Breast, Formula and Combination Feeding in Relation to Childhood Obesity in Nova Scotia, Canada

Systematic review and meta-analysis of breastfeeding and later overweight or obesity expands on previous study for World Health Organization

AIM

To update a systematic review and meta-analysis of the association of breastfeeding with overweight or obesity that had been commissioned by the World Health Organization. We also assessed the likelihood of residual confounding.

METHODS

Two independent reviewers searched MEDLINE, LILACS and Web of Science for manuscripts published between August 2014 and May 2021. Studies that only evaluated infants were excluded. Random-effects models were used to pool the estimates.

RESULTS

The review comprised 159 studies with 169 estimates on the association of breastfeeding with overweight or obesity, and most of the studies were carried out among individuals aged 1-9 years (n = 130). Breastfeeding protected against overweight or obesity (pooled odds ratio:0.73, 95% confidence interval:0.71; 0.76). And, even among the 19 studies that were less susceptible to publication bias, residual confounding and misclassification, a benefit was observed (pooled odds ratio:0.85, 95% confidence interval:0.77; 0.93). Among those studies that were clearly susceptible to positive confounding by socioeconomic status, a benefit of breastfeeding was observed even after adjusting for socioeconomic status (pooled odds ratio:0.76, 95% confidence interval: 0.69; 0.83).

CONCLUSION

Breastfeeding reduced the odds of overweight or obesity, and this association was unlikely to be due to publication bias and residual confounding.

Multiomic Analyses of Nascent Preterm Infant Microbiomes Differentiation Suggest Opportunities for Targeted Intervention

The first week after birth is a critical time for the establishment of microbial communities for infants. Preterm infants face unique environmental impacts on their newly acquired microbiomes, including increased incidence of cesarean section delivery and exposure to antibiotics as well as delayed enteral feeding and reduced human interaction during their intensive care unit stay. Using contextualized paired metabolomics and 16S sequencing data, the development of the gut, skin, and oral microbiomes of infants is profiled daily for the first week after birth, and it is found that the skin microbiome appears robust to early life perturbation, while direct exposure of infants to antibiotics, rather than presumed maternal transmission, delays microbiome development and prevents the early differentiation based on body site regardless of delivery mode. Metabolomic analyses identify the development of all gut metabolomes of preterm infants toward full-term infant profiles, but a significant increase of primary bile acid metabolism only in the non-antibiotic treated vaginally birthed late preterm infants. This study provides a framework for future multi-omic, multibody site analyses on these high-risk preterm infant populations and suggests opportunities for monitoring and intervention, with infant antibiotic exposure as the primary driver of delays in microbiome development.

Differences in infant feeding practices between Indian-born mothers and Australian-born mothers living in Australia: a cross-sectional study

Background

Immigrant children from low- and middle-income countries (e.g. India) have higher obesity rates than children from high-income countries (e.g. Australia). Infant feeding practices are a key modifiable risk factor to prevent childhood obesity. This study compared infant feeding practices such as breastfeeding, infant formula feeding, timing of introduction to other liquids and solids of Indian-born versus Australian-born mothers living in Australia.

Methods

Data of children aged between 0–24 months from the 2010–2011 Australian National Infant Feeding Survey were analysed. Infant feeding practices between Indian-born mothers (n = 501) and Australian-born mothers (n = 510) were compared. Multiple regression models with adjustments for covariates, such as maternal demographic factors, were conducted.

Results

Compared to infants of Australian-born mothers, infants of Indian-born mothers were breastfed for 2.1 months longer, introduced solids 0.6 months later and water 0.4 months later (p < 0.001). Moreover, infants of Indian-born mothers were 2.7 times more likely to be currently breastfeeding, 70% less likely to currently consume solids and 67% less likely to consume solids before six months (p < 0.001). In contrast, infants of Indian-born mothers were introduced to fruit juice 2.4 months earlier, water-based drinks 2.8 months earlier and cow’s milk 2.0 months earlier than infants of Australian-born mothers (p < 0.001). Additionally, infants of Indian-born mothers were 2.7 times more likely to consume fruit juice (p < 0.001) than the infants of Australian-born mothers.

