Birth weight, maternal body mass index, and early childhood growth: a prospective birth cohort study in China

Fitness of INTERGROWTH-21st birth weight standards for Chinese-ethnicity babies

OBJECTIVE

To determine the fitness of the INTERGROWTH-21st birth weight standards (INTERGROWTH21) for ethnic Chinese babies compared with a local reference (FOK2003).

DESIGN

Population-based analysis of territory-wide birth data.

SETTING

All public hospitals in Hong Kong.

PARTICIPANTS

Live births between 24 and 42 complete weeks' gestation during 2006-2017.

MAIN OUTCOME MEASURES

Babies' birth weight Z-scores were calculated using published methods. The two references were compared in three aspects: (1) the proportions of large-for-gestational-age (LGA) or small-for-gestational-age (SGA) infants, (2) the gestation-specific and sex-specific mean birth weight Z-scores and (3) the predictive power for SGA-related complications.

RESULTS

488 896 infants were included. Using INTERGROWTH21, among neonates born <33 weeks' gestation, the mean birth weight Z-scores per week were closer to zero (-0.2 to 0.05), while most of them were further from zero (0.06 to 0.34) after excluding infants with a high risk of abnormal intrauterine growth. Compared with FOK2003, INTERGROWTH21 classified smaller proportions of infants as SGA (8.3% vs 9.6%) and LGA (6.6% vs 7.9%), especially SGA among preterm infants (13.1% vs 17.0%). The area under the receiver operating characteristic curve for predicting SGA-related complications was greater with FOK2003 (0.674, 95% CI 0.670 to 0.677) than INTERGROWTH21 (0.658, 95% CI 0.655 to 0.661) (p<0.001).

CONCLUSIONS

INTERGROWTH21 performed less well than FOK2003, a local reference for ethnic Chinese babies, especially in infants born <33 weeks' gestation. Although the differences are clinically small, both these references performed poorly for extremely preterm infants, and thus a more robust chart based on a larger sample of appropriately selected infants is needed.

Prevalence of overweight/obesity and associated factors among under-five children in Ethiopia: A multilevel analysis of nationally representative sample

Background

Childhood overweight and obesity are emerging public health challenges of the twety-first century. There was a 24% increase in the number of overweight children under the age of 5 years in low-income countries. Despite the significant risk of childhood overweight/obesity for non-communicable diseases, premature death, disability, and reproductive disorders in their adult life, little attention has been given. Therefore, we aimed to assess the prevalence of overweight/obesity and associated factors among under-five children.

Methods

This study was conducted using data from a nationally representative sample of the 2019 Ethiopia Mini Demographic and Health Survey (EMDHS). The Mini EDHS was a community-based cross-sectional study that covered all the administrative regions of Ethiopia. The data collection was conducted between March 21, 2019 and June 28, 2019. Both descriptive and analytic findings were produced. The overweight/obesity was measured by the weight-for-height (WFH) index, more than two standard deviations (+2 SD) above the median of the reference population based on the BMI Z-score. To identify significantly asso.

Results

A total of 5,164 under-five children were included in this study cited factors of overweight/obesity, a multilevel binary logistic regression model was fitted to account for the hierarchical nature of the data. Adjusted odds ratio (aOR) with a corresponding 95% confidence interval (CI) was reported to show the strength of association and statistical significance. The overall prevalence of overweight/obesity was 2.14% (95% CI: 1.74-2.53). The odds of overweight/obesity was higher among children aged <6 months (aOR = 5.19; 95% CI: 2.98-9.04), 6-24 months (aOR = 1.97; 95% CI: 1.18-3.29), delivered by cesarean section (aOR = 1.75; 95% CI: 1.84-3.65), living in Addis Ababa city (aOR = 2.16; 95% CI: 1.59-7.81), Oromia region (aOR = 1.93; 95% CI: 1.71-5.24), having mothers with the age 40-49 years (aOR = 3.91; 95% CI: 1.90-16.92), uses traditional contraceptive methods (aOR = 2.63; 95% CI: 1.66-10.47) and households headed by male (aOR = 1.71; 95% CI: 1.84-3.48).

Conclusion

This study showed that the prevalence of overweight/obesity among under-five was low in Ethiopia. There were several factors that affect childhood overweight/obesity including child age, maternal age, mode of delivery, sex of head of household, contraception use, and geography of residence. Therefore, strategies to reduce childhood overweight and obesity should consider an identified multitude of contributing factors.

