Participants included 1116 mother-child pairs (63% white, 17% black, and 4% Hispanic) EXPOSURE Mother's report of child's race/ethnicity. MAIN OUTCOMES AND MEASURES Age- and sex-specific body mass index (BMI) z score, total fat mass index from dual-energy x-ray absorptiometry, and overweight or obesity, defined as a BMI in the 85th percentile or higher at age 7 years. RESULTS Black (0.48 U [95% CI, 0.31 to 0.64]) and Hispanic (0.43 [0.12 to 0.74]) children had higher BMI z scores, as well as higher total fat mass index and overweight/obesity prevalence, than white children. After adjustment for socioeconomic confounders and parental BMI, differences in BMI z score were attenuated for black and Hispanic children (0.22 U [0.05 to 0.40] and 0.22 U [-0.08 to 0.52], respectively). Adjustment for pregnancy risk factors did not substantially change these estimates. However, after further adjustment for infancy and childhood risk factors, we observed only minimal differences in BMI z scores between whites, blacks (0.07 U [-0.11 to 0.26]), and Hispanics (0.04 U [-0.27 to 0.35]). We observed similar attenuation of racial/ethnic differences in adiposity and prevalence of overweight or obesity. CONCLUSIONS AND RELEVANCE Racial/ethnic disparities in childhood adiposity and obesity are determined by factors operating in infancy and early childhood. Efforts to reduce obesity disparities should focus on preventing early life risk factors.

The role of dietary fatty acids for early human adipose tissue growth

Childhood obesity is increasing worldwide, and all previous attempts to stop this epidemic have shown little success. There is now growing evidence that the risk of childhood obesity is strongly influenced by perinatal determinants, including prepregnancy body mass index (BMI), gestational weight gain, and—at least in animal studies—dietary factors during pregnancy and lactation. This review addresses the issue of whether modulation of fat intake and its composition in this early-life period has a potential for primary prevention of childhood obesity. Of particular interest is the question of whether supplementation with n–3 long-chain PUFAs (LC-PUFAs) may exert an antiobesity effect. Retrospective analysis of human randomized controlled trials with fish-oil intervention during pregnancy and lactation gave inconsistent results concerning BMI and obesity development in offspring. A recent prospective human intervention study aimed at reducing the n–6:n–3 LC-PUFA ratio did not show an effect on adipose tissue growth in offspring up to the age of 1 y. Therefore, there is currently little evidence to support the hypothesis that dietary intervention to modify fat composition during pregnancy and lactation would be a promising strategy to prevent childhood obesity in humans, but more research is clearly needed to address the question if and how the risk of developing obesity can be modified by dietary intervention early in life.

Estimating overweight risk in childhood from predictors during infancy

OBJECTIVE

The aim of this study was to develop and validate a risk score algorithm for childhood overweight based on a prediction model in infants.

METHODS

Analysis was conducted by using the UK Millennium Cohort Study. The cohort was divided randomly by using 80% of the sample for derivation of the risk algorithm and 20% of the sample for validation. Stepwise logistic regression determined a prediction model for childhood overweight at 3 years defined by the International Obesity Task Force criteria. Predictive metrics R(2), area under the receiver operating curve (AUROC), sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated.

RESULTS

Seven predictors were found to be significantly associated with overweight at 3 years in a mutually adjusted predictor model: gender, birth weight, weight gain, maternal prepregnancy BMI, paternal BMI, maternal smoking in pregnancy, and breastfeeding status. Risk scores ranged from 0 to 59 corresponding to a predicted risk from 4.1% to 73.8%. The model revealed moderately good predictive ability in both the derivation cohort (R(2) = 0.92, AUROC = 0.721, sensitivity = 0.699, specificity = 0.679, PPV = 38%, NPV = 87%) and validation cohort (R(2) = 0.84, AUROC = 0.755, sensitivity = 0.769, specificity = 0.665, PPV = 37%, NPV = 89%).

CONCLUSIONS

Using a prediction algorithm to identify at-risk infants could reduce levels of child overweight and obesity by enabling health professionals to target prevention more effectively. Further research needs to evaluate the clinical validity, feasibility, and acceptability of communicating this risk.

Exposure to parental smoking and child growth and development: a cohort study

Background

Studies on adverse childhood health and development outcomes associated with parental smoking have shown inconsistent results. Using a cohort of Belarusian children, we examined differences in cognition, behaviors, growth, adiposity, and blood pressure at 6.5 years according to prenatal and postnatal exposure to parental smoking.

