Effects of prolonged and exclusive breastfeeding on child height, weight, adiposity, and blood pressure at age 6.5 y: evidence from a large randomized trial

Impact of nutrition since early life on cardiovascular prevention

The cardiovascular disease represents the leading cause of morbidity and mortality in Western countries and it is related to the atherosclerotic process. Cardiovascular disease risk factors, such as dyslipidemia, hypertension, insulin resistance, obesity, accelerate the atherosclerotic process which begins in childhood and progresses throughout the life span. The cardiovascular disease risk factor detection and management through prevention delays the atherosclerotic progression towards clinical cardiovascular disease. Dietary habits, from prenatal nutrition, breastfeeding, complementary feeding to childhood and adolescence nutrition play a basic role for this topic.

The metabolic and neuroendocrine environment of the fetus is fundamental in the body’s “metabolic programming”. Further several studies have demonstrated the beneficial effects of breastfeeding on cardiovascular risk factors reduction. Moreover the introduction of complementary foods represents another important step, with particular regard to protein intake. An adequate distribution between macronutrients (lipids, proteins and carbohydrates) is required for correct growth development from infancy throughout adolescence and for prevention of several cardiovascular disease risk determinants in adulthood.

The purpose of this review is to examine the impact of nutrition since early life on disease.

La malattia cardiovascolare rappresenta la principale causa di morbilità e mortalità dei paesi occidentali ed è correlata a degenerazione vascolare aterosclerotica. I fattori di rischio cardiovascolari quali dislipidemia, ipertensione, insulino resistenza e obesità accelerano tale processo il cui esordio è noto sin dell’età pediatrica ed evolve nel corso della vita. L’individuazione e la cura dei fattori di rischio cardiovascolari mediante la prevenzione dei fattori causali ritardano la progressione dell’aterosclerosi e l’insorgenza dei sintomi cardiovascolari. La nutrizione svolge un ruolo preventivo fondamentale sin dall’epoca prenatale e nelle diverse età della crescita.

La condizione metabolica e neuro-endocrino cui è sottoposto il feto è rilevante per la “programmazione metabolica”. E’ dimostrata inoltre l’importanza delle modalità di allattamento e divezzamento con particolare interesse per l’assunzione di proteine nel controllo dei fattori di rischio cardiovascolari. La corretta distribuzione di macronutrienti (lipidi, proteine e carboidrati) dall’infanzia all’adolescenza favorisce una crescita corretta e risulta utile a prevenire l’insorgenza dei determinanti di rischio di malattia cardiovascolare in età adulta.

Nella presente review verrà esaminato l’impatto della nutrizione dalle più precoci fasi delle vita sul rischio cardiovascolare.

Q-learning for estimating optimal dynamic treatment rules from observational data

The area of dynamic treatment regimes (DTR) aims to make inference about adaptive, multistage decision-making in clinical practice. A DTR is a set of decision rules, one per interval of treatment, where each decision is a function of treatment and covariate history that returns a recommended treatment. Q-learning is a popular method from the reinforcement learning literature that has recently been applied to estimate DTRs. While, in principle, Q-learning can be used for both randomized and observational data, the focus in the literature thus far has been exclusively on the randomized treatment setting. We extend the method to incorporate measured confounding covariates, using direct adjustment and a variety of propensity score approaches. The methods are examined under various settings including non-regular scenarios. We illustrate the methods in examining the effect of breastfeeding on vocabulary testing, based on data from the Promotion of Breastfeeding Intervention Trial.

Exclusive breastfeeding and other foods in the first six months of life: effects on nutritional status and body composition of Brazilian children

OBJECTIVE

To evaluate the effect of exclusive breastfeeding and consumption of other foods in the first six months of life in the nutritional status and body composition of children.

METHODS

A retrospective cohort study with 185 children aged from 4 to 7 years was monitored during the first months of life in a program of support to breastfeeding. We evaluated weight, height, waist circumference, and body composition by using DEXA. The nutritional status was assessed by the BMI/age index. The parameters of adiposity were classified by using as the cutoff point, the 85th percentile of the sample itself, according to gender and age. Confounding factors considered were variables related to maternal, pregnancy, birth, sociodemographic, health, lifestyle, and diet. Bivariate and multivariate analyses were performed, the latter by means of multiple logistic regression.

RESULTS

The median exclusive breastfeeding was 3 months. Of the children, 42.7% received cow's milk and 35.7% received infant formula. Regarding nutritional status, 21.1% of the children showed changes. The variables of infant feeding were not independently associated with nutritional status and body composition of the children and there were no differences between the groups studied.

CONCLUSION

Breastfeeding was not a protective factor to overweight and body fat in children.

Childhood obesity

Childhood obesity has important consequences for health and wellbeing both during childhood and also in later adult life. The rising prevalence of childhood obesity poses a major public health challenge in both developed and developing countries by increasing the burden of chronic non-communicable diseases. Despite the urgent need for effective preventative strategies, there remains disagreement over its definition due to a lack of evidence on the optimal cut-offs linking childhood BMI to disease risks, and limited evidence on the most effective components of interventions to prevent childhood obesity. This article reviews the trends in childhood obesity, its genetic, nutritional and other risk factors, and preventative and treatment strategies. Particular emphasis is given to early-onset obesity in pre-school children, which, as a precursor to later childhood and adult obesity, provides insights into the developmental and genetic origins of obesity and also offers the potential for early preventative approaches with long-lasting benefits.

An information criterion for marginal structural models

Marginal structural models were developed as a semiparametric alternative to the G-computation formula to estimate causal effects of exposures. In practice, these models are often specified using parametric regression models. As such, the usual conventions regarding regression model specification apply. This paper outlines strategies for marginal structural model specification and considerations for the functional form of the exposure metric in the final structural model. We propose a quasi-likelihood information criterion adapted from use in generalized estimating equations. We evaluate the properties of our proposed information criterion using a limited simulation study. We illustrate our approach using two empirical examples. In the first example, we use data from a randomized breastfeeding promotion trial to estimate the effect of breastfeeding duration on infant weight at 1 year. In the second example, we use data from two prospective cohorts studies to estimate the effect of highly active antiretroviral therapy on CD4 count in an observational cohort of HIV-infected men and women. The marginal structural model specified should reflect the scientific question being addressed but can also assist in exploration of other plausible and closely related questions. In marginal structural models, as in any regression setting, correct inference depends on correct model specification. Our proposed information criterion provides a formal method for comparing model fit for different specifications.

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.

Optimal duration of exclusive breastfeeding

BACKGROUND

Although the health benefits of breastfeeding are widely acknowledged, opinions and recommendations are strongly divided on the optimal duration of exclusive breastfeeding. Since 2001, the World Health Organization has recommended exclusive breastfeeding for six months. Much of the recent debate in developed countries has centred on the micronutrient adequacy, as well as the existence and magnitude of health benefits, of this practice.

OBJECTIVES

To assess the effects on child health, growth, and development, and on maternal health, of exclusive breastfeeding for six months versus exclusive breastfeeding for three to four months with mixed breastfeeding (introduction of complementary liquid or solid foods with continued breastfeeding) thereafter through six months.

SEARCH METHODS

We searched The Cochrane Library (2011, Issue 6), MEDLINE (1 January 2007 to 14 June 2011), EMBASE (1 January 2007 to 14 June 2011), CINAHL (1 January 2007 to 14 June 2011), BIOSIS (1 January 2007 to 14 June 2011), African Index Medicus (searched 15 June 2011), Index Medicus for the WHO Eastern Mediterranean Region (IMEMR) (searched 15 June 2011), LILACS (Latin American and Caribbean Health Sciences) (searched 15 June 2011). We also contacted experts in the field.The search for the first version of the review in 2000 yielded a total of 2668 unique citations. Contacts with experts in the field yielded additional published and unpublished studies. The updated literature review in December 2006 yielded 835 additional unique citations.

SELECTION CRITERIA

We selected all internally-controlled clinical trials and observational studies comparing child or maternal health outcomes with exclusive breastfeeding for six or more months versus exclusive breastfeeding for at least three to four months with continued mixed breastfeeding until at least six months. Studies were stratified according to study design (controlled trials versus observational studies), provenance (developing versus developed countries), and timing of compared feeding groups (three to seven months versus later).

