Does maternal smoking during pregnancy have a direct effect on future offspring obesity? Evidence from a prospective birth cohort study

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.

Faster growth rate in ad libitum-fed cats: a risk factor predicting the likelihood of becoming overweight during adulthood

In human subjects, the risk of becoming overweight (OW) in adulthood is largely determined early in childhood. However, early-life factors have not been considered for feline obesity. A total of eighty colony cats, fed ad libitum, were studied; various breeds, ages and sex were included, with thirty-six (45 %) being OW and forty-four (55 %) being of ideal weight (IW). The effects of various factors (including age, sex, neuter status, breed (pure v. mixed), mean daily food intake (FI), housing status (indoor with outdoor access v. exclusively indoor) and body weight at 1 year of age (BW1y)) on weight status were assessed. Initial statistical analyses identified BW1y as the main significant variable. Body weight (BW) and FI were then assessed between 1 and 8·5 years of age, with group differences (OW v. IW) noted for BW, which increased significantly with age only in the OW group (P < 0·001). However, no difference in BW (P = 0·17) was noted when BW1y was included as a covariate in the model. FI did not change with age in either group. Finally, given the importance of BW1y, changes in BW from 3 to 12 months were then assessed with BW at 3 months of age included as a covariate. Whereas at 3 months of age, no group difference in BW was observed, a faster rate of weight gain was seen in OW cats. In conclusion, as in human subjects, the rate of growth is a key risk factor for cats becoming OW, although the factors responsible are currently not known.

The Maternal Obesity Management (MOM) Trial Protocol: a lifestyle intervention during pregnancy to minimize downstream obesity

BACKGROUND

Maternal obesity and/or high gestational weight gain (GWG) are associated with downstream child obesity. Pregnancy represents a critical period for prevention as women are highly motivated and more receptive to behavior change.

OBJECTIVE

This pilot study was developed to test the feasibility of intervening with the mother, specifically keeping her GWG within the Institute of Medicine (IOM) limits, with the intended target of preventing obesity in her child downstream. We are testing the practicality of delivering a structured physical activity and nutrition intervention to pregnant women during gestation and then following mom and baby to 24 months of age.

STUDY DESIGN

This study is a two-arm, parallel group, randomized controlled trial being conducted in Ottawa. Pregnant women, with pregravid BMI >18.5, between 12 and 20 weeks gestation are randomized to one of two groups: intervention (n=30) who receive the MOM trial Handbook (guide to healthy gestation) plus a structured physical activity and nutrition program, or a standard clinical care control group (n=30). The intervention lasts 25-28 weeks (6 months) depending on anticipated delivery date, with follow-up assessment on mother and child at 3, 6, 12 and 24 months post-delivery.

SIGNIFICANCE

Pregnancy, a critical time of growth, development and physiological change, provides an opportunity for early lifestyle intervention. The goal of identifying an effective lifestyle program for the gestational period that leads to healthy fetal development and subsequently normal weight offspring, less likely to develop obesity and its co-morbidities, is unique and could possibly attenuate the inter-generational cycle of obesity.

Developmental origins of obesity and type 2 diabetes: molecular aspects and role of chemicals

Obesity is a leading risk factor for impaired glucose tolerance and type 2 diabetes (T2D). Although the cause of the obesity epidemic is multi-factorial and not entirely clear, the recent acceleration in incidence is too rapid to be accounted for only by genetics, the wide availability of calorie-rich foods, and increasingly sedentary lifestyles. Accumulating data suggest that the important causes of the obesity epidemic may be related to developmental and early life environmental conditions. The concept of the developmental origins of health and disease (DOHaD) suggests that adverse influences early in development, particularly during intrauterine life, may result in permanent changes in the physiology and metabolism of the infant, which in turn result in an increased risk of non-communicable diseases in adulthood. For example, undernutrition during pregnancy and rapid postnatal weight gain are associated with obesity and T2D in the adult offspring. Moreover, increasing evidence suggests that early-life exposure to a wide range of chemicals has a significant impact on the causes of metabolic disorders. Although the underlying molecular mechanisms remain to be determined, these factors can affect epigenetic processes, such as DNA methylation, allowing the developmental environment to modulate gene transcription. The objective of this review article was to summarize recent progress in the biomedical implications of the DOHaD concept, focusing on the pathogenesis of obesity and T2D, and to discuss a future direction for preventive strategies from a public health perspective.

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.

Life course association of maternal smoking during pregnancy and offspring's height: data from the 1993 Pelotas (Brazil) birth cohort

PURPOSE

To evaluate the effect of (1) maternal smoking during pregnancy; and (2) partner smoking on offspring's height in infancy, childhood, and adolescence.

METHODS

All hospital live births from 1993 (5,249) were identified, and these infants were followed up at several ages. Height for age, expressed as z-scores using the World Health Organization growth curves, was measured at all follow-up visits. Maternal smoking during pregnancy was collected retrospectively at birth and analyzed as number of cigarettes/day smoked categorized in four categories (never smoked, <10, 10-19, and ≥ 20 cigarettes/day). Partner smoking was analyzed as a dichotomous variable (No/Yes). Unadjusted and adjusted analyses were performed by use of linear regression.

RESULTS

The prevalence of self-reported maternal smoking during pregnancy was 33.5%. In the crude analysis, the number of cigarettes/day smoked by the mother during pregnancy negatively affected offspring's height in infancy, childhood, and adolescence. After adjustment for confounders and mediators, this association remained statistically significant, although the magnitude of the regression coefficients was reduced. Paternal smoking was not associated with offspring's height in the adjusted analyses.

CONCLUSIONS

In addition to the well-known harmful effects of smoking, maternal smoking during pregnancy negatively affects offspring's height. Public health policies aimed at continuing to reduce the prevalence of maternal smoking during pregnancy must be encouraged.

Evaluation of the 'healthy start to pregnancy' early antenatal health promotion workshop: a randomized controlled trial

BACKGROUND

Pregnancy is an ideal time to encourage healthy lifestyles as most women access health services and are more receptive to health messages; however few effective interventions exist. The aim of this research was to deliver a low-intensity, dietitian-led behavior change workshop at a Maternity Hospital to influence behaviors with demonstrated health outcomes.

METHODS

Workshop effectiveness was evaluated using an RCT; 'usual care' women (n = 182) received a nutrition resource at their first antenatal visit and 'intervention' women also attended a one-hour 'Healthy Start to Pregnancy' workshop (n = 178). Dietary intake, physical activity levels, gestational weight gain knowledge, smoking cessation, and intention to breastfeed were assessed at service-entry and 12 weeks later. Intention-to-treat (ITT) and per-protocol (PP) analyses examined change over time between groups.

