The association between caesarean section and childhood obesity revisited: a cohort study

Caesarean Section Delivery Is Associated with Childhood Overweight and Obesity, Low Childbirth Weight and Postnatal Complications: A Cross-Sectional Study

Background and Objectives: In the last decades, simultaneously increasing trends have been recorded for both caesarean section delivery and childhood overweight/obesity around the world, which are considered serious public health concerns, negatively affecting child health. Aim: The present study aims to investigate whether caesarean section is associated with the increased rates of childhood overweight/obesity, low childbirth anthropometric indices and postnatal complications in pre-school age. Materials and Methods: This is a cross-sectional study in which 5215 pre-school children aged 2–5 years old were enrolled from nine different Greek regions after applying specific inclusion and exclusion criteria. Non-adjusted and adjusted statistical analysis was performed to assess the impact of caesarean section in comparison to vaginal delivery. Results: Children delivered by caesarean section were significantly more frequently overweight or obese at the age of 2–5 years, also presenting a higher prevalence of low birth weight, length and head circumference. Caesarean section was also associated with higher incidence of asthma and diabetes type I at the age of 2–5 years. In a multivariate analysis, caesarean section increased the risk of childhood overweight/obesity and low childbirth anthropometric indices even if adjusting for several childhood and maternal confounding factors. Conclusions: Increasing trends were recorded for both caesarean section delivery and childhood overweight/obesity, which are considered serious public health concerns. Caesarean section independently increased childhood overweight/obesity in pre-school age, highlighting the emergent need to promote health policies and strategies to inform future mothers about its short and long-term risks and that this mode of delivery should preferably be performed only when there are strong medical recommendations in emergency obstetric conditions.

Cesarean birth and risk of obesity from birth to adolescence: A cohort study

BACKGROUND

Recent studies have shown associations between cesarean birth and overweight. However, very few studies have evaluated weight gain or adiposity throughout life, and the majority are restricted to analysis during childhood. The purpose of this study was to analyze the effect of cesarean birth on obesity risk from birth to adolescence.

METHODS

The study sample was drawn from live births that occurred in 1999 and 2000 in Mato Grosso-Brazil. Participants were evaluated once when they were between 0 and 5 years of age and again after approximately 10 years (2009-2011). To measure the association between cesarean birth and obesity (Body Mass Index/age >+2 z-scores), we used generalized estimation equations (GEE) with binomial distribution and log-binomial models for repeated measures, controlled by the following confounding factors: weight and length at birth, sex, gestational age, breastfeeding, maternal age and schooling, economic class in childhood, and maternal smoking during pregnancy. The exposure-time interaction term was evaluated to verify differences in the change in the risk of obesity over time.

RESULTS

56.8% of children in the sample were born by cesarean birth. Children born by cesarean had a higher risk of obesity from birth through adolescence (RR = 1.22, 95% CI = 1.02; 1.46), even after adjusting for covariates, when compared with those born vaginally. However, the time-exposure interaction term was not significant, which indicates that there was no increased risk of obesity over time.

CONCLUSION

Cesarean birth was positively associated with obesity from birth to adolescence, with a persistent risk in the period evaluated.

Relationship between caesarean section delivery and risk of overweight/obesity among children aged 6–23 months in the Tamale Metropolis of Ghana

The recent exponential increase in caesarean section (CS) rates in many countries including Ghana requires an understanding of the potential long-term consequences on child health. The present study investigated the relationship between CS delivery and risk of childhood overweight/obesity. A retrospective cohort study was conducted from October 2019 to March 2020 in Ghana. Using multi-stage sampling, 553 mother–child pairs aged 6–23 months were selected from ten health facilities during child welfare clinic (CWC) services. We assessed the association between delivery mode (caesarean v. vaginal) and subsequent body mass index for age (BMI/age Z-score) using hierarchical multivariable linear regression analysis. The prevalence of overweight/obesity (BMI/age Z-score > +2 sd) in children was 3⋅6 %. After adjusting for maternal gestational weight gain, macrosomia and child feeding practices, children who were born through CS had mean BAZ which was 0⋅105 standard units significantly higher than their colleagues who were delivered through normal vaginal [beta coefficient (β) 0⋅105, (95 % CI 0⋅03, 0⋅55)]. CS birth was also associated with 3⋅2 times higher odds of overweight/obesity than vaginal delivery (AOR 3⋅23; 95 % CI 1⋅14, 9⋅13). Consequently, CS delivery was associated positively with increased body mass (adiposity) in the study sample. The association between CS delivery and risk of childhood obesity was attenuated after adjusting for macrosomia. These results would be important for informing clinicians and expectant mothers in considering CS delivery.

Cesarean delivery and metabolic health and inflammation biomarkers during mid-childhood and early adolescence

BACKGROUND

We assessed differences in plasma levels of metabolic health and inflammation biomarkers during mid-childhood and early adolescence between children born by cesarean section vs. vaginal delivery.

METHODS

Mother-child pairs (N = 942) enrolled during pregnancy in obstetric practices and child follow-up started at birth. Risk biomarkers were assessed in blood samples collected at the mild-childhood (median = 7 years) and early adolescence (median = 13 years) in-person visits.

RESULTS

Two hundred and six children (22%) were born by cesarean section. There were no significant differences in biomarker levels between children born by cesarean and children born vaginally in mid-childhood. However, adolescents born by cesarean section had significantly lower adiponectin [% difference (95% confidence interval (CI)) = -11.3 (-18.1, -4.0) µg/mL] compared to vaginal delivery. We also found some suggestion of higher insulin resistance [insulin levels % difference (95% CI) = 11.5 (-0.40, 25.0) µU/mL and HOMA-IR (homeostatic model assessment of insulin resistance) % difference (95% CI) = 9.1 (-2.30, 21.8) U] in adolescents born by cesarean section compared to those born vaginally.

CONCLUSIONS

We found suggestive evidence that adolescents born by cesarean section show differences in certain metabolic health biomarkers relative to adolescents born by vaginal delivery. Further studies are needed to reevaluate these associations since the clinical significance of these differences is unclear.

IMPACT

Multiple studies show that children born by cesarean section are at higher risk of obesity compared to those born vaginally. It is unclear yet to what extent this elevated risk may extend to a more adverse profile of biomarkers of metabolic health and inflammation. Adolescents born by cesarean section show small differences in adiponectin and insulin relative to adolescents born by vaginal delivery. Adolescents born by cesarean section may be at higher risk to a more adverse profile of biomarkers of metabolic health and inflammation, but the clinical significance of these differences is uncertain.

Linkage Between 2 Information Systems: Combined Live Births and Food and Nutrition Surveillance as a Public Health Tool for Investigation of the Determinants of Obesity Among Children and Adolescents in Southern Brazil

BACKGROUND

Childhood obesity has been growing steadily, at an earlier age, and currently comprises a public health issue. A number of studies have pointed to perinatal factors as possible determinants in the development of childhood obesity.

OBJECTIVE

To evaluate the influence of perinatal factors on the development of obesity in children and adolescents in southern Brazil.