DATA COLLECTION AND ANALYSIS

We independently assessed study quality and extracted data.

MAIN RESULTS

We identified 23 independent studies meeting the selection criteria: 11 from developing countries (two of which were controlled trials in Honduras) and 12 from developed countries (all observational studies). Definitions of exclusive breastfeeding varied considerably across studies. Neither the trials nor the observational studies suggest that infants who continue to be exclusively breastfed for six months show deficits in weight or length gain, although larger sample sizes would be required to rule out modest differences in risk of undernutrition. In developing-country settings where newborn iron stores may be suboptimal, the evidence suggests that exclusive breastfeeding without iron supplementation through six months may compromise hematologic status. Based on the Belarusian study, six months of exclusive breastfeeding confers no benefit (versus three months of exclusive breastfeeding followed by continued partial breastfeeding through six months) on height, weight, body mass index, dental caries, cognitive ability, or behaviour at 6.5 years of age. Based on studies from Belarus, Iran, and Nigeria, however, infants who continue exclusive breastfeeding for six months or more appear to have a significantly reduced risk of gastrointestinal and (in the Iranian and Nigerian studies) respiratory infection. No significant reduction in risk of atopic eczema, asthma, or other atopic outcomes has been demonstrated in studies from Finland, Australia, and Belarus. Data from the two Honduran trials and from observational studies from Bangladesh and Senegal suggest that exclusive breastfeeding through six months is associated with delayed resumption of menses and, in the Honduran trials, more rapid postpartum weight loss in the mother.

AUTHORS' CONCLUSIONS

Infants who are exclusively breastfed for six months experience less morbidity from gastrointestinal infection than those who are partially breastfed as of three or four months, and no deficits have been demonstrated in growth among infants from either developing or developed countries who are exclusively breastfed for six months or longer. Moreover, the mothers of such infants have more prolonged lactational amenorrhea. Although infants should still be managed individually so that insufficient growth or other adverse outcomes are not ignored and appropriate interventions are provided, the available evidence demonstrates no apparent risks in recommending, as a general policy, exclusive breastfeeding for the first six months of life in both developing and developed-country settings.

What do Kramer's Baby-Friendly Hospital Initiative PROBIT studies tell us? A review of a decade of research

BACKGROUND

Kramer et al's PROBIT (Promotion of Breastfeeding Intervention Trial) research in Belarus studied effects of the Baby-Friendly Hospital Initiative (BFHI) training on breastfeeding duration, exclusivity, and health outcomes.

AIMS

To critique inclusion criteria, context, approaches to data analysis, and health outcome results.

METHOD

Twenty-two articles were retrieved from PubMed and the PROBIT Website for 2001-2010; 6 were excluded as not focusing on breastfeeding and health outcomes.

RESULTS

PROBIT data from the cluster randomized hospital comparisons included only breastfed babies since all non-breastfed babies were excluded from the research. Context may affect outcomes, knowing that Belarus has good basic health services, 3-year maternity leaves with little use of daycare, 95% breastfeeding initiation rate, and a well-educated population. PROBIT data were analyzed in 2 ways: (a) intent-to-treat analyses of breastfeeding and health differences by cluster randomized intervention and control site mother/baby pairs; and (b) as an observational cohort study of health outcomes for all mother/baby pairs, analyzed by various breastfeeding categorizations and controlling for biases. PROBIT demonstrated links between BFHI and longer breastfeeding duration (19.7% vs 11.4% at 12 months, P < .001) and exclusivity (43.3% vs 6.4% at 3 months, P < .001), reductions in gastrointestinal episodes and rashes, higher verbal IQ scores, and longer exclusive breastfeeding rates for subsequent children but no statistically significant differences in the child's body mass index, blood pressure, or dental health.

CONCLUSION

PROBIT provides foundational evidence for BFHI policy and follow-up care. Knowing that non-breastfed babies were excluded, caution must be exercised for health comparisons.

Infant nutrition and later health: a review of current evidence

There is a growing recognition of the need for a lifecourse approach to understanding the aetiology of adult disease, and there is now significant evidence that links patterns of infant feeding to differences in health outcomes, both in the short and longer term. Breastfeeding is associated with lower rates of infection in infancy; in high-income populations, it is associated with reductions in blood pressure and total blood cholesterol, and lower risks of obesity and diabetes in adult life. Breastfeeding rates are suboptimal in many countries, and strategies to promote breastfeeding could therefore confer important benefits for health at a population level. However, there are particular challenges in defining nutritional exposures in infancy, including marked social gradients in initiation and duration of breastfeeding. In recent studies of low and middle-income populations of children and young adults, where the influences on infant feeding practice differ, beneficial effects of breastfeeding on blood pressure, BMI and risk of diabetes have not been confirmed, and further information is needed. Little is currently known about the long-term consequences of differences in the timing and nature of the weaning diet. Future progress will depend on new studies that provide detailed prospective data on duration and exclusivity of breastfeeding together with appropriate characterisation of the weaning diet.

Determinants of infant formula use and relation with growth in the first 4 months

The wide variety of infant formula available on the market can be confusing for parents and physicians. We aimed to determine associations between predominant type of formula used from birth to 4 months and parental and child characteristics and type of physician consulted, and then to describe relations between type of formula used and growth. Our analyses included 1349 infants from the EDEN mother-child cohort. Infant's feeding mode and type of formula used were assessed at 4 months by maternal self-report. Infant's weight and height from birth to 4 months, measured in routine follow-up, were documented by health professionals in the infant's personal health record. Anthropometric z-scores were calculated by using World Health Organization growth standards. Multinomial logistic regression was used to identify factors associated with the type of formula predominantly used; relations with growth were analysed by linear regressions. Partially hydrolysed formulas were more likely to be used by primiparous women (P < 0.001), those breastfeeding longer (P < 0.001) and for infants with family history of allergies (P = 0.002). Thickened formulas were more often used by mothers returning to employment in the first 4 months (P = 0.05) and breastfeeding shortly (P < 0.001). No significant relation was found between infant's growth and type of formula (P > 0.20). Infants breastfed shorter showed higher weight-for-age (P < 0.001) and length-for-age (P = 0.001) z-score changes between birth and 4 months. The use of a specific type of infant formula seems to be mainly related to parental characteristics. Infant's growth in the first 4 months is related to other factors than to the type of formula used.

Associations of infant nutrition with insulin resistance measures in early adulthood: evidence from the Barry-Caerphilly Growth (BCG) study

Background

Previous studies suggest that over-nutrition in early infancy may programme long-term susceptibility to insulin resistance.

Objective

To assess the association of breast milk and quantity of infant formula and cows' milk intake during infancy with insulin resistance measures in early adulthood.

Design

Long-term follow-up of the Barry Caerphilly Growth cohort, into which mothers and their offspring had originally been randomly assigned, between 1972–1974, to receive milk supplementation or not. Participants were the offspring, aged 23–27 years at follow-up (n = 679). Breastfeeding and formula/cows' milk intake was recorded prospectively by nurses. The main outcomes were insulin sensitivity (ISI₀) and insulin secretion (CIR₃₀).

Results

573 (84%) individuals had valid glucose and insulin results and complete covariate information. There was little evidence of associations of breastfeeding versus any formula/cows' milk feeding or of increasing quartiles of formula/cows' milk consumption during infancy (<3 months) with any outcome measure in young adulthood. In fully adjusted models, the differences in outcomes between breastfeeding versus formula/cows' milk feeding at 3 months were: fasting glucose (−0.07 mmol/l; 95% CI: −0.19, 0.05); fasting insulin (8.0%; −8.7, 27.6); ISI₀ (−6.1%; −11.3, 12.1) and CIR₃₀ (3.8%; −19.0, 32.8). There was also little evidence that increasing intakes of formula/cows' milk at 3 months were associated with fasting glucose (increase per quartile of formula/cows' milk intake = 0.00 mmol/l; −0.03, 0.03); fasting insulin (0.8%; −3.2, 5.1); ISI ₀ (−0.9%; −5.1, 3.5) and CIR₃₀ (−2.6%; −8.4, 3.6).