Conclusion

Significant differences exist in infant feeding practices of Indian-born and Australian-born mothers (some health promoting and some potentially obesogenic). The evidence of early introduction of sweetened fluids in infants of Indian-born mothers provides an opportunity to support parents to delay introduction to promote optimal infant growth..

Examining patterns of postnatal feeding in relation to infant's weight during the first year

BACKGROUND

There is mixed evidence regarding specific infant feeding behaviors and later risk for overweight and obesity. We sought to detect underlying patterns in duration of breastfeeding, introduction of solid foods and sweetened beverages, in order to understand the relation to later weight.

METHODS

Patterns of postnatal feeding were examined among infants enrolled in the Infant Feeding Practices Study II (N = 3033). At monthly intervals, mothers reported on the duration of any and exclusive breastfeeding, age of solid food and sweetened beverage introduction, and reported infant weight at ages 9- and 12-months. Latent profile analysis was used to empirically derive patterns of postnatal feeding and examine associations with weight z-scores at 9 and 12 months.

RESULTS

Two profiles emerged: (1) Short breastfeeding duration and early introduction to solid foods and sweetened beverages (Short BF/Early Introduction; 53%) and (2) longer breastfeeding duration and later introduction to solid foods and sweetened beverages (Longer BF/Later Introduction; 43%). Infants in the Shorter BF/Early Introduction profile had significantly greater weight z-scores at 9 (M = 0.18) and 12 months (M = 0.26), compared to those in the Longer BF/Later Introduction profile (M = -0.21; M = -0.17, respectively).

CONCLUSIONS

Overall, shorter BF duration and earlier food and sweetened beverage introduction is associated with higher weight z-scores at 9 and 12 months. Early intervention should aim to promote breastfeeding and later introduction of solids and discourage consumption of sweetened beverages. These postnatal patterns of feeding behaviors provides important context to inform targeted interventions aimed at reducing risk for later obesity.

Association of Socioeconomic Factors and Infant Nutrition Decisions: Breastfeeding and Type of Formula

Objective: Breastfeeding is considered the gold standard of infant feeding during the first year of life. However, many women experience difficulty breastfeeding and do not breastfeed to the extent that they initially planned. Our aims were to present factors influencing parents' choices of infant nutrition and to examine whether these choices are influenced by socioeconomic status (SES). Materials and Methods: We conducted a cross-sectional survey by interviewing mothers attending family health centers in various areas of Tel Aviv, Israel. Results: A total of 239 mothers participated in the survey. The choice of source of their infants' nutrition up to the age of 6 months was divided between exclusive breastfeeding, a combination of infant formula (IF) and breastfeeding, and exclusive IF (36%, 34%, and 30%, respectively). Exclusive breastfeeding was related to a higher SES (p = 0.02). The leading cause for combining IF in the infant's diet was maternal difficulty in breastfeeding (60%). The leading factors that influenced the choice of a specific IF product were continuation from the IF given in the hospital nursery (20%), advice from friends or family (20%) and cost (10%). There was a significant difference based on SES. A greater proportion of responders in a higher SES continued the IF that was supplied in the hospital, whereas lower SES parents tended to choose a formula according to its price (p < 0.05 for both). Conclusion: There is an overall lower prevalence of exclusive breastfeeding among low-income families. The maternal choice of the type of IF is associated with parental SES, with the choice of high SES mothers what was fed in the hospital and the choice of low SES related to price.

ASSOCIATION BETWEEN BREASTFEEDING AND OVERWEIGHT/OBESITY IN SCHOOLCHILDREN AGED 7-14 YEARS

Objective:

To evaluate the prevalence of breastfeeding (BF) and the association between occurrence/duration of BF and overweight/obesity in schoolchildren aged 7-14 years.