RESULTS

Approximately half (48.3%) the intervention women attended the workshop and overall response rate at time 2 was 67.2%. Significantly more women in the intervention met pregnancy fruit guidelines at time 2 (+4.3%, p = 0.011) and had a clinically-relevant increase in physical activity (+27 minutes/week) compared with women who only received the resource (ITT). Women who attended the workshop increased their consumption of serves of fruit (+0.4 serves/day, p = 0.004), vegetables (+0.4 serves/day, p = 0.006), met fruit guidelines (+11.9%, p < 0.001), had a higher diet quality score (p = 0.027) and clinically-relevant increases in physical activity (+21.3 minutes/week) compared with those who only received the resource (PP).

CONCLUSIONS

The Healthy Start to Pregnancy workshop attendance facilitates improvements in important health behaviors. Service changes and accessibility issues are required to assist women's workshop attendance to allow more women to benefit from the workshop's effects.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry ACTRN12611000867998.

Intravenous gestational nicotine exposure results in increased motivation for sucrose reward in adult rat offspring

BACKGROUND

Prenatal tobacco smoke exposure is associated with alterations in motivated behavior in offspring, such as increased consumption of highly palatable foods and abused drugs. Animal models show that gestational nicotine (GN) exposure mediates changes in responding for sucrose and drug reward.

METHODS

A novel, intermittent low-dose intravenous (IV) exposure model was used to administer nicotine (0.05 mg/kg/injection) or saline 3×/day to rats on gestational days 8-21. Two experiments investigated the effect of IV GN on (1) the habituation of spontaneous locomotor activity and on (2) sucrose reinforced responding in offspring. For the operant experiments, animals acquired fixed-ratio (FR-3) responding for sucrose, 26% (w/v), and were tested on varying concentrations (0, 3, 10, 30, and 56%; Latin-square) according to a FR-3, and then a progressive-ratio (PR) schedule. Male and female adult offspring were used.

RESULTS

IV GN did not alter birth or growth weight, or the number of pups born. No between-group differences in habituation to spontaneous locomotor activity were observed. FR testing produced an inverted U-shaped response curve, and rats showed peak responding for 10% sucrose reinforcement. Neither gestation nor sex affected responding, suggesting equivalent sensitivity to varying sucrose concentrations. PR testing revealed that GN rats showed greater motivation for sucrose reinforcement relative to controls.

CONCLUSIONS

A low-dose, IV GN exposure model resulted in increased motivation to respond for sucrose reinforcement in adult offspring. This suggests that using a low number of cigarettes throughout pregnancy will result in increased motivation for highly palatable foods in adult, and perhaps, adolescent offspring.

Cigarette smoking and brain regulation of energy homeostasis

Cigarette smoking is an addictive behavior, and is the primary cause of cardiovascular and pulmonary disease, and cancer (among other diseases). Cigarette smoke contains thousands of components that may affect caloric intake and energy expenditure, although nicotine is the major addictive substance present, and has the best described actions. Nicotine exposure from cigarette smoke can change brain feeding regulation to reduce appetite via both energy homeostatic and reward mechanisms, causing a negative energy state which is characterized by reduced energy intake and increased energy expenditure that are linked to low body weight. These findings have led to the public perception that smoking is associated with weight loss. However, its effects at reducing abdominal fat mass (a predisposing factor for glucose intolerance and insulin resistance) are marginal, and its promotion of lean body mass loss in animal studies suggests a limited potential for treatment in obesity. Smoking during pregnancy puts pressure on the mother's metabolic system and is a significant contributor to adverse pregnancy outcomes. Smoking is a predictor of future risk for respiratory dysfunction, social behavioral problems, cardiovascular disease, obesity, and type-2 diabetes. Catch-up growth is normally observed in children exposed to intrauterine smoke, which has been linked to subsequent childhood obesity. Nicotine can have a profound impact on the developing fetal brain, via its ability to rapidly and fully pass the placenta. In animal studies this has been linked with abnormal hypothalamic gene expression of appetite regulators such as downregulation of NPY and POMC in the arcuate nucleus of the hypothalamus. Maternal smoking or nicotine replacement leads to unhealthy eating habits (such as junk food addiction) and other behavioral disorders in the offspring.

Smoking or alcohol dependence among Indigenous Australians: treatment may be needed, not just education

BACKGROUND

In trying to help Aboriginal and Torres Strait Islander (Indigenous) individuals or communities to stop smoking or reduce the harms from alcohol, it is important to be aware of the strong biological basis of the drive to return to nicotine or alcohol.

METHODS

In this paper we briefly describe the social and neurobiological factors that drive a dependent smoker or drinker to keep using. We set out the current range of pharmacological treatments for dependence, their role in assisting a person to either stop using or avoid relapse, and we discuss issues relating to their use in Aboriginal Australians.

CONCLUDING COMMENTS

There is a firm evidence base for the use of pharmacological treatments for nicotine or alcohol dependence, particularly in severe dependence or when counselling or non-pharmacological approaches have failed. Indigenous Australians should be able to access the full range of approaches to managing these conditions. Working in partnership with Indigenous health staff and agencies can help ensure that appropriate access to treatment and quality treatment delivery occurs.

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.

Television watching from adolescence to adulthood and its association with BMI, waist circumference, waist-to-hip ratio and obesity: a longitudinal study

OBJECTIVE

To examine the prospective association of television (TV) watching from adolescence to young adulthood with BMI, waist circumference (WC), waist-to-hip ratio (WHR) and obesity.

DESIGN

A community-based longitudinal cohort study.

SETTING

Mater-University of Queensland Study of Pregnancy (MUSP) Cohort, Brisbane, Australia.

SUBJECTS

A sub-sample of 2439 children was followed up at ages 14 years and 21 years as part of a population-based birth cohort. Offspring reported the number of TV viewing hours each day at 14 and 21 years. BMI, WC and WHR were measured at 21 years.

RESULTS

In the adjusted model, offspring who watched TV for <3 h/d at 14 years but for ≥ 3 h/d at 21 years, or who watched TV for ≥ 3 h/d at 14 and 21 years, had greater BMI, WC and WHR at 21 years. Offspring who watched TV for ≥ 3 h/d at 14 years but for <3 h/d at 21 years had similar mean BMI, WC and WHR at 21 years to those who watched TV for <3 h/d at 14 and 21 years. Those offspring who reduced their TV watching hours to <3 h/d during the transition from adolescence into young adulthood were at less risk of becoming obese and those who continued or increased their TV watching to ≥ 3 h/d were at greater risk of becoming obese. This association remained independent of the potential confounding factors considered.

CONCLUSIONS

The present findings suggest that our efforts to decrease obesity by reducing TV watching hours among adults should consider interventions to reduce TV time among adolescents.

Role of environmental chemicals in diabetes and obesity: a National Toxicology Program workshop review

BACKGROUND

There has been increasing interest in the concept that exposures to environmental chemicals may be contributing factors to the epidemics of diabetes and obesity. On 11-13 January 2011, the National Institute of Environmental Health Sciences (NIEHS) Division of the National Toxicology Program (NTP) organized a workshop to evaluate the current state of the science on these topics of increasing public health concern.