Conclusions

We found no evidence that increasing consumption of formula/cows' milk in early infancy was associated with insulin resistance in young adulthood.

Ongoing monitoring of data clustering in multicenter studies

Background

Multicenter study designs have several advantages, but the possibility of non-random measurement error resulting from procedural differences between the centers is a special concern. While it is possible to address and correct for some measurement error through statistical analysis, proactive data monitoring is essential to ensure high-quality data collection.

Methods

In this article, we describe quality assurance efforts aimed at reducing the effect of measurement error in a recent follow-up of a large cluster-randomized controlled trial through periodic evaluation of intraclass correlation coefficients (ICCs) for continuous measurements. An ICC of 0 indicates the variance in the data is not due to variation between the centers, and thus the data are not clustered by center.

Results

Through our review of early data downloads, we identified several outcomes (including sitting height, waist circumference, and systolic blood pressure) with higher than expected ICC values. Further investigation revealed variations in the procedures used by pediatricians to measure these outcomes. We addressed these procedural inconsistencies through written clarification of the protocol and refresher training workshops with the pediatricians. Further data monitoring at subsequent downloads showed that these efforts had a beneficial effect on data quality (sitting height ICC decreased from 0.92 to 0.03, waist circumference from 0.10 to 0.07, and systolic blood pressure from 0.16 to 0.12).

Conclusions

We describe a simple but formal mechanism for identifying ongoing problems during data collection. The calculation of the ICC can easily be programmed and the mechanism has wide applicability, not just to cluster randomized controlled trials but to any study with multiple centers or with multiple observers.

Community volunteers can improve breastfeeding among children under six months of age in the Democratic Republic of Congo crisis

Background

Malnutrition is a major public health problem in developing countries and exclusive breastfeeding is an efficient strategy that can be used to prevent malnutrition and reduce child mortality. The objective of this study is to evaluate the effectiveness of community volunteers in promoting exclusive breastfeeding from birth in an area of endemic malnutrition.

Methods

This evaluation analyzed the impact of the community-based nutrition project in Katana health district of the Democratic Republic of Congo from 2004 to 2006. Each of the villages in this sector had a nutritional village committee made up of five members responsible for continuously working to raise awareness of the importance of exclusive breastfeeding from birth among pregnant women and community leaders in their respective villages. The program worked with community volunteers with a mean age of 37 years, most of whom were married (86%). Eighty percent of the community volunteers had completed secondary school or a higher level of education. Data related to the period of exclusive breastfeeding and to the number of visits made to the health services for 208 children. The data were compared with data from 178 infants collected from another health sector, which had never developed a community-based nutrition program.

Results

The duration of exclusive breastfeeding from birth (median, range) was 6 months (2 to 7) in the intervention area compared with 4 months (1 to 6) in the comparison area (p < 0.001). The proportion of infants receiving exclusive breastfeeding at six months of age was higher in the intervention area than in the comparison area: 57.7% (95% Confidence Interval, CI, 50.9 to 64.5) versus 2.7% (95%CI, 1.1 to 6.6) (p < 0.001). The intervention group had a higher mean weight at 12 months (standard deviation): 8.42 kg (1.41) compared to 7.97 kg (1.02), although this difference was not statistically significant (p = 0.055).

Conclusions

The promotion of breastfeeding by community volunteers in an area of endemic malnutrition in rural Democratic Republic of Congo increased the duration of exclusive breastfeeding from birth.

The relationship between breastfeeding and weight status in a national sample of Australian children and adolescents

Background

Breastfeeding has been shown consistently in observational studies to be protective of overweight and obesity in later life. This study aimed to investigate the association between breastfeeding duration and weight status in a national sample of Australian children and adolescents.

Methods

A secondary analysis of the 2007 Australian National Children's Nutrition and Physical Activity Survey data involving 2066, males and females aged 9 to 16 years from all Australian states and territories. The effect of breastfeeding duration on weight status was estimated using multivariate logistic regression analysis.

Results

Compared to those who were never breastfed, children breastfed for ≥6 months were significantly less likely to be overweight (adjusted odds ratio: 0.64, 95%CI: 0.45, 0.91) or obese (adjusted odds ratio: 0.51, 95%CI: 0.29, 0.90) in later childhood, after adjustment for maternal characteristics (age, education and ethnicity) and children's age, gender, mean energy intake, level of moderate and vigorous physical activity, screen time and sleep duration.

Conclusions

Breastfeeding for 6 or more months appears to be protective against later overweight and obesity in this population of Australian children. The beneficial short-term health outcomes of breastfeeding for the infant are well recognised and this study provides further observational evidence of a potential long-term health outcome and additional justification for the continued support and promotion of breastfeeding to six months and beyond.

The impact of neonatal breast-feeding on growth trajectories of youth exposed and unexposed to diabetes in utero: the EPOCH Study

Objective

To evaluate the influence of breastfeeding on the body mass index (BMI) growth trajectory from birth through 13 years of age among offspring of diabetic pregnancies (ODP) and offspring of non-diabetic pregnancies (ONDP) participating in the EPOCH study.

Subjects

There were 94 ODP and 399 ONDP who had multiple BMI measures obtained from birth throughout childhood. A measure of breast milk-months was derived from maternal self-report to categorize breastfeeding status as adequate (≥6 breast milk-months) or low (<6 breast milk-months). Mixed linear effects models were constructed to assess the impact of breastfeeding on the BMI growth curves during infancy (birth to 27 months) and childhood (27 months to 13 years).

Results

ODP who were adequately breastfed had a slower BMI growth trajectory during childhood (p=0.047) and slower period-specific growth velocity with significant differences between 4 to 6 years of age (p=0.03) and 6 to 9 years of age (p=0.01) compared to ODP with low breastfeeding. A similar pattern was seen in the ONDP, with adequate breastfeeding associated with lower average BMI in infancy (p=0.03) and childhood (p=0.0002) and a slower growth trajectory in childhood (p=0.0002). Slower period-specific growth velocity was seen among the ONDP associated with adequate breastfeeding with significant differences between 12–26 months (p=0.02), 4–6 years (p=0.03), 6–9 years (p=0.0001) and 9–13 years of age (p<.0001).

Conclusion

Our study provides novel evidence that breastfeeding is associated with long-term effects on childhood BMI growth that extend beyond infancy into early and late childhood. Importantly, these effects are also present in the high-risk offspring, exposed to overnutrition during pregnancy. Breastfeeding in the early postnatal period may represent a critical opportunity to reduce the risk of childhood obesity.

Global nutrition transition and the pandemic of obesity in developing countries

Decades ago, discussion of an impending global pandemic of obesity was thought of as heresy. But in the 1970s, diets began to shift towards increased reliance upon processed foods, increased away-from-home food intake, and increased use of edible oils and sugar-sweetened beverages. Reductions in physical activity and increases in sedentary behavior began to be seen as well. The negative effects of these changes began to be recognized in the early 1990s, primarily in low- and middle-income populations, but they did not become clearly acknowledged until diabetes, hypertension, and obesity began to dominate the globe. Now, rapid increases in the rates of obesity and overweight are widely documented, from urban and rural areas in the poorest countries of sub-Saharan Africa and South Asia to populations in countries with higher income levels. Concurrent rapid shifts in diet and activity are well documented as well. An array of large-scale programmatic and policy measures are being explored in a few countries; however, few countries are engaged in serious efforts to prevent the serious dietary challenges being faced.

Prevention of Overweight in Infancy (POI.nz) study: a randomised controlled trial of sleep, food and activity interventions for preventing overweight from birth

BACKGROUND

Rapid weight gain during the first three years of life predicts child and adult obesity, and also later cardiovascular and other morbidities. Cross-sectional studies suggest that infant diet, activity and sleep are linked to excessive weight gain. As intervention for overweight children is difficult, the aim of the Prevention of Overweight in Infancy (POI.nz) study is to evaluate two primary prevention strategies during late pregnancy and early childhood that could be delivered separately or together as part of normal health care.

