Breastfeeding helps explain racial and socioeconomic status disparities in adolescent adiposity

Breastfeeding duration and brain-body development in 9-10-year-olds: modulating effect of socioeconomic levels

OBJECTIVE

To investigate relationships of breastfeeding duration with brain structure and adiposity markers in youth and how these relationships are modified by neighborhood socioeconomic environments (SEEs).

METHODS

This was a cross-sectional study of youth enrolled in the Adolescent Brain and Cognitive Development (ABCD) Study® (n = 7511). Mixed effects models examined associations of breastfeeding duration with global brain measures and adiposity markers, adjusting for sociodemographic, pre- and post-natal covariates. Stratified analysis was performed by area deprivation index (ADI) tertiles.

RESULTS

Total cortical surface area (SA) (False Discovery Rate - FDR corrected P < 0.001), cortical (FDR corrected P < 0.001) and subcortical gray matter (GM) volume (FDR corrected P < 0.001) increased with increased breastfeeding duration. Body mass index (BMI) z-scores (FDR corrected P = 0.001), waist circumference (FDR corrected P = 0.002) and waist-to-height ratio (WHtR) (FDR corrected P = 0.001) decreased with increased breastfeeding duration. Breastfeeding duration was inversely associated with adiposity in youth from high- and medium- ADI neighborhoods, but positively associated with SA across ADI tertiles.

CONCLUSIONS

In this cross-sectional study, longer breastfeeding duration was associated with lower adiposity indices, particularly in youth from lower SEEs and greater SA across SEE levels. Longer breastfeeding duration showed long-term associations with brain and body development for offspring.

IMPACT

Building on previous findings that longer breastfeeding duration is associated with healthier weight gain, lower obesity risk, and brain white matter development in infancy, our results find longer breastfeeding duration to be associated with lower adiposity indices and greater cortical and subcortical gray matter volume, and cortical surface area during peri-adolescence. Children from lower socioeconomic environments (SEEs) demonstrated stronger negative associations of breastfeeding duration and adiposity indices, and children across SEEs showed positive relationships between breastfeeding duration and cortical surface area. Promoting breastfeeding, particularly among women from lower SEEs would confer long-term benefits to offspring.

Associations of Prenatal Per- and Polyfluoroalkyl Substance (PFAS) Exposures with Offspring Adiposity and Body Composition at 16-20 Years of Age: Project Viva

BACKGROUND

Findings on the associations between prenatal PFAS exposures and offspring adiposity are inconsistent. Whether such associations may extend to adolescence is especially understudied.

OBJECTIVES

We investigated associations of prenatal PFAS exposures with offspring adiposity and body composition at 16-20 years of age.

METHODS

We studied 545 mother-child pairs in the prospective prebirth cohort Project Viva (Boston, Massachusetts). We measured six PFAS (PFOA, PFOS, PFNA, PFHxS, EtFOSAA, and MeFOSAA) in maternal early pregnancy (median age = 9.6 wk , range: 5.7-19.6 wk) plasma samples. At the late adolescence visit (median age = 17.4 y, range: 15.9-20.0 y), we obtained anthropometric measures and assessed body composition using bioelectrical impedance analysis and dual-energy X-ray absorptiometry. We examined associations of individual PFAS with obesity [i.e., age- and sex-specific body mass index (BMI) ≥ 95 th percentile] and adiposity and body composition using multivariable Poisson and linear regression models, respectively. We assessed PFAS mixture effects using Bayesian kernel machine regression (BKMR) and quantile g-computation. We used fractional-polynomial models to assess BMI trajectories (at 3-20 years of age) by prenatal PFAS levels.

RESULTS

Thirteen percent (n = 73 ) of the children had obesity in late adolescence. After multivariable adjustment, higher prenatal PFAS concentrations were associated with higher obesity risk [e.g., 1.59 (95% CI: 1.19, 2.12), 1.24 (95% CI: 0.98, 1.57), and 1.49 (95% CI: 1.11, 1.99) times the obesity risk per doubling of PFOS, PFOA, and PFNA, respectively]. BKMR showed an interaction between PFOA and PFOS, where the positive association between PFOS and obesity was stronger when PFOA levels were lower. Each quartile increment of the PFAS mixture was associated with 1.52 (95% CI: 1.03, 2.25) times the obesity risk and 0.52 (95% CI: - 0.02 , 1.06) kg / m 2 higher BMI. Children with higher prenatal PFOS, EtFOSAA, and MeFOSAA concentrations had higher rates of BMI increase starting from 9-11 years of age.

