Association of pre- and post-natal parental smoking with offspring body mass index: an 8-year follow-up of a birth cohort

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

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

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

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

Serum cotinine cut-points for secondhand smoke exposure assessment in children under 5 years: A systemic review

Background

Serum cotinine has become the most widely used biomarker of secondhand smoke exposure (SHS) over time in all ages. The aim of this study was to review the serum cotinine cut-points used to classify children under 5 years as exposed to SHS.

Methods

A systematic review performed in the Pubmed (MEDLINE) and EMBASE databases up to April 2021 was conducted using as key words "serum cotinine", “tobacco smoke pollution” (MeSH), "secondhand smoke", "environmental tobacco smoke" and “tobacco smoke exposure”. Papers which assessed SHS exposure among children younger than 5 years old were included. The PRISMA 2020 guidelines were followed. Analysis was pre-registered in PROSPERO (registration number: CRD42021251263).

Results

247 articles were identified and 51 fulfilled inclusion criteria. The selected studies were published between 1985–2020. Most of them included adolescents and adults. Only three assessed postnatal exposure exclusively among children under 5 years. None of the selected studies proposed age-specific cut-points for children < 5 years old. Cut-point values to assess SHS exposure ranged from 0.015 to 100 ng/ml. The most commonly used cut-point was 0.05 ng/ml, derived from the assay limit of detection used by the National Health and Nutrition Examination Survey (NHANES).

Conclusions

No studies have calculated serum cotinine age-specific cut-points to ascertained SHS exposure among children under 5 years old. Children’s age-specific cut-points are warranted for health research and public health purposes aimed at accurately estimating the prevalence of SHS exposure and attributable burden of disease to such exposure, and at reinforcing 100% smoke-free policies worldwide, both in homes, private vehicles and public places.

Parental Adherence to Ideal Cardiovascular Health Status Was Associated With a Substantially Lower Prevalence of Overweight and Obesity in Their Offspring Aged 6-18 Years

Background: Parental health status had a potential influence on offspring health. This study aimed to investigate the separate associations between paternal and maternal cardiovascular health statuses and the prevalence of childhood overweight and obesity in the offspring. Methods: Data were from a cross-sectional study conducted in seven provinces or cities of China in 2013. A total of 29,317 children aged 6-18 years old and their parents, making up 9,585 father-offspring pairs and 19,732 mother-offspring pairs, were included in the final analysis. Information on parental cardiovascular health status factors (dietary behaviors, body mass index (BMI), smoking, physical activity, hypertension, and diabetes mellitus) was obtained from the structured self-administrated questionnaires. Based on the health status factors, we then generated an ideal cardiovascular health (iCVH) score. The overweight and obesity of children were defined using age- and sex-specific cutoffs based on the International Obesity Task Force criteria. A multilevel log-binomial regression model was used to assess the association between parental cardiovascular health status and prevalence of childhood overweight and obesity in the offspring. Results: The prevalence of pediatric overweight and obesity was 22.0% in the father-offspring subset and 23.8% in the mother-offspring subset, respectively. Fathers with ideal BMI, non-smoking, and absence of hypertension and diabetes, and mothers with ideal BMI, ideal physical activity, and absence of hypertension and diabetes were found to be associated with lower prevalence of overweight and obesity in the offspring. The prevalence of offspring overweight and obesity was significantly decreased with the parental iCVH scores increased. Each additional increase in paternal and maternal iCVH factor was associated with a 30% and 27% lower prevalence of overweight and obesity in the offspring. Compared with children whose parental iCVH scores ≤ 3, offspring whose fathers or mothers met all six iCVH factors had 67% [prevalence ratio (PR): 0.33, 95%CI: 0.25-0.42] and 58% (PR: 0.42, 95%CI: 0.29-0.62) lower prevalence of overweight and obesity, respectively. Conclusions: Parental adherence to iCVH status was associated with a lower prevalence of pediatric overweight and obesity in offspring. Our findings support the intervention strategy that parents should involve in the obesity intervention program for children.