METHODS/DESIGN

This four-arm randomised controlled trial is being conducted with 800 families recruited at booking in the only maternity unit in the city of Dunedin, New Zealand. Mothers are randomised during pregnancy to either a usual care group (7 core contacts with a provider of government funded "Well Child" care over 2 years) or to one of three intervention groups given education and support in addition to "Well Child" care: the Food, Activity and Breastfeeding group which receives 8 extra parent contacts over the first 2 years of life; the Sleep group which receives at least 3 extra parent contacts over the first 6 months of life with a focus on prevention of sleep problems and then active intervention if there is a sleep problem from 6 months to 2 years; or the Combination group which receives all extra contacts. The main outcome measures are conditional weight velocity (0-6, 6-12, 12-24 months) and body mass index z-score at 24 months, with secondary outcomes including sleep and physical activity (parent report, accelerometry), duration of breastfeeding, timing of introduction of solids, diet quality, and measures of family function and wellbeing (parental depression, child mindedness, discipline practices, family quality of life and health care use). This study will contribute to a prospective meta-analysis of early life obesity prevention studies in Australasia.

DISCUSSION

Infancy is likely to be the most effective time to establish patterns of behaviour around food, activity and sleep that promote healthy child and adult weight. The POI.nz study will determine the extent to which sleep, food and activity interventions in infancy prevent the development of overweight.

TRIAL REGISTRATION

Clinical Trials NCT00892983. Prospective meta-analysis registered on PROSPERO CRD420111188. Available from http://www.crd.york.ac.uk/PROSPERO.

Associations of growth trajectories in infancy and early childhood with later childhood outcomes

BACKGROUND

Weight and length at birth (which represent fetal growth) and weight and length or height gain during childhood (which potentially represent catch-up growth) may be related to later health outcomes. However, methods for the assessment of such relations are complex and underdeveloped.

OBJECTIVES

We aimed to describe childhood weight and length or height trajectories and to relate these to later outcomes by using rash at age 6.5 y as an example.

DESIGN

The data came from a prospective cohort study in Belarus in 10,494 children born in 31 hospitals that participated in a cluster randomized trial of breastfeeding promotion. Weight and length or height were measured at birth, at scheduled clinic visits up to 1 y, and at 6.5 y; intermediate measures were obtained from routine child health records. Linear spline multilevel models for weight and length or height were used to estimate each child's deviance from average birth weight, birth length, weight, and length or height gain velocity in each time period. Logistic regression was used to relate the outcome (parental report of rash at 6.5 y) to these weight and length or height estimates.

RESULTS

The best-fitting splines for length or height and weight had knots at 3 and 12 mo, with another knot at 34 mo for height. The only relation between weight and length or height and reported rash was a positive association with weight gain velocity between 12 and 34 mo (odds ratio per SD increase in weight gain velocity: 1.11; 95% CI: 1.01, 1.22).

CONCLUSION

Advantages of multilevel models include no restriction to measures at arbitrary times or to individuals with complete data and allowance for measurement error. This trial was registered at isrctn.org as ISRCTN37687716.

Breastfeeding duration, age of starting solids and high BMI risk and adiposity in Indian children

This study utilized data from a prospective birth cohort study on 568 Indian children, to determine whether a longer duration of breastfeeding and later introduction of solid feeding were associated with a reduced higher body mass index (BMI) and less adiposity. Main outcomes were high BMI (>90th within-cohort sex-specific BMI percentile) and sum of skinfold thickness (triceps and subscapular) at age 5. Main exposures were breastfeeding (six categories from 1-4 to ≥21 months) and age of starting regular solid feeding (four categories from ≤3 to ≥6 months). Data on infant-feeding practices, socio-economic and maternal factors were collected by questionnaire. Birthweight, maternal and child anthropometry were measured. Multiple regression analysis that accounted for potential confounders demonstrated a small magnitude of effect for breastfeeding duration or introduction of solid feeds on the risk of high BMI but not for lower skinfold thickness. Breastfeeding duration was strongly negatively associated with weight gain (0-2 years) [adjusted β = -0.12 standard deviation, 95% confidence interval (CI): -0.19 to -0.05 per category change in breastfeeding duration, P = 0.001], and weight gain (0-2 years) was strongly associated with high BMI at 5 years (adjusted odds ratio = 3.8, 95% CI: 2.53-5.56, P < 0.001). In our sample, findings suggest that longer breastfeeding duration and later introduction of solids has a small reduction on later high BMI risk and a negligible effect on skinfold thickness. However, accounting for sampling variability, these findings cannot exclude the possibility of no effect at the population level.

Renal function, renal volume, and blood pressure in infants with antecedent of antenatal steroids

Steroids have been used for more than 20 years in preterm infants to induce pulmonary maturity; however, some long-term effects have been reported, such as insulin resistance and elevation of blood pressure. The aim of our study was to compare renal volume, renal function, and blood pressure in infants between 12-36 months of age with and without antecedent of antenatal steroid treatment. This was a cross-sectional study comprised of three groups of infants (n = 30, respectively): preterm infants with and without antecedent of receiving antenatal steroids, respectively, and full-term infants. Blood pressure, renal volume, glomerular filtration rate, and tubular function were measured. Blood pressure and cystatin C levels and glomerular filtration rate were higher in both groups of preterm infants than in the control group (p < 0.01). However, no difference in any of the tested variables between the steroid and non-steroid group of preterm infants. Renal volume was similar in preterm and control infants. Based on these results, we conclude that prematurity independent of antenatal steroid use is associated with higher cystatin C and blood pressure levels and a higher glomerular filtration rate in infants between 12-36 months of age.

Is infant weight associated with childhood blood pressure? Analysis of the Promotion of Breastfeeding Intervention Trial (PROBIT) cohort

BACKGROUND

Weight gain during infancy may programme later health outcomes, but examination of this hypothesis requires appropriate lifecourse methods and detailed weight gain measures during childhood. We examined associations between weight gain in infancy and early childhood and blood pressure at the age of 6.5 years in healthy children born at term.

METHODS

We carried out an observational analysis of data from a cluster-randomized breastfeeding promotion trial in Belarus. Of 17 046 infants enrolled between June 1996 and December 1997, 13 889 (81.5%) had systolic and diastolic blood pressure measured at 6.5 years; 10 495 children with complete data were analysed. A random-effects linear spline model with three knot points was used to estimate each individual's birthweight and weight gain from birth to 3 months, 3 months to 1 year and 1-5 years. Path analysis was used to separate direct effects from those mediated through subsequent weight gain.

RESULTS

In boys, after controlling for confounders and prior weight gain, the change in systolic blood pressure per z-score increase in weight gain was 0.09 mmHg [95% confidence interval (95% CI) -0.14 to 0.31] for birthweight; 0.41 mmHg (95% CI 0.19-0.64) for birth to 3 months; 0.69 mmHg (95% CI 0.47-0.92) for 3 months to 1 year and 0.82 mmHg (95% CI 0.58-1.06) for 1-5 years. Most of the associations between weight gain and blood pressure were mediated through weight at the age of 6.5 years. Findings for girls and diastolic blood pressure were similar.

CONCLUSIONS

Children who gained weight faster than their peers, particularly at later ages, had higher blood pressure at the age of 6.5 years, with no association between birthweight and blood pressure.

Aleitamento materno exclusivo e adiposidade

OBJETIVO: Associar o tempo de amamentação exclusiva da criança à adiposidade central e periférica, por meio do índice de massa corporal, dos perímetros da cintura e do braço, e das dobras cutâneas triciptal, subescapular e a somatória destas em pré-escolares. MÉTODOS: Pesquisa de delineamento transversal, em que 134 pré-escolares entre três e cinco anos de idade de uma escola par-ticular de Brasília, DF, foram avaliados quanto a: massa corporal, estatura, perímetros do braço e da cintura, dobras cutâneas triciptal e subescapular. Os pais das crianças responderam a um questionário sobre tempo de amamentação. O diagnóstico de sobrepeso e obe-sidade foi realizado de acordo com a classificação da Organização Mundial da Saúde para o índice de massa corporal por idade. RESULTADOS: As meninas tiveram maior concentração adiposa na dobra cutânea triciptal (p=0,001), subescapular (p=0,044) e na somatória destas (p=0,003) em relação aos meninos. A prevalência de sobrepeso e obesidade foi similar nos dois sexos (25,4% nos meninos e 22,6% nas meninas), assim como o tempo médio de amamentação exclusiva (4,3 meses para meninos e 4,6 meses para meninas). Notou-se correlação inversa significativa entre tempo de amamentação exclusiva e perímetro da cintura (r=-0,166; p=0,05). As demais variáveis também mostraram tendência de correlação inversa com o tempo de aleitamento materno exclusivo, porém sem valores significativos. CONCLUSÕES: A associação inversa entre o tempo de ama-mentação e o perímetro da cintura mostra um possível efeito do aleitamento materno sobre a distribuição de gordura corporal no pré-escolar.