DISCUSSION

Prenatal PFAS exposures may have obesogenic effects into late adolescence. https://doi.org/10.1289/EHP12597.

Long-term benefits of breastfeeding on brain and body development among 9-10-year-olds: modulated by socioeconomic environment

Importance

It is yet unknown if breastfeeding (bf) benefits, to brain and body development of children, persist into peri-adolescence and vary by socioeconomic environments (SEEs).

Objective

We aim to investigate SEE-independent and SEE-modulated relationships between bf duration and child brain structure and adiposity markers during peri-adolescence.

Design setting and participants

This was a cross-sectional study of children aged 9-10 enrolled in the multi-center Adolescent Brain and Cognitive Development (ABCD) Study®.

Exposures

Bf duration was self-reported. Neighborhood-level SEE was assessed using area deprivation index (ADI).

Main Outcomes

T1-weighted magnetic resonance imaging was used to assess global brain measures: volumes of white, cortical, and subcortical gray matter (GM), cortical thickness, and surface area (SA). Adiposity markers included age- and sex-specific body mass index (BMI z- scores), waist circumference, and waist-to-height ratio (WHtR). Mixed effects models examined associations of bf duration with brain structure and adiposity markers controlling for sociodemographic, pre- and post-natal covariates. Stratified analysis was performed by tertiles of ADI.

Results

The sample consisted of 7,511 children (51.7% males; 18.8% no bf, 35.3% 1-6 months, 24.9% 7-12 months, 21.0% >12 months). Child's total SA (β (95% CI) = 0.053 (0.033, 0.074); FDR corrected P <0.001), cortical (β (95% CI) = 0.021 (0.010, 0.032); FDR corrected P <0.001) and subcortical GM volume (β (95% CI) = 0.016 (0.003, 0.030); FDR corrected P <0.001) increased monotonically with bf duration, after controlling for covariates. Child's BMI z -scores (β (95% CI) = -0.040 (-0.063, -0.016); FDR corrected P =0.001), waist circumference (β (95% CI) = -0.037 (-0.060, -0.014), FDR corrected P =0.002) and WHtR (β (95% CI) = -0.040 (-0.064, -0.018), FDR corrected P =0.001) decreased monotonically with increased bf duration, after controlling for covariates. Bf duration was inversely associated with adiposity in children from high- and medium-ADI neighborhoods. Bf duration was positively associated with SA across ADI tertiles.

Conclusions and Relevance

Our results imply that long-term benefits of bf on body and brain development in offspring increase as bf duration increases, particularly in children from low SEEs. Policies and social support aimed to incremental increases in bf duration among women from low SEEs would confer long-term benefits for offspring.

Key Points

Question: Do benefits of breastfeeding(bf), on children's brain and body development, persist long-term and are these benefits uniform across socioeconomic environments (SEEs)?Findings: Longer bf duration is associated with lower adiposity, greater cortical and subcortical gray matter volume, and cortical surface area in 9-10-year-old children. Children from lower SEEs showed stronger negative relationships between bf duration and adiposity. Children across all SEEs demonstrated positive relationships between bf duration and surface area.Meaning: Our results imply that long-term benefits to child brain and body development increase with bf duration; and children from lower SEEs benefited more from longer bf duration.

Work as an Understudied Driver of Racial Inequities in Breastfeeding

Breastfeeding inequities by race are a persistent public health problem in the United States. Inequities in occupation and working conditions likely contribute to relatively less breastfeeding among Black compared to White mothers, yet little research has addressed these interrelationships. Here, we offer a critical review of the literature and a conceptual framework to guide future research about work and racial inequities in breastfeeding. There is a strong public health case for promoting breastfeeding equity for mothers across race groups and occupation types. Existing theory suggests that employment opportunities and working conditions are a likely pathway that connects structural racism to Black-White breastfeeding inequities, in addition to other known factors. We propose a new conceptual model for studying the interrelationships among work, race, and breastfeeding outcomes.

Association between sociodemographic characteristics and age stopped breastfeeding on early childhood weight status

INTRODUCTION

Epidemiological studies have suggested that breastfeeding is associated with child weight status. However, the length of breastfeeding in relation to child weight remains poorly understood. Therefore, this study investigated the association between age stopped breastfeeding and child weight status by sociodemographic characteristics.

METHODS

This cross-sectional analysis utilized a nationally representative sample of 3248 U.S. children ages 2-6 years from 2009 to 2018, from parents interviewed as part of the National Health and Nutrition Examination Survey. Child body weight and height were measured during physical examination. Information on age stopped breastfeeding and other demographic characteristics were assessed using questionnaires. Multivariable logistic regression models were performed to examine the association between age stopped breastfeeding and child weight status, adjusting for potential confounders.