DESIGN

Retrospective cohort study in which a linkage was made between anthropometric data of children and adolescents aged 0 to 15 years who had been registered in the Food and Nutrition Surveillance System (SISVAN) from 2008 to 2016 and their perinatal data registered in the Live Birth Information System (SINASC) from 2000 to 2014. The SINASC was used to extract maternal covariables (age, schooling, marital status), prenatal variables (parity and number of prenatal visits), and perinatal variables (type of delivery, sex, and birth weight). Variables such as age, inclusion in the Bolsa Família income transfer program, and the number of anthropometric evaluations were extracted from SISVAN.

RESULTS

The sample comprised 537 children and adolescents. The median age was 8 years (interquartile range: 2-11 years). The prevalence of obesity was 15.1%. Poisson regression revealed a higher risk of obesity in children born via cesarean delivery (relative risk [RR] = 1.48; 95% CI: 1.01-2.17), children of primiparous mothers (RR = 1.72; 95% CI: 1.16-2.53), girls (RR = 1.77; 95% CI:1.21-2.60), and those aged between 5 and 9 years (RR = 26.8; 95% CI: 3.75-191.55) and older than 10 years (RR = 20.74; 95% CI: 2.89-148.61).

CONCLUSIONS

The linkage between SINASC and SISVAN allowed identification of prenatal and perinatal risk factors for the development of childhood obesity. These findings should contribute to the development of health promotion and prevention policies.

Association of Mode of Obstetric Delivery With Child and Adolescent Body Composition

IMPORTANCE

Although the literature on the association between birth by cesarean delivery and children's anthropometry has continued to increase, only a few studies have examined the association of cesarean delivery with measures of body composition assessed using dual-energy x-ray absorptiometry (DXA), which allows the differentiation of fat and lean mass overall and in specific regions of the body.

OBJECTIVE

To investigate whether differences exist in DXA-measured body composition between children and adolescents born by cesarean delivery and those born by vaginal delivery.

DESIGN, SETTING, AND PARTICIPANTS

This prospective cohort study included singleton children of mothers enrolled between April 1999 and July 2002 in Project Viva, a longitudinal prebirth cohort of mother-child pairs in Massachusetts. The children had at least 1 DXA scan at a follow-up visit during middle childhood (2007-2010) and/or early adolescence (2013-2016). Data analysis was performed from October 16, 2020, to May 9, 2021.

EXPOSURES

Mode of delivery (cesarean vs vaginal).

MAIN OUTCOMES AND MEASURES

Total lean mass index, total and truncal fat mass indexes, visceral adipose tissue (VAT), subcutaneous abdominal adipose tissue, and total abdominal adipose tissue (TAAT) were estimated using DXA. Multivariable linear regression models were used to estimate the association between mode of delivery and DXA-derived outcomes with adjustment for confounders. Stabilized inverse probability weights were used to control for potential selection bias owing to loss to follow-up.

RESULTS

A total of 975 mother-child pairs were included in the study. The mean (SD) maternal age at study entry was 32.0 (5.5) years, and the mean (SD) self-reported prepregnancy body mass index (BMI; calculated as weight in kilograms divided by height in meters squared) was 25.0 (5.4). Of the children included in the study, 491 (50%) were female; 212 (22%) were born by cesarean delivery and 763 (78%) by vaginal delivery. Body composition in middle childhood as measured by DXA did not differ by mode of delivery. In early adolescence, participants born by cesarean delivery had a significantly greater total lean mass index (β, 0.4; 95% CI, 0.0-0.7), total fat mass index (β, 0.6; 95% CI, 0.1-1.1), truncal fat mass index (β, 0.3; 95% CI, 0.0-0.5), VAT area (β, 4.7; 95% CI, 0.9-8.6), and TAAT area (β, 23.8; 95% CI, 0.8-46.8) in a model adjusted for child sex and age at the time of DXA measurements; maternal age, educational level, race and ethnicity, total gestational weight gain, and smoking status during pregnancy; birth-weight-per-gestational-age z score; and paternal BMI. Associations between mode of delivery and measures of adiposity were found for cesarean deliveries performed in the absence of labor (total fat mass index: β, 1.3; 95% CI, 0.3-2.3; truncal fat mass index: β, 0.6; 95% CI, 0.1-1.0; VAT area: β, 10.7; 95% CI, 3.1-18.3; TAAT area: β, 47.3; 95% CI, 2.3-92.2). There were no associations after adjustment for maternal self-reported prepregnancy BMI (total lean mass index: β, 0.2; 95% CI, -0.1 to 0.6; total fat mass index: β, 0.4; 95% CI, -0.1 to 0.9; truncal fat mass index: β, 0.2; 95% CI, -0.1 to 0.4; VAT area: β, 3.0; 95% CI, -0.6 to 6.7; TAAT area: β, 13.6; 95% CI, -8.2 to 35.3).

CONCLUSIONS AND RELEVANCE

In this cohort study, adolescents born by cesarean delivery had significantly higher measures of lean mass, fat mass, and central adiposity compared with those born by vaginal delivery, but associations did not remain after adjustment for the mothers' self-reported prepregnancy BMI. The findings suggest that the association between birth by cesarean delivery and adolescent adiposity may partly be explained by maternal self-reported prepregnancy BMI.

Delivery by caesarean section and offspring adiposity and cardio-metabolic health at ages 6.5, 11.5 and 16 years: results from the PROBIT cohort in Belarus

BACKGROUND

Caesarean delivery has been associated with later adiposity, perhaps via early programming or perhaps because of residual confounding by maternal or birth characteristics.

OBJECTIVES

Examine associations of caesarean delivery with adiposity and cardio-metabolic biomarkers.

METHODS

Observational analysis of 15 069 children in the PROBIT cohort in Belarus. We examined measures of child anthropometry and blood pressure at 6.5, 11.5 and 16 years and fasting blood (11.5 years).

RESULTS

Caesarean-delivered children were slightly heavier at 6.5 (mean BMI 15.8 vs. 15.6 kg/m² ), 11.5 (18.4 vs. 18.2) and 16 years (21.5 vs. 21.3). After adjustment for prenatal characteristics including maternal third trimester BMI, however, we observed no association of caesarean versus vaginal delivery with child BMI (β 0.05 kg/m² ; 95%CI: -0.03, 0.14), sum of skinfolds (0.14 mm; -0.13, 0.42), waist circumference (-0.07 cm; -0.23, 0.10), obesity (OR 0.99; 0.76, 1.29), or systolic (-0.20 mmHg; -0.70, 0.30) or diastolic (-0.17 mmHg, -0.60, 0.26) blood pressure at 6.5 years; results were similar at 11.5 and 16 years. At 11.5 years, we observed a modest association of caesarean delivery with fasting insulin (0.33 mU/L; 0.00, 0.65).

CONCLUSIONS

Caesarean delivery had little or no association with adiposity or related cardio-metabolic biomarkers in childhood. Adjustment for maternal BMI attenuated all outcome effect estimates.