Babies fed breastmilk by breast versus by bottle: a pilot study evaluating early growth patterns

BACKGROUND

Numerous studies have documented short- and long-term differences in growth and body composition based on whether an infant is breastfed or formula-fed. However, little is known about whether these differences result from the substance consumed (breastmilk vs. formula) or from the delivery method (breast vs. bottle). This prospective pilot study compared the growth and body composition patterns of 19 predominantly breastfed/nursing infants (NG) and 18 infants fed significant quantities of breastmilk by bottle (BG) during the first 6 months of life.

METHODS

Infants were measured in a laboratory setting each month by trained staff. Growth measures (length, weight, and head circumference) were compared to World Health Organization growth standards. Body composition, including relative fat mass (%FM), was measured using an air-displacement plethysmography system (Pea Pod(®), Life Measurement, Inc., Concord, CA).

RESULTS

With the exception of small differences in length and weight scaled for length (body mass index and weight-for-length z-score) present at birth and continuing for the first 1-2 months of life, NG and BG infants were similar in weight, weight-for-age z-scores, head circumference, fat mass, and %FM. However, BG infants were three times more likely to exceed the 85(th) percentile for weight velocity during the 4-6-month age interval than NG infants (33% vs. 10%, respectively), but this did not reach statistical significance in this sample size (p = 0.12).

CONCLUSIONS

This pilot study suggests the delivery method (breast vs. bottle) for breastmilk may not dramatically affect growth for the first 4 months of life; however, future research with larger samples will be needed to carefully evaluate longer-term growth patterns in infants fed breastmilk by bottle.

Socioeconomic inequalities in height, leg length and trunk length among children aged 6.5 years and their parents from the Republic of Belarus: evidence from the Promotion of Breastfeeding Intervention Trial (PROBIT)

BACKGROUND

Lower socioeconomic position is associated with shorter stature, in particular shorter leg length, but the magnitude of these associations in non-Western countries has received little attention.

AIM

To examine socioeconomic differentials in height, leg and trunk length in 6.5 year olds from the Republic of Belarus and compare these to differentials in parental height.

METHODS

Multivariable linear regression was used to examine associations in a cohort of 13 889 children.

RESULTS

Children from non-manual households were 1.0 cm (95% confidence interval: 0.7-1.3 cm) taller than those from manual households. Mothers and fathers from non-manual backgrounds were 0.7 cm (0.5-0.8) and 1.8 cm (1.6-2.0) taller than those from manual backgrounds, respectively. Associations with higher parental educational attainment were similar. The magnitudes of the associations of socioeconomic position with leg length were similar to those with trunk length. Adjusting for mid-parental height and number of older siblings attenuated associations markedly.

CONCLUSIONS

In Belarus, similar socioeconomic differentials in height were observed in both children and their parents. Among children, height differentials were partly explained by mid-parental height and number of older siblings. Leg length was not a more sensitive indicator of childhood socioeconomic conditions than trunk length.

Metabolic programming of long-term outcomes due to fatty acid nutrition in early life

Understanding of the importance of dietary fatty acids has grown beyond a simple source of energy to complex roles in regulating gene expression and cell and intracellular communication. This is important because the metabolic and neuroendocrine environment of the fetus and infant plays a key role in guiding the set point of neural receptors that regulate energy homeostasis and expression of genes that control energy storage and oxidation. Early deviations in these pathways have the potential to lead to lasting adaptations, termed metabolic programming, which may combine to increase the risk of metabolic syndrome in later life. The quality of fatty acids in human diets has undergone major changes in the last 50 years, characterized by an increase in ω-6 and decrease in ω-3 fatty acids. Evidence is accumulating to support the concept that the maternal intake of ω-6 and ω-3 fatty acids in gestation and lactation, possibly involving both excess ω-6 and inadequate ω-3 fatty acids, can impact the developing infant tissue lipids and neuroendocrine and metabolic pathways relevant to metabolic programming. Further work is needed to understand the needs for different ω-6 and ω-3 fatty acids during fetal and infant life, and their roles with respect to development of energy homeostasis and metabolism.

Socioeconomic status and weight gain in early infancy

CONTEXT

The association between low socioeconomic status (SES) and childhood obesity foreshadows lifelong inequalities in health. Insight into the causal mechanisms linking childhood adversity to long-term health could be provided by discovering when the negative SES gradient in weight emerges and what early life experiences are associated with it.

OBJECTIVE

SES differences in infant weight gain in the first 3 months of life were examined, and contributions of parental body mass index, maternal smoking and feeding method to this association were assessed.

DESIGN

Observational study using longitudinal weight data from 2402 families taking part in the Gemini Study; a twin birth cohort recruited from all twin births between March and December 2007 in England and Wales.

OUTCOME MEASURES

Infant weights at birth and 3 months converted to standard deviation scores (SDS), change in weight SDS and rapid growth. SES was indexed by occupation and maternal education.

RESULTS

There were no SES differences in birth weight, but lower SES was associated with higher 3-month weight, greater change in weight and a higher prevalence of rapid growth (all P < 0.01), with graded associations across levels of SES. Including parental overweight or smoking in pregnancy in the regression model did not affect the association between SES and weight gain, but including feeding method attenuated the SES effect on weight gain by at least 62% and rendered it nonsignificant.

CONCLUSION

The foundations for lifelong socioeconomic inequalities in obesity risk may be laid in early infancy, with infant-feeding practices having a part in the diverging weight trajectories.

Impact of breastfeeding duration on age at menarche

The study aims to assess the relation between breastfeeding duration and age at menarche. Analysis was based on a cohort of 994 Filipino girls born in 1983-1984 and followed up from infancy to adulthood by the Cebu Longitudinal Health and Nutrition Survey. The main outcome was self-reported age at menarche. Cox regression was used to investigate the relation between duration of exclusive and any breastfeeding with age at menarche with adjustment sequentially for specific sets of known socioeconomic, maternal, genetic, and prenatal confounders. The estimated median of age at menarche was 13.08 years. After adjustment for potential confounders of the association of breastfeeding with age at menarche, exclusive breastfeeding duration retained an independent and significant association with age at menarche. An increase in 1 month of exclusive breastfeeding decreases the hazard of attaining earlier menarche by 6% (hazard ratio = 0.94, 95% confidence interval: 0.90, 0.98). Any breastfeeding duration was not associated with age at menarche. Although this is the first longitudinal study that reveals a negative association between exclusive breastfeeding and early menarche, the relation is still elusive. Further longitudinal studies within different contexts are warranted to assess the generalizability of these findings.

Breastfeeding and infant size: evidence of reverse causality

Infants who receive prolonged and exclusive breastfeeding grow more slowly during the first year of life than those who do not. However, infant feeding and growth are dynamic processes in which feeding may affect growth, and prior growth and size may also influence subsequent feeding decisions. The authors carried out an observational analysis of 17,046 Belarusian infants who were recruited between June 1996 and December 1997 and who participated in a cluster-randomized trial of a breastfeeding promotion intervention. To assess the effects of infant size on subsequent feeding, the authors restricted the analysis to infants breastfed (or exclusively breastfed) at the beginning of each follow-up interval and examined associations between weight or length at the beginning of the interval and weaning or discontinuation of exclusive breastfeeding by the end of the interval. Smaller size (especially weight for age) was strongly and statistically significantly associated with increased risks of subsequent weaning and of discontinuing exclusive breastfeeding (adjusted odds ratios = 1.2-1.6), especially between 2 and 6 months, even after adjusment for potential confounding factors and clustered measurement. The authors speculate that similar dynamic processes involving infant crying, other signs of hunger, and supplementation/weaning undermine causal inferences about the "effect" of prolonged and exclusive breastfeeding on slower infant growth.