RESULTS

Children breastfed for ≤ 11 months had an increased odds of being overweight and obese with the strongest association observed among those classified as obese (OR=2.12; 95%CI 1.23, 3.64) compared with children breastfed for > 11-24 months. The association between breastfeeding and child weight status was observed by racial/ethnic groups. Non-Hispanic white and Black children breastfed for ≤ 11 months had an associated increased likelihood of being overweight than their counterparts breastfed for > 11-24 months. Among Hispanic children, we observed elevated odds of being obese when breastfed for ≤ 11 months (OR=1.98; 95%CI 1.00, 3.91) than those breastfed for > 11-24 months.

CONCLUSION

Child weight status was associated with age stopped breastfeeding, where likelihood of being overweight and obese were greatest among children breastfed for ≤ 11 months.

Prevalence of Overweight and Obesity Among African American Children and Adolescents: Risk Factors, Health Outcomes, and Prevention/Intervention Strategies

This paper examines the biological, psychosocial, cultural, and obesogenic environmental factors that might account for the high prevalence rates of overweight and obesity among African American young children (aged 2-11) and adolescents (aged 12-19). Research findings are discussed on the practices associated with the development of childhood obesity including maternal overweight and obesity, physiological predisposition, infant feeding practices, breastfeeding, rapid infant weight gain, sleep disruption, low nutrition diets, physical inactivity, and sedentary behavior. The psychological correlates of overweight and obesity are discussed. Consistent with the obesogenic arguments, this paper examines the development of childhood obesity as a function of socioeconomic disadvantages, social inequities, urban environmental contingencies, and media food product messages. The potential deleterious health consequences of overweight and obesity are discussed. There is an examination of the structural-level and individual-level prevention/intervention strategies necessary for sustainable declines in childhood overweight and obesity.

Breastfeeding and offspring's compassion and empathy in adulthood: A study with an over 30-year follow-up

This study investigated whether breastfeeding predicts offspring's dispositional compassion and empathy from early adulthood to middle age. The parents of the participants (N = 1,394) of the Young Finns study answered questions about breastfeeding in 1983, and the participants' compassion and empathy were evaluated in 1997-2012 (participants were aged 20-50 years). Breastfeeding did not predict the course of compassion or empathy in adulthood at the age of 20-50 years. The associations remained non-significant, when adjusted for age, gender, socioeconomic factors, and a wide range of characteristics of the family environment (including mother's gestational age; premature birth; birth weight; number of other children at home; parental mental disorder; parental relationship status; parental postnatal smoking; parental postnatal alcohol use; parenting behavior; and child's externalizing behavior). In conclusion, breastfeeding seems not to predict offspring's compassion or empathy in adulthood. The findings may present a hopeful perspective for children growing up with non-breastfeeding caregivers.

Feeding Practices and Infant Growth: Quantifying the Effects of Breastfeeding Termination and Complementary Food Introduction on BMI z-Score Growth Velocity through Growth Curve Models

BACKGROUND

Infant feeding practices are a focus of early obesity prevention. We tested whether infant growth velocity increased after breastfeeding termination and complementary food introduction.

METHODS

Our secondary analysis included a sample of 547 mother-infant dyads from a longitudinal randomized controlled trial conducted in Michigan and Colorado. Infant anthropometrics at birth, baseline, and 6- and 12-month follow-up were standardized to BMI-for-age z-score (ZBMI) according to World Health Organization (WHO) growth charts. We used growth curve models with time-varying predictors to quantify effects of breastfeeding termination and timing of complementary food introduction on growth velocity.

RESULTS

Median breastfeeding duration was 2.0 months [confidence interval (CI) = 2.0-2.5]; median introduction of complementary foods occurred at 3.0 months (CI = 2.8-3.2). Breastfed infants not yet introduced to complementary foods had an average ZBMI growth velocity of 0.050 (CI = -0.013 to 0.113) z-score units per month [zpm], not significantly faster than WHO growth trajectory (p = 0.118) defined as 0 zpm. Breastfeeding termination had negligible effect on ZBMI growth velocity (γ₁₁ = 0.001, CI = -0.027 to 0.030, p = 0.927). Introduction of complementary foods increased ZBMI growth velocity relative to an average child in the sample, but not significantly (γ₁₂ = 0.033, CI = -0.034 to 0.100, p = 0.334). Growth velocities for infants receiving complementary foods both before and after breastfeeding termination were significantly faster than the WHO growth trajectory (0.083 zpm, CI = 0.052-0.114, and 0.084 zpm, CI = 0.064-0.105, respectively, p's < 0.001).