OBJECTIVE

The main objective of the workshop was to develop recommendations for a research agenda after completing a critical analysis of the literature for humans and experimental animals exposed to certain environmental chemicals. The environmental exposures considered at the workshop were arsenic, persistent organic pollutants, maternal smoking/nicotine, organotins, phthalates, bisphenol A, and pesticides. High-throughput screening data from Toxicology in the 21st Century (Tox21) were also considered as a way to evaluate potential cellular pathways and generate -hypotheses for testing which and how certain chemicals might perturb biological processes related to diabetes and obesity.

CONCLUSIONS

Overall, the review of the existing literature identified linkages between several of the environmental exposures and type 2 diabetes. There was also support for the "developmental obesogen" hypothesis, which suggests that chemical exposures may increase the risk of obesity by altering the differentiation of adipocytes or the development of neural circuits that regulate feeding behavior. The effects may be most apparent when the developmental exposure is combined with consumption of a high-calorie, high-carbohydrate, or high-fat diet later in life. Research on environmental chemical exposures and type 1 diabetes was very limited. This lack of research was considered a critical data gap. In this workshop review, we outline the major themes that emerged from the workshop and discuss activities that NIEHS/NTP is undertaking to address research recommendations. This review also serves as an introduction to an upcoming series of articles that review the literature regarding specific exposures and outcomes in more detail.

Obesogens, stem cells and the developmental programming of obesity

Obesogens are chemicals that directly or indirectly lead to increased fat accumulation and obesity. Obesogens have the potential to disrupt multiple metabolic signalling pathways in the developing organism that can result in permanent changes in adult physiology. Prenatal or perinatal exposure to obesogenic endocrine disrupting chemicals has been shown to predispose an organism to store more fat from the beginning of its life. For example, excess oestrogen or cortisol exposure in the womb or during early life resulted in an increased susceptibility to obesity and metabolic syndrome later in life. This review focuses on the effects of environmental chemicals, such as the model obesogen, tributyltin (TBT), on the development of obesity. We discuss evidence linking the obesogenic effects of TBT with its ability to activate the peroxisome proliferator-activated receptor gamma and stimulate adipogenesis. We also discuss how TBT and other environmental obesogens may lead to epigenetic changes that predispose exposed individuals to subsequent weight gain and obesity. This suggests that humans, who have been exposed to obesogenic chemicals during sensitive windows of development, might be pre-programmed to store increased amounts of fat, resulting in a lifelong struggle to maintain a healthy weight and exacerbating the deleterious effects of poor diet and inadequate exercise.

Maternal smoking during pregnancy and offspring trajectories of height and adiposity: comparing maternal and paternal associations

BACKGROUND

Maternal smoking during pregnancy is associated with reduced offspring birth length and has been postulated as a risk factor for obesity. Causality for obesity is not established. Causality is well-supported for birth length, but evidence on persistence of height deficits is inconsistent.

METHODS

We examined the association between maternal smoking during pregnancy and trajectories of offspring height (0-10 years, N = 9424), ponderal index (PI) (0-2 years, N = 9321) and body mass index (BMI) (2-10 years, N = 8887) in the Avon Longitudinal Study of Parents and Children. To strengthen inference, measured confounders were controlled for, maternal and partner smoking associations were compared, dose-response and associations with post-natal smoking were examined.

RESULTS

Maternal smoking during pregnancy was associated with shorter birth length, faster height growth in infancy and slower growth in later childhood. By 10 years, daughters of women who smoke during pregnancy are on average 1.11 cm (SE = 0.27) shorter after adjustment for confounders and partner smoking; the difference is 0.22 cm (SE = 0.22) for partner's smoking. Maternal smoking was associated with lower PI at birth, faster PI increase in infancy, but not with BMI changes 2-10 years. Associations were stronger for maternal than partner smoking for PI at birth and PI changes in infancy, but not for BMI changes after 2 years. A similar dose-response in both maternal and partner smoking was seen for BMI change 2-10 years.

CONCLUSION

Maternal smoking during pregnancy has an intrauterine effect on birth length, and possibly on adiposity at birth and changes in height and adiposity in infancy. We do not find evidence of a specific intrauterine effect on height or adiposity changes after the age of 2 years.

Early determinants of obesity: genetic, epigenetic, and in utero influences

There is an emerging body of work indicating that genes, epigenetics, and the in utero environment can impact whether or not a child is obese. While certain genes have been identified that increase one's risk for becoming obese, other factors such as excess gestational weight gain, gestational diabetes mellitus, and smoking can also influence this risk. Understanding these influences can help to inform which behaviors and exposures should be targeted if we are to decrease the prevalence of obesity. By helping parents and young children change certain behaviors and exposures during critical time periods, we may be able to alter or modify one's genetic predisposition. However, further research is needed to determine which efforts are effective at decreasing the incidence of obesity and to develop new methods of prevention. In this paper, we will discuss how genes, epigenetics, and in utero influences affect the development of obesity. We will then discuss current efforts to alter these influences and suggest future directions for this work.

Is low birth weight associated with adiposity in contemporary U.S. youth? The Exploring Perinatal Outcomes among Children (EPOCH) Study

Little is known about the relationship between low birth weight (BW), as a marker of under-nutrition in utero, and childhood body mass index (BMI) and adiposity parameters, including skinfold thickness, abdominal subcutaneous (SAT) and visceral adipose tissues (VAT) and intramyocellular accumulation of lipids (IMCL). The EPOCH Study (Exploring Perinatal Outcomes among Children) explored the association between BW and markers of adiposity in contemporary, multi-ethnic children from Colorado. A total of 442 youth age 6-13 years (50% male, mean age 10.5 years) had anthropometric measurements, abdominal SAT and VAT measured by magnetic resonance imaging and IMCL deposition in the soleus muscle measured by nuclear magnetic resonance spectroscopy. BW and gestational age were ascertained from an electronic perinatal database. A weak positive association between BW and current BMI (P=0.05) was seen, independent of demographic, perinatal, socio-economic and current lifestyle factors. When adjusted for current BMI, every one standard deviation decrease in BW (~500 g), was associated with a 8.8 cm(2) increase in SAT, independent of potential confounders. In conclusion, in a contemporary cohort of youth, BW was positively, but weakly, associated with BMI and inversely, though weakly, associated with SAT, independent of current BMI. There were no significant associations between BW and waist circumference, skinfolds, VAT and IMCL. Our results provide some support to the hypothesis that under-nutrition in utero, as reflected by lower BW, is associated with lower overall childhood body size, but an increased propensity for abdominal adiposity, reflected in this young age-group, predominantly as subcutaneous fat.