Caesarean delivery is associated with an absolute increase in the prevalence of overweight in the offspring: The SENDO project

AIM

The association between caesarean delivery and the risk of overweight/obesity in the offspring has been previously reported using conventional measures of association (relative risks or odds ratios). We aimed at refining the existing evidence by calculating the marginal effect of the exposure and estimating the unmeasured residual confounding.

METHODS

In the 'SEguimiento del Niño para un Desarrollo Óptimo' Project, a dynamic multipurpose paediatric cohort study, we collected information from parents through self-administered online questionnaires. We estimated the offspring's risk of overweight/obesity at age 4-6 years, associated with the type of delivery through marginal effect of the exposure. Unmeasured residual confounding was assessed using the E-value.

RESULTS

Among 407 participants (mean-age: 5.0 years (standard deviation: 0.9)), 86 (21.1%) were born by caesarean delivery. Children born by caesarean delivery had higher odds of overweight/obesity than those born vaginally. Subgroup analyses showed similar results. The multivariable adjusted marginal effect showed that caesarean delivery was associated with an 8.0% (95% confidence interval: 0.2-15.7) absolute increase in the prevalence of overweight/obesity. The estimated residual confounding showed an E-value of 4.03, higher than the OR obtained for all the confounding factors we accounted for.

CONCLUSIONS

Caesarean delivery was associated with an 8% absolute increase in the risk of overweight/obesity that is very unlikely explained by residual confounding.

Amino Acids Regulate Glycolipid Metabolism and Alter Intestinal Microbial Composition

Amino acids (AAs) and their metabolites regulate key metabolic pathways that are necessary for growth, reproduction, immunity and metabolism of the body. It has been convinced that metabolic diseases are closely related to disorders of glycolipid metabolism. A growing number of studies have shown that AAs are closely related to energy metabolism. This review focuses on the effects of amino acids (arginine, branched-chain amino acids, glutamine) and their metabolites (short chain fatty acids) on glycolipid metabolism by regulating PI3K/AKT/mTOR and AMPK signaling pathways and GPCRs receptors, reducing intestinal Firmicutes/Bacteroidetes ratio associated with obesity.

Association between cesarean delivery types and obesity in preadolescence

Background/Objectives:

The association between mode of delivery and childhood obesity remains inconclusive. Because few studies have separated C-section types (planned or unplanned C-section), our objective was to assess how these subtypes relate to pre-adolescent obesity.

Subjects/Methods:

The study consisted of 570 maternal-child pairs drawn from the WHEALS birth cohort based in Detroit, Michigan. Children were followed-up at 10 years of age where a variety of anthropometric measurements were collected. Obesity was defined based on BMI percentile (≥95th percentile), as well as through gaussian finite mixture modeling on the anthropometric measurements. Risk ratios (RRs) and 95% confidence intervals (CIs) for obesity comparing planned and unplanned C-sections to vaginal deliveries were computed, which utilized inverse probability weights to account for loss to follow-up and multiple imputation for covariate missingness. Mediation models were fit to examine the mediation role of breastfeeding.

Results:

After adjusting for marital status, maternal race, prenatal tobacco smoke exposure, maternal age, maternal BMI, any hypertensive disorders during pregnancy, gestational diabetes, prenatal antibiotic use, child sex, parity, and birthweight z-score, children born via planned C-section had 1.77 times higher risk of obesity (≥95th percentile), relative to those delivered vaginally ((95% CI)=(1.16,2.72); p=0.009). No association was found comparing unplanned C-section to vaginal delivery (RR (95% CI)=0.75 (0.45, 1.23); p=0.25). Results were similar but slightly stronger when obesity was defined by anthropometric class (RR (95% CI)=2.78 (1.47, 5.26); p=0.002). Breastfeeding did not mediate the association between mode of delivery and obesity.

Conclusions:

These findings indicate that children delivered via planned C-section—but not unplanned C-section—have a higher risk of pre-adolescent obesity, suggesting that partial labor or membrane rupture (typically experienced during unplanned C-section delivery) may offer protection. Additional research is needed to understand the biological mechanisms behind this effect, including whether microbiological differences fully or partially account for the association.

The association between caesarean section delivery and later life obesity in 21-24 year olds in an Urban South African birth cohort

BACKGROUND

Obesity is an important public health problem and rates have reached epidemic proportions in many countries. Studies have explored the association between infants delivered by caesarean section and their later life risk of obesity, in many countries outside Africa. As a result of the increasing caesarean section and obesity rates in South Africa, we investigated the association in this country.

METHODS

This was a retrospective analysis of data that were collected from a prospective South African birth cohort (Birth to Twenty Plus), established in 1990. A total of 889 young adults aged 21-24 years were included in the analysis. Poisson regression models were fitted to assess the association between mode of delivery and early adulthood obesity.

RESULTS

Of the 889 young adults, 106 (11.9%) were obese while 72 (8.1%) were delivered by caesarean section; of which 14 (19.4%) were obese. Caesarean section delivery was significantly associated with obesity in young adults after adjusting for potential confounders like young adults' sex and birth weight, mothers' parity, and education (incidence rate ratio 1.64, 95% CI 1.01-2.68, p = 0.045).

CONCLUSION

The association of caesarean section with early adulthood obesity should be interpreted with caution because data on certain key confounding factors such as mothers' pre-pregnancy body mass index and gestational diabetes were not available. Further research from Africa, with larger sample sizes and databases with useful linking of maternal and infant data, should be conducted.

Cesarean birth and the growth of Yucatec Maya and Toba/Qom children

OBJECTIVE

Cesarean delivery is often epidemiologically associated with childhood obesity. However, little attention is paid to post-birth modulatory environments, and most studies are conducted in settings where obesity arises for a number of reasons in addition to birth mode. We therefore assess population differences in the relationship between birth mode and childhood growth using data from rural and peri-urban Latin American indigenous populations, and test predictions developed using life history theory.

METHODS

Child height and weight were measured monthly in 80 Yucatec Maya and 58 Toba/Qom children aged 1-48 months (2007-2014, 3812 observations). Random-effects linear mixed models were used to compare children's growth by population, sex, and birth mode, accounting for potential confounders.

RESULTS

Cesarean delivery rates were 47% (Toba/Qom) and 20% (Yucatec Maya). Childhood obesity and overweight rates were low in both populations. Cesarean-delivered children had significantly greater weight gain (but similar height grain) compared to vaginally-delivered children. By age 4, cesarean delivered Yucatec Maya girls and boys, and Toba/Qom boys (not girls), had significantly higher weight-for-age compared to vaginally-delivered children from their own sex and population.

CONCLUSIONS

This provides one of the first attempts to document differences in children's growth patterns according to mode of birth in modernizing indigenous populations. Cesarean delivery is associated with young children's growth patterns, even in the absence of many obesity-inducing factors. There are also population, age, and sex differences in the relationship between birth mode and childhood weight trajectories that warrant future investigation.

Mode of delivery and offspring adiposity in late adolescence: The modifying role of maternal pre-pregnancy body size

Objective

To study the association between mode of delivery and offspring BMI in late adolescence in a large cohort that predated the obesity epidemic, and assess the role of maternal pre-pregnancy BMI (ppBMI) in this association.