CONCLUSIONS

Average postcomplementary food introduction growth velocity was significantly higher than WHO growth trajectory, but did not differ from the sample's initial average trajectory. Growth curve models can accurately estimate effects of feeding practices on infant growth to direct obesity prevention efforts.

Mediators of socioeconomic differences in adiposity among youth: a systematic review

BACKGROUND

Youth with a low socioeconomic position in developed countries are at a disproportionately higher risk of being overweight or obese than their counterparts. Tackling these inequalities requires that the mechanisms behind them are well understood.

OBJECTIVES

The aim of this review was to summarize existing evidence regarding the factors that mediate or contribute to the explanation of the relationship between socioeconomic position and adiposity among youth.

METHODS AND RESULTS

A systematic literature search, conducted using the databases Medline, Embase, Web of Science and PsycINFO, yielded 28 eligible studies. These studies were of low to moderate methodological quality. The most consistent mediators of the association between socioeconomic position and adiposity identified in this review were as follows: consumption of sugar-sweetened beverages, television viewing, computer use, parental body mass index, breastfeeding duration, breakfast consumption, maternal smoking during pregnancy and infant feeding practices. The mediating role of physical activity as well as fruit and vegetable consumption was found to be indeterminate. Other potential mediators were explored in too few studies to make conclusions about their mediating role.

CONCLUSION

The review found several modifiable factors that could be targeted as feasible in interventions aimed at reducing socioeconomic differences in overweight and obesity among youth.

A Review of the Relationship Between Socioeconomic Position and the Early-Life Predictors of Obesity

A range of important early-life predictors of later obesity have been identified. Children of lower socioeconomic position (SEP) have a steeper weight gain trajectory from birth with a strong socioeconomic gradient in child and adult obesity prevalence. An assessment of the association between SEP and the early-life predictors of obesity has been lacking. The review involved a two-stage process: Part 1, using previously published systematic reviews, we developed a list of the potentially modifiable determinants of obesity observable in the pre-natal, peri-natal or post-natal (pre-school) periods; and part 2, conducting a literature review of evidence for socioeconomic patterning in the determinants identified in part 1. Strong evidence was found for an inverse relationship between SEP and (1) pre-natal risk factors (pre-pregnancy maternal body mass index (BMI), diabetes and pre-pregnancy diet), (2) antenatal/peri natal risk factors (smoking during pregnancy and low birth weight) and (3) early-life nutrition (including breastfeeding initiation and duration, early introduction of solids, maternal and infant diet quality, and some aspects of the home food environment), and television viewing in young children. Less strong evidence (because of a lack of studies for some factors) was found for paternal BMI, maternal weight gain during pregnancy, child sleep duration, high birth weight and lack of physical activity in young children. A strong socioeconomic gradient exists for the majority of the early-life predictors of obesity suggesting that the die is cast very early in life (even pre-conception). Lifestyle interventions targeting disadvantaged women at or before child-bearing age may therefore be particularly important in reducing inequality. Given the likely challenges of reaching this target population, it may be that during pregnancy and their child's early years are more feasible windows for engagement.

Does Breastfeeding Protect Against Childhood Obesity? Moving Beyond Observational Evidence

Human milk is the optimal feeding choice for infants, as it dynamically provides the nutrients, immunity support, and other bioactive factors needed for infants at specific stages during development. Observational studies and several meta-analyses have suggested that breastfeeding is protective against development of obesity in childhood and beyond. However, these findings are not without significant controversy. This review includes an overview of observational findings to date, then focuses on three specific pathways that connect human milk and infant physiology: maternal obesity, microbiome development in the infant, and the development of taste preference and diet quality. Each of these pathways involves complex interactions between mother and infant, includes both biologic and non-biologic factors, and may have both direct and indirect effects on obesity risk in the offspring. This type of integrated approach to examining breastfeeding and childhood obesity is necessary to advance research in this area beyond observational findings.