Association between maternal smoking during pregnancy and offspring overweight in U.S.-born children

BACKGROUND

The criticism of the literature on smoking during pregnancy and offspring overweight was the confounding from postnatal factors. Interaction between gestational age and prenatal maternal smoking has not yet assessed.

METHODS

We used the Third National Health and Nutrition Examination Survey (1988-1994), linked with natality files of US-born singletons aged 2 to 6 years. A body mass index in the 85th percentile or higher were considered overweight, including obesity. Gestational age was dichotomized as preterm (<37 weeks, n = 240) or full-term (n = 2125). Smoking status during pregnancy was ascertained by a questionnaire-based interview during National Health and Nutrition Examination Survey.

RESULTS

The prevalence of offspring overweight and obesity combined was 17.3% (SE = 1.3%). And 24.0% (1.3%) of mothers smoked while pregnant. A significant interaction was observed between maternal smoking and gestational age. In preterm children, a higher prevalence of overweight (34.3% [6.7%]) was found among the offspring of smoking mothers compared to non-smoking mothers (15.8% [3.6%]). After adjustment for socio-demographics, prenatal and postnatal factors, in preterm born offspring, the odds ratio of being born to smoking mothers was 2.46 (95% confidence intervals: 1.13-5.37) among children with overweight/obesity compared to children with healthy weight born to non-smoking mothers. In full-term children, the OR of being born to smoking mothers was 0.72 (0.50-1.03) among offspring with overweight/obesity relative to offspring with healthy weight born to non-smoking mothers.

CONCLUSIONS

Maternal smoking during pregnancy was strongly associated with offspring overweight and obesity in preterm births after control for postnatal factors. Preterm children of smoking mothers should be prioritized for obesity prevention.

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

OBJECTIVE

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

INTRODUCTION

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

INCLUSION CRITERIA

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Impact of Carers' Smoking Status on Childhood Obesity in the Growing up in Ireland Cohort Study

Childhood obesity is a growing concern worldwide. The association between childhood obesity and maternal smoking and/or paternal smoking has been reported. However, few studies have explored the association between childhood obesity and exposure to carers’ smoking status. This study aimed to assess the impact of carers’ smoking status on childhood obesity in a cohort of children enrolled in the Growing up in Ireland (GUI) study. Participants from the GUI infant cohort were categorized into four groups based on their exposure status: Neither caregiver smoked (60.4%), only primary caregiver smoked (13.4%), both caregivers smoked (10.9%). Exposure to primary carers’ smoking (98% are biological mothers) was found to be significantly associated with childhood overweight/obesity at age three (Odds Ratio: 1.30, 95% CI: 1.17–1.46) and at age five (OR: 1.31, 95% CI: 1.16–1.49). Exposure to both carers’ smoking status was significantly associated with increased odds of childhood overweight/obesity across both waves. These findings emphasize the health burden of childhood obesity that may be attributable to maternal smoking postnatally and through early childhood in Ireland.

In utero sFlt-1 exposure differentially affects gene expression patterns in fetal liver

The soluble fms-like tyrosine kinase factor 1 (sFlt-1) is a major contributor to antiangiogenesis during preeclampsia. However, little is known about the effects of sFlt-1 on fetal health. In this study we aim to evaluate the effects of the sFlt-1 concentration during pregnancy on fetal liver physiology. We used adenoviral gene delivery in Sprague-Dawley dams (seven females, 10 weeks old) during mid-gestation (gestational day 8) with adenovirus overexpressing sFlt-1, and age-matched controls (six females, 10 weeks old) with empty adenoviral virus in order to quantify the sFlt-1 concentrations in pregnant dams. Dams exposed to adenoviral sFlt-1 delivery were subdivided into a low (n=4) and high sFlt-1 (n=3) group based on host response to the virus. One-way analysis of variance showed that fetuses (five per dam) exposed to high sFlt-1 concentrations in utero show fetal growth restriction (1.84±0.043 g high sFlt-1 v. 2.32±0.036 g control; mean (M)±s.e.m.; P&lt;0.001), without hypertension or proteinuria in the dams. In continuation, the microarray analysis of the fetal liver of the high sFlt-1 group showed significant enrichment of key genes for fatty acid metabolism and Ppara targets. In addition, using pyrosequencing, we found that the Ppara enrichment in the high sFlt-1 group is accompanied by decreased methylation of its promoter (1.89±0.097 mean % methylation in high sFlt-1 v. 2.26±0.095 mean % methylation in control, M±s.e.m., P&lt;0.02). Our data show that high sFlt-1 concentrations during pregnancy have detrimental effects on the fatty acid metabolism genes and the Ppara targets in the fetal liver.