Methods:

This is a cross-sectional study, conducted in 2012-2013, on schoolchildren aged 7-14 years from Florianópolis, Santa Catarina, Southern Brazil. Weight and height were measured according to procedures of the World Health Organization. Breastfeeding and sociodemographic data were obtained from a questionnaire responded by parents/guardians. BF was categorized as a dichotomous variable (yes/no) and according to duration (months). Nutritional status was evaluated according to the Z score of the body mass index per age for sex and it was categorized into two groups: normal weight (<Z score+1) and overweight/obesity (≥Z score+1). The adjusted analysis was performed by logistic regression in two age strata (age groups of 7-10 and 11-14 years).

Results:

6.6% of schoolchildren had never breastfed; 16.8% had been breastfed for ≤3 months; 16.7%, for 4-6 months; and 59.9%, for ≥7 months. No statistically significant differences were found in the occurrence and duration of BF between the age groups. The prevalence of overweight/obesity was 34.2%. For age groups (7-10 and 11-14 years), the prevalence of overweight/obesity was 36.7% and 29.8%, respectively. Chance of overweight/obesity for the age group of 7-10 years was lower among schoolchildren who were breastfed (OR=0.54; 95%CI 0.33-0.88), when compared with those who never breastfed. When categorized, the chance of overweight/obesity in the age group of 7-10 years was lower for duration of BF ≤3 months (OR=0.41; 95%CI 0.20-0.83), and 4-6 months (OR=0.48; 95%CI 0.28-0.82) when compared with children who never breastfed.

Conclusions:

BF for at least six months was associated with a lower chance of overweight/obesity for schoolchildren aged 7-10 years. No association was found for schoolchildren aged 11-14 years.

A Practical Screening Tool to Predict Early Childhood Obesity Risk: Examining a Birth Cohort

Children obese at the age of 5 years are at greater risk of lifelong obesity. Because certain risks of obesity can be identified in early infancy, a tool for obesity risk prediction in early life would be clinically useful. We investigated predictors of obesity risk in a novel, prospectively collected healthy birth cohort recruited for demographic risks to develop iron deficiency at 1 year, a cohort leveraged because risk factors for iron deficiency and obesity overlap. Obesity at the age of 5 years was defined as age- and sex-specific body mass index Z-score (zBMI) >2SD. For each child, obesity risk factors were summed. Of 10 total risk factors, the following 4 key risks were identified: maternal obesity, maternal diabetes, large for gestational age, or breastfeeding <6 months. Childhood obesity was predicted by either ≥3 total number of risks (P < .033), any key risk (P < .002), or summing key risks (P < .0001). In clinical practice, summing early life risk factors may be a useful strategy for preemptive counseling.

Low selenium intake is associated with postpartum weight retention in Chinese women and impaired physical development of their offspring

The aim of this study was to investigate the association between daily Se intake and postpartum weight retention (PPWR) among Chinese lactating women, and the impact of their Se nutritional status on infants' physical development. Se contents in breast milk and plasma collected from 264 lactating Chinese women at the 42nd day postpartum were analysed with inductively coupled plasma MS. Daily Se intake was calculated based on plasma Se concentration. The dietary data of 24-h records on three consecutive days were collected. Infant growth status was evaluated with WHO standards by Z-scores. Linear regression analyses and multinomial logistic regression were conducted to examine the impact of Se disequilibrium (including other factors) on PPWR and growth of infants, respectively. The results indicated that: (1) the daily Se intake of the subjects was negatively associated with their PPWR (B = -0·002, 95 % CI - 0·003, 0·000, P = 0·039); (2) both insufficient Se daily intake (B = -0·001, OR 0·999, 95 % CI 0·998, 1·000, P = 0·014) and low level of Se in milk (B = -0·025, OR 0·975, 95 % CI 0·951, 0·999, P = 0·021) had potential associations with their infants' wasting, and low level of Se in milk (B = -0·159, OR 0·853, 95 % CI 0·743, 0·980, P = 0·024) had a significant association with their infants' overweight. In conclusion, the insufficient Se nutritional status of lactating Chinese women was first found as one possible influencing factor of their PPWR as well as low physical development of their offspring.

Meal regularity is associated with self-esteem among grade 5 children

BACKGROUND

Meal regularity is associated with many aspects of mental health. However, few studies have examined whether a relationship exists between meal regularity and self-esteem in children.

OBJECTIVES

The objective of this study was to determine whether an association exists between meal regularity and self-esteem in grade 5 children.