Early feeding practices and family structure: associations with overweight in children

The aim of this review is to examine two factors that may be associated with development of childhood overweight: early feeding, namely exclusive breastfeeding practices; family structure. Findings from the Identification and prevention of Dietary- and lifestyle-induced health EFfects In Children and infantS (IDEFICS) study are presented in the context of the literature. IDEFICS is a multi-centre European study exploring the risks for overweight and obesity in children, which recruited 16,224 children aged 2-9 years from September 2007 to June 2008 at survey centres in Italy, Estonia, Cyprus, Belgium, Sweden, Hungary, Germany and Spain. Among the IDEFICS sample, after controlling for confounders, exclusive breastfeeding for 4-6 months was protective of overweight (including obesity) when compared with children never exclusively breastfed (OR 0·73, 95% CI 0·63, 0·85). Family structure and number of siblings may also be associated with overweight. IDEFICS children without siblings were more likely (OR 1·52, 95% CI 1·34, 1·72) to be overweight than their peers with siblings when controlling for factors related to childhood overweight such as country, parental education, parental weight, maternal age, child's age, birth weight and gender. Both early feeding practices and family structure play a role in the future development of obesity. The impact of breastfeeding on future development of overweight is dependent upon the dose. Exclusive breastfeeding for the recommended 6 months appears to be protective of overweight. Family structure is also an important component and emerging research suggests only children are at increased risk for overweight in comparison with those with siblings. In European countries, approximately 22 million children are overweight. Early dietary exposures, genetic, environmental and social factors have all been proposed as potential causal factors. Two such factors include exclusive breastfeeding and the impact of being an only child. We have investigated these two factors for associations with overweight; our studies, in the context of previous findings, are the focus of this review.

The role of early life factors in the development of ethnic differences in growth and overweight in preschool children: a prospective birth cohort

BACKGROUND

Ethnic differences in childhood and adulthood are known, but ethnic differences in preschool overweight and associated factors are less studied. We assessed ethnic differences in pre-school age overweight, and studied the mediating role of early life factors in this association. Furthermore, we assessed body mass index (BMI) z-score development from birth to age 4 years to study ethnic-specific differences in BMI z-score trajectory.

METHODS

We used data on 4581 children participating in a birth cohort who were born between 2002 and 2006 in Rotterdam, the Netherlands. Child's ethnicity was defined according to country of birth of the parents. Weight and length/height was repeatedly measured between 1 and 45 months of age. Overweight at age 4 years was defined according to cut-off points for BMI from the international obesity task force. We performed logistic regression to obtain independent estimates of the association between ethnicity and preschool-age overweight, and to assess the mediating role of early life risk factors. Mixed models were used to describe BMI-z development for each ethnic group from birth to preschool age.

RESULTS

Relative to native Dutch children, non-Dutch children were more likely to be overweight at age 4 years, except for Surinamese-Hindustani children. Socio-demographic factors, parental BMI, and infant weight change in the first 6 months after birth reduced associations. After full adjustment, Turkish (OR: 2.02, 95% CI: 1.34-3.04) and Antillean/Surinamese Creole (OR: 1.78, 95% CI: 1.06-3.02) children were still more likely to be overweight at age 4 years.

CONCLUSION

Ethnic differences on the prevalence of overweight in preschool children can be partially explained by maternal educational level, parental overweight and early infant weight change. These may be possible targets to reduce ethnic inequalities in preschool age overweight.

Infant feeding practices and prevalence of obesity in eight European countries - the IDEFICS study

OBJECTIVE

To assess the association between exclusive breast-feeding and childhood overweight.

DESIGN

Cross-sectional data are from the baseline survey of the longitudinal cohort study IDEFICS. Exclusive rather than partial breast-feeding is the focus of the study due to the theoretical relationship between exclusive breast-feeding and development of dietary self-regulation. Children's measured heights and weights were used to calculate weight status, while waist-to-height ratio (WtHR) and skinfold measures were examined as alternative indicators of adiposity and fat patterning.

SETTING

Examination centres in eight European countries (Italy, Estonia, Cyprus, Belgium, Sweden, Hungary, Germany and Spain).

SUBJECTS

The analysis included 14 726 children aged 2-9 years for whom early feeding practices were reported by parents in standardized questionnaires.

RESULTS

After controlling for education, income and other potential confounders, breast-feeding exclusively for 4-6 months was protective of overweight (including obesity) when compared with children never exclusively breast-fed (OR = 0·73; 95 % CI 0·63, 0·85) across all measures of overweight. Exclusively breast-feeding for 6 months offered slightly more protection than for 4 and 5 months combined (OR = 0·71; 95 % CI 0·58, 0·85). The associations could not be explained by socio-economic characteristics or maternal overweight.

CONCLUSIONS

This multi-country investigation indicated that exclusive breast-feeding for 4-6 months may confer protection against overweight in addition to other known benefits. There was no demonstrated benefit of exclusive breast-feeding for more than 6 months or combination feeding for any duration across all measures of overweight examined.