Maternal smoking during pregnancy and childhood obesity: results from the CESAR Study

Childhood obesity is a worldwide public health concern. Recent studies from high income countries have demonstrated associations between maternal smoking during pregnancy and children's excess body weight. We examine associations between maternal smoking during pregnancy and children's overweight or obesity, in six countries in the less affluent Central/Eastern European region. Questionnaire data were analysed, for 8,926 singleton children aged 9-12 years. Country-specific odds ratios for effects of maternal smoking during pregnancy on being overweight, and on obesity, were estimated using logistic regression. Heterogeneity between country-specific results, and mean effects (allowing for heterogeneity) were estimated. Positive associations between maternal smoking and overweight were seen in all countries but Romania. While not individually statistically significant, the mean odds ratio was 1.26 (95% CI 1.03-1.55), with no evidence of between-country heterogeneity. Obese children were few (2.7%), and associations between obesity and maternal smoking during pregnancy were more heterogeneous, with odds ratios ranging from 0.71 (0.32-1.57) in Poland to 5.49 (2.11-14.30) in Slovakia. Between-country heterogeneity was strongly related to average persons-per-room, a possible socioeconomic indicator, with stronger associations where households were less crowded. Estimates of dose-response relationships tended to be small and non-significant, even when pooled. Our results provide evidence of a link between maternal smoking in pregnancy and childhood overweight. Associations with obesity, though strong in some countries, were less consistent. Maternal smoking may confer an addition to a child's potential for obesity, which is more likely to be realised in affluent conditions.

Tobacco smoke exposure before, during, and after pregnancy and risk of overweight at age 6

Maternal smoking during pregnancy has been associated with overweight and obesity in childhood and is strongly correlated with children's tobacco smoke exposure before and after pregnancy. We investigated the independent association of tobacco smoke exposure at various pre- and postnatal periods and overweight at age 6. A total of 1,954 children attending the 2001-2002 school entrance health examination in the city of Aachen, Germany, were included into this study. Height and weight were measured, BMI was calculated. Tobacco smoke exposure at various periods, other lifestyle and sociodemographic factors were ascertained by questionnaire. Multiple logistic regression models were used to assess the association between tobacco smoke exposure and overweight. Prevalence of overweight was 8.9%. Significant positive associations were found with maternal smoking before and during pregnancy and during the first and sixth year of life. When all smoking periods were included into one logistic model simultaneously, secondhand smoke exposure after birth remained positively associated with overweight at age 6 at either one of the two time periods (first year only: odds ratio (OR) (95% confidence interval (CI)): 2.94 (1.30-6.67), sixth year only: 2.57 (1.64-4.04), respectively) or at both (4.43 (2.24-8.76)). Exposure to tobacco smoke during the first years of life appears to be a key risk factor for development of childhood overweight.

Maternal cigarette smoke exposure contributes to glucose intolerance and decreased brain insulin action in mice offspring independent of maternal diet

BACKGROUND

Maternal smoking leads to intrauterine undernutrition and is associated with low birthweight and higher risk of offspring obesity. Intrauterine smoke exposure (SE) may alter neuroendocrine mediators regulating energy homeostasis as chemicals in cigarette smoke can reach the fetus. Maternal high-fat diet (HFD) consumption causes fetal overnutrition; however, combined effects of HFD and SE are unknown. Thus we investigated the impact of combined maternal HFD and SE on adiposity and energy metabolism in offspring.

METHOD

Female Balb/c mice had SE (2 cigarettes/day, 5 days/week) or were sham exposed for 5 weeks before mating. Half of each group was fed HFD (33% fat) versus chow as control. The same treatment continued throughout gestation and lactation. Female offspring were fed chow after weaning and sacrificed at 12 weeks.

RESULTS

Birthweights were similar across maternal groups. Faster growth was evident in pups from SE and/or HFD dams before weaning. At 12 weeks, offspring from HFD-fed dams were significantly heavier than those from chow-fed dams (chow-sham 17.6±0.3 g; chow-SE 17.8±0.2 g; HFD-sham 18.7±0.3 g; HFD-SE 18.8±0.4 g, P<0.05 maternal diet effect); fat mass was significantly greater in offspring from chow+SE, HFD+SE and HFD+sham dams. Both maternal HFD and SE affected brain lactate transport. Glucose intolerance and impaired brain response to insulin were observed in SE offspring, and this was aggravated by maternal HFD consumption.

CONCLUSION

While maternal HFD led to increased body weight in offspring, maternal SE independently programmed adverse health outcomes in offspring. A smoke free environment and healthy diet during pregnancy is desirable to optimize offspring health.

Cardiovascular and metabolic influences of fetal smoke exposure

Many epidemiological studies showed associations of low birth weight with cardiovascular disease, type 2 diabetes and obesity. The associations seem to be consistent and stronger among subjects with a postnatal catch up growth. It has been suggested that developmental changes in response to adverse fetal exposures might lead to changes in the fetal anatomy and physiology. These adaptations may be beneficial for short term, but may lead to common diseases in adulthood. Maternal smoking during pregnancy is one of the most important adverse fetal exposures in Western countries, and is known to be associated with a 150-200 g lower birth weight. An accumulating body of evidence suggests that maternal smoking during pregnancy might be involved in pathways leading to both low birth weight and common diseases, including cardiovascular disease, type 2 diabetes and obesity, in adulthood. In this review, we discuss epidemiological studies focused on the associations of maternal smoking with fetal growth and development and cardiovascular and metabolic disease in later life. We also discuss potential biological mechanisms, and challenges for future epidemiological studies.

Cardiovascular and metabolic influences of fetal smoke exposure

Many epidemiological studies showed associations of low birth weight with cardiovascular disease, type 2 diabetes and obesity. The associations seem to be consistent and stronger among subjects with a postnatal catch up growth. It has been suggested that developmental changes in response to adverse fetal exposures might lead to changes in the fetal anatomy and physiology. These adaptations may be beneficial for short term, but may lead to common diseases in adulthood. Maternal smoking during pregnancy is one of the most important adverse fetal exposures in Western countries, and is known to be associated with a 150–200 g lower birth weight. An accumulating body of evidence suggests that maternal smoking during pregnancy might be involved in pathways leading to both low birth weight and common diseases, including cardiovascular disease, type 2 diabetes and obesity, in adulthood. In this review, we discuss epidemiological studies focused on the associations of maternal smoking with fetal growth and development and cardiovascular and metabolic disease in later life. We also discuss potential biological mechanisms, and challenges for future epidemiological studies.

Obesity in rural youth: looking beyond nutrition and physical activity

Contributors to excessive obesity in rural youth include well-documented nutrition and physical activity behaviors. However, emerging research suggests that preventing excessive weight gain and smoking during pregnancy, teen pregnancy, and child abuse also could reduce obesity in this vulnerable population. These traditional and emerging, nontraditional factors need to be addressed within the confines of current challenges faced by rural communities. An enhanced ecological model provides a framework for combining traditional and nontraditional factors into a more comprehensive approach that addresses the complexity of the issues contributing to youth obesity.

Parental smoking during pregnancy, early growth, and risk of obesity in preschool children: the Generation R Study

BACKGROUND

Maternal smoking during pregnancy seems to be associated with obesity in offspring. Not much is known about the specific critical exposure periods or underlying mechanisms for this association.