METHODS

Among 4009 grade 5 students (mean age = 11.0 years ± SEM = 0.006) from the 2011 Children's Lifestyle and School Performance Study (CLASS-II; Nova Scotia, Canada), cross-sectional meal regularity survey data (family supper, supper in front of the television, supper alone, skipping breakfast, and skipping lunch) were collected using the Harvard Youth/Adolescent Food Frequency Questionnaire and examined in relation to self-esteem. Multilevel mixed-effects logistic regression was used to determine the ORs and 95% CIs associated with low self-esteem. Analyses were stratified by sex and adjusted for sociodemographic and lifestyle covariates.

RESULTS

Compared to children who ate supper in front of the television or alone either never or less than once/week, children had greater odds of low self-esteem if 5 or more times/week they ate supper in front of the television (OR = 1.85; 95% CI, 1.40-2.43) or alone (OR = 4.23; 95% CI, 2.58-6.95). Compared to children who ate family supper 5 or more times/week, children who ate family supper never or less than once/week had greater odds of low self-esteem (OR: 1.97; 95% CI, 1.51-2.56). Skipping breakfast and skipping lunch were associated with greater odds of low self-esteem [OR = 2.92 (95% CI, 1.87-4.57) and OR = 4.82 (95% CI, 2.14-10.87) respectively].

CONCLUSIONS

In our study of grade 5 children, all 5 indicators of meal regularity tested are significantly and consistently associated with self-esteem.

Mixed milk feeding: a systematic review and meta-analysis of its prevalence and drivers

CONTEXT

Extensive literature is available on exclusive breastfeeding and formula-feeding practices and health effects. In contrast, limited and unstructured literature exists on mixed milk feeding (MMF), here defined as the combination of breastfeeding and formula feeding during the same period in term infants > 72 hours old (inclusion criterion).

OBJECTIVE

A systematic review and meta-analysis were performed, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, on the global prevalence of MMF (primary outcome) and related drivers and practices (secondary outcomes).

DATA SOURCES

The search of MMF in generally healthy populations was conducted across 6 databases, restricted to publications from January 2000 to August 2018 in English, Spanish, French, and Mandarin.

DATA EXTRACTION

Two reviewers independently performed screenings and data extraction according to a priori inclusion and exclusion criteria.

DATA ANALYSIS

Of the 2931 abstracts identified, 151 full-text publications were included for data extraction and 96 of those were included for data synthesis (the majority of those were cross-sectional and cohort studies). The authors summarized data across 5 different categories (feeding intention prenatally, and 4 age intervals between > 72 hours and > 6-23 months) and 5 regional subgroups. The overall prevalence of MMF across different age intervals and regions varied between 23% and 32%; the highest rate was found for the age group 4-6 months (32%; 95% confidence interval, 27%-38%); regional comparisons indicated highest MMF rates in Asia (34%), North and South America (33%), and Middle East and Africa together (36%), using a random effects meta-analysis model for proportions. Some drivers and practices for MMF were identified.

CONCLUSION

MMF is a widespread feeding reality. A shared and aligned definition of MMF will help shed light on this feeding practice and evaluate its influence on the duration of total breastfeeding, as well as on infants' nutrition status, growth, development, and health status in the short and long terms. PROSPERO registration number CRD42018105337.

Associations between maternal BMI, breastfeeding practices and infant anthropometric status in Colombia; secondary analysis of ENSIN 2010

BACKGROUND

Maternal malnutrition and infant feeding mode impact short and long term infant and child morbidity and mortality. The period of lactation may provide an opportunity to modulate the risk of disease later in life. Our aim was to estimate the effect of maternal body mass index (BMI) and infant feeding mode, particularly breastfeeding practices, on the anthropometric status of children under 2 years in Colombia.

METHODS

A secondary analysis was performed using the data from ENSIN 2010. Term infants under 2y, singleton, with a mother older than 18y, were included in the analysis. Outcomes were wasting (WLZ < -2SD), overweight (WLZ > +2SD) and stunting (LAZ < -2SD). Predictors were infant feeding (exclusive and predominant BF constructed from 24-h recall, age at introduction of liquids, semisolids and solids) and maternal BMI. Socioeconomic variables, maternal education and age, conditions during pregnancy and birth weight were analyzed as covariates.