Integrating risks for type 2 diabetes across childhood: a life course perspective

Type 2 diabetes (T2DM) emerged among children, due in large measure to a strong physiological link between increased weight states and T2DM. In this article, cumulative risk factors for T2DM across childhood and its underlying mechanisms are reviewed. The points of intervention for T2DM should occur throughout childhood. The use of Halfon and Hochstein's framework enables practitioners and researchers in the nursing field to better understand a child's individual risk for T2DM. Only with this long view will prevention and interventions be successful in stemming the tide of the "twin epidemic" threatening children worldwide.

Prepregnancy body mass index, socioeconomic status, race/ethnicity and breastfeeding practices

OBJECTIVE

While socioeconomic status (SES) and race/ethnicity are known predictors of breastfeeding practices, the added disparity caused by the rising rates of obesity among women of childbearing age remains untested. The purpose of this study was to examine differences in breastfeeding initiation and duration among black, white and Hispanic women of low and middle SES within the context of prepregnancy body mass index (BMI).

METHODS

Data from the Early Childhood Longitudinal Study-Birth Cohort were analyzed. Adjusted logistic regression models were built to examine differences in breastfeeding initiation and duration for the three racial/ethnic groups of low and middle SES.

RESULTS

Normal BMI Hispanic women of low SES demonstrated higher rates of breastfeeding initiation (74%) compared to other groups. Overweight/obese black women of low SES had lower rates of breastfeeding initiation. Overweight/obese Hispanic women of middle SES were significantly less likely to continue breastfeeding up to 4 months (OR: 0.65, 95% CI: 0.41, 0.98) compared to their white counterparts. Among women who initiated breastfeeding, overweight/obese white women of low SES had the highest rate of stopping within two months of giving birth (66.7%).

CONCLUSIONS

Examination of SES and racial/ethnic differences within the context of prepregnancy weight revealed specific groups with low rates of breastfeeding initiation and duration. Interventions tailored for these at-risk groups are needed to increase the overall proportion of mothers and infants who benefit from the positive health outcomes associated with breastfeeding.

Combination feeding of breast milk and formula: evidence for shorter breast-feeding duration from the National Health and Nutrition Examination Survey

OBJECTIVE

To examine combination breast milk and formula-feeding (CBFF), defined as daily breast-feeding and formula-feeding begun in the first week of life and to examine associations between CBFF and overall breast-feeding duration.

STUDY DESIGN

We used the National Health and Nutrition Examination Survey, 1999-2006, to determine the prevalence of CBFF in both univariable and multivariable analyses. We examined breast-feeding duration using Kaplan-Meier and Cox proportional hazards analyses.

RESULTS

Among 6788 children ages 0-71 months, 8% were CBFF and 55% were exclusively breast-fed during the first week of life. Factors independently associated with CBFF were Hispanic ethnicity (adjusted OR, 3.81) and black race (adjusted OR, 2.59). CBFF was associated with decreased overall breast-feeding duration in the full cohort (P < .001) but not in the Hispanic or black subgroups. CBFF and formula-feeding, when compared with 4 months of exclusive breast-feeding, were associated with an increased risk for overweight/obesity between ages 2 and 6 years.

CONCLUSIONS

In a nationally representative sample, CBFF is associated with shorter overall breast-feeding duration in white but not Hispanic or black mother-baby dyads. A significant number of US infants, though breast-fed, do not receive the health benefits of exclusive breast-feeding.

Overweight at age two years in a multi-ethnic cohort (ABCD study): the role of prenatal factors, birth outcomes and postnatal factors

BACKGROUND

Childhood overweight/obesity is a major public health problem worldwide which disproportionally affects specific ethnic groups. Little is known about whether such differences already exist at an early age and which factors contribute to these ethnic differences. Therefore, the present study assessed possible ethnic differences in overweight at age 2 years, and the potential explanatory role of prenatal factors, birth outcomes and postnatal factors.

METHODS

Data were derived from a multi-ethnic cohort in the Netherlands (the ABCD study). Weight and height data of 3,156 singleton infants at age 2 years were used. Five ethnic populations were distinguished: Dutch native (n = 1,718), African descent (n = 238), Turkish (n = 162), Moroccan (n = 245) and other non-Dutch (n = 793). Overweight status was defined by the International Obesity Task Force guidelines. The explanatory role of prenatal factors, birth outcomes and postnatal factors in ethnic disparities in overweight (including obesity) was assessed by logistic regression analysis.