OBJECTIVE

We assessed the associations of active maternal and paternal smoking during pregnancy with early growth characteristics and risks of overweight and obesity in preschool children.

DESIGN

This study was a population-based, prospective cohort study from early fetal life until the age of 4 y in 5342 mothers and fathers and their children. Growth characteristics [head circumference, length, weight, and body mass index (BMI; in kg/m(2))] and overweight and obesity were repeatedly measured at the ages of 1, 2, 3, and 4 y.

RESULTS

In comparison with children from nonsmoking mothers, children from mothers who continued smoking during pregnancy had persistently smaller head circumferences and heights until the age of 4 y, whereas their weights were lower only until the age of 3 mo. This smaller length and normal to higher weight led to an increased BMI [SD score difference: 0.11; 95% CI: 0.02, 0.20; P < 0.05)] and an increased risk of obesity (odds ratio: 1.61; 95% CI: 1.03, 2.53; P < 0.05) at the age of 4 y. In nonsmoking mothers, paternal smoking was not associated with postnatal growth characteristics or risk of obesity in offspring. Maternal smoking during pregnancy was associated with a higher BMI at the age of 4 y in children with a normal birth weight and in those who were small for gestational age at birth.

CONCLUSION

Our findings suggest that direct intrauterine exposure to smoke until late pregnancy leads to different height and weight growth adaptations and increased risks of overweight and obesity in preschool children.

Endocrine disrupting chemicals and the developmental programming of adipogenesis and obesity

Obesity and related disorders are a burgeoning public health epidemic, particularly in the U.S. Currently 34% of the U.S. population is clinically obese (BMI > 30) and 68% are overweight (BMI > 25), more than double the worldwide average and 10-fold higher than Japan and South Korea. Obesity occurs when energy intake exceeds energy expenditure; however, individuals vary widely in their propensity to gain weight and accrue fat mass, even at identical levels of excess caloric input. Clinical, epidemiological, and biological studies show that obesity is largely programmed during early life, including the intrauterine period. The environmental obesogen hypothesis holds that prenatal or early life exposure to certain endocrine disrupting chemicals can predispose exposed individuals to increased fat mass and obesity. Obesogen exposure can alter the epigenome of multipotent stromal stem cells, biasing them toward the adipocyte lineage at the expense of bone. Hence, humans exposed to obesogens during early life might have an altered stem cell compartment, which is preprogrammed toward an adipogenic fate. This results in a higher steady state number of adipocytes and potentially a lifelong struggle to maintain a healthy weight, which can be exacerbated by societal influences that promote poor diet and inadequate exercise. This review focuses on the developmental origins of the adipocyte, the relationship between adipocyte number and obesity, and how obesogenic chemicals may interfere with the highly efficient homeostatic mechanisms regulating adipocyte number and energy balance.

[Obesity in adolescence and its main determinants]

The objective of this paper was to discuss the main environmental factors determining overweight and obesity in adolescents, based on a critical review of the subject. The main national and international health databases, Medline/PubMed, Web of Science, SciELO, and Lilacs were searched including publications from 1975 to 2009. The following key-words and respective MeSH terms were used: "overweight", "obesity", "adolescence", "adolescents", "physical activity", "food intake". The findings showed that changes in dietary patterns in recent decades as the increased consumption of simple sugars, processed foods, and inadequate intake of fruits and vegetables have contributed directly to the weight gain in this population. In addition, the progressive reduction in physical activity associated with increased time spent with low-intensity activities like television viewing, playing computer and video games has contributed to the weight gain of adolescents. In conclusion, variables related to dietary pattern and physical activity should be prioritized interventions directed toward the prevention of obesity among adolescents.

Maternal smoking, weight status and dietary behaviours during pregnancy: findings from first-time mothers in south-west Sydney, Australia

BACKGROUND

Few studies have been conducted examining the relationship between maternal smoking, weight status and dietary behaviours during pregnancy.

AIM

The objective of the study was to examine the relationship between maternal smoking, weight status and dietary behaviours during pregnancy.

METHODS

An analysis of cross-sectional baseline survey data was conducted with 406 first-time mothers participating in the Healthy Beginnings Trial (HBT) conducted in south-west Sydney, Australia. Mothers' reports of their smoking status, dietary behaviours and pre-pregnancy weight and height were collected through face-to-face interviews. The relationships were examined using log-binomial regression modelling.

RESULTS

Maternal smoking status was not associated with weight status. However, smoking was positively associated with soft drink consumption and negatively associated with daily fruit intake. After adjusting for age, marital status and education level, mothers who reported consuming >1 cup of soft drink per day were more likely to smoke than those consuming less soft drink (adjusted risk ratio, ARR 1.48, 95% CI 1.02-2.22, P = 0.05). Mothers who reported having ≥2 serves of fruit daily were significantly less likely to smoke than those having less fruit (ARR 0.54, 95% CI 0.29-0.95, P = 0.04).

CONCLUSIONS

The study found no evidence linking maternal smoking and weight status and did not support the notion that smoking could lead to a lower weight status. However, maternal smoking was associated with fruit and soft drink consumption and needs to be considered while examining dietary behaviours and weight status.

Prenatal tobacco exposure and cortisol levels in infants of teen mothers

AIMS

prenatal tobacco exposure (PTE) is an important public health concern for the offspring of teen mothers. We examined whether PTE is associated with baseline cortisol levels in four-month-old infants of teenage mothers.

METHODS

we assessed salivary cortisol levels of 212 infants. PTE was measured by using self-reports of cigarette smoking during pregnancy. We used a propensity scores matching analysis to compare infants with PTE and those without.

RESULTS

of 212 mothers, 151 smoked during pregnancy. However, there was no association between PTE and infant cortisol levels.

CONCLUSIONS

we could not support a relation between PTE and cortisol levels in a sample of four-month-old infants of teenage mothers.

Predicting the risk of newborn children to become overweight later in childhood: the PIAMA birth cohort study

OBJECTIVE

To develop a decision rule by which children with a high risk to develop overweight can be distinguished at birth from children at low risk.

DESIGN, SETTING AND PARTICIPANTS

Data of 1 687 Dutch children born in 1996/1997 who participated in the Prevention and Incidence of Asthma and Mite Allergy (PIAMA) longitudinal birth cohort study were analysed. Perinatal candidate predictors of overweight at 8 years of age were selected and a prediction model was developed using stepwise model selection based on the Akaike Information Criterion (AIC). The prediction model was internally validated using resampling techniques. Outcome measure. Overweight at the age of 8 years.

RESULTS

A total of 13.9% (n = 253) of the children were overweight at 8 years of age. Independent positive predictors of overweight were paternal and maternal body mass index, female gender, smoking in the parental house, birth weight and hospital delivery. From the model, a decision rule was derived by which an overweight score could be calculated. Of the children with an overweight score below 89.45, only 2.7% were overweight at the age of 8, whereas in children with an overweight score above 105.02 the prevalence of overweight was 35.4%.