Explorations on risk profiles for overweight and obesity in 9501 preschool-aged children

BACKGROUND

Childhood obesity places a major burden on global public health. We aimed to identify and characterize potential factors, both individually and jointly, in association with overweight and obesity in Chinese preschool-aged children.

METHODS

We cross-sectionally recruited 9501 preschool-aged children from 30 kindergartens in Beijing and Tangshan. Overweight and obesity are defined according to the World Health Organization (WHO), International Obesity Task Force (IOTF), and China criteria.

RESULTS

After multivariable adjustment, eating speed, sleep duration, birthweight, and paternal body mass index (BMI) were consistently and significantly associated with childhood overweight and obesity under three growth criteria at a significance level of 5%. Additional fast food intake frequency, maternal BMI, gestational weight gain (GWG) and maternal pre-pregnancy BMI were significant factors for overweight (WHO criteria) and obesity (both IOTF and China criteria). Importantly, there were significant interactions between parental obesity and eating speed for childhood obesity. Finally, for practical reasons, risk nomogram models were constructed for childhood overweight and obesity based on significant factors under each criterion, with good prediction accuracy.

CONCLUSION

Our findings indicated a synergistic association of lifestyle, fetal and neonatal, and family-related factors with the risk of experiencing overweight and obesity among preschool-aged children.

Differences in Rates of Low Birth Weight among Prefectures in Japan: An Ecological Study Using Government Statistics Data

The differences in the rates and trends of the overall low birth weight and term low birth weight in recent years are unknown for the Japanese prefectures. In this ecological study, we revealed the rates for each prefecture and investigated the factors affecting the regional differences in these outcomes. Aggregated vital statistics data from 2007 to 2019 were obtained from the Ministry of Health, Labour, and Welfare in Japan. The association between the outcomes and the variables, including the infants’ birth characteristics, medical characteristics, and socioeconomic characteristics of the prefectures, were analyzed. An analysis of repeated-measures data was conducted using the data from 2013 and 2018 for each prefecture. The trend for the rates of overall low birth weight and term low birth weight over the years differed among the prefectures. Moreover, the proportions of multiple births and lean (body mass index <18.5 kg/m2) and obese (body mass index ≥25.0 kg/m2) women had a statistically significant positive association with both the overall low birth weight rate and the term low birth weight rate among the prefectures. It was suggested that to resolve the difference in these outcomes among the prefectures, being obese or underweight needs to be addressed in mothers.

Associations Between Anthropometric Indicators in Early Life and Cardiorespiratory Fitness, Physical Activity, and Sedentary Time in Adolescence

BACKGROUND

To explore the associations between birth weight and body mass index (BMI) from 6 months to 6 years of age, with cardiorespiratory fitness (CRF), physical activity, and sedentary time in adolescence.

METHODS

Retrospective school-based study with 539 adolescents (292 girls), mean age of 13.94 (1.62) years. Anthropometric data from birth up to 6 years were extracted from individual child health booklets. CRF was estimated by 20-m shuttle run test. Physical activity and sedentary time were assessed with accelerometers.

RESULTS

Birth weight was not associated with any outcome measured in adolescence. From the age of 6 months onwards in girls, and from 3 years in boys, BMI associated inversely with CRF in adolescence. In girls, BMI (at 12 mo and at 3 y of age) associated positively with sedentary time in adolescence, but not with physical activity. In boys, positive associations between BMI at the ages of 3, 5, and 6 years old and time spent in some intensities of physical activity in adolescence were found.

CONCLUSIONS

BMI during the early years was negatively associated with CRF in adolescence, in a consistent way, for both genders, but with physical activity and sedentary time the associations were scarce and inconsistent, depending on the gender.

Intrapartum prediction of birth weight with a simplified algorithmic approach derived from maternal characteristics

Objective To derive and validate a population-specific multivariate approach for birth weight (BW) prediction based on quantitative intrapartum assessment of maternal characteristics by means of an algorithmic method in low-risk women. Methods The derivation part (n = 200) prospectively explored 10 variables to create the best-fit algorithms (70% correct estimates within ±10% of actual BW) for prediction of BW at term; vertex presentation with engagement. The algorithm was then cross validated with samples of unrelated cases (n = 280) to compare the accuracy with the routine abdominal palpation method. Results The best-fit algorithms were parity-specific. The derived simplified algorithms were (1) BW (g) = 100 [(0.42 × symphysis-fundal height (SFH; cm)) + gestational age at delivery (GA; weeks) - 25] in nulliparous, and (2) BW (g) = 100 [(0.42 × SFH (cm)) + GA - 23] in multiparous. Cross validation showed an overall 69.3% accuracy within ±10% of actual BW, which exceeded routine abdominal palpation (60.4%) (P = 0.019). The algorithmic BW prediction was significantly more accurate than routine abdominal palpation in women with the following characteristics: BW 2500-4000 g, multiparous, pre-pregnancy weight <50 kg, current weight <60 kg, height <155 cm, body mass index (BMI) <18.5 kg/m2, cervical dilatation 3-5 cm, station <0, intact membranes, SFH 30-39 cm, maternal abdominal circumference (mAC) <90 cm, mid-upper arm circumference (MUAC) <25 cm and female gender of the neonates (P < 0.05). Conclusion An overall accuracy of term BW prediction by our simplified algorithms exceeded that of routine abdominal palpation.