RESULTS

Compared to the native Dutch (7.1%), prevalence of overweight was higher in the Turkish (19.8%) and Moroccan (16.7%) group, whereas the prevalence was not increased in the African descent (9.2%) and other non-Dutch (8.8%) group. Although maternal pre-pregnancy body mass index partly explained the ethnic differences, the odds ratio (OR) of being overweight remained higher in the Turkish (OR: 2.66; 95%CI: 1.56-4.53) and Moroccan (OR: 2.11; 95%CI: 1.31-3.38) groups after adjusting for prenatal factors. The remaining differences were largely accounted for by weight gain during the first 6 months of life (postnatal factor). Maternal height, birth weight and gender were independent predictors for overweight at age 2 years, but did not explain the ethnic differences.

CONCLUSION

Turkish and Moroccan children in the Netherlands have 2- to 3-fold higher odds for being overweight at age 2 years, which is largely attributed to maternal pre-pregnancy BMI and weight gain during the first 6 months of life. Further study on the underlying factors of this early weight gain is required to tackle ethnic differences in overweight among these children.

Comparison of growth between native and immigrant infants between 0-3 years from the Dutch ABCD cohort

BACKGROUND

In the Netherlands separate reference charts have been developed for native and immigrant groups to deal with differences in growth patterns in later childhood. The use of these charts, however, is complicated by methodological issues; they do not represent all large Dutch immigrant groups in separate charts despite the differences that have been suggested and the evidence of ethnic disparities in growth dates back to 1997.

AIM

Anthropometric measurements from a contemporary multi-ethnic cohort study were created to quantify differences in childhood growth by creating growth charts, separately for boys and girls between the ages of 0-3 years.

SUBJECTS AND METHODS

The infants modelled in the charts had a mother born in the Netherlands (n = 3107), Suriname (n = 225), Turkey (n = 203) and Morocco (n = 336). Charts with and without correction for country of origin of the mother were created by using the LMST method.

RESULTS

All models including the covariate country of origin of the mother fitted the data better (p < 0.0005), but the observed differences were small.

CONCLUSION

Most remarkable differences were found in the BMI and weight measurements for age charts. Especially girls from mothers born in Turkey and Morocco had an increasingly heavier weight for their age than girls from mothers born in the Netherlands.

Early-life determinants of overweight and obesity: a review of systematic reviews

The aim of this paper was to review the evidence for early-life (from conception to 5 years of age) determinants of obesity. The design is review of published systematic reviews. Data sources included Medline, Embase, Web of Science, Cochrane Library, CINAHL, PsycINFO. Identification of 22 eligible reviews from a database of 12,021 independent publications. Quality of selected reviews assessed using the Assessment of Multiple Systematic Reviews score. Articles published after the reviews were used to confirm results. No review was classified as high quality, 11 as moderate and 11 as low. Factors associated with later overweight and obesity: maternal diabetes, maternal smoking, rapid infant growth, no or short breastfeeding, obesity in infancy, short sleep duration, <30 min of daily physical activity, consumption of sugar-sweetened beverages. Other factors were identified as potentially relevant, although the size of their effect is difficult to estimate. Maternal smoking, breastfeeding, infant size and growth, short sleep duration and television viewing are supported by better-quality reviews. It is difficult to establish a causal association between possible determinants and obesity, and the relative importance of each determinant. Future research should focus on early-life interventions to confirm the role of protective and risk factors and to tackle the high burden obesity represents for present and future generations.

[Social disparities in the prevalence of overweight and obesity in adolescents]

INTRODUCTION

Many social factors have a role in determining the risk of overweight/obesity in children and adolescents, and are the main barriers in their management. This study tries to define the effect that some familial and social factors have on the risk of overweight/obesity in children and adolescents.

METHOD

Population sample of 11- and 14-years old children recruited in three Primary Care Centres in Palencia. Their weight, height and skin folds were measured, and information gathered about sport activities, TV watching, and parental data (weight, height, educational status and occupation). Multivariate models were used to analyse the effect of these variables on the weight status and on the body fat.

RESULTS

Three hundred and twenty-two children were included. Prevalence of obesity was 5.6% and that of any degree of overweight was 28.9%. Overweight was not related to educational status or occupation, but it was more often found in males (OR 2.07; 95% CI; 1.12-3.83), in children whose father (OR 2.18; 95% CI; 1.14-4.15) or mother (OR 2.17; 95% CI; 1.18-3.98) were overweight, and in those who spent ≥2 h daily watching TV (OR 2.72; 95% CI; 1.43-5.19), and it was less frequent in 14 than in 11-year old children (OR 0.42; 95% CI; 0.23-0.78). Obesity was only related to a low educational level (OR 19.45; 95% CI; 1.95-193.82).