Study design

We conducted a historical prospective study in the setting of the Jerusalem Perinatal Study (JPS), a population-based cohort that includes all 17,003 births to residents of West Jerusalem, between 1974 and 1976. Offspring’s BMI at age 17 was obtained upon army recruitment and was available for 11,001 of cohort participants. The associations were examined using logistic regressions, adjusting for socio-demographic characteristics and for proxies for indication for C-Section birth. Analyses were then stratified by quartiles of ppBMI.

Results

C-Section was associated with offspring overweight/obesity, with adjusted OR of 1.44 (95%CI:1.14–1.82). Significant interaction of ppBMI with mode of delivery was observed, such that the associations of C-Section with overweight/obesity were limited to the upper quartile of ppBMI (adjusted OR = 1.70, 95%CI:1.18–2.43). Restricting the analyses to singleton first births and excluding pregnancies complicated with toxemia and gestational diabetes yielded similar findings.

Conclusions

C-Section was positively associated with being overweight/obese at age 17. Importantly, ppBMI modified this association, with a significant association between C-Section and overweight/obesity evident only among offspring born to mothers in the highest ppBMI quartile. In light of the growing rates of obesity in women of reproductive age, these results should be considered in patient-doctor shared decisions related to selection of mode of delivery, in the absence of a clear medical indication.

Association of Elective and Emergency Cesarean Delivery With Early Childhood Overweight at 12 Months of Age

IMPORTANCE

Global cesarean delivery (CD) rates have more than doubled over the past 2 decades, with an increasing contribution from elective CDs. Cesarean delivery has been linked to early childhood overweight and obesity, but limited studies have examined elective and emergency CDs separately.

OBJECTIVE

To investigate whether elective or emergency CD was associated with risk of early childhood overweight.

DESIGN, SETTING, AND PARTICIPANTS

Data were drawn from the Growing Up in Singapore Toward Healthy Outcomes (GUSTO) study, an ongoing prospective mother-child birth cohort study. Participants were pregnant women aged 18 years or older with homogeneous parental ethnic background in their first trimester recruited between June 2009 and September 2010 (n = 1237) at 2 major public hospitals in Singapore. Those with type 1 diabetes or undergoing chemotherapy or psychotropic drug treatment were excluded. Data analysis commenced in October 2017.

EXPOSURES

Delivery mode obtained from clinical records. Elective and emergency CD examined separately against vaginal delivery as reference.

MAIN OUTCOMES AND MEASURES

Body mass index-for-age z scores at age 12 months calculated based on 2006 World Health Organization Child Growth Standards from infant weight and recumbent crown-heel length measurements taken between December 2010 and April 2012. High body mass index status at risk of overweight was defined as a z score of more than 1 SD and less than or equal to 2 SDs. Overweight was defined as a z score of more than 2 SDs.

RESULTS

Among 727 infants analyzed (51.2% [372] male), 30.5% (222) were born via CD, of which 33.3% (74) were elective. Prevalence of at risk of overweight and overweight at age 12 months was 12.2% (89) and 2.3% (17), respectively. Elective CD was significantly associated with at risk of overweight or overweight at age 12 months after adjusting for maternal ethnicity, age, education, parity, body mass index, antenatal smoking, hypertensive disorders of pregnancy, gestational diabetes, and sex-adjusted birth weight-for-gestational age (odds ratio, 2.05; 95% CI, 1.08-3.90; P = .03). The association persisted after further adjustment for intrapartum antibiotics and first 6 months infant feeding, 2 potential mediators of early childhood overweight and obesity (odds ratio, 2.02; 95% CI, 1.05-3.89; P = .04). No significant associations were found for emergency CD. Analysis with multiple imputation for missing covariates yielded similar results.

CONCLUSIONS AND RELEVANCE

Choice of delivery mode may influence risk of early childhood overweight. Clinicians are encouraged to discuss potential long-term implications of elective CD on child metabolic outcomes with patients who intend to have children.

The Impact of Caesarean Section on the Risk of Childhood Overweight and Obesity: New Evidence from a Contemporary Cohort Study

Caesarean section (CS) rates are increasing globally and exceed 50% in some countries. Childhood obesity has been linked to CS via lack of exposure to vaginal microflora although the literature is inconsistent. We investigated the association between CS birth and the risk of childhood obesity using the nationally representative Growing-Up-in-Ireland (GUI) cohort. The GUI study recruited randomly 11134 infants. The exposure was categorised into normal vaginal birth (VD) [reference], assisted VD, elective (planned) CS and emergency (unplanned) CS. The primary outcome measure was obesity defined according to the International Obesity Taskforce criteria. Statistical analysis included multinomial logistic regression with adjustment for potential confounders. Infants delivered by elective CS had an adjusted relative risk ratio (aRRR) = 1.32; [95% confidence interval (CI) 1.01-1.74] of being obese at age three years. This association was attenuated when macrosomic children were excluded (aRRR = 0.99; [95% CI 0.67-1.45]). Infants delivered by emergency CS had an increased risk of obesity aRRR = 1.56; [95% CI 1.20-2.03]; this association remained after excluding macrosomic children. We found insufficient evidence to support a causal relationship between elective CS and childhood obesity. An increased risk of obesity in children born by emergency CS, but not elective, suggests that there is no causal effect due to vaginal microflora.

Risk Factors for Obesity and Overfat among Primary School Children in Mashonaland West Province, Zimbabwe

Associated childhood obesity risk factors are not well established in developing countries such as Zimbabwe and this information is essential for tailored intervention development. This study aimed to identify prominent risk factors for overweight/obese and overfat/obese among primary school children of Mashonaland West Province in Zimbabwe. A school-based cross-sectional study was conducted using multi-stage random cluster sampling approach (30 × 30). Bivariate and multivariable logistic regression was employed and identified the risk factors for overweight/obese and overfat/obese. A total of 974 participants were enrolled in the study. Prominent significant risk factors of overweight/obese after multivariable adjustment were higher socio-economic households; parental diabetes status; and living in Makonde, Zvimba, Sanyati or Mhondoro-Ngezi district as opposed to Hurungwe district. Risk factors for overfat/obese that remained statically significant were children in urban areas (aOR = 3.19, 95% CI: 2.18-4.66, p = 0.000), being one child in a household, and parents who have diabetes mellitus. Living in Makonde, Sanyati, and Zvimba district remained associated with overfat/obese compared to Hurungwe district. This study has identified prominent proximal determinants of overweight/obese and overfat/obese among primary school children in Zimbabwe, to better assist policy guidance. Aggressive education on good nutrition activities should be tailored and targeted to most affected urban areas within high-risk districts.

Overweight in children and its perception by parents: cross-sectional observation in a general pediatric outpatient clinic

BACKGROUND

Childhood overweight is a growing problem in industrialized countries. Parents play a major role in the development and the treatment of overweight in their children. A key factor here is the perception of their child's weight status. As we know of other studies, parental perception of children's weight status is very poor. This study aimed to determine factors associated with childhood overweight and parental misperception of weight status. The height and weight of children, as reported by parents were compared with measured data.