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

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

The effect of paternal factors on perinatal and paediatric outcomes: a systematic review and meta-analysis

BACKGROUND

Maternal factors, including increasing childbearing age and various life-style factors, are associated with poorer short- and long-term outcomes for children, whereas knowledge of paternal parameters is limited. Recently, increasing paternal age has been associated with adverse obstetric outcomes, birth defects, autism spectrum disorders and schizophrenia in children.

OBJECTIVE AND RATIONALE

The aim of this systematic review is to describe the influence of paternal factors on adverse short- and long-term child outcomes.

SEARCH METHODS

PubMed, Embase and Cochrane databases up to January 2017 were searched. Paternal factors examined included paternal age and life-style factors such as body mass index (BMI), adiposity and cigarette smoking. The outcome variables assessed were short-term outcomes such as preterm birth, low birth weight, small for gestational age (SGA), stillbirth, birth defects and chromosomal anomalies. Long-term outcome variables included mortality, cancers, psychiatric diseases/disorders and metabolic diseases. The systematic review follows PRISMA guidelines. Relevant meta-analyses were performed.

OUTCOMES

The search included 14 371 articles out of which 238 met the inclusion criteria, and 81 were included in quantitative synthesis (meta-analyses). Paternal age and paternal life-style factors have an association with adverse outcome in offspring. This is particularly evident for psychiatric disorders such as autism, autism spectrum disorders and schizophrenia, but an association is also found with stillbirth, any birth defects, orofacial clefts and trisomy 21. Paternal height, but not BMI, is associated with birth weight in offspring while paternal BMI is associated with BMI, weight and/or body fat in childhood. Paternal smoking is found to be associated with an increase in SGA, birth defects such as congenital heart defects, and orofacial clefts, cancers, brain tumours and acute lymphoblastic leukaemia. These associations are significant although moderate in size, with most pooled estimates between 1.05 and 1.5, and none exceeding 2.0.

WIDER IMPLICATIONS

Although the increased risks of adverse outcome in offspring associated with paternal factors and identified in this report represent serious health effects, the magnitude of these effects seems modest.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

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

Association of prenatal passive smoking and metabolic gene polymorphisms with child growth from birth to 3years of age in the Hokkaido Birth Cohort Study on Environment and Children's Health

Although the effects of prenatal passive smoking on birth weight have been reported, the effects of metabolic gene polymorphisms on passive smoking have not been studied. Therefore, we investigated the effects of maternal passive smoking and metabolic gene polymorphisms on child growth up to 3years of age using cotinine as a biomarker. We included 1356 Japanese participants in a prospective cohort between 2003 and 2007 (cotinine levels at the third trimester≤0.21ng/mL and 0.22 to 11.48ng/mL for non-passive and passive smokers, respectively), and measured child outcomes such as weight, length, head circumference, and Kaup index. Additionally, we analyzed cytochrome P450 1A1 (CYP1A1), epoxide hydrolase 1 (EPHX1), and two N-acetyltransferase 2 (NAT2) genotypes using real-time polymerase chain reaction methods. Associations were investigated using multiple regression models. Kaup index gain from birth up to 3years of age was significantly smaller in children born to passive smokers than in those born to non-passive smokers (-0.34kg/m²; 95% confidence interval: -0.67, -0.01). Maternal CYP1A1 genotype was not associated with prenatal passive smoking and Kaup index gain, but was significantly associated with prenatal passive smoking and head circumference gain from birth up to 3years of age (-0.75cm; 95% confidence interval: -1.39, -0.12). Thus, this study suggests that prenatal passive smoking may have potent effects on postnatal growth from birth up to 3years of age. Moreover, children with maternal CYP1A1 genotype may be more susceptible to the effects of prenatal passive smoking.