Association of low birth weight with thinness and severe obesity in children aged 3-12 years: a large-scale population-based cross-sectional study in Shanghai, China

OBJECTIVES

Low birth weight (BW) is a general symbol of inadequate intrauterine conditions that elicit abnormal fetal growth and development. The aim of current study is to investigate the relationship between low BW and thinness or severe obesity during maturation.

DESIGN

A large-scale cross-sectional population-based survey.

SETTING

134 kindergartens and 70 elementary schools.

PARTICIPANTS

70 284 Chinese children aged 3-12 years.

OUTCOME MEASURES

International Obesity Task Force body mass index (BMI) cut-offs were used to define grade 1, grade 2 and grade 3 thinness, overweight, obesity and severe obesity. Multinomial logistic regression was used to estimate the association between BW and BMI category.

RESULTS

A total of 70 284 children participated in the survey. The percentage of grade 1 thinness and severe obesity in children with low BW is significantly higher than that in children with normal BW (p<0.05). Low BW was associated with an increased risk of grade 1 thinness (OR 1.56, 95% CI 1.38 to 1.75), grade 2 thinness (OR 1.34, 95% CI 1.10 to 1.64), grade 3 thinness (OR 1.99, 95% CI 1.63 to 2.42) and severe obesity (OR 1.27, 95% CI 1.03 to 1.55) but was not associated with obesity (OR 0.85, 95% CI 0.67 to 1.06).

CONCLUSION

There is a positive association between low BW and thinness or severe obesity risk.

Risk factors for childhood obesity: Do the birth weight, type of delivery, and mother's overweight have an implication on current weight status?

BACKGROUND

The aim of this study was to identify risk factors, including the type of delivery, breastfeeding and its duration, birth weight, the timing of solid food introduction, the mother's education level at birth, and smoking status during pregnancy, that are associated with obesity in children living in Istanbul.

METHODS

This study involving 4990 healthy children aged 2-14 years, at an outpatient clinic in a tertiary care hospital from June 2012 to July 2014.

RESULTS

The overall rates of overweight and obesity in children were 13.1% and 7.8%, respectively. Results demonstrated that 44.5% of children were delivered by caesarean section. In all age groups, 7.8% of children delivered by caesarean section were obese compared with 7.9% of children born vaginally. No significant association between caesarean section delivery and obesity in childhood was found in our study [odds ratio (OR)=0.98, 95% confidence interval (CI)=0.64-2.87, P=0.454]. There was also no association between duration of breastfeeding and the introduction of solid foods before 4 months or after 6 months of age and childhood obesity (OR=0.95, 95% CI=0.69-1.3, P=0.771; OR=0.99, 95% CI=0.64-1.53, P=0.261). Regression analyses revealed that children with birth weights greater than 3801 g or those with maternal body mass index (BMI) equal to or greater than 30 had an increased risk of being obese or overweight (OR=1.78, 95% CI=1.19-2.65; OR=3.95, 95% CI=1.94-5.81).

CONCLUSIONS

This study demonstrated that increased birth weight and maternal BMI are significant risk factors for obesity in children living in Istanbul, Turkey. No relation between caesarean section delivery and childhood obesity was found in this study.

Differences in the anthropometry of Asian children and its role in metabolic health in later life: A narrative review

BACKGROUND

The increasing incidence of childhood obesity in Asia could be a reflection of early life programming in which environmental/nutritional challenges during pregnancy and first two years of life (the so-called first 1000 days) influence later health.

OBJECTIVE OF NARRATIVE REVIEW

To assess differences/similarities of anthropometric measures in early life and their influences on metabolic health risk in later life among children in Asia.