METHODS

The study was conducted at a general pediatric outpatient clinic in Vienna, Austria. A total of 600 children (aged 0-14 years) participated in the study. Collection of data was performed by means of a questionnaire comprising items relating to parental weight and social demographics. The parents were also asked to indicate their children's weight and height, as well as the estimated weight status. Children were weighed and measured and BMI was calculated, allowing a comparison of estimated values and weight categories with the measured data.

RESULTS

Parental BMI, parental weight and a higher birth weight were identified as factors associated with childhood overweight. No association with the parents' educational status or citizenship could be proven. We compared parents' estimations of weight and height of their children with measured data. Here we found, that parental estimated values often differ from measured data. Using only parental estimated data to define weight status leads to misclassifications. It could be seen that parents of overweight children tend to underestimate the weight status of their children, compared to parents of children with normal weight.

CONCLUSIONS

Pediatricians should bear in mind that parental assessment often differs from the measured weight of their children. Hence children should be weighed and measured regularly to prevent them from becoming overweight. This is of particular importance in children with higher birth weight and children of overweight parents.

TRIAL REGISTRATION

Study was not registered. The study was approved by the Ethic committee of the city of Vienna. (EK 13-146-VK).

Increased weight gain by C-section: Functional significance of the primordial microbiome

Epidemiological evidence supports a direct association between early microbiota impact-including C-section-and obesity. We performed antibiotic-free, fostered C-sections and determined the impact on the early microbiota and body weight during development. Mice in the C-section group gained more body mass after weaning, with a stronger phenotype in females. C-section-born mice lacked the dynamic developmental gut microbiota changes observed in control mice. The results demonstrate a causal relationship between C-section and increased body weight, supporting the involvement of maternal vaginal bacteria in normal metabolic development.

The Brain-Derived Neurotrophic Factor Val66Met Polymorphism, Delivery Method, Birth Weight, and Night Sleep Duration as Determinants of Obesity in Vietnamese Children of Primary School Age

BACKGROUND

Obesity is a complex disease that involves both environmental and genetic factors in its pathogenesis. Several studies have identified multiple obesity-associated loci in many populations. However, their contribution to obesity in the Vietnamese population is not fully described, especially in children. The study aimed to investigate the association of obesity with Val66Met polymorphism in brain-derived neurotrophic factor (BDNF) gene, delivery method, birth weight, and lifestyle factors in Vietnamese primary school children.

METHODS

A case-control study was conducted on 559 children aged 6-11 years (278 obese cases and 281 normal controls). The obesity of the children was classified using both criteria of International Obesity Task Force (IOTF, 2000) and World Health Organization (WHO, 2007). Lifestyle factors, birth delivery, and birth weight of the children were self-reported by parents. The BDNF genotype was analyzed using the polymerase chain reaction-restriction fragment length polymorphism method. Association was evaluated by multivariate logistic regression and cross-validated by the Bayesian model averaging method.

RESULTS

The most significantly independent factors for obesity were delivery method (cesarean section vs. vaginal delivery, β = 0.56, p = 0.007), birth weight (>3500 to <4000 g vs. 2500-3500 g, β = 0.52, p = 0.035; ≥4000 g vs. 2500-3500 g, β = 1.06, p = 0.015), night sleep duration (<8 h/day vs. ≥8 h/day, β = 0.99, p < 0.0001), and BDNF Val66Met polymorphism (AA and GG vs. AG, β = 0.38, p = 0.039).

CONCLUSIONS

The study suggested the significant association of delivery method, birth weight, night sleep duration, and BDNF Val66Met polymorphism, with obesity in Vietnamese primary school children.

Factors Influencing the Gut Microbiota, Inflammation, and Type 2 Diabetes

The gut microbiota is a complex community of bacteria residing in the intestine. Animal models have demonstrated that several factors contribute to and can significantly alter the composition of the gut microbiota, including genetics; the mode of delivery at birth; the method of infant feeding; the use of medications, especially antibiotics; and the diet. There may exist a gut microbiota signature that promotes intestinal inflammation and subsequent systemic low-grade inflammation, which in turn promotes the development of type 2 diabetes. There are preliminary studies that suggest that the consumption of probiotic bacteria such as those found in yogurt and other fermented milk products can beneficially alter the composition of the gut microbiome, which in turn changes the host metabolism. Obesity, insulin resistance, fatty liver disease, and low-grade peripheral inflammation are more prevalent in patients with low α diversity in the gut microbiome than they are in patients with high α diversity. Fermented milk products, such as yogurt, deliver a large number of lactic acid bacteria to the gastrointestinal tract. They may modify the intestinal environment, including inhibiting lipopolysaccharide production and increasing the tight junctions of gut epithelia cells.

The Gut Microbiome, Obesity, and Weight Control in Women's Reproductive Health

The microbes residing in the human gut, referred to as the microbiome, are intricately linked to energy homeostasis and subsequently obesity. Integral to the origins of obesity, the microbiome is believed to affect not only health of the human gut but also overall health. This microbiome-obesity association is mediated through the process of energy extraction, metabolism, and cross talk between the brain and the gut microbiome. Host exposures, including diet, that potentially modify genetic predisposition to obesity and affect weight management are reviewed. The higher prevalence of obesity among women and recent evidence linking obesity during pregnancy with offspring health make this topic particularly relevant. Current limitations in microbiome research to address obesity and future advances in this field are described. Applications of this science with respect to applied nursing and overall health care in general are included, with emphasis on the reproductive health of women and their offspring.

Caesarean section and adiposity at 6, 18 and 30 years of age: results from three Pelotas (Brazil) birth cohorts

Background

Association between caesarian section (C-section) and obesity is controversial and mostly based on body mass index (BMI), which has inherent limitations. Using direct estimates of body fat mass, we aimed to assess the association between C-section and adiposity using fat mass index and BMI z-score in three birth cohort studies from Pelotas, Brazil.

Methods

We measured weight, height and fat mass (using dual X-ray absorptiometry (DXA)) at ages 6, 18 and 30 years among participants in the 2004, 1993 and 1982 population-based Pelotas Birth Cohort Studies, respectively. We used multiple linear regression analysis to examine the crude and adjusted association between C-section and the body composition indicators. We also modelled height as an outcome to explore the presence of residual confounding.

Results

We observed that fat mass index and BMI z-score were strongly and positively associated with C-section in the crude analysis. However, when we adjusted for socioeconomic characteristics, maternal BMI, parity, age and smoking during pregnancy, effect estimates were attenuated towards the null, except for 30-year-old women. In those women from the 1982 cohort, C-section remained associated with fat mass index (β = 0.82; CI95% 0.32;1.32) and BMI z-score (β = 0.15; CI95% 0.03;0.28), even after adjusting for all potential confounders, suggesting an increase in fat mass index and BMI at 30 years among those born by C-section.

Conclusion

We found no consistent association of C-section with fat mass index measured by DXA and BMI z-score in individuals aged 6, 18 and 30 years, except for women in the latter group, which might be explained by residual confounding. Confounding by socioeconomic and maternal characteristics accounted for all the other associations.