Maternal smoking and risk of obesity in school children: Investigating early life theory from the GRECO study

Based on the Early Life Theory, maternal smoking may be a factor affecting child weight status, adiposity level and blood pressure later in life. The purpose of this study was primarily to examine the risk of maternal smoking during pregnancy with overweight and obesity, central and total adiposity in school children. Secondarily, to assess the effect of maternal smoking, with children's blood pressure (BP). Data from the Greek Childhood Obesity cross sectional study (GRECO), conducted from October 2008 to May 2009, were used. A total of 2400 questionnaires gathered from children and their parents were analysed. Maternal and gestational data were gathered by a self-administered questionnaire. Women were categorized as non-smokers or smokers if they smoked ≥ 1 cigarettes/day during pregnancy. Children's body weight, height, waist circumference and BP were measured. Multiple logistic and linear regression analysis was conducted, adjusting for covariates. Four models were used in the process. The study found that children of maternal-smokers were more likely to be overweight or obese (OR: 1.6 to 1.82) and to have a larger waist circumference (OR: 1.73 to 1.85), compared to children of non-smokers in all models used. Total fat percentage was not significantly associated with maternal smoking when adjusted. Systolic and diastolic BP was not associated with maternal smoking. Results of this study strengthen the need for smoking cessation during pregnancy in order to possibly reduce the childhood obesity epidemic. Creating public health awareness of the potential risk of maternal-smoking on children's weight status later in life is warranted.

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

Background

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

Methods

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

Results

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

Conclusion

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

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

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

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

Comparing Weight-for-Length Status of Young Children in Two Infant Feeding Programs

Objectives A cross-sectional study comparing weight-for-length status of children 6-24 months old who participated in Nurse-Family Partnership (NFP) or Special Supplemental Program for Women, Infants, and Children (WIC). Methods Secondary analysis of NFP (n = 44,980) and WIC (n = 31,294) national datasets was conducted to evaluate infant and toddler growth trajectories. Weight-for-length status was calculated at 6, 12, 18, and 24 months based on World Health Organization criteria. Demographics and breastfeeding rates were also evaluated. Binary logistic regression was used to calculate odds ratios for high weight-for-length (≥97.7 percentile) at each time point. Results At 6 months, approximately 10 % of WIC and NFP children were classified as high weight-for-length. High weight-for-length rates increased for both groups similarly until 24 months. At 24 months, NFP children had significantly lower rates of excess weight (P = 0.03) than WIC children, 15.5 and 17.5 % respectively. At all time points, non-Hispanic white children had lower rates of high-weight for length than Hispanic and non-Hispanic black children. NFP infants were also found to have higher rates of ever being breastfed than WIC infants (P < 0.0001). Conclusions for Practice Infant and toddler populations served by NFP or WIC were found to be at increased risk for high weight-for-length. This study found NFP participation was associated with a small, but significant, protective impact on weight-for-length status at 24 months. Continued efforts need to be made in addressing weight-related racial/ethnic and socioeconomic disparities during early childhood.

The association between passive and active tobacco smoke exposure and child weight status among Spanish children

OBJECTIVE

To assess the impact of passive and active tobacco smoke exposure, both pre- and postnatally, on child body mass index (BMI) and overweight.

METHODS

Pregnant women were enrolled into the Spanish INMA prospective birth cohort during 1997 to 2008. Tobacco smoke exposure was assessed by questionnaire and corroborated by pre- and postnatal cotinine measurements. Children were followed up until 4 years in newer subcohorts (N = 1866) and until 14 years in one older subcohort (N = 427). Child age- and sex-specific BMI Z-scores were calculated, and generalized estimating equations were used to model their relationship with repeated measures of tobacco smoke exposure.

RESULTS

Associations between prenatal passive exposure to tobacco smoke (adjusted β = 0.15, 95% CI: 0.05-0.25) and active maternal smoking (adjusted β = 0.20, 95% CI: 0.08-0.33) and child zBMI up to 4 years were observed. Stronger associations were observed in the older subcohort between both prenatal and child passive smoke exposure and zBMI up to 14 years.