Methods

Using cluster-adjusted multivariable regression, effects of exposure to prenatal smoking were examined by comparing (1) children whose mothers smoked during pregnancy with those of mothers who smoked neither during nor after pregnancy and (2) children whose mothers smoked during and after pregnancy with those whose mothers smoked after pregnancy only; effects of postnatal smoking were examined by comparing (1) children whose mothers smoked after pregnancy only with those of mothers who smoked neither during nor after pregnancy and (2) children whose fathers smoked with those whose fathers did not smoke among children of non-smoking mothers after adjusting for a wide range of socioeconomic and family characteristics.

Results

After adjusting for confounders, children exposed vs unexposed to prenatal maternal smoking had no differences in mean IQ, teacher-rated behavioral problems, adiposity, or blood pressure. Children exposed to maternal postnatal smoking had slightly increased behavioral problems [0.9, 95% CI: 0.6, 1.2 for total difficulties], higher body mass index [0.2, 95% CI: 0.1, 0.3], greater total skinfold thickness [0.4, 95% CI: 0.04, 0.71], and higher odds of overweight or obesity [1.4, 95% CI; 1.1, 1.7]. Similar magnitudes of association were observed with postnatal paternal smoking.

Conclusions

No adverse cognitive, behavioral and developmental outcomes were associated with exposure to maternal prenatal smoking. Observed associations with postnatal smoking of both parents may reflect residual confounding by genetic and family environmental factors.

Gestational weight gain in accordance to the IOM/NRC criteria and the risk for childhood overweight: a meta-analysis

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

Gestational weight gain is a modifiable risk factor for childhood overweight.

WHAT THIS STUDY ADDS

Exceeding the recommended gestational weight gain increases the risk for childhood overweight by about 30%. Interventions to avoid excessive weight gain are needed.

BACKGROUND

Overweight and obesity in children are thought to be related to prenatal priming. Gestational weight gain (GWG) might be a potential modifiable risk factor for childhood overweight.

OBJECTIVE

To quantify the associations of inadequate and excessive GWG with childhood overweight.

METHODS

The electronic literature search in six databases was complemented by a hand search for relevant articles. Papers were selected and quality was assessed. The effect estimates of the individual studies were pooled using a random-effects model.

RESULTS

The literature search yielded 1492 results in total, of which seven observational studies met the inclusion criteria. The studies had medium to good quality. The pooled estimate for the association between excessive GWG and childhood overweight yielded an odds ratio (OR) of 1.38 (95% confidence interval [CI]: 1.21-1.57). The association between inadequate GWG and childhood overweight yielded an OR of 0.91 (95% CI: 0.85-0.98).

CONCLUSION

These data provide evidence for at least a 21% risk for childhood overweight related to excessive GWG. Therefore, further efforts to design appropriate interventions against excessive GWG may appear warranted.

The impact of maternal prenatal smoking on the development of childhood overweight in school-aged children

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

Maternal smoking during pregnancy likely increase the risk of childhood overweight. Childhood overweight is influenced by socioeconomic characteristics of mothers. Characteristics of child at birth determine the likelihood of overweight.

WHAT THIS STUDY ADDS

Children of mothers who smoked 1 year before birth (including pregnancy) were likely to be overweight during school ages than those of mothers who never smoked. Confirmation that socioeconomic characteristics of mothers influence the likelihood of childhood overweight during school age. Smoking cessation should be targeted at mothers 1 year before birth to improve their health status and that of offspring.

OBJECTIVES

To examine associations between maternal smoking and overweight among school-aged children and also identify mothers and offspring characteristics that affect children's weight.

METHODS

We used data from the National Institute of Child Health and Human Development (NICHD) Study of Early Child Care and Youth Development (SECCY). Childhood overweight was defined as having Body Mass Index (BMI) of 85th percentile or above. Smoking patterns among mothers were assessed by questioning smoking behaviour 1 year before birth of the target child: never or ever smoking. Standardized procedures were used to measure height and weight. Descriptive statistics and generalized estimating equations (GEE) were used for the analysis.