METHODS

Literature search for publication in English using selected key words from Medline (PubMed), Scopus, Science Direct and Google Scholar published from 1994 to October 2014. Some comparisons with Caucasian setting were made when relevant.

RESULTS

From 152 publications selected for this narrative review, differences in foetal growth and birth weight were deducted between Asian and Caucasian children. Infants in India and Hong Kong had increased fat mass at birth and early infancy as compared to those from other parts of the world. Pre- and during pregnancy conditions influenced birth weight; feeding practices and gender influenced post-natal growth and body composition development. High and low birth weights followed by rapid postnatal growth were linked to increased risks of obesity, insulin resistance and high blood pressure in later life.

CONCLUSION

Foetal and postnatal growth trajectories are different between countries within and outside Asia. Extremes in birth weight followed by rapid postnatal growth were linked to increased risks of metabolic health of children in this region. As there is limited evidence in Asia, it is important to conduct thorough investigations by using longitudinal studies on early life programming.

Birth weight and childhood obesity: a 12-country study

OBJECTIVES

Few studies have investigated the association between the full range of birth weight and the risk of childhood obesity in high-, middle- and low-income countries. The aim of the present study is to assess the association between different levels of birth weight and the risk of obesity among children aged 9-11 years in 12 countries.

METHODS

A multinational, cross-sectional study of 5141 children aged 9-11 years was conducted in 12 countries. Height and weight were obtained using standardized methods. Time spent in moderate-to-vigorous physical activity (MVPA), sedentary and sleeping were objectively measured using 24-h, waist-worn accelerometer (Actigraph GT3X+) monitored for 7 days. Birth weight and other factors (regions, parental education, maternal history of gestational diabetes, children age, gender, breast feeding, gestational age, unhealthy diet scores and healthy diet scores) were collected by parental and children's questionnaires. Multilevel modeling was used to account for the nested nature of the data.

RESULTS

The overall prevalence of obesity (BMI z-score>+2 s.d.) was 15.4% for boys and 10.0% for girls. There was a positive association between birth weight and BMI z-scores. The multivariable-adjusted odds ratios (ORs) of childhood obesity were significantly higher among children whose birth weights were 3500-3999 g (OR 1.45; 95% confidence interval (CI): 1.10-1.92), and >4000 g (OR 2.08; 95% CI: 1.47-2.93), compared with the reference group (2500-2999 g). The positive association between birth weight and the odds of childhood obesity was seen in girls, whereas a U-shaped association appeared in boys.

CONCLUSIONS

High levels of birth weight, defined as birth weight ⩾3500 g, were associated with increased odds of obesity among 9-11-year-old children in 12 countries. However, sex differences in the association between birth weight and the risk of obesity need to be considered when planning interventions to reduce childhood obesity.

Family-related risk factors of obesity among preschool children: results from a series of national epidemiological surveys in China

Background

Family-based child obesity prevention and control strategy has not yet established in many countries or regions, including China, thus what it needs to do now is to continuously develop and improve the strategies. The purpose of this study were to describe a wider spectrum of risk factors of obesity among preschool children and add to the mounting evidence for further improving suggested intervention measures in future family-based programs.

Methods

Data was collected as part of a series of national epidemiological surveys in childhood conducted in 9 Chinese cities. A population-based, 1:1 matched case–control design was employed to examine risk factors of obesity by means of conditional logistic regression. Obesity was defined as the International Obesity Task Force (IOTF) BMI-for-age cut offs. Eligible subjects were 1234 boys and 610 girls aged 3–7 years in 1996 and 2290 boys and 1008 girls in 2006, including obese and non-obese.

Results

High birth weight, gestational hypertension and parents’ BMI were closely associated with childhood obesity. Breast feeding in the first 4 months was a protective factor in univariate model in 2006 (OR = 0.834, P = 0.0234), but the association was not seen in multivariate. Appetite, eating speed, daily time and intensity for outdoor activities, night sleep time, and time for TV viewing were identified statistically by multivariate model. Those children brought up in extended family or mainly raised by their grandparents or lived in high income or low education families might have an increased risk of becoming obese. Parents’ attitudes on weight control of their children significantly differed between obese and non-obese groups.

Discussion

A wider spectrum of risk factors and an empirical aggregation of family-related risk factors are discussed to further improve future family-based child obesity prevention and control strategies. Most of the risk factors identified by this study presented ranked or quantitative characteristics which might be transformed from unhealthy threshold to healthy range by behavior modification. Some variables are likely to interact each other, such as appetite and eating speed, or outdoor activity and TV viewing, or BMI and income, but which needs to be further explored in future surveys.