CONCLUSIONS

Evidence for an effect of both passive and maternal active smoking on child postnatal growth has been provided. Although residual confounding cannot be completely ruled out, associations were robust to adjustment for a range of lifestyle factors.

A Novel Method to Describe Early Offspring Body Mass Index (BMI) Trajectories and to Study Its Determinants

Background

Accurately characterizing children’s body mass index (BMI) trajectories and studying their determinants is a statistical challenge. There is a need to identify early public health measures for obesity prevention. We describe a method that allows studies of the determinants of height, weight and BMI growth up to five years of age. We illustrated this method using maternal smoking during pregnancy as one of the early-life factors that is potentially involved in prenatal programming of obesity.

Methods

Individual height and weight trajectories were fitted using the Jenss-Bayley model on 28,381 and 30,515 measurements, respectively, from 1,666 children to deduce BMI trajectories. We assessed global associations between smoking and growth trajectories and cross-sectional associations at specific ages.

Results

Children exposed in late pregnancy had a 0.24 kg/m² (95% confidence interval: 0.07, 0.41) higher BMI at 5 years of age compared with non-exposed children. Although the BMIs of children exposed during late pregnancy became significantly higher compared with those of non-exposed children from 2 years onwards, the trajectories began to diverge during the first weeks of life.

Conclusion

Our method is relevant for studies on the relationships between individual-level exposures and the dynamics and shapes of BMI growth during childhood, including key features such as instantaneous growth velocities and the age or BMI value at the BMI infancy peak that benefit from the monotonic pattern of height and weight growth.

Maternal smoking in pregnancy association with childhood adiposity and blood pressure

BACKGROUND

Maternal smoking during pregnancy has been associated with increased risk of childhood overweight/obesity defined by body mass index (BMI). We examined its association with a range of adiposity measures and cardiovascular indicators in children aged 3-10 years.

METHODS

We used data from a cross-sectional study of schoolchildren across mainland Portuguese districts (2009-2010). We applied quantile regressions to examine maternal smoking associations with adiposity (n = 17 286), blood pressure (BP) and resting pulse rate (RPR) (n ≈ 2500) measures across the age range, adjusting for prenatal and early life factors.

RESULTS

Maternal smoking during pregnancy was associated with increases in offspring adiposity levels. The difference in median BMI between children of smokers and non-smokers was 0.39 kg m(-2) (95% confidence interval: 0.25, 0.53) in boys and 0.46 kg m(-2) (0.31, 0.62) in girls; 0.55 cm (0.24, 0.87) and 0.82 cm (0.45, 1.19), respectively, in median waist circumference; and 0.94 mm (0.49, 1.40) and 1.47 mm (0.87, 2.07) in median sum of (triceps, subscapular, suprailiac) skin-folds. The associations appeared to be stronger with increasing age. The differences in the 90th centile tended to be greater than those in median. There was no consistent association of maternal smoking with BP and RPR.

CONCLUSIONS

Children whose mother smoked during pregnancy had higher adiposity levels than children of non-smokers, across several measures, particularly among older children. Although there was no consistent association with cardiovascular indicators, maternal smoking association with childhood obesity may have implications for cardiovascular risk factors over the life course.

Maternal post-natal tobacco use and current parental tobacco use is associated with higher body mass index in children and adolescents: an international cross-sectional study

BACKGROUND

We investigated whether maternal smoking in the first year of life or any current parental smoking is associated with childhood or adolescent body mass index (BMI).

METHODS

Secondary analysis of data from a multi-centre, multi-country, cross-sectional study (ISAAC Phase Three). Parents/guardians of children aged 6-7 years completed questionnaires about their children's current height and weight, whether their mother smoked in the first year of the child's life and current smoking habits of both parents. Adolescents aged 13-14 years completed questionnaires about their height, weight and current parental smoking habits. A general linear mixed model was used to determine the association between BMI and parental smoking.