RESULTS

Descriptive results showed that children of mothers who smoked anytime within 1 year before birth were more likely to be overweight and have higher BMI percentile averages. GEE results showed that children of mothers who were ever smokers 1 year before birth were more likely to be overweight (OR = 1.39, 95% CI: 1.01, 1.94) and have higher BMI percentile averages (β = 4.46, P = 0.036) from grades 1 through 6 than those of mothers who were never smokers. Additionally, the level of mother's education and birth weight were significantly associated with childhood overweight.

CONCLUSIONS

Confirmed relationships between maternal smoking and overweight among school-aged children have important implications for public health policy because this evidence can be used to enhance smoking cessation 1 year before birth to improve the health status of mothers and offspring.

Identification of distinct body mass index trajectories in Australian children

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

Recent studies have identified distinct trajectories of obesity development in children, but more research is required to further explore these trajectories. Several socio-demographic variables such as parental education and obesity are associated with these trajectories.

WHAT THIS STUDY ADDS

This study further demonstrates that there are distinct trajectories of body mass index in children. The use of raw body mass index values is more sensitive to changes in body composition compared with body mass index categories (e.g. lean vs. overweight). Hence the present results provide a more detailed insight into development patterns of obesity. The socio-demographic predictors of the trajectories offer potential avenues for future obesity interventions.

BACKGROUND

A limited number of studies have demonstrated that there may be distinct developmental trajectories of obesity during childhood.

OBJECTIVE

To identify distinct trajectories of body mass index (BMI) in a large sample of Australian children.

METHODS

Participants included 4601 children aged 4-5 years at baseline, who were followed up at ages 6-7 years, 8-9 years and 10-11 years. Height and weight were measured at each of these time points, and used to calculate BMI. Growth Mixture Modelling was used to identify the presence of distinct BMI trajectories.

RESULTS

Four distinct trajectories were identified (i) High Risk Overweight; (ii) Early Onset Overweight; (iii) Later Onset Overweight and (iv) Healthy Weight. Further analyses indicated that factors such as parental overweight, parent education, parent smoking and child birth weight were significant predictors of these trajectories.

CONCLUSION

These findings indicate that different patterns of BMI development exist in children, which may require tailored interventions.

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.

Timing of solid food introduction and obesity: Hong Kong's "children of 1997" birth cohort

BACKGROUND

Some observational studies in Western settings show that early introduction of solid food is associated with subsequent obesity. However, introduction of solid food and obesity share social patterning. We examined the association of the timing of the introduction of solid food with BMI and overweight (including obesity) into adolescence in a developed non-Western setting, in which childhood obesity is less clearly socially patterned.

METHODS

We used generalized estimating equation models to estimate the adjusted associations of the timing of the introduction of solid food (<3, 3-4, 5-6, 7-8, and >8 months) with BMI z score and overweight (including obesity) at different growth phases (infancy, childhood, and puberty) in 7809 children (88% follow-up) from a Chinese birth cohort, "Children of 1997." We assessed if the associations varied with gender or breastfeeding. We used multiple imputation for missing exposure and confounders.

RESULTS

The introduction of solid food at <3 months of age was associated with lower family socioeconomic position (SEP) but was not clearly associated with BMI or overweight (including obesity) in infancy [mean difference in BMI z score: 0.01; 95% confidence interval (CI): -0.14 to 0.17], childhood (0.14; 95% CI: -0.11 to 0.40), or at puberty (0.22; 95% CI: -0.07 to 0.52), adjusted for SEP and infant and maternal characteristics.

CONCLUSIONS

In a non-Western developed setting, there was no clear association of the early introduction of solid food with childhood obesity. Together with the inconsistent evidence from studies in Western settings, this finding suggests that any observed associations might simply be residual confounding by SEP.

Maternal nicotine exposure during lactation alters hypothalamic neuropeptides expression in the adult rat progeny