RESULTS

Mothers of overweight infants had higher BMI (Mean dif = 1.47 kg/m²; 95% CI = 2.1, 0.8) than those with normal weight infants. Stunting and wasting were not predicted by maternal anthropometry or infant feeding mode. Fewer maternal years of education were associated with wasting (OR = 0.90; 95% CI = 0.86, 0.97; p = 0.003) and stunting (OR = 0.92; 95% CI = 0.89, 0.94; p < 0.0001), while more maternal years of education were associated with overweight (OR = 1.06; 95% CI = 1.02, 1.01; p = 0.001); higher birth weight was associated with overweight (OR = 1.001; 95% CI = 1.00, 1.001; p < 0.0001) and lower birth was associated with stunting (OR = 0.99; 95% CI = 0.89; p < 0.0001) in the final regression model.

CONCLUSIONS

Maternal BMI is a modifiable target for public health policy to promote healthy infant growth. Infant nutritional status is affected by direct and indirect factors that need to be addressed in further studies.

Effect of feeding patterns on growth and nutritional status of children aged 0-24 months: A Chinese cohort study

Objective

This study was aimed to examine the effect of feeding patterns on growth and nutritional status of children aged 0~24 months.

Methods

We conducted a cohort study with an initial sample of 927 children. Considering the follow-up losses, 903, 897, 895, 897, 883, 827 and 750 children were followed up at 1, 3, 6, 8, 12, 18 and 24 months, respectively. Children were grouped according to exclusive breastfeeding (EBF) duration in the first 6 months: (1) never EBF; (2) EBF ≤ 3 months: EBF ≤ 3 months and stopped BF after 3 months or EBF ≤ 3 months and BF = 6 months or EBF ≤ 3 months and BF after 3 months, had formula and/or solids; (3) EBF for 3 ~ 6 months: BF < 3 months and EBF for 3 ~ 6 months or EBF for 3 ~ 6 months and BF < 3 months, had formula and/or solids; (4) EBF = 6 months. We used Z-scores to evaluate the growth and nutritional status of children, used the generalized estimation equation to compare the difference between feeding patterns.

Results

The generalized estimation equation results showed that Weight-for-age Z-score (WAZ), Length-for-age Z-score (LAZ), and Weight-for-length Z-score (WLZ) in different feeding patterns had statistical significance. The WAZ in EBF for 6 months group was higher in the first 8 months, in never EBF group was higher after 12 months old; the LAZ in EBF for 6 month group was lower than other groups; the WLZ in EBF for 6 months group was higher than EBF for 3 ~ 6 months group. The EBF ≤ 3 months group had higher underweight, stunting, and wasting rates. The EBF for 6 months had a higher stunting rate; the never EBF and EBF for 6 months groups had higher overweight and obesity rates.

Conclusions

In conclusion, different feeding patterns affect growth and nutritional status in children, so proper guidelines should be implemented to improve nutritional status and promote the growth of children.

Prenatal Maternal Depressive Symptoms Predict Early Infant Health Concerns

INTRODUCTION

Recent research suggests that health disparities among low-SES and ethnic minority populations may originate from prenatal and early life exposures. Postpartum maternal depressive symptoms have been linked to poorer infant physical health, yet prenatal depressive symptoms not been thoroughly examined in relation to infant health.

METHODS

In a prospective study of low-income Mexican American mothers and their infants, women (N = 322, median age 27.23, IQR = 22.01-32.54) completed surveys during pregnancy (median gestation 39.50, IQR = 38.71-40.14 weeks) and 12 weeks after birth. We investigated (1) if prenatal depressive symptoms predicted infant physical health concerns at 12 weeks of age, (2) whether these associations occurred above and beyond concurrent depressive symptoms, and (3) if birth weight, gestational age, and breastfeeding were mediators of prenatal depression predicting subsequent infant health.