RESULTS

77,192 children (18 countries) and 194 727 adolescents (35 countries) were included. The BMI of children exposed to maternal smoking during their first year of life was 0.11 kg/m(2) greater than those who were not (P = 0.0033). The BMI of children of currently smoking parents was greater than those with non-smoking parents (maternal smoking: +0.08 kg/m(2) (P = 0.0131), paternal smoking: +0.10 kg/m(2) (P < 0.0001)). The BMI of female adolescents exposed to maternal or paternal smoking was 0.23 kg/m(2) and 0.09 kg/m(2) greater respectively than those who were not exposed (P < 0.0001). The BMI of male adolescents was greater with maternal smoking exposure, but not paternal smoking (0.19 kg/m(2), P < 0.0001 and 0.03 kg/m(2), P = 0.14 respectively).

CONCLUSION

Parental smoking is associated with higher BMI values in children and adolescents. Whether this is due to a direct effect of parental smoking or to confounding cannot be established from this observational study.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Age-specific influence of wheezing phenotypes on pre-adolescent and adolescent health-related quality of life

INTRODUCTION

Asthma is associated with diminished health-related quality of life (HRQoL). Particularly in adolescence, asthma may be under-diagnosed and undertreated or poorly managed. Therefore, we aimed to determine the association between childhood wheezing phenotypes rather than asthma and adolescent HRQoL in children aged 10-17 yr.

METHODS

We analyzed the data from two prospective population-based cohort studies (n = 604 and n = 1804) conducted in southern Germany with baseline assessments in 2000 and 2006 and follow-ups at frequent intervals. Parent-reported wheeze was categorized into never, early transient, persistent, and late-onset wheeze. We assessed child-reported HRQoL in seven scales using the validated KINDL-R. Multivariate linear regression models were computed.

RESULTS

Participants with late-onset wheeze had significantly lower values in all HRQoL scales, but physical well-being compared to never wheezers. Early transient wheeze was negatively associated with three HRQoL scales only (family, school, and total). These effects were confined to the oldest age group (≥13.5 yr) in one study. Persistent wheeze was not associated with HRQoL.

CONCLUSIONS

In teenagers, late-onset wheezers seem to be particularly vulnerable for impairments in psychosocial aspects of health-related quality of life. They may therefore require particular attention with regard to education about asthma management and potentially family-based psychosocial intervention.

Risk of childhood overweight after exposure to tobacco smoking in prenatal and early postnatal life

OBJECTIVE

To investigate the association between exposure to mothers smoking during prenatal and early postnatal life and risk of overweight at age 7 years, while taking birth weight into account.

METHODS

From the Danish National Birth Cohort a total of 32,747 families were identified with available information on maternal smoking status in child's pre- and postnatal life and child's birth weight, and weight and height at age 7 years. Outcome was overweight according to the International Obesity Task Force gender and age specific body mass index. Smoking exposure was categorized into four groups: no exposure (n = 25,076); exposure only during pregnancy (n = 3,343); exposure only postnatally (n = 140); and exposure during pregnancy and postnatally (n = 4,188). Risk of overweight according to smoking status as well as dose-response relationships were estimated by crude and adjusted odds ratios using logistic regression models.

RESULTS

Exposure to smoking only during pregnancy, or both during pregnancy and postnatally were both significantly associated with overweight at 7 years of age (OR: 1.31, 95% CI: 1.15-1.48, and OR: 1.76, 95% CI: 1.58-1.97, respectively). Analyses excluding children with low birth weight (<2,500 gram) revealed similar results. A significant prenatal dose-response relationship was found. Per one additional cigarette smoked per day an increase in risk of overweight was observed (OR: 1.02, 95% CI: 1.01-1.03). When adjusting for quantity of smoking during pregnancy, prolonged exposure after birth further increased the risk of later overweight in the children (OR 1.28, 95% CI:1.09-1.50) compared with exposure only in the prenatal period.

CONCLUSIONS

Mother's perinatal smoking increased child's OR of overweight at age 7 years irrespective of birth weight, and with higher OR if exposed both during pregnancy and in early postnatal life. Clear dose-response relationships were observed, which emphasizes the need for prevention of any tobacco exposure of infants.