Maternal exposure to nicotine during lactation causes hyperleptinemia in the pups and, at adulthood, these animals are overweight and hyperleptinemic, while, in their hypothalamus, the leptin signaling pathway is reduced, evidencing a central leptin resistance. Then, we evaluated the expression of pro-opiomelanocortin (POMC), alpha-melanocyte stimulating hormone (α-MSH), cocaine and amphetamine-regulated transcript (CART), neuropeptide Y (NPY), agouti-related peptide (AgRP) and others in different hypothalamic nuclei in order to better understand the mechanisms underlying the obese phenotype observed in these animals at adulthood. On the 2nd postnatal day (P2), dams were subcutaneously implanted with osmotic minipumps releasing nicotine (NIC-6 mg/kg/day) or saline for 14 days. Offspring were killed in P180 and immunohistochemistry and Western blot analysis were carried out. Significance data had p<0.05. Adult NIC offspring showed more intense NPY staining in the paraventricular nucleus (PVN) (+21%) and increased number of POMC-positive cells in the: arcuate nucleus (+33%), as an increase in fiber density of α-MSH in PVN (+85%). However, the number of CART-positive cells was reduced in the PVN (-25%). CRH staining was more intense in NIC offspring (+136%). Orexins and AgRP were not altered. Thus, maternal nicotine exposure changes hypothalamic neuropeptides in the adult progeny that is partially compatible with leptin resistance.

The effect of the season of birth and of selected maternal factors on linear enamel thickness in modern human deciduous incisors

OBJECTIVE

Development of human tooth enamel is a part of a foetus's development; its correctness is the outcome of genetic and maternal factors shaping its prenatal environment. Many authors reported that individuals born in different seasons experience different early developmental conditions during pregnancy. In this study, we investigated the effects of season of birth and selected maternal factors on enamel thickness of deciduous incisors.

DESIGN

Dental sample comprises 60 deciduous incisors. The parents who handed over their children's teeth for research fill in questionnaires containing questions about the course of pregnancy. All teeth were sectioned in the labio-linqual plane using diamond blade (Buechler IsoMet 1000). The final specimens were observed by way of scanning electron microscopy at magnifications 80× and 320×. The thickness of total enamel (TE), prenatally (PE) and postnatally (PSE) formed enamel was measured.

RESULTS

Children born in summer and in spring (whose first and second foetal life fall on autumn and winter) have the thinnest enamel. Season of birth, number of children in family, diseases and spasmolytic medicines using by mother during pregnancy explained almost 13% of the variability of TE. Regression analysis proved a significant influence of the season of birth and selected maternal factors on the PE thickness - these factors explained over 17% of its variability. Neither of analysed variables had influenced PSE.

CONCLUSIONS

Our findings suggests that the thickness of enamel of deciduous incisors depends on the season of birth and some maternal factors. The differences were observed only in the prenatally formed enamel.

Fetal programming and the risk of noncommunicable disease

The "developmental origins of health and disease" (DOHaD) hypothesis proposes that environmental conditions during fetal and early post-natal development influence lifelong health and capacity through permanent effects on growth, structure and metabolism. This has been called 'programming'. The hypothesis is supported by epidemiological evidence in humans linking newborn size, and infant growth and nutrition, to adult health outcomes, and by experiments in animals showing that maternal under- and over-nutrition and other interventions (e.g., glucocorticoid exposure) during pregnancy lead to abnormal metabolism and body composition in the adult offspring. Early life programming is now thought to be important in the etiology of obesity, type 2 diabetes, and cardiovascular disease, opening up the possibility that these common diseases could be prevented by achieving optimal fetal and infant development. This is likely to have additional benefits for infant survival and human capital (e.g., improved cognitive performance and physical work capacity). Fetal nutrition is influenced by the mother's diet and body size and composition, but hard evidence that the nutrition of the human mother programmes chronic disease risk in her offspring is currently limited. Recent findings from follow-up of children born after randomised nutritional interventions in pregnancy are mixed, but show some evidence of beneficial effects on vascular function, lipid concentrations, glucose tolerance and insulin resistance. Work in experimental animals suggests that epigenetic phenomena, whereby gene expression is modified by DNA methylation, and which are sensitive to the nutritional environment in early life, may be one mechanism underlying programming.

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.

The origins of health and disease: the influence of maternal diseases and lifestyle during gestation

According to the Barker hypothesis, the period of pregnancy and the intrauterine environment are crucial to the tendency to develop diseases like hypertension, diabetes, coronary heart disease, metabolic disorders, pulmonary, renal and mental illnesses. The external environment affects the development of a particular phenotype suitable for an environment with characteristics that closely resemble intrauterine conditions. If the extra-uterine environment differs greatly from the intra-uterine one, the fetus is more prone to develop disease. Subsequent studies have shown that maternal diseases like depression and anxiety, epilepsy, asthma, anemia and metabolic disorders, like diabetes, are able to determine alterations in growth and fetal development. Similarly, the maternal lifestyle, particularly diet, exercise and smoking during pregnancy, have an important role in determining the risk to develop diseases that manifest themselves both during childhood and particularly in adulthood. Finally, there are abundant potential sources of pollutants, both indoor and outdoor, in the environment in which the child lives, which can contribute to an increased probability to the development of several diseases and that in some cases could be easily avoided.