What are the causal effects of breastfeeding on IQ, obesity and blood pressure? Evidence from comparing high-income with middle-income cohorts

BACKGROUND

A novel approach is explored for improving causal inference in observational studies by comparing cohorts from high-income with low- or middle-income countries (LMIC), where confounding structures differ. This is applied to assessing causal effects of breastfeeding on child blood pressure (BP), body mass index (BMI) and intelligence quotient (IQ).

METHODS

Standardized approaches for assessing the confounding structure of breastfeeding by socio-economic position were applied to the British Avon Longitudinal Study of Parents and Children (ALSPAC) (N ≃ 5000) and Brazilian Pelotas 1993 cohorts (N ≃ 1000). This was used to improve causal inference regarding associations of breastfeeding with child BP, BMI and IQ. Analyses were extended to include results from a meta-analysis of five LMICs (N ≃ 10 000) and compared with a randomized trial of breastfeeding promotion. Findings Although higher socio-economic position was strongly associated with breastfeeding in ALSPAC, there was little such patterning in Pelotas. In ALSPAC, breastfeeding was associated with lower BP, lower BMI and higher IQ, adjusted for confounders, but in the directions expected if due to socioeconomic patterning. In contrast, in Pelotas, breastfeeding was not strongly associated with BP or BMI but was associated with higher IQ. Differences in associations observed between ALSPAC and the LMIC meta-analysis were in line with those observed between ALSPAC and Pelotas, but with robust evidence of heterogeneity detected between ALSPAC and the LMIC meta-analysis associations. Trial data supported the conclusions inferred by the cross-cohort comparisons, which provided evidence for causal effects on IQ but not for BP or BMI.

CONCLUSION

While reported associations of breastfeeding with child BP and BMI are likely to reflect residual confounding, breastfeeding may have causal effects on IQ. Comparing associations between populations with differing confounding structures can be used to improve causal inference in observational studies.

Infant-feeding patterns and cardiovascular risk factors in young adulthood: data from five cohorts in low- and middle-income countries

BACKGROUND

Infant-feeding patterns may influence lifelong health. This study tested the hypothesis that longer duration of breastfeeding and later introduction of complementary foods in infancy are associated with reduced adult cardiovascular risk.

METHODS

Data were pooled from 10 912 subjects in the age range of 15-41 years from five prospective birth-cohort studies in low-/middle-income countries (Brazil, Guatemala, India, Philippines and South Africa). Associations were examined between infant feeding (duration of breastfeeding and age at introduction of complementary foods) and adult blood pressure (BP), plasma glucose concentration and adiposity (skinfolds, waist circumference, percentage body fat and overweight/obesity). Analyses were adjusted for maternal socio-economic status, education, age, smoking, race and urban/rural residence and infant birth weight.

RESULTS

There were no differences in outcomes between adults who were ever breastfed compared with those who were never breastfed. Duration of breastfeeding was not associated with adult diabetes prevalence or adiposity. There were U-shaped associations between duration of breastfeeding and systolic BP and hypertension; however, these were weak and inconsistent among the cohorts. Later introduction of complementary foods was associated with lower adult adiposity. Body mass index changed by -0.19 kg/m(2) [95% confidence interval (CI) -0.37 to -0.01] and waist circumference by -0.45 cm (95% CI -0.88 to -0.02) per 3-month increase in age at introduction of complementary foods.

CONCLUSIONS

There was no evidence that longer duration of breastfeeding is protective against adult hypertension, diabetes or overweight/adiposity in these low-/middle-income populations. Further research is required to determine whether 'exclusive' breastfeeding may be protective. Delaying complementary foods until 6 months, as recommended by the World Health Organization, may reduce the risk of adult overweight/adiposity, but the effect is likely to be small.

Familial associations of adiposity: findings from a cross-sectional study of 12,181 parental-offspring trios from Belarus

BACKGROUND

It is suggested that maternal adiposity has a stronger association with offspring adiposity than does paternal adiposity. Furthermore, a recent small study reported gender assortment in parental-offspring adiposity associations. We aimed to examine these associations in one of the largest studies to date using data from a low-middle income country that has recently undergone a major political and economic transition.

METHODS AND PRINCIPAL FINDINGS

In a cross-sectional study of 12,181 parental-offspring trios from Belarus (mean age (SD) of mothers 31.7 (4.9), fathers 34.1 (5.1) and children 6.6 (0.3) at time of assessment), we found positive graded associations of mother's and father's BMI with offspring adiposity. There was no evidence that these associations differed between mothers and fathers. For example, the odds ratio of offspring overweight or obesity (based on BMI) comparing obese and overweight mothers to normal weight mothers was 2.03 (95%CI 1.77, 2.31) in fully adjusted models; the equivalent result for father's overweight/obesity was 1.81 (1.58, 2.07). Equivalent results for offspring being in the top 10% waist circumference were 1.91 (1.67, 2.18) comparing obese/overweight to normal weight mothers and 1.72 (1.53, 1.95) comparing obese/overweight to normal weight fathers. Similarly, results for offspring being in the top 10% of percent fat mass were 1.58 (1.36, 1.84) and 1.76 (1.49, 2.07), for mother's and father's obese/overweight exposures respectively. There was no strong or consistent evidence of gender assortment--i.e. associations of maternal adiposity exposures with offspring outcomes were similar in magnitude for their daughters compared to equivalent associations in their sons and paternal associations were also similar in sons and daughters.

CONCLUSIONS/SIGNIFICANCE

These findings suggest that genetic and/or shared familial environment explain family clustering of adiposity. Interventions aimed at changing overall family lifestyle are likely to be important for population level obesity prevention.

Can exclusive breastfeeding reduce the likelihood of childhood obesity in some regions of Canada?

OBJECTIVES

The prevalence of childhood obesity in Canada is a major concern. Studies report a small but significant inverse relationship between exclusive breastfeeding and childhood obesity. The study objectives were to determine the prevalence of overweight and obesity in a preschool population living in Newfoundland and Labrador (NL) and to examine the relationship between exclusive breastfeeding and preschool obesity.

METHODS

This was a cross-sectional analysis of 1,026 children born in 2001 who participated in the Pre Kindergarten Health Fairs in 2005. Heights and weights were collected and body mass index (BMI) calculated. The BMI-for-age references used by the Centers for Disease Control (CDC) in the United States were used to classify the weight status of children. Infant feeding information was collected through a survey. The relationship between breastfeeding and childhood obesity was examined using logistic regression models controlling for child's age and gender, mother's education and smoking status, and whether the baby was preterm or full-term.

RESULTS

In 2005, 65%, 19% and 16% of preschool children were normal, overweight and obese, respectively. 74% of women initiated breastfeeding and 43% exclusively breastfed to 3 months. Exclusive breastfeeding to 3 months was protective of preschool obesity (adjusted odds ratio (AOR) 0.65, 95% CI 0.45-0.96).

CONCLUSION

Obesity is prevalent in preschool children in NL. Exclusive breastfeeding appeared to be a protective factor for obesity in preschoolers. Given the known benefits of breastfeeding and the adverse health consequences of obesity, efforts should be made to increase exclusive breastfeeding which may help to prevent the development of obesity in young children.

The fat:carbohydrate energy ratio of the weaning diet programs later susceptibility to obesity in male sprague dawley rats

Dietary fat intake, which is high during suckling, is markedly reduced when food and drinks are introduced into the diet. We investigated whether alterations in the fat:carbohydrate (CHO) content of the weaning diet influenced the later development of adiposity and insulin sensitivity. Three groups of male rats (24/group) were fed from age 16-37 d (phase I) with weaning diets varying in their fat:CHO energy (E) ratios, 10:70 low-fat, high-CHO (LFHC); 30:50 medium-fat, medium-CHO (MFMC), and 60:30 high-fat, high-CHO (HFLC), on an isocaloric basis. Then, all groups consumed ad libitum first a low-fat diet (13% fat E) for 30 wk (phase II) and subsequently a high-fat diet (45% fat E) for another 18 wk (phase III). At the end of phase I, the group fed the HFLC diet demonstrated higher plasma glucose and insulin responses to an oral glucose tolerance test (P < 0.05), but this effect was transient and did not persist into adulthood (phases II and III). By contrast, when challenged with a high-fat diet later in life (age 35.3-53.3 wk), the LFHC group had greater gains in weight (as percent initial weight) and body fat (as absolute and percent body weight) than the other 2 groups that had been weaned with diets higher in fat (P < 0.04 for all). These results provide evidence that metabolic programming by altering the dietary fat:CHO ratio can occur during the weaning period and emphasizes the importance of the fat:CHO ratio of the complementary diet and its relation to the susceptibility to develop adiposity later in life.