CONCLUSION

The risk of overweight at the age of 8 years can be predicted with six characteristics that are available at birth. The decision rule developed in this study may help to target early preventive measures against overweight in high-risk children.

Does early-life exposure to organophosphate insecticides lead to prediabetes and obesity?

Human exposures to organophosphate insecticides are ubiquitous. Although regarded as neurotoxicants, increasing evidence points toward lasting metabolic disruption from early-life organophosphate exposures. We gave neonatal rats chlorpyrifos, diazinon or parathion in doses devoid of any acute signs of toxicity, straddling the threshold for barely-detectable cholinesterase inhibition. Organophosphate exposure during a critical developmental window altered the trajectory of hepatic adenylyl cyclase/cyclic AMP signaling, culminating in hyperresponsiveness to gluconeogenic stimuli. Consequently, the animals developed metabolic dysfunction resembling prediabetes. When the organophosphate-exposed animals consumed a high fat diet in adulthood, metabolic defects were exacerbated and animals gained excess weight compared to unexposed rats on the same diet. At the same time, the high fat diet ameliorated many of the central synaptic defects caused by organophosphate exposure, pointing to nonpharmacologic therapeutic interventions to offset neurodevelopmental abnormalities, as well as toward fostering dietary choices favoring high fat intake. These studies show how common insecticides may contribute to the increased worldwide incidence of obesity and diabetes.

Socioeconomic status, birth weight, maternal smoking during pregnancy and adiposity in early adult life: an analysis using structural equation modeling

We describe here an example of structural equation modeling in epidemiology. The association between birth weight and adiposity in early adult life, adjusted for the number of cigarettes smoked during pregnancy and socioeconomic status at birth, was evaluated. Data involving 2,063 adults from the 1978/1979 Ribeirão Preto cohort study were used. Adiposity was measured by body mass index (BMI), waist circumference (WC) and the sum of triceps and subscapular skinfolds (STSS). Models were submitted to maximum likelihood estimation, separately for men and women. Birth weight had a small and significant effect on adiposity in men (standardized coefficient, SC = 0.08) and women (SC = 0.09). Smoking during pregnancy did not influence adiposity in men (SC = 0.004), but its effect was marginally significant in women (SC = 0.07; P = 0.056). Socioeconomic status at birth had a small and positive effect on adiposity in men (SC = 0.08) and a moderate and negative effect in women (SC = -0.16). In this young adult population, BMI, WC and STSS used alone or in combination were valid estimators of body adiposity.

Prenatal exposure to maternal cigarette smoking and accumulation of intra-abdominal fat during adolescence

In industrialized countries, prenatal exposure to maternal cigarette smoking (PEMCS) is the most common environmental insult to the fetus. Here, we tested the hypothesis that PEMCS amplifies accumulation of abdominal fat during the accelerated weight gain occurring in late puberty. This hypothesis was tested in 508 adolescents (12-18 years, 237 exposed prenatally to maternal cigarette smoking) in whom subcutaneous and intra-abdominal fat were quantified with magnetic resonance imaging (MRI). We found that, in early puberty, exposed and nonexposed adolescents did not differ in MRI-based measures of adiposity. In late puberty, on the other hand, exposed compared with nonexposed adolescents demonstrated markedly higher quantities of both subcutaneous fat (by 26%, P = 0.004) and intra-abdominal fat (by 33%, P = 0.001). These group differences remained virtually unchanged after adjusting for sex and potential confounders, including birth weight and breastfeeding. As such, our results suggest that PEMCS may represent a major risk factor for the development of abdominal obesity at the later stages of puberty.

Familial factors confound the association between maternal smoking during pregnancy and young adult offspring overweight

BACKGROUND

Smoking during pregnancy has been shown to increase the risks of several adverse birth outcomes. Associations with overweight and/or obesity in the offspring have also been suggested. We aim to investigate whether familial factors confound the association between maternal smoking during pregnancy and overweight in early adulthood in young Swedish males born 1983-88.

METHODS

In a population-based Swedish cohort comprising 124 203 singleton males born to Nordic mothers between 1983 and 1988, we examined the association between maternal smoking during pregnancy and the risk of overweight in the offspring at age ∼18 years. We also investigated the association within siblings, controlling for common genes and shared environment.

RESULTS

In the cohort analyses, the risk of overweight was increased in sons of smoking mothers compared with sons of non-smokers: adjusted odds ratios 1.41, 95% confidence interval (CI) 1.34-1.49, and 1.56, 95% CI 1.46-1.66, for one to nine cigarettes per day, and >10 cigarettes per day, respectively. Stratifying for maternal smoking habits across two subsequent male pregnancies, there was an increased risk of overweight for the second son only if the mother was smoking in both male pregnancies. The effect of smoking during pregnancy on the offspring's body mass index was not present when the association was evaluated within full and half sibling pairs.

CONCLUSION

The association between maternal smoking during pregnancy and offspring's risk of overweight appears to be confounded by familial factors.

Maternal smoking during pregnancy and offspring obesity: meta-analysis

BACKGROUND

Recent reports have suggested that maternal smoking may increase the risk of development of obesity in the unborn child in later life, but relatively few cohort studies have been done on the relationship between maternal smoking during pregnancy and future development of metabolic syndrome.

METHODS

A systematic review and meta-analysis of observational studies reporting effect estimates and 95% confidence intervals (95%CI) was conducted on the association between maternal smoking during pregnancy and obesity of future offspring.

RESULTS

Seventeen papers were identified from 444 English-language papers (key word search: maternal smoking and obesity) in PubMed. All papers showed a positive association between maternal smoking during pregnancy and childhood obesity. The meta-analysis, using the DerSimonian-Laird method, found the association to be statistically significant. In association with maternal smoking during pregnancy and body mass index with more than 95%CI in the offspring aged 3-33 years, the pooled odds ratio calculated from 16 of these 17 studies was 1.64 (95%CI: 1.42-1.90). After adjustment for publication bias, the pooled adjusted odds ratio was 1.52 (95%CI: 1.36-1.70). In addition, confounders of maternal obesity, low social status, low birthweight and not being breast-fed seemed to be risk factors for offspring obesity.

CONCLUSION

Maternal smoking during pregnancy may cause future obesity and metabolic syndrome.