Perinatal and early childhood factors for overweight and obesity in young Canadian children

BACKGROUND

This study assessed potential early-life factors and their interrelationships with obesity among young Canadian children.

METHODS

Data from a nationally representative sample of children aged 6 to 11 years in the Canadian Health Measures Survey were analyzed. The associations of perinatal and early childhood behaviours and socio-economic factors with overweight or obesity were evaluated using multivariate logistic regression models. Adjusted population attributable risk fractions (PARFs) were calculated using multivariate logistic regression models.

RESULTS

Of 968 term-born children, 21% were overweight and another 13% were obese. Maternal smoking during pregnancy (adjusted odds ratio, 2.26; 95% confidence interval, 1.23-4.15) was positively associated with obesity. This association was mediated by birth weight (suppression effect); once controlled, the strength of the association between smoking and child obesity increased by 12%. Birth weight per 100 g (1.05; 1.005-1.09) was significantly associated with obesity. Exclusive breastfeeding for 6 months (0.44; 0.31-0.61), adequate sleep hours (0.39; 0.16-0.94) and being physically active (0.50; 0.26-0.93) were found to be protective. Breastfeeding, whether exclusive or not, significantly reduced obesity risk among children whose mothers never smoked in pregnancy. PARFs indicated that 24.4%, 11.5%, 11.3% and 6.0% prevalent cases of child obesity might be prevented by exclusive breastfeeding, smoking cessation during pregnancy, adequate sleep during childhood, and avoiding high birth weight, respectively.

CONCLUSIONS

This study identified multiple perinatal and childhood factors associated with obesity in young Canadian children. Effective prevention strategies targeting four modifiable maternal and child risk factors may reduce childhood obesity by up to 54% in Canada.

Trends in blood pressure in 9 to 11-year-old children in the United Kingdom 1980-2008: the impact of obesity

OBJECTIVES

High blood pressure (BP) is a major public health issue, both in the United Kingdom and worldwide. Although BP levels in UK adults are declining, there is little published information on BP trends in children, a particular concern in the context of the rising levels of childhood adiposity. Our aims are to determine whether BP in children has changed over time and whether the change reflected trends in adiposity.

METHODS

We collated data from seven population-based BP studies conducted in the United Kingdom between 1980 and 2008. Children of white European origin were included (9-11 years, mean 10.3 years). Adjustments were made to account for differences in mean ages, BP devices and cuff sizes used in different studies.

RESULTS

Mean SBP increased over time both in boys and girls: annual increases were 0.45 mmHg (95% CI: 0.43, 0.48) for boys; 0.51 mmHg (0.49, 0.53) for girls. Mean BMI increased by 0.064 kg/m(2) (0.060, 0.068) per year for boys; 0.070 kg/m(2) (0.065, 0.074) for girls; the prevalence of overweight/obesity increased from 5.7 to 21.1% and from 9.7 to 24.1%, respectively. The SBP trends occurred both in children with low and high BMI, but were more marked in low BMI group; BMI explained only 15.3% (15.1%, 15.6%) of increases in SBP for boys and 14.9% (14.6%, 15.1%) for girls. The BMI/SBP association appeared to become weaker over time (P < 0.001 for negative interaction from 1984). There was only a modest annual increase in DBP (<0.1 mmHg).

CONCLUSIONS

SBP levels have increased with time, but the increase is not explained by increased BMI. Further research is needed to identify the factors responsible.