Longer breastfeeding is associated with increased lower body explosive strength during adolescence

Our aim in this study was to examine the association between breastfeeding duration and cardiorespiratory fitness, isometric strength, and explosive strength during adolescence. A total of 2567 adolescents (1426 girls) from the Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) cross-sectional study aged 12.5-17.5 y were included. Information about duration of any and exclusive breastfeeding was obtained retrospectively by means of a parental questionnaire. The 20-m shuttle run, handgrip strength, and standing long jump tests were used to assess physical fitness. Significant differences among the categories of breastfeeding duration were tested using ANCOVA after adjusting for a set of potential confounders: gestational and current age, birth weight, sexual maturation, fat mass, fat-free mass, maternal education, parental weight status, country, smoking behavior, and days of vigorous physical activity. Longer breastfeeding (either any or exclusive) was associated with a higher performance in the standing long jump test in both boys and girls (P < 0.001), regardless of fat mass, fat-free mass, and the rest of potential confounders. In adolescents who were breastfed for 3-5 mo or ≥6 mo, the risk of having a standing long jump performance below the 5th percentile was reduced by half compared with those who were never breastfed [odds ratio (OR) = 0.54, 95% CI = 0.30-0.96, P < 0.05; and OR = 0.40, 95% CI = 0.22-0.74, P < 0.01, respectively). These findings suggest a role of breastfeeding in determining lower body explosive strength during adolescence.

Delivery after previous cesarean: long-term outcomes in the child

In subsequent pregnancies after a cesarean delivery, women must choose between attempting to deliver vaginally or undergoing another cesarean delivery. Information relevant to this choice includes the long-term benefits and harms to the baby. In this article we discuss the relationship of mode of delivery (planned trial of labor, either with or without vaginal delivery, or elective repeat cesarean delivery) and long-term outcomes, including brachial plexus palsy, neurodevelopmental impairment, and asthma. No randomized trials are available that relate directly to the choice of delivery method after previous cesarean. Observational studies suggest that cesarean delivery might be associated with a greater risk of asthma, caused perhaps by altered gut colonization, increased risk of neonatal respiratory disease, decreased gestational age at birth or decreased likelihood of breastfeeding. By contrast, vaginal delivery after a previous cesarean delivery is associated with greater risks of neurodevelopmental impairment and upper-extremity motor impairment, caused, respectively, by greater risks of perinatal hypoxic-ischemic encephalopathy and brachial plexus injury. Available information does not provide a precise estimate of the relative risks for infants delivered after a trial of labor versus elective cesarean delivery.

Childhood obesity

Worldwide prevalence of childhood obesity has increased greatly during the past three decades. The increasing occurrence in children of disorders such as type 2 diabetes is believed to be a consequence of this obesity epidemic. Much progress has been made in understanding of the genetics and physiology of appetite control and from these advances, elucidation of the causes of some rare obesity syndromes. However, these rare disorders have so far taught us few lessons about prevention or reversal of obesity in most children. Calorie intake and activity recommendations need reassessment and improved quantification at a population level because of sedentary lifestyles of children nowadays. For individual treatment, currently recommended calorie prescriptions might be too conservative in view of evolving insight into the so-called energy gap. Although quality of research into both prevention and treatment has improved, high-quality multicentre trials with long-term follow-up are needed. Meanwhile, prevention and treatment approaches to increase energy expenditure and decrease intake should continue. Recent data suggest that the spiralling increase in childhood obesity prevalence might be abating; increased efforts should be made on all fronts to continue this potentially exciting trend.

Socio-economic position and adiposity among children and their parents in the Republic of Belarus

BACKGROUND

Socio-economic differences in the prevalence of overweight/obesity may be one factor through which health inequalities arise and may vary by the population studied.

METHODS

Analysing a cohort of 13 889 children born in Belarus between June 1996 and December 1997, the authors investigated associations of parental educational attainment and highest household occupation with: (i) measured body mass index (BMI), waist circumference and skinfold thicknesses at age 6.5 years and (ii) the parents' reported BMI.

RESULTS

Overall, 10% of children, 37% of mothers and 53% of fathers were either overweight or obese. Children from non-manual households were 27% [95% confidence interval (CI): 10%, 47%] more likely to be overweight/obese (based on BMI) than those from manual households. They also had larger waist circumferences and higher percentage body fat (calculated from subscapular and triceps skinfolds). Similar associations for being overweight/obese were seen for fathers [odds ratio (OR), 1.10; 95% CI: 1.02, 1.18], but mothers from non-manual households were less likely to be overweight/obese: (OR, 0.84; 95% CI: 0.79, 0. 90). Associations of childhood and parental overweight/obesity with higher educational status of either parent were similar to those observed for non-manual households.

CONCLUSION

We observed socio-economic differentials in overweight/obesity prevalence among children and their parents in Belarus. More affluent children and their fathers were more likely to be overweight/obese but the reverse was found for mothers.

Late introduction of complementary feeding, rather than duration of breastfeeding, may protect against adult overweight

BACKGROUND

Early nutrition may affect the risk of overweight in later life.

OBJECTIVE

The objective was to explore the effect of the duration of breastfeeding (BF) and age at introduction of complementary feeding (CF) on body mass index (BMI) during childhood through adulthood.

DESIGN

The study was based on a subsample of the Copenhagen Perinatal Cohort established in 1959-1961 (n = 5068). Information on BF and available information on CF (age of introduction of "spoon-feeding," "vegetables," "egg," "meat," and "firm food") and several covariates were collected in infancy and linked with information on BMI from follow-up examinations in childhood and adulthood at age 42 y.

RESULTS

The median (10th, 90th percentiles) durations of any BF and age at introduction of spoon-feeding were 2.50 (0.23, 6.50) and 3.50 (2.00, 6.00) mo, respectively. After 1 y of age and throughout childhood and adolescence, no association between BF and BMI was found in regression models also adjusted for age at introduction of spoon-feeding and covariates. The risk of overweight at age 42 y decreased or tended to decrease with increasing age (in mo) at introduction of spoon-feeding [odds ratio (OR): 0.94; 95% CI: 0.86, 1.02], vegetables (OR: 0.90; 95% CI: 0.81, 0.98), meat (OR: 0.93; 95% CI: 0.87, 1.00), and firm food (OR: 0.92; 95% CI: 0.86, 0.98) but not egg (OR: 0.98; 95% CI: 0.91, 1.05).

CONCLUSION

The findings of this study suggest that introduction of CF at a later age (within the range of 2 to 6 mo) is protective against overweight in adulthood but do not support a protective effect of a longer duration of BF.

The double jeopardy of clustered measurement and cluster randomisation

Michael S Kramer and colleagues suggest that double clustering might explain the negative results of some cluster randomised trials and describe some strategies for avoiding the problem

Breast-feeding: A commentary by the ESPGHAN Committee on Nutrition

This medical position article by the European Society for Paediatric Gastroenterology, Hepatology, and Nutrition summarises the current status of breast-feeding practice, the present knowledge on the composition of human milk, advisable duration of exclusive and partial breast-feeding, growth of the breast-fed infant, health benefits associated with breast-feeding, nutritional supplementation for breast-fed infants, and contraindications to breast-feeding. This article emphasises the important role of paediatricians in the implementation of health policies devised to promote breast-feeding.The European Society for Paediatric Gastroenterology, Hepatology, and Nutrition Committee on Nutrition recognises breast-feeding as the natural and advisable way of supporting the healthy growth and development of young children. This article delineates the health benefits of breast-feeding, reduced risk of infectious diarrhoea and acute otitis media being the best documented. Exclusive breast-feeding for around 6 months is a desirable goal, but partial breast-feeding as well as breast-feeding for shorter periods of time are also valuable. Continuation of breast-feeding after the introduction of complementary feeding is encouraged as long as mutually desired by mother and child.The role of health care workers, including paediatricians, is to protect, promote, and support breast-feeding. Health care workers should be trained in breast-feeding issues and counselling, and they should encourage practices that do not undermine breast-feeding. Societal standards and legal regulations that facilitate breast-feeding should be promoted, such as providing maternity leave for at least 6 months and protecting working mothers.