CONCLUSIONS

Overweight is related with genetic-environmental factors and the modern society way of life, and occurs across the whole social spectrum. But obesity is strongly related to a low educational status of the family, and it still is a marker for health disparities.

Maternal hospital experiences associated with breastfeeding at 6 months in a northern California county

A retrospective cohort study of infant-feeding practices at 6 months of age was conducted for 382 breastfed infants in a semirural northern California county. The authors hypothesized that almost exclusive breastfeeding at 6 months would be related to maternal experiences in the hospital. Multiple logistic regression analysis, controlling for maternal age and education, found that almost exclusive breastfeeding at 6 months was positively associated with receiving a telephone number for breastfeeding help from the hospital (odds ratio, 6.45; 95% confidence interval, 1.23-33.9), use of a breast pump in the first 6 months (odds ratio, 2.19; 95% confidence interval, 1.01-4.76), and gestational age (odds ratio, 2.26; 95% confidence interval, 1.08-4.71 for a 4-week age difference), whereas formula supplementation at the hospital had a negative association (odds ratio, 0.27; 95% confidence interval, 0.13-0.56). Making postpartum breastfeeding support easily accessible and offering breast pumps at low or no cost may help to increase exclusive breastfeeding rates in this county.

Maternal obesity, health status during pregnancy, and breastfeeding initiation and duration

OBJECTIVE

The purpose of this study was to determine whether maternal prepregnancy overweight/obesity has independent effects on breastfeeding initiation and duration and whether these effects are different for women who experience medical problems during pregnancy or labor/delivery complications in comparison with those who have no medical or labor/delivery complications.

METHODS

We used the early childhood longitudinal study-birth cohort data. Kaplan-Meier survival functions, logistic, and Cox regression modeling were used in the analyses.

RESULTS

Findings indicate that overweight/obese women with medical or labor/delivery complications were less likely to initiate breastfeeding in comparison with their counterparts of normal weight. We did not find an independent effect of prepregnancy overweight/obesity on breastfeeding initiation among women with no medical problems. This group of women, however, had an 11% increased risk of stopping breastfeeding with each additional month of breastfeeding duration in comparison to those of normal weight.

CONCLUSIONS

It is important to evaluate the health history and pregnancy complications among overweight/obese mothers in developing interventions for successful initiation and duration of breastfeeding.

Mediation analyses: applications in nutrition research and reading the literature

Mediation analysis is a newer statistical tool that is becoming more prominent in nutrition research. Its use provides insight into the relationship among variables in a potential causal chain. For intervention studies, it can define the influence of different programmatic components and, in doing so, allows investigators to identify and refine a program's critical aspects. We present an overview of mediation analysis, compare mediators with other variables (confounders, moderators, and covariates), and illustrate how mediation analysis permits interpretation of the change process. A framework is outlined for the critical appraisal of articles purporting to use mediation analysis. The framework's utility is demonstrated by searching the nutrition literature and identifying articles citing mediation cross referenced with the terms "nutrition," "diet," "food," and "obesity." Seventy-two articles were identified that involved human subjects and behavior outcomes, and almost half mentioned mediation without tests to define its presence. Tabulation of the 40 articles appropriately assessing mediation demonstrates an increase in these techniques' appearance and the breadth of nutrition topics addressed. Mediation analysis is an important new statistical tool. Familiarity with its methodology and a framework for assessing articles will allow readers to critically appraise the literature and make informed independent evaluations of works using these techniques.

Growth of breastfed infants

Understanding normal growth for the healthy breastfed infant is an important component of promoting and supporting child health in general and breastfeeding in particular. In this article, we summarize what is known regarding differences in growth between breastfed and formula-fed infants; we describe the development and use of infant growth references and growth standards; we introduce the new World Health Organization growth velocity standards for early infancy (which provide standards for gain in g/day during the first weeks of life); and, in closing, we present a snapshot of recent data from a cohort of breastfed newborns in Sacramento, CA, and examine how their early weight gain compares to the new growth velocity standards.

Current world literature

This bibliography is compiled by clinicians from the journals listed at the end of this publication. It is based on literature entered into our database between 1 February 2008 and 31 January 2009 (articles are generally added to the database about two and a half months after publication). In addition, the bibliography contains every paper annotated by reviewers; these references were obtained from a variety of bibliographic databases and published between the beginning of the review period and the time of going to press. The bibliography has been grouped into topics that relate to the reviews in this issue.