RESULTS

Higher prenatal depressive symptoms were associated with more infant physical health concerns at 12 weeks (p < .001), after accounting for 12-week maternal depressive symptoms, breastfeeding, gestational age, and birth weight. Twelve-week maternal depressive symptoms were concurrently associated with more infant health concerns (p < .01). Birth weight, gestational age, and breastfeeding were not associated with maternal depression or infant health concerns.

DISCUSSION

Results establish a link between prenatal depressive symptoms and an elevated risk of poor health evident shortly after birth. These findings underscore the importance of the prenatal period as a possible sensitive period for infants' health, and the need for effective interventions for depression during pregnancy to mitigate potentially teratogenic effects on the developing fetus and reduce risks for later health concerns.

Differences in infant feeding practices between Chinese-born and Australian-born mothers living in Australia: a cross-sectional study

BACKGROUND

Chinese immigrants are the third largest immigrant group in Australia. Recent qualitative evidence from Victorian Maternal and Child Health nurses indicate that infants of Chinese parents commonly have rapid growth trajectories and that high value is placed on rapid growth and having a fatter child; with low breastfeeding rates and overfeeding of infant formula. The aim of this study was to compare infant feeding practices (breastfeeding, infant formula, other liquids, solids) of Chinese-born and Australian-born mothers living in Australia.

METHODS

Using the Australian National Infant Feeding Survey dataset (2010-2011), infant feeding data from Chinese-born mothers (n = 602) were compared with a random sub-sample of Australian-born mothers (n = 602). Group differences on feeding practices were tested using Chi-square or t-tests and the effect of ethnicity on infant feeding behaviours assessed using regression.

RESULTS

Compared to infants of Australian-born mothers, infants of Chinese-born mothers were younger when they first consumed infant formula, water-based drinks and fruit juice and older when they first ate solid foods (p < 0.05). Furthermore, infants of Chinese-born mothers were less likely to have ever had cow's milk (OR: 0.37 95%CI:, 0.18-0.78) and solids (0.41, 0.25-0.68); but were more likely to have ever had infant formula (2.19, 1.32-3.62), water (2.45, 1.55-3.87), toddler milk (3.39, 1.60-7.18), water-based drinks (e.g. cordial, soft drink, tea; 2.48, 1.12-5.49), and fruit juice (4.03, 2.50-6.51). Those ≤4 months of age were more likely to have had water-based drinks (7.77, 1.96-30.77) and fruit juice (3.44, 1.14-10.38) (p < 0.05) compared to infants of Australian-born mothers.

CONCLUSION

Differences in mothers' early infant feeding practices exist between Chinese-born and Australian-born mothers living in Australia. Better understanding these ethnically patterned infant feeding practices is important for identifying key opportunities to promote best nutrition and growth in early life in different ethnic groups within our population.

Effects of infant formula composition on long-term metabolic health

Early nutrition may have long-lasting metabolic impacts in adulthood. Even though breast milk is the gold standard, most infants are at least partly formula-fed. Despite obvious improvements, infant formulas remain perfectible to reduce the gap between breastfed and formula-fed infants. Improvements such as reducing the protein content, modulating the lipid matrix and adding prebiotics, probiotics and synbiotics, are discussed regarding metabolic health. Numerous questions remain to be answered on how impacting the infant formula composition may modulate the host metabolism and exert long-term benefits. Interactions between early nutrition (composition of human milk and infant formula) and the gut microbiota profile, as well as mechanisms connecting gut microbiota to metabolic health, are highlighted. Gut microbiota stands as a key actor in the nutritional programming but additional well-designed longitudinal human studies are needed.

Relationship Between Exclusive Breastfeeding and Lower Risk of Childhood Obesity: A Narrative Review of Published Evidence

BACKGROUND

The pattern of infant feeding during the first 1000-day period-from conception to the second birthday-has a significant influence on the child's growth trajectory. The relationship between exclusive breastfeeding and lower risk of childhood obesity has elicited much scientific interest, given the fact that this form of malnutrition is becoming a global epidemic.

AIM

This narrative review aims to examine the evidence in the literature linking exclusive breastfeeding with reduction in obesity in children.