Fetal and postnatal growth and body composition at 6 months of age

OBJECTIVES

The objectives of the study was to examine which parental, fetal, and postnatal characteristics are associated with fat and lean mass at the age of 6 months and examine the effect of growth (catch-down, catch-up) in fetal life and early infancy on fat and lean mass.

DESIGN

This study was embedded in the Generation R Study, a prospective cohort study from early fetal life onward. Body composition was measured by dual-energy X-ray absorptiometry in 252 infants at 6 months. Parental, fetal, and postnatal data were collected by physical and fetal ultrasound examinations and questionnaires.

RESULTS

Children with fetal catch-up in weight (gain in weight sd score >0.67) in the second trimester tended to have a higher fat mass percentage [FM(%)] at 6 months of age, whereas children with fetal catch-down in weight had a lower FM(%) compared with nonchangers. In the third trimester, both catch-up and catch-down in weight were associated with an increase in FM(%) at 6 months. Children with catch-down in the third trimester had a greater risk for postnatal catch-up in weight greater than 0.67 sd score. Birth weight and weight at 6 wk were positively associated with fat mass at 6 months. Postnatal catch-up in weight within 6 wk after birth had the highest association with total and truncal FM(%) at 6 months. Total and truncal FM were higher in girls.

CONCLUSION

Catch-down in weight in the third trimester was strongly associated with postnatal catch-up within 6 wk after birth, and both were associated with an increase in fat mass at the age of 6 months. Our study shows that fetal as well as postnatal growth patterns are associated with body composition in early childhood.

Human milk adiponectin is associated with infant growth in two independent cohorts

BACKGROUND

Adiponectin, a circulating adipocyte protein, is associated with lower obesity. We have previously shown that adiponectin is present in human milk. This study determined whether higher milk adiponectin is associated with infant growth and investigated milk adiponectin's oligomeric form.

DESIGN AND METHODS

This is a study of two parallel longitudinal cohorts of breastfed infants born between 1998 and 2005. Forty-five mother-infant pairs from Cincinnati, OH and 277 mother-infant pairs from Mexico City, Mexico were analyzed. All participants were healthy, term infants breastfed at least 1 month who completed 6 months of follow-up. Monthly milk samples (n = 1,379) up to 6 months were assayed for adiponectin by radioimmunoassay. Infant weight-for-age, length-for-age, and weight-for-length Z-scores up to 6 months of age were calculated using World Health Organization standards. Repeated-measures analysis was conducted. The structural form of human milk adiponectin was assessed by western blot.

RESULTS

In the population studies, initial milk adiponectin was 24.0 +/- 8.6 microg/L and did not differ by cohort. Over the first 6 months, higher milk adiponectin was associated with lower infant weight-for-age Z-score (-0.20 +/- 0.04, p < 0.0001) and weight-for-length Z-score (-0.29 +/- 0.08, p = 0.0002) but not length-for-age Z-score, adjusted for covariates, with no difference by cohort. By western blot, human milk adiponectin was predominantly in the biologically active high-molecular-weight form.

CONCLUSIONS

Our data suggest milk adiponectin may play a role in the early growth and development of breastfed infants.

Potential determinants of obesity among children and adolescents in Germany: results from the cross-sectional KiGGS Study

BACKGROUND

Obesity among children and adolescents is a growing public health problem. The aim of the present paper is to identify potential determinants of obesity and risk groups among 3- to 17-year old children and adolescents to provide a basis for effective prevention strategies.

METHODS

Data were collected in the German Health Interview and Examination Survey for Children and Adolescents (KiGGS), a nationally representative and comprehensive data set on health behaviour and health status of German children and adolescents. Body height and weight were measured and body mass index (BMI) was classified according to IOTF cut-off points. Statistical analyses were conducted on 13,450 non-underweight children and adolescents aged 3 to 17 years. The association between overweight, obesity and several potential determinants was analysed for this group as well as for three socio-economic status (SES) groups. A multiple logistic regression model with obesity as the dependent variable was also calculated.

RESULTS

The strongest association with obesity was observed for parental overweight and for low SES. Furthermore, a positive association with both overweight (including obesity) and obesity was seen for maternal smoking during pregnancy, high weight gain during pregnancy (only for mothers of normal weight), high birth weight, and high media consumption. In addition, high intakes of meat and sausages, total beverages, water and tea, total food and beverages, as well as energy-providing food and beverages were significantly associated with overweight as well as with obesity. Long sleep time was negatively associated with obesity among 3- to 10-year olds. Determinants of obesity occurred more often among children and adolescents with low SES.

CONCLUSION

Parental overweight and a low SES are major potential determinants of obesity. Families with these characteristics should be focused on in obesity prevention.

Breastfeeding and childhood obesity: shift of the entire BMI distribution or only the upper parts?

A protective effect of breastfeeding on overweight (binary) has been reported by meta-analyses using logistic regression, whereas studies using linear regression and BMI (continuous) detected no significant association. To assess the relationship of these differences with different outcome classification, we compared results for linear, logistic, and quantile regression models in a cross-sectional data set of considerable size. Height, weight, and questionnaire data on 9,368 preschool children were collected during school-entry examinations in 1999 and 2002 in Bavaria, Southern Germany. We calculated multivariable linear, logistic, and quantile regression models with outcomes BMI, overweight, obesity, and BMI quantiles (as appropriate). Models considered the covariates breastfeeding (breastfed vs. never breastfed), gender, age, smoking in pregnancy, TV watching, maternal BMI, parental education, and early infant weight gain. No significant association was found in the linear regression model. In the logistic model, a significant association was observed for obesity (odds ratio: 0.72 (95% confidence interval (CI) 0.55, 0.94)). In quantile regression no significant point estimates were observed for the percentiles of 0.4-0.8. However, breastfeeding reduced the BMI of children having values on the 90th and 97th percentiles by -0.23 (95% CI -0.39, -0.07) and -0.26 (95% CI -0.45, -0.07) kg/m(2), respectively, on average. In contrast, breastfeeding was significantly associated with a low shift toward higher BMI values for BMI quantiles of 0.03 and from 0.1 to 0.3. The detection of associations between breastfeeding and childhood body composition might be related to the coding of the response variable (continuous or binary) and the statistical method used (linear, logistic, or quantile regression). Quantile regression should additionally be applied in such studies.

Maternal weight gain during pregnancy and child weight at age 3 years

OBJECTIVES

To determine the importance of pregnancy weight gain as a predictor of overweight (Body Mass Index [BMI] >85th percentile) in offspring at age 3 years and if its influence varies by maternal BMI.

METHODS

Chi-square and logistic regression analyses were conducted on a sample of 208 mother-child pairs from an earlier observational cohort study on postpartum weight retention.

RESULTS

In the final reduced regression model, maternal early pregnancy BMI was positively and significantly associated with overweight in offspring, as were birth weight above the sample median of 3,600 g and maternal smoking during pregnancy (P < or = 0.01). In addition, a significant interaction was found between maternal BMI and gestational weight gain (P = 0.03). The risk of offspring overweight that is associated with 5 excess pounds of net pregnancy weight gain increases with maternal BMI.

CONCLUSIONS

Excess pregnancy weight gain is associated with increased risk of child overweight at age 3 years and its impact is greater among high and obese BMI women than it is in normal BMI women. Reducing maternal BMI in the preconception period in overweight women and preventing excessive weight gain in pregnancy for all women appear to be appropriate strategies to address the childhood obesity epidemic.