Evidence of inappropriate cardiovascular risk assessment in middle-age women based on recommended cut-points for waist circumference

BACKGROUND AND AIMS

Diverse waist circumference thresholds for assessment of metabolic and cardiovascular risk in Caucasians are recommended by different health professional organizations. We aimed to determine optimal sex-specific thresholds for anthropometric measures showing the strongest association with cardiovascular risk factors in a cohort of middle-aged Germans.

METHODS AND RESULTS

Statistical analyses are based on data from 426 mothers and 267 fathers of participants of the Ulm Birth Cohort Study undergoing a clinical follow-up examination in 2008 (median age 41 years) using logistic regression analyses. The prevalence of many cardiometabolic risk factors was significantly higher in men than in women; hypertension: 45%/17% (p < 0.0001), apolipoprotein ratio B/A1 > 0.72: 35%/9% (<0.0001), hyperglycemia: 11%/14% (p = 0.3), which is in contrast to the predicted cardiovascular risk of 52%/70% and 24%/36% based on thresholds for waist circumference proposed by International Diabetes Federation and American Heart Association, respectively. We determined optimal thresholds for waist circumference between 90 and 95 cm for men and women. Using a threshold of 92 cm the prevalence of abdominal obesity was 59% in men and 24% in women, which was in agreement with the higher prevalence of overweight and obesity in men than in women (Body Mass Index (BMI) > 25: 64%/35%). The prediction of cardiometabolic risk factors by waist circumference and waist-to-height ratio did not outperform the prediction by BMI. In contrast to BMI, waist circumference was correlated with body height independent of sex.

CONCLUSION

Currently proposed thresholds for waist circumference spuriously overestimate the cardiovascular risk in women, but not in men in a German population.

Restrained and external-emotional eating patterns in young overweight children-results of the Ulm Birth Cohort Study

Childhood obesity is one of the greatest public health challenges in Western countries. Abnormal eating behavior is thought to be a developmental trajectory to obesity. The Eating Pattern Inventory for Children (EPI-C) has not been used for children as young as eight years, and possible associations with body weight have not yet been established. Five hundred and twenty-one children of the Ulm Birth Cohort Study (UBCS; age eight) filled out the EPI-C and BMI was assessed. Adequacy of the scales was tested with confirmatory factor analysis and a MANOVA and cluster analysis established associations between eating patterns and BMI. The factor structure of the EPI-C was confirmed (GFI = .968) and abnormal eating behavior was associated with overweight (χ²(8) = 79.29, p<.001). The EPI-C is a valid assessment tool in this young age group. Overweight children consciously restrain their eating.

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

BACKGROUND

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Cross-sectional and longitudinal changes in DNA methylation with age: an epigenome-wide analysis revealing over 60 novel age-associated CpG sites

Understanding the role of epigenetic modifications, e.g. DNA methylation, in the process of aging requires the characterization of methylation patterns in large cohorts. We analysed >480 000 CpG sites using Infinium HumanMethylation450 BeadChip (Illumina) in whole blood DNA of 965 participants of a population-based cohort study aged between 50 and 75 years. In an exploratory analysis in 400 individuals, 200 CpG sites with the highest Spearman correlation coefficients for the association between methylation and age were identified. Of these 200 CpGs, 162 were significantly associated with age, which was verified in an independent cohort of 498 individuals using mixed linear regression models adjusted for gender, smoking behaviour, age-related diseases and random batch effect and corrected for multiple testing by Bonferroni. In another independent cohort of 67 individuals without history of major age-related diseases and with a follow-up of 8 years, we observed a gain in methylation at 96% (52%, significant) of the positively age-associated CpGs and a loss at all (89%, significant) of the negatively age-associated CpGs in each individual while getting 8 years older. A regression model for age prediction based on 17 CpGs as predicting variables explained 71% of the variance in age with an average accuracy of 2.6 years. In comparison with cord blood samples obtained from the Ulm Birth Cohort Study, we observed a more than 2-fold change in mean methylation levels from birth to older age at 86 CpGs. We were able to identify 65 novel CpG sites with significant association of methylation with age.