Low-grade, systemic inflammation in adolescents: association with early-life factors, gender, and lifestyle

Low-grade, systemic inflammation is related to increased risk of cardiovascular disease in adults. The proinflammatory state tracks from adolescence to adulthood. Identifying correlates of inflammation in adolescents could provide opportunities to prevent cardiovascular disease in adulthood. However, population-based data on correlates of inflammation in adolescence are limited. Therefore, the authors studied the associations of early-life factors, gender, and lifestyle with inflammation (measured by high-sensitivity C-reactive protein and leukocyte count) at age 16 years (2001-2002) in the prospective, population-based Northern Finland Birth Cohort 1986 Study (n = 5,240). In females, being born small for gestational age and current use of oral contraceptives were associated with the proinflammatory state. The association of birth size with inflammation was not observed in males. In logistic regression analyses, oral contraceptive use (odds ratio (OR) = 2.83), abdominal obesity (OR = 5.17), and smoking (OR = 2.72) were associated with elevation of both inflammation markers in females; abdominal obesity (OR = 5.72) and smoking (OR = 2.02) were associated in males. Thus, females appear more susceptible to the adverse effects of being born small for gestational age than males. Given the widespread use of oral contraceptives and the potential pathophysiologic consequences of the proinflammatory state, the association of oral contraceptive use with inflammation in adolescence may have public health implications.

Additive and synergistic effects of fetal nicotine and dexamethasone exposure on cholinergic synaptic function in adolescence and adulthood: Implications for the adverse consequences of maternal smoking and pharmacotherapy of preterm delivery

Maternal smoking contributes to preterm delivery; glucocorticoids are the consensus treatment for prematurity, thus producing fetal coexposure to nicotine and dexamethasone. We administered nicotine to pregnant rats throughout gestation at a dose (3 mg/kg/day) producing plasma levels typical of smokers. Later in gestation, animals received dexamethasone (0.2 mg/kg). We assessed developmental indices for acetylcholine (ACh) synaptic function throughout adolescence, young adulthood and later adulthood, evaluating brain regions possessing major ACh projections and cell bodies; we measured choline acetyltransferase activity, hemicholinium-3 binding to the presynaptic choline transporter and nicotinic ACh receptor binding. In general, nicotine and dexamethasone, alone or in combination, produced regionally-selective increases or decreases in choline acetyltransferase activity but larger, consistent elevations in hemicholinium-3 and nicotinic ACh receptor binding; the patterns were indicative of ACh synaptic hyperactivity. Superimposed on these overall effects, there were significant disparities in temporal and regional relationships among the different treatments, notably involving effects that emerged later in life, after a period of apparent normality. This indicates that nicotine and dexamethasone do not simply produce an initial ACh neuronal injury that then persists throughout the lifespan but rather, they alter the developmental trajectory of ACh function. Most importantly, the combined exposure to nicotine + dexamethasone elicited greater changes than either of the individual exposures, involving both additive and synergistic effects. Our results thus point to potentially worse neurobehavioral outcomes of the pharmacotherapy of preterm labor in the offspring of smokers.

Fatores socioeconômicos, demográficos, ambientais e comportamentais associados ao excesso de peso em adolescentes: uma revisão sistemática da literatura

OBJETIVO: Identificar fatores socioeconômicos, ambientais e comportamentais associados ao excesso de peso (EP) em adolescentes por meio de uma revisão sistemática da literatura. MÉTODOS: Foram consultadas seis bases de dados (Lilacs, Adolec, SciELO, Medline via Pubmed, ISI Web of Knowlwdge e Cochrane Library) entre os dias 3 e 13 de janeiro de 2008. Os descritores e respectivos termos MeSH utilizados foram: "sobrepeso", "obesidade", "adolescência", "adolescentes", "fatores de risco", "fatores associados". Foram avaliados artigos em inglês, espanhol e português publicados entre 1997 e 2007, e incluídos estudos observacionais que estudaram adolescentes com idades entre 10 e 19 anos, cujo desfecho era o EP diagnosticado por critérios internacionalmente utilizados. Foram excluídos estudos com base em amostras de conveniência ou que não investigavam fatores sociais, ambientais e psicocomportamentais entre as variáveis independentes. RESULTADOS: Da leitura dos títulos e resumos, e da aplicação inicial dos critérios de elegibilidade, resultaram 202 artigos. A revisão das publicações completas permitiu a inclusão e análise de 56 artigos. Observou-se que o nível socioeconômico associou-se inversamente com o EP em países desenvolvidos e de forma direta em países em desenvolvimento. Dieta para emagrecer, número de horas alocadas em TV/vídeo por dia, mãe e/ou pais obesos e ocorrência de EP na infância associaram-se diretamente com o EP. Foram identificados como fatores protetores o hábito de consumir desjejum e a prática de atividade física. CONCLUSÃO: Variáveis socioeconômicas, comportamentais, familiares e do início da vida associaram-se com EP e estas devem ser consideradas nas intervenções dirigidas para este agravo entre adolescentes.

Prenatal exposure to cigarette smoke induces diet- and sex-dependent dyslipidemia and weight gain in adult murine offspring

BACKGROUND

Cardiovascular disease (CVD) affects 71 million American adults and remains the leading cause of death in the United States and Europe. Despite studies that suggest that the development of CVD may be linked to intrauterine growth or early events in childhood, little direct experimental evidence supports the notion.

OBJECTIVE

We investigated whether exposure to cigarette smoke in utero alters the risk of developing CVD later in life.

METHODS

We exposed B(6)C(3)F(1) mice (via whole-body inhalation) to either filtered air or mainstream cigarette smoke (MCS, at a particle concentration of 15 mg/m(3)) from gestational day 4 to parturition. Adult offspring were fed a normal chow diet or switched to a high-fat diet 2 weeks before sacrifice. We measured dam and offspring body weight, plasma lipid parameters, lipoprotein subclass particle numbers and sizes, and total antioxidant capacities.

RESULTS

Adult female mice prenatally exposed to MCS demonstrated significantly higher body weight and levels of plasma high-density lipoprotein (HDL) and low-density lipoprotein than did their air-exposed counterparts. When fed a high-fat diet for 2 weeks, males, but not females, exposed prenatally to MCS gained substantially more weight and exhibited dramatic alterations in total cholesterol and HDL levels compared with their air-exposed counterparts.

CONCLUSIONS

These data provide, for the first time, direct experimental evidence supporting the notion that prenatal exposure to cigarette smoke affects offspring weight gain and induces a lipid profile that could alter the offspring's risk of developing CVD later in life.

Childhood overweight status predicts diabetes at age 21 years: a follow-up study

We examined the prospective association of childhood BMI z-score and BMI categories (normal or overweight) with young adult diabetes, controlling for early life, childhood, and adolescence factors. A subsample of 2,639 young adults from the Mater-University study of pregnancy (MUSP) and its outcomes, a prospective birth cohort who were born in Brisbane, Australia and for whom we had measured height and weight at 5 years and self-reported diabetes at age 21 years. The risk of developing diabetes by age 21 years was greater among young adults who had greater BMI z-score or were overweight at age 5 years than those who had normal BMI at age 5 years. Young adults who were overweight at age 5 years had an increased odds ratio of 2.60 (95% confidence interval (CI): 1.29, 5.22, in age- and sex-adjusted model) of experiencing diabetes by age 21 years. Adjustment for potential confounders and mediators including intrauterine environmental factors, childhood dietary patterns, television watching, participation in sports and exercise, and current weight, did not substantively alter these associations. Overweight and increasing BMI z-score at childhood is an independent predictor of young adult's type 1 and type 2 diabetes. Findings of this study suggest that childhood BMI may be central to the development and rising incidence of all diabetes.