Parental smoking in pregnancy and the risks of adult-onset hypertension

Fetal exposure to parental smoking may lead to developmental adaptations and promote various diseases in later life. This study evaluated the associations of parental smoking during pregnancy with the risk of hypertension in the daughter in adulthood, and assessed whether these associations are explained by birth weight or body weight throughout life. We used data on 33086 participants of the Nurses' Health Study II and the Nurses' Mothers' Cohort. Cox proportional hazards models were used to examine the associations of maternal and paternal smoking during pregnancy with the nurse daughter, with self-reported physician-diagnosed hypertension from 1989 until 2007. Overall, 8575 (25.9%) mothers and 18874 (57.0%) fathers smoked during pregnancy. During follow-up, 7825 incident cases of adult-onset hypertension were reported. Both maternal and paternal smoking of ≥ 15 cigarettes/d during pregnancy were associated with increased risks of hypertension (rate ratio, 1.19; 95% CI, 1.09-1.29; and rate ratio, 1.18; 95% CI, 1.12-1.25, respectively) in the age-adjusted models. Further adjustment for birth weight did not affect the effect estimates appreciably, whereas additional adjustment for body shape and weight until age 18, or current body mass index, attenuated the associations with both maternal and paternal smoking (rate ratio, 1.07; 95% CI, 0.98-1.16; and rate ratio, 1.06; 95% CI, 1.01-1.12, respectively). The associations of parental smoking during pregnancy with the risk of hypertension in the offspring were largely explained by body weight throughout life, suggesting that these associations may not reflect direct intrauterine mechanisms.

Association of breastfeeding and exposure to maternal smoking during pregnancy with children's general health status later in childhood

BACKGROUND

Maternal smoking during pregnancy is associated with a variety of risks on fetal health, whereas breastfeeding may protect infants from infections in the early postpartum period. Little has been reported regarding their associations with children's general health later in childhood.

SUBJECTS AND METHODS

Parent-rated children's general health status was investigated among 14,836 children and adolescents 3-17 years old who participated in the German Health Interview and Examination Survey for Children and Adolescents (KiGGS) in 2003-2006. Data on breastfeeding and maternal smoking during pregnancy were collected by parent-administered questionnaires. SPSS complex samples logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (95% CIs).

RESULTS

Exclusive breastfeeding and non-exposure to maternal smoking during pregnancy were associated with better health status overall among all children in the KiGGS (both p<0.001). After adjusting for potential confounding factors including other prior and current exposures, exclusive breastfeeding over 6 months remained significant overall among all children (OR 1.21, 95% CI 1.05-1.38) and in the age groups 7-10 years (OR 1.27, 95% CI 1.01-1.60) and 11-17 years (OR 1.23, 95% CI 1.01-1.50), while non-exposure to maternal smoking during pregnancy remained significant in the age group 11-17 years only (OR 1.49, 95% CI 1.06-2.10).

CONCLUSIONS

Exclusive breastfeeding and non-exposure to maternal smoking during pregnancy may be associated with better children's general health status later in childhood, particularly when children reach adolescence. Further studies are required to elucidate these possible and biologically plausible associations. Health professionals should take opportunities to promote breastfeeding and cessation of smoking among (expectant) mothers for a healthy future of their children.

Systematic review and meta-analyses of risk factors for childhood overweight identifiable during infancy

OBJECTIVE

To determine risk factors for childhood overweight that can be identified during the first year of life to facilitate early identification and targeted intervention.

DESIGN

Systematic review and meta-analysis.

SEARCH STRATEGY

Electronic database search of MEDLINE, EMBASE, PubMed and CAB Abstracts.

ELIGIBILITY CRITERIA

Prospective observational studies following up children from birth for at least 2 years.

RESULTS

Thirty prospective studies were identified. Significant and strong independent associations with childhood overweight were identified for maternal pre-pregnancy overweight, high infant birth weight and rapid weight gain during the first year of life. Meta-analysis comparing breastfed with non-breastfed infants found a 15% decrease (95% CI 0.74 to 0.99; I(2)=73.3%; n=10) in the odds of childhood overweight. For children of mothers smoking during pregnancy there was a 47% increase (95% CI 1.26 to 1.73; I(2)=47.5%; n=7) in the odds of childhood overweight. There was some evidence associating early introduction of solid foods and childhood overweight. There was conflicting evidence for duration of breastfeeding, socioeconomic status at birth, parity and maternal marital status at birth. No association with childhood overweight was found for maternal age or education at birth, maternal depression or infant ethnicity. There was inconclusive evidence for delivery type, gestational weight gain, maternal postpartum weight loss and 'fussy' infant temperament due to the limited number of studies.

CONCLUSIONS

Several risk factors for both overweight and obesity in childhood are identifiable during infancy. Future research needs to focus on whether it is clinically feasible for healthcare professionals to identify infants at greatest risk.