LITERATURE SEARCH

Using appropriate search terms, PubMed database was searched for relevant articles that met the review objective.

RESULTS

Evidence for the protective effect of exclusive breastfeeding against childhood obesity have been provided by studies which explored 5 physiologic mechanisms and those that established the causality between breastfeeding and lower risk of obesity. The few studies that disputed this relationship highlighted the influence of confounding factors. A new insight on molecular mechanisms, however, points to a direct and indirect effect of human milk oligosaccharides on the prevention of overweight and obesity.

CONCLUSIONS

The preponderance of current evidence strongly suggests that exclusivity in breastfeeding can prevent the development of obesity in children.

Independent effect of type of breastfeeding on overweight and obesity in children aged 12-24 months

This study aimed to analyze the effect of type of breastfeeding on the nutritional status of children between 12-24 months of age. This cohort study included 435 children born in 2012 in a public hospital in Joinville, Santa Catarina State, Brazil. Two years after delivery the mothers and their children were contacted in their homes for a new investigation of demographic, economic, nutritional, and anthropometric data. In the unadjusted analysis, children who were not exclusively breastfed were more likely to be overweight (including obesity) at 2 years of age (OR = 1.6; p = 0.049) than exclusively breastfed children. After adjusting for several covariates, children who were not exclusively breastfed had a 12% higher risk of overweight including obesity compared to unadjusted analysis (OR = 2.6 vs. OR = 1.8; p = 0.043). In addition, birthweight was also an independent determinant of overweight including obesity (OR = 2.5; p = 0.002). The practice of exclusive breastfeeding can reduce the risk of overweight in children from developing countries such as Brazil.

Biological, environmental, and social influences on childhood obesity

The prevalence of childhood obesity has increased globally over the past three decades, with evidence of recent leveling off in developed countries. Reduction in the, currently high, prevalence of obesity will require a full understanding of the biological and social pathways to obesity in order to develop appropriately targeted prevention strategies in early life. Determinants of childhood obesity include individual level factors, including biological, social, and behavioral risks, acting within the influence of the child's family environment, which is, in turn, imbedded in the context of the community environment. These influences act across childhood, with suggestions of early critical periods of biological and behavioral plasticity. There is evidence of sex and gender differences in the responses of boys and girls to their environments. The evidence that determinants of childhood obesity act at many levels and at different stages of childhood is of policy relevance to those planning early health promotion and primary prevention programs as it suggests the need to address the individual, the family, the physical environment, the social environment, and social policy. The purpose of this narrative review is to summarize current, and emerging, literature in a multilevel, life course framework.

The Influence of Early Infant-Feeding Practices on the Intestinal Microbiome and Body Composition in Infants

Despite many years of widespread international recommendations to support exclusive breastfeeding for the first six months of life, common hospital feeding and birthing practices do not coincide with the necessary steps to support exclusive breastfeeding. These common hospital practices can lead to the infant receiving formula in the first weeks of life despite mothers' dedication to exclusively breastfeed. Consequently, these practices play a role in the alarmingly high rate of formula-feeding worldwide. Formula-feeding has been shown to alter the infant gut microbiome in favor of proinflammatory taxa and increase gut permeability and bacterial load. Furthermore, several studies have found that formula-feeding increases the risk of obesity in later childhood. While research has demonstrated differences in the intestinal microbiome and body growth between exclusively breast versus formula-fed infants, very little is known about the effects of introducing formula to breastfed infants either briefly or long term on these outcomes. Understanding the relationships between mixed-feeding practices and infant health outcomes is complicated by the lack of clarity in the definition of mixed-feeding as well as the terminology used to describe this type of feeding in the literature. In this commentary, we highlight the need for hospitals to embrace the 10 steps of the Baby Friendly Hospital Initiative developed by UNICEF and the WHO for successful breastfeeding. We present a paucity of studies that have focused on the effects of introducing formula to breastfed infants on the gut microbiome, gut health, growth, and body composition. We make the case for the need to conduct well-designed studies on mixed-feeding before we can truly answer the question: how does brief or long-term use of formula influence the health benefits of exclusive breastfeeding?