Association Between Cesarean Birth and Risk of Obesity in Offspring in Childhood, Adolescence, and Early Adulthood

IMPORTANCE

Cesarean birth has been associated with higher risk of obesity in offspring, but previous studies have focused primarily on childhood obesity and have been hampered by limited control for confounders.

OBJECTIVE

To investigate the association between cesarean birth and risk of obesity in offspring.

DESIGN, SETTING, AND PARTICIPANTS

A prospective cohort study was conducted from September 1, 1996, to December 31, 2012, among participants of the Growing Up Today Study, including 22 068 offspring born to 15 271 women, followed up via questionnaire from ages 9 to 14 through ages 20 to 28 years. Data analysis was conducted from October 10, 2015, to June 14, 2016.

EXPOSURE

Birth by cesarean delivery.

MAIN OUTCOMES AND MEASURES

Risk of obesity based on International Obesity Task Force or World Health Organization body mass index cutoffs, depending on age. Secondary outcomes included risks of obesity associated with changes in mode of delivery and differences in risk between siblings whose modes of birth were discordant.

RESULTS

Of the 22 068 offspring (20 950 white; 9359 male and 12 709 female), 4921 individuals (22.3%) were born by cesarean delivery. The cumulative risk of obesity through the end of follow-up was 13% among all participants. The adjusted risk ratio for obesity among offspring delivered via cesarean birth vs those delivered via vaginal birth was 1.15 (95% CI, 1.06-1.26; P = .002). This association was stronger among women without known indications for cesarean delivery (adjusted risk ratio, 1.30; 95% CI, 1.09-1.54; P = .004). Offspring delivered via vaginal birth among women who had undergone a previous cesarean delivery had a 31% (95% CI, 17%-47%) lower risk of obesity compared with those born to women with repeated cesarean deliveries. In within-family analysis, individuals born by cesarean delivery had 64% (8%-148%) higher odds of obesity than did their siblings born via vaginal delivery.

CONCLUSIONS AND RELEVANCE

Cesarean birth was associated with offspring obesity after accounting for major confounding factors. Although additional research is needed to clarify the mechanisms underlying this association, clinicians and patients should weigh this risk when considering cesarean delivery in the absence of a clear indication.

Childhood body mass is positively associated with cesarean birth in Yucatec Maya subsistence farmers

OBJECTIVE

The epidemiologic link between cesarean birth and childhood obesity is unresolved, partly because most studies come from industrialized settings where many post-birth factors affect the risk for obesity. We take advantage of an unusual ethnographic situation where hospital and cesarean birth modes have recently been introduced among Yucatec Maya subsistence farmers, but young children have had minimal exposure to the nutritional transition. While we expect to find very low rates of childhood obesity, we predict that cesarean-born children will be larger and heavier than vaginally born children.

METHODS

Weight and height were collected monthly on 108 children aged 0-5 (3576 observations total). Birth mode and birthweight were collected by maternal interview. Data were analyzed using linear mixed models that compare child growth [Maya population-specific Z-scores for weight-for-age and body mass index-for-age (WAZ and BMIZ)] in cesarean and vaginally born children aged 0-5 years.

RESULTS

The cesarean rate was 20%, no children were obese, and 5% were overweight. Cesarean birth was a significant predictor of child WAZ and BMIZ after accounting for maternal effects, child birthweight, and sex. Children who were born by cesarean to mothers with high BMI had the highest WAZ of all children by 5 years of age, and the highest BMIZ of all children at all ages.

CONCLUSION

Cesarean-born Maya children had higher BMI than vaginally born children, even in the absence of many known confounding factors that contribute to childhood obesity. Child growth was most sensitive to birth mode when mothers had high BMI.

Differential attentional responding in caesarean versus vaginally delivered infants

Little is known about the role that the birth experience plays in brain and cognitive development. Recent research has suggested that birth experience influences the development of the somatosensory cortex, an area involved in spatial attention to sensory information. In this study, we explored whether differences in spatial attention would occur in infants who had different birth experiences, as occurs for caesarean versus vaginal delivery. Three-month-old infants performed either a spatial cueing task or a visual expectation task. We showed that caesarean-delivered infants' stimulus-driven, reflexive attention was slowed relative to vaginally delivered infants', whereas their cognitively driven, voluntary attention was unaffected. Thus, types of birth experience influence at least one form of infants' attention, and possibly any cognitive process that relies on spatial attention. This study also suggests that birth experience influences the initial state of brain functioning and, consequently, should be considered in our understanding of brain development.

Risk Factors for Childhood Obesity in the First 1,000 Days: A Systematic Review

CONTEXT

Mounting evidence suggests that the origins of childhood obesity and related disparities can be found as early as the "first 1,000 days"-the period from conception to age 2 years. The main goal of this study is to systematically review existing evidence for modifiable childhood obesity risk factors present from conception to age 2 years.

EVIDENCE ACQUISITION

PubMed, Embase, and Web of Science were searched for studies published between January 1, 1980, and December 12, 2014, of childhood obesity risk factors present during the first 1,000 days. Prospective, original human subject, English-language research with exposure occurrence during the first 1,000 days and with the outcome of childhood overweight or obesity (BMI ≥85th percentile for age and sex) collected between age 6 months and 18 years were analyzed between December 13, 2014, and March 15, 2015.

EVIDENCE SYNTHESIS

Of 5,952 identified citations, 282 studies met inclusion criteria. Several risk factors during the first 1,000 days were consistently associated with later childhood obesity. These included higher maternal pre-pregnancy BMI, prenatal tobacco exposure, maternal excess gestational weight gain, high infant birth weight, and accelerated infant weight gain. Fewer studies also supported gestational diabetes, child care attendance, low strength of maternal-infant relationship, low SES, curtailed infant sleep, inappropriate bottle use, introduction of solid food intake before age 4 months, and infant antibiotic exposure as risk factors for childhood obesity.

CONCLUSIONS

Modifiable risk factors in the first 1,000 days can inform future research and policy priorities and intervention efforts to prevent childhood obesity.

Does pet-keeping modify the association of delivery mode with offspring body size?

Caesarean-section (CS) delivery increases risk of childhood obesity, and is associated with a distinct early-life gut microbiome, which may contribute to obesity. Household pets may alter human gut microbiome composition. We examined if pet-keeping modified the association of CS with obesity at age 2 years in 639 Wayne County Health, Environment, Allergy and Asthma Longitudinal Study birth cohort participants. Pet-keeping was defined as having a dog or cat (indoors ≥1 h/day) at child age 2 years. We used logistic regression to test for an interaction between CS and pet-keeping with obesity (BMI ≥ 95th percentile) at age 2 years, adjusted for maternal obesity. A total of 328 (51.3 %) children were male; 367 (57.4 %) were African American; 228 (35.7 %) were born by CS; and 55 (8.6 %) were obese. After adjusting for maternal obesity, CS-born children had a non-significant (P = 0.25) but elevated 1.4 (95 % CI 0.8, 2.5) higher odds of obesity compared to those born vaginally. There was evidence of effect modification between current pet-keeping and delivery mode with obesity at age 2 years (interaction P = 0.054). Compared to children born vaginally without a pet currently in the home, children born via CS without a pet currently in the home had a statistically significant (P = 0.043) higher odds (odds ratio 2.00; 95 % CI 1.02, 3.93) of being obese at age 2 years. Pets modified the CS-BMI relationship; whether the underlying mechanism is through effects on environmental or gut microbiome requires specific investigation.