Environmental factors associated with overweight and obesity in taiwanese children

BACKGROUND

We explored the relationship among sociodemographic, behavioural, household environmental and perinatal factors, and risks of childhood overweight and obesity in Taiwan.

METHODS

A total of 7930 children aged 9 to 14 years were recruited from 14 randomly selected Taiwanese communities in 2007 and 2010. Height and weight were measured using standard protocols during school visits. Questionnaires that contained children's family information, birth conditions, exercise habits and household environmental factors were answered by the parents. Associations between risk factors and childhood overweight and obesity were estimated through odds ratio and 95% confidence interval from mixed models.

RESULTS

In this cohort, 32.3% of the children were overweight and 17.5% were obese. Male gender, high birthweight, exposure to in utero maternal smoking and current exposure to household environmental tobacco smoke (stronger effect of maternal than paternal smoking) were positively associated with childhood overweight/obesity. In contrast, higher parental education level, number of siblings, active exercise habits and taking vitamins were associated with reduced risks of childhood obesity. Birthweight revealed a J-shaped relationship with the probability of childhood overweight/obesity.

CONCLUSIONS

This study uncovers several modifiable risk factors for childhood overweight and obesity, and parents are encouraged to provide an anti-obesity environment such as quitting smoking, controlling birthweight of child during pregnancy and building up exercise habits.

Maternal and Early Childhood Risk Factors for Overweight and Obesity among Low-Income Predominantly Black Children at Age Five Years: A Prospective Cohort Study

Objective. To identify maternal and early childhood risk factors for obesity and overweight among children at age 5 in the state of Alabama. Methods. We recruited 740 mothers during early pregnancy from University of Alabama Prenatal Clinics in a prospective cohort study and followed them throughout pregnancy. We followed their children from birth until 5 years of age. The main outcome measure was obesity (BMI for age and sex ≥ 95th percentile) at 5 years of age. We used poisson regression with robust variance estimation to compute risk ratio (RR). Results. At the 5th year of followup, 71 (9.6%) of the children were obese and 85 (11.5%) were overweight (BMI ≥ 85th-<95th percentile). In multivariable analysis, maternal prepregnancy overweight (RR: 2.30, 95% CI: 1.29-4.11) and obesity (RR: 2.53, 95% CI: 1.49-4.31), and child's birth weight >85th percentile (RR: 2.04, 95% CI: 1.13-3.68) were associated with childhood obesity. Maternal prepregnancy BMI, birth weight, and maternal smoking were associated with the child being overweight 1-12 cigarettes/day versus 0 cigarettes/day (RR: 1.40, 95% CI: 1.02-1.91). Conclusion. Children of overweight and obese mothers, and children with higher birth weight, are more likely to be obese and overweight at age 5. Maternal smoking 1-12 cigarettes per day is associated with the child being overweight.

Exploring the reach and program use of Hello World, an email-based health promotion program for pregnant women in the Netherlands

Background

In 2006, the Dutch government initiated Hello World, an email-based program promoting healthy lifestyles among pregnant women through quizzes with pregnancy-related questions. In 2008, an updated version was released.

The present study aimed to (1) examine the reach of Hello World and the representativeness of its users for all pregnant women in the Netherlands, (2) explore the relationship between program engagement and lifestyle characteristics, and (3) explore the relationship between the program content participants accessed (content on smoking, physical activity, and nutrition) and their lifestyle characteristics.

Methods

Data from 4,363 pregnant women were included. After registration, women received an online questionnaire with demographic and lifestyle questions. To evaluate their representativeness, their demographic characteristics were compared with existing data for Dutch (pregnant) women. Women were classified on the following lifestyle characteristics: smoking, nutrition, physical activity, and pre-pregnancy weight status. Program use was tracked and the relationships between lifestyle characteristics, program engagement, and the percentage of smoking, physical activity, and nutrition questions accessed after opening a quiz were explored using Mann–Whitney U tests and Kruskal-Wallis tests.

Results

Hello World reached ±4% of its target population. Ten percent of participants were low educated and 22% immigrants. On average, women received 6.1 (SD:2.8) quiz emails and opened 32% of the associated quizzes (2.0, SD:2.1). A significant positive association was found between the number of quizzes opened and the number of healthy lifestyle characteristics. After opening a quiz, women accessed most smoking, nutrition, and physical activity questions. Significant relationships were found between several lifestyle characteristics and the percentage of smoking, physical activity, and nutrition questions accessed. However, between-group differences were small, quiz topics were largely unrelated to their lifestyle characteristics, and inconsistencies were found regarding the directions of these associations.