Endocrine disrupters as obesogens

The recent dramatic rise in obesity rates is an alarming global health trend that consumes an ever increasing portion of health care budgets in Western countries. The root cause of obesity is thought to be a prolonged positive energy balance. Hence, the major focus of preventative programs for obesity has been to target overeating and inadequate physical exercise. Recent research implicates environmental risk factors, including nutrient quality, stress, fetal environment and pharmaceutical or chemical exposure as relevant contributing influences. Evidence points to endocrine disrupting chemicals that interfere with the body's adipose tissue biology, endocrine hormone systems or central hypothalamic-pituitary-adrenal axis as suspects in derailing the homeostatic mechanisms important to weight control. This review highlights recent advances in our understanding of the molecular targets and mechanisms of action for these compounds and areas of future research needed to evaluate the significance of their contribution to obesity.

Predictors of starting to smoke cigarettes in patients with first episode psychosis

INTRODUCTION

Cigarette smoking is common in psychotic disorders and may be initiated in an attempt to control features of illness. However, genetic, obstetric and early life conditions are risks for starting to smoke in the general population but their role in psychotic patients is unclear.

METHOD

Smoking history and the putative predictors of starting to smoke were assessed in a community-wide sample of 115 first episode psychosis patients. The proportion that initiated smoking was compared with that from population surveys and the impact of risk factors was assessed within the patient sample.

RESULTS

Most patients began smoking before illness onset and the proportion who initiated smoking was significantly high by the onset of a functional decline. Gestational tobacco exposure was a risk for smoking and was also associated with low birthweight, poor academic achievement, and obesity. Low familial socioeconomic position but not familial psychiatric problems also predicted smoking initiation.

DISCUSSION

In most cases, smoking preceded illness onset and was not a response to early features of illness. General population predictors of starting to smoke were also associated with smoking initiation in psychotic patients. Of these risks, exposure to tobacco during gestation is noteworthy in that it affects brain development and is associated with cognitive, behavioral, psychiatric and general health problems. In addition, nicotine interacts with other substances of abuse. The initiation of smoking before illness onset and the association with developmental problems raises the question of whether cigarette smoking influences some aspects of illness in patients with psychosis.

Associations between sleep duration patterns and overweight/obesity at age 6

OBJECTIVE

To investigate whether longitudinal sleep duration patterns during early childhood is a risk factor of overweight or obesity at school entry while controlling for a variety of obesogenic environmental factors.

DESIGN, SETTING, AND PARTICIPANTS

This is a prospective cohort study (March-December 1998 to December 2004) of a representative sample of infants born in 1997-1998 in the Canadian province of Quebec. Body mass index (BMI) was measured at ages 2.5 and 6 years. Sleep duration was reported yearly from 2.5 to 6 years of age by their mothers. Prenatal, postnatal (5 and 29 months), and lifestyle (6 y) potentially confounding factors for excess weight were assessed by interviews, questionnaires and hospital records. A group-based semiparametric mixture model was used to estimate developmental patterns of sleep duration. The relationship between sleep duration patterns and BMI was tested using multivariate logistic regression models to control for potentially confounding factors on 1138 children.

RESULTS

Four sleep duration patterns were identified: short persistent (5.2%), short increasing (4.7%), 10-hour persistent (50.7%), and 11-hour persistent (39.4%). After controlling for potentially confounding factors, the risk for overweight or obesity was almost 4.2 times higher for short persistent sleepers (odds ratio [OR], 4.2; 95% confidence interval [CI], 1.6 to 11.1; P = 0.003) than for 11-hour persistent sleepers.

CONCLUSIONS

Persistently short sleep duration (<10 h) during early childhood significantly increases the risk of excess weight or obesity in childhood, and appears to be independent of other obesogenic factors.

Maternal smoking cessation in early pregnancy and offspring weight status at four years of age. A prospective birth cohort study

BACKGROUND

Maternal smoking during pregnancy is associated with fetal growth restriction, but also with increased risk for overweight in childhood. If the mother stops smoking in early pregnancy fetal growth is not restricted, but whether the risk for later overweight persists is unclear.

AIM

To study if four year old children of mothers who stopped smoking in early pregnancy have higher mean body mass index (BMI) and/or increased odds of being overweight compared with children of non-smokers.

STUDY DESIGN

Prospective population based study on Norwegian mothers and children.

SUBJECTS

Among 711 children available for analysis, 540 were children of never smoking mothers, 114 of mothers who stopped smoking in early pregnancy, and 57 of mothers who continued to smoke throughout pregnancy.

OUTCOME MEASURES

BMI and overweight defined by international criteria at age four.

RESULTS

Compared with children of never smoking mothers, children of smoking mothers had higher mean BMI (mean difference: 0.47; 95% CI: 0.10, 0.84 kg/m(2)), whereas mean BMI was not higher among children of mothers who stopped smoking (mean difference: 0.02; 95% CI: -0.24, 0.28 kg/m(2). Similarly, children of smoking mothers had increased odds for overweight (adjusted OR: 2.83; 95% CI: 1.13, 7.10), whereas children of mothers who stopped smoking did not have increased odds (adjusted OR: 1.29; 95% CI: 0.62, 2.68) compared with children of never smoking mothers.

CONCLUSIONS

In this study, the association between smoking exposure and childhood overweight did not persist in children of mothers who stopped smoking early in pregnancy.

Dose-response associations between maternal smoking during pregnancy and subsequent childhood obesity: effect modification by maternal race/ethnicity in a low-income US cohort

Studies suggest that children exposed to cigarette smoke in utero are at risk of becoming obese. Few researchers have evaluated the dose-response association between maternal smoking during pregnancy and childhood obesity or whether this association varies by maternal race/ethnicity. The authors obtained retrospective cohort data by linking records from the Pregnancy Nutrition Surveillance System and the Pediatric Nutrition Surveillance System on 155,411 low-income children born during 1995-2001 in 9 US states and 2 tribal nations. The authors examined maternal smoking status, duration of smoking, quantity of smoking, and both duration and quantity combined. Childhood obesity was based on a body mass index greater than or equal to the 95th percentile for sex and age, assessed at age 2-4 years. Maternal race/ethnicity modified the association between smoking during pregnancy and childhood obesity. Among non-Hispanic White mothers, both duration and quantity of smoking were positively associated with childhood obesity in a dose-response manner. Among non-Hispanic Black mothers, only heavy smoking was positively associated with childhood obesity. Among Hispanics, American Indians/Alaska Natives, and Asians/Pacific Islanders, smoking was not associated with childhood obesity. The inconsistent association between smoking during pregnancy and childhood obesity across race/ethnicity categories merits further investigation into potential explanations for this variation, which may include confounding, reporting bias, or unexplored biologic mechanisms.