Race-specific Association of Caesarean-Section Delivery with Body Size at Age 2 Years

OBJECTIVE

African American children are at higher risk of obesity than White children and African American women are more likely to undergo caesarean-section (CS) delivery than White women. CS is associated with childhood obesity; however, little is known whether this relationship varies by race. We examined if the association of CS with obesity at age 2 years varied by race.

DESIGN

Longitudinal birth cohort.

SETTING

Birth cohort conducted in a health care system in metropolitan Detroit, Michigan with follow-up at age 2 years.

PARTICIPANTS

639 birth cohort participants; 367 children (57.4%) were born to African American mothers and 230 (36.0%) children were born via CS.

MAIN OUTCOME MEASURES

Obesity defined as body mass index ≥95th percentile at age 2 years.

RESULTS

Slightly more children of African American (n=37; 10.1%) than non-African American mothers (n=18; 6.6%) were obese (P=.12). There was evidence of effect modification between race and delivery mode with obesity at age 2 years (interaction P=.020). In children of African American mothers, CS compared to vaginal birth was associated with a significantly higher odds of obesity (aOR=2.35 (95% CI: 1.16, 4.77), P=.017). In contrast, delivery mode was not associated with obesity at age 2 years in children of non-African American mothers (aOR=.47 (95% CI: .13, 1.71), P=.25).

CONCLUSIONS

There is evidence for a race-specific effect of CS on obesity at age 2 years; potential underlying mechanisms may be racial differences in the developing gut microbiome or in epigenetic programming. Future research is needed to determine if this racial difference persists into later childhood.

Caesarean delivery and the risk of offspring overweight and obesity over the life course: a systematic review and bias-adjusted meta-analysis

A causal role of Caesarean delivery (CD) on developing overweight and obesity in the life course of offspring has been postulated. However, the true strength of this association is not clear and the potential for confounding has not been adequately addressed. A systematic review and meta-analysis were conducted to evaluate the strength of this association, this time using a bias-adjusted model in addition to conventional methods. Our search yielded 32 estimates from 14 publications (n = 261,000) for meta-analysis. The pooled analysis of seven estimates (n = 194,463) demonstrated a trend only towards a risk increase (RR = 1.15; 95% CI:0.94, 1.40) in overweight and obesity combined (ow+ob) due to CD in early childhood (0-5 years) and a similar trend was observed for mid-childhood and adolescence (5-18 years). In adulthood, a moderate increase in risk for ow+ob due to CD was observed (n = 30,200) (RR = 1.28; 95% CI 1.02, 1.34). Results for obesity and overweight separately were stronger for obesity and demonstrated a decreasing effect across the three life stages. Conventional methods of analysis suggested less uncertainty than we report and publication bias assessment was strongly suggestive of a bias in favour of positive studies. The current analysis therefore suggests that the small effects seen with CD in this and previous meta-analyses are probably a cumulative consequence of several biases we have outlined, including confounding effect and publication bias.

Developmental trajectories of adiposity from birth until early adulthood and association with cardiometabolic risk factors

OBJECTIVE

To identify developmental trajectories of adiposity from birth until early adulthood, and to investigate how they relate with cardiometabolic risk factors at 21 years of age.

METHODS

Participants' weight and height measurements were obtained using the EPITeen cohort protocol at 13, 17 and 21 years of age, and extracted from child health books as recorded during health routine evaluations since birth. Blood pressure, triglycerides, cholesterol and insulin resistance (HOMA-IR) were assessed at 21 years. Trajectories were defined using 719 participants contributing 11 459 measurements. The individual growth curves were modelled using mixed-effects fractional polynomial, and the trajectories were estimated using normal mixture modelling for model-based clustering. Differences in cardiometabolic risk factors at 21 years according to adiposity trajectories were estimated through analysis of covariance (ANCOVA), and adjusted means are presented.

RESULTS

Two trajectories-'Average body mass index (BMI) growth' (80.7%) and 'Higher BMI growth' (19.3%)-were identified. Compared with those in 'Average BMI growth', 'Higher BMI growth' participants were more frequently delivered by caesarean section, mothers were younger and had higher BMI, and parental education was lower; and at 21 years showed higher adjusted mean systolic (111.6 vs 108.3 mm Hg, P<0.001) and diastolic blood pressure (71.9 vs 68.4 mm Hg, P<0.001), and lower high-density lipoprotein cholesterol (53.3 vs 57.0 mg dl(-1), P=0.001). As there was a significant interaction between trajectories and sex, triglycerides and HOMA-IR were stratified by sex and we found significantly higher triglycerides, in males, and higher HOMA-IR in both sexes in 'Higher BMI growth' trajectory. All the differences were attenuated after adjustment for BMI at 21 years.

CONCLUSIONS

In this long-term follow-up, we were able to identify two adiposity trajectories, statistically related to the BMI and cardiometabolic profile in adulthood. Our results also suggest that the impact of the adiposity trajectory on cardiometabolic profile is mediated by current BMI.

Delivery by caesarean section and risk of childhood obesity: analysis of a Peruvian prospective cohort

Objectives. We aimed to assess if Caesarean section is a risk factor for overnutrition in early- and late-childhood, and to assess the magnitude of the effect of child- versus family-related variables in these risk estimates.

Methods. Longitudinal data from Peruvian children from the Young Lives Study was used. Outcomes assessed were overweight, obesity, overnutrition (overweight plus obesity), and central obesity (waist circumference) at the age 5 (first follow-up) and 7 (second follow-up) years. The exposure of interests was delivery by Caesarean section. Relative risks (RR) and 95% confidence intervals (95% CI) were calculated using multivariable models adjusted for child-related (e.g., birth weight) and family-related (e.g., maternal nutritional status) variables.

Results. At baseline, mean age was 11.7 (± 3.5) months and 50.1% were boys. Children born by Caesarean section were 15.6%. The 10.5% of the children were overweight and 2.4% were obese. For the obesity outcome, data from 6,038 and 9,625 children-years was included from baseline to the first and second follow-up, respectively. Compared to those who did not experience Caesarean delivery, the risk of having obesity was higher in the group born by Caesarean: RRs were higher at early-childhood (first follow-up: 2.25; 95% CI [1.36–3.74]) than later in life (second follow-up: 1.57; 95% CI [1.02–2.41]). Family-related variables had a greater effect in attenuating the risk estimates for obesity at the first, than at the second follow-up.

Conclusion. Our results suggest a higher probability of developing obesity, but not overweight, among children born by Caesarean section delivery. The magnitude of risk estimates decreased over time, and family-related variables had a stronger effect on the risk estimates at early-childhood.