Conclusions

Hello World reached ±4% of its target population, which is lower than the reach of its previous version (±8%). Relatively few low educated and immigrant women registered for the program. Active participation in the program was positively associated with the number of healthy behaviours participants engaged in. The program content participants chose to access was largely unrelated to their lifestyle characteristics.

Perinatal and family factors associated with preadolescence overweight/obesity in Greece: the GRECO study

OBJECTIVE

To explore associations of perinatal and family factors with preadolescence overweight and obesity in a sample of Greek schoolchildren.

METHODS

A nationwide cross-sectional study among 2093 students (10.9 ± 0.72 years, 44.9% boys) and their parents were conducted. Anthropometric (e.g., height, weight, mother's body mass index (BMI) at the time of the study and at conception), socio-demographic (e.g., age, education, socio-economic status), diet and other major lifestyle characteristics (e.g., smoking, alcohol intake, physical activity and inactivity) and perinatal factors (e.g., breast- and formula-feeding) were collected with validated questionnaires. Height and weight of students were measured. Overweight/obesity was classified using IOTF cut-offs. Multivariable logistic and linear regression analyses were used to identify major independent factors of overweight/obesity among preadolescents and factors related with the percentage change of mother's BMI, respectively.

RESULTS

Increased age at pregnancy [odds ratios (OR)=0.95, 95% Confidence Interval (CI): 0.93-0.97], higher BMI at conception (OR=1.17, 95% CI: 1.12-1.22) and heavy smoking (OR = 2.02, 95% CI: 1.23-3.33) were positively associated with child's overweight/obesity status. Moreover, mother's age and TV viewing, indicating inactivity, were the strongest factors of the percentage increase in mother's BMI (b ± se = 0.23 ± 0.07, p = 0.002; b ± se=0.32 ± 0.10, p = 0.002, respectively).

CONCLUSIONS

Preadolescent obesity is associated with mother's pre-pregnancy weight, age and heavy smoking at conception and mother's BMI change after gestation.

Maternal smoking during pregnancy predicts adult offspring cardiovascular risk factors - evidence from a community-based large birth cohort study

Background

Maternal smoking during pregnancy is associated with offspring obesity. However, little is known about whether maternal smoking in pregnancy predicts other offspring cardiovascular risk factors including waist circumference (WC), waist-hip-ratio (WHR), pulse rate (PR), systolic (SBP), and diastolic blood pressure (DBP).

Methods

We studied a sub-sample of 2038 (50% males) young adults who were born in Brisbane, Australia to investigate the prospective association of maternal smoking during pregnancy with young adult cardiovascular risk factors. We compared offspring mean BMI, WC, WHR, SBP, DBP and PR and the risk of being overweight and obese at 21 years by three mutually exclusive categories of maternal smoking status defined as never smoked, smoked before and/or after pregnancy but not in pregnancy or smoked during pregnancy and other times.

Results

Offspring of mothers who smoked during pregnancy had greater mean BMI, WC, WHR and PR and they were at greater risk of being obese at 21 years compared to offspring of those mothers who never smoked. The mean of these risk factors among those adult offspring whose mothers stopped smoking during pregnancy, but who then smoked at other times in the child's life, were similar to those mothers who never smoked. These results were independent of a range of potential confounding factors.

Conclusion

The findings of this study suggest a prospective association of maternal smoking during pregnancy and offspring obesity as well as PR in adulthood, and reinforce the need to persuade pregnant women not to smoke.

The endocrine effects of nicotine and cigarette smoke

With a current prevalence of approximately 20%, smoking continues to impact negatively upon health. Tobacco or nicotine use influences the endocrine system, with important clinical implications. In this review we critically evaluate the literature concerning the impact of nicotine as well as tobacco use on several parameters of the endocrine system and on glucose and lipid homeostasis. Emphasis is on the effect of smoking on diabetes mellitus and obesity and the consequences of smoking cessation on these disorders. Understanding the effects of nicotine and cigarettes on the endocrine system and how these changes contribute to the pathogenesis of various endocrine diseases will allow for targeted therapies and more effective approaches for smoking cessation.