Association between caesarean section and childhood obesity: a systematic review and meta-analysis

Birth by caesarean section has been recently implicated in the aetiology of childhood obesity, but studies examining the association have varied with regard to their settings, designs, and adjustment for potential confounders. We conducted a systematic review and meta-analysis to summarize the available evidence and to explore study characteristics as sources of heterogeneity. A search of Medline, EMBASE, and Web of Science identified 28 studies. Random effects meta-analysis was used to calculate pooled risk ratios (RR) with 95% confidence intervals (CI). Caesarean section had a RR of 1.34 (CI 1.18-1.51) for obesity in the child compared with vaginal birth. The RR was lower for studies that adjusted for maternal pre-pregnancy weight than for studies that did not (1.29, CI 1.16-1.44 vs. 1.55, CI 1.11-2.17). Studies that examined multiple early life factors reported lower RRs than studies that specifically examined caesarean section (1.39, CI 1.23-1.57 vs. 1.23, CI 0.97-1.56). Effect estimates did not vary by child's age at obesity assessment, study design or country income. Children born by caesarean section are at higher risk of developing obesity in childhood. Findings are limited by a moderate heterogeneity among studies and the potential for residual confounding and publication bias.

Women are designed to deliver vaginally and not by cesarean section: an obstetrician's view

Worldwide, there is a rapid increase in deliveries by cesarean section. The large differences among countries, from about 16% to more than 60%, suggest that the cesarean delivery (CD) rate has little to do with evidence-based medicine. In this review, the background for the increasing CD rate is discussed as well as the limited positive effects on neonatal outcome in both term and preterm neonates. Negative effects of CD, including direct maternal morbidity, complications of subsequent pregnancies and iatrogenic early delivery resulting in increased neonatal morbidity, are discussed in addition to long-term implications for the offspring involving altered development of the immune system. The 'battle' to lower the CD rate will be difficult, but we should not forget that women are designed to deliver vaginally and not by cesarean section.

Prenatal exposure to antibiotics, cesarean section and risk of childhood obesity

BACKGROUND/OBJECTIVES

Cesarean section (CS) and antibiotic use during pregnancy may alter normal maternal-offspring microbiota exchange, thereby contributing to aberrant microbial colonization of the infant gut and increased susceptibility to obesity later in life. We hypothesized that (i) maternal use of antibiotics in the second or third trimester of pregnancy and (ii) CS are independently associated with higher risk of childhood obesity in the offspring.

SUBJECTS/METHODS

Of the 727 mothers enrolled in the Northern Manhattan Mothers and Children Study, we analyzed the 436 mother-child dyads followed until 7 years of age with complete data. We ascertained prenatal antibiotic use by a questionnaire administered late in the third trimester, and delivery mode by medical record. We derived age- and sex-specific body mass index (BMI) z-scores using the CDC SAS Macro, and defined obesity as BMI z⩾95th percentile. We used binary regression with robust variance and linear regression models adjusted for maternal age, ethnicity, pre-gravid BMI, maternal receipt of public assistance, birth weight, sex, breastfeeding in the first year and gestational antibiotics or delivery mode.

RESULTS

Compared with children not exposed to antibiotics during the second or third trimester, those exposed had 84% (33-154%) higher risk of obesity, after multivariable adjustment. Second or third trimester antibiotic exposure was also positively associated with BMI z-scores, waist circumference and % body fat (all P<0.05). Independent of prenatal antibiotic usage, CS was associated with 46% (8-98%) higher offspring risk of childhood obesity. Associations were similar for elective and non-elective CS.

CONCLUSIONS

In our cohort, CS and exposure to antibiotics in the second or third trimester were associated with higher offspring risk of childhood obesity. Future studies that address the limitations of our study are warranted to determine if prenatal antibiotic use is associated with offspring obesity. Research is also needed to determine if alterations in neonatal gut microbiota underlie the observed associations.

Cesarean section and increased body mass index in school children: two cohort studies from distinct socioeconomic background areas in Brazil

Background

Recent studies have raised controversy regarding the association between cesarean section and later obesity in the offspring. The purpose of this study was to assess the association of cesarean section with increased body mass index (BMI) and obesity in school children from two Brazilian cities with distinct socioeconomic backgrounds.

Methods

Two birth cohorts respectively born in 1994 in Ribeirao Preto, a wealthy city in Southeast, and in 1997/98 in Sao Luis, a less wealthy city in Northeast of Brasil, were evaluated. After birth, 2,846 pairs of mothers-newborns were evaluated in Ribeirao Preto and 2,542 in Sao Luis. In 2004/05, 790 children aged 10/11 years were randomly reassessed in Ribeirao Preto and 673 at 7/9 years in Sao Luis. Information on type of delivery, maternal and child characteristics, socioeconomic position and anthropometric measurements were collected after birth and at school age. Obesity was defined as BMI ≥ 95th percentile at school age.

Results

Obesity rate was 13.0% in Ribeirao Preto and 2.1% in Sao Luis. Cesarean section was associated with obesity and remained significant after adjustment only in Ribeirao Preto [OR = 1.74 (95% CI: 1.04; 2.92)]. The association between cesarean section and BMI remained significant after adjustment for maternal schooling, maternal smoking during pregnancy, duration of breastfeeding, gender, birth weight and gestational age, type of school and, only in Sao Luis, pre-pregnancy maternal weight. In Ribeirao Preto children born by cesarean section had BMI 0.31 kg/m² (95%CI: 0.11; 0.51) higher than those born by vaginal delivery. In Sao Luis BMI of children born by cesarean section was 0.28 kg/m² higher (95%CI: 0.08; 0.49) than those born by vaginal delivery.

Conclusion

A positive association between cesarean section and increased BMI z-score was demonstrated in areas with different socioeconomic status in a middle-income country.

Mode of delivery and adiposity: Hong Kong's "Children of 1997" birth cohort

PURPOSE

To examine whether mode of delivery was associated with childhood adiposity in a developed non-Western context.

METHODS

We used generalized estimating equations to estimate the association of mode of delivery (vaginal or cesarean) with body mass index (BMI) z-score and overweight (including obesity) from 3 months to 13 years, in 7809 term birth (94% follow-up) from a population-representative Chinese birth cohort, "Children of 1997." We used multiple imputation for missing data.

RESULTS

The cesarean section rate (26%) was higher for children born in private hospitals, with lower gestational age, lower birth order, higher maternal age, higher maternal BMI, and higher family socioeconomic position. Cesarean section was not associated with BMI z-score from 3 months to 13 years (mean difference, 0.03; 95% confidence interval, -0.02 to 0.09) or overweight from 3 years to 13 years (odds ratio, 0.98; 95% confidence interval, 0.77 to 1.25) after adjusting for infant and maternal characteristics and family socioeconomic position.

CONCLUSIONS

In a non-Western developed setting, mode of delivery was not clearly associated with BMI or overweight (including obesity) into late childhood. From a public health perspective, the role of mode of delivery and its mechanistic pathway in the current burgeoning epidemic of obesity needs to be clarified.