Conclusions

The family-related risk factors were summarized from our identified risk factors of obesity among preschool children which strongly supported the further development of family-based programs in preschool period.

Maternal Body Mass Index Correlates with the Neonatal Physique of Male Infants

Recently, in Japan, the percentage of leanness has risen in young women, and the average birth weight has decreased. An increase in the risk of low birth weight has been reported in lean expectant mothers. In this study, we aimed to clarify the relationship between mother's physique at the beginning of pregnancy and the infant's physique, by focusing on sex differences. The participants were 3,722 mothers who attended health checkups for 18-month-old infants in an urban Japanese city. The participants were limited to those with full-term births, thereby excluding the influence of gestational length. A total of 1,287 mothers, with 621 boys and 666 girls, were analyzed. Public health professionals interviewed the mothers, and transferred the required information from their maternity passbooks. We examined the physical characteristics of the mothers and their infants. Partial correlation analysis, adjusted by gestational length and the mother's age at delivery, was applied to study the association between the mother's BMI and the infant's physique at birth. In the primipara group, only the boys showed significant positive correlation between the mother's BMI and the birth weight (P = 0.025) and the Kaup index (P = 0.035). In the pluripara group, only the boys showed significant positive correlation between the mother's BMI and the head circumference (P = 0.035). Thus, mother's physique may have a stronger influence on the physique of male infants, compared to female infants. The growth-promoting effect of the mother's physique is more apparent in the infants born to the pluripara.

Effects of Prepregnancy Body Mass Index and Gestational Weight Gain on Pregnancy Outcomes

To investigate the single and joint effects of prepregnancy body mass index (BMI) and gestational weight gain (GWG) on pregnancy outcomes, electronic medical records of 14 196 women who delivered singleton live infant at a maternal and child health hospital in Beijing, China, in 2012 were reviewed. Logistic regression was used to assess the associations, adjusting for maternal age, height, education, parity, and offspring sex. Women of high prepregnancy BMI or excessive GWG had higher risks of gestational diabetes mellitus, hypertensive disorders in pregnancy, postpartum hemorrhage, caesarean delivery, macrosomia, and large for gestational age infant, while women of inadequate GWG had higher risks of preterm delivery, low birth weight, and small for gestational age infant. Findings suggest that antenatal care providers should help pregnant women control their GWG to normal.

ADHD and overweight in boys: cross-sectional study with birth weight as a controlled factor

Population studies indicate a strong relationship between birth weight (BW) and body size in later life. However, BW as a variable was never accounted for in studies on the relationship between attention-deficit/hyperactivity disorder (ADHD) and overweight. This study aims to assess the relationship between ADHD and overweight with control of birth weight and other confounding factors. Prevalence of overweight was compared in clinical sample of 219 boys with ADHD and 396 boys without ADHD, aged 6-18 years. The following factors were controlled: BW, parents income and education level, place of residence, ADHD type, selected comorbid disorders and stimulant treatment. Overweight and obesity were diagnosed according to the criteria proposed by the International Obesity Task Force. Logistic regression analysis was used to estimate the association between ADHD and the prevalence of overweight and obesity. Boys with ADHD differed significantly from the control group in distribution of low BW (8.2 vs. 3.0 %, χ (2) = 8.23, p = 0.02). Low BW was associated with a lower prevalence of overweight than normal and high BW (0 vs. 12.14 %, χ (2) = 4.12, p = 0.04). Overweight was observed significantly more often in boys with ADHD (17.3 vs. 8.3 %, χ (2) = 11.23, p < 0.001) even after adjustment for BW and other variables (OR = 2.44, 95 % CI 1.38-4.29, p = 0.002) and after controlling for ADHD type, stimulant treatment and selected comorbid disorders. Independently to applied analysis, obesity was not associated with ADHD. Lower birth weight is over twice more often observed in boys with ADHD than in control group. Although this phenomenon may reduce the rate of overweight in the studied group, ADHD remains strongly associated with increased prevalence of overweight.

Factors associated with birth weight inequalities in Jordan

BACKGROUND

Birth weight is a good indicator of mothers' and neonates' nutritional status, and it contributes to the newborn baby's survival, health, growth and development.

AIM

This study identified social factors associated with differences in the mean birth weight of newborn babies in Jordan.

METHODS

This retrospective study analysed medical records to determine possible risk factors associated with differences in newborn BW in the Irbid governorate of Jordan. All full-term singleton births during the year 2010 were reviewed. Abstracted data included mother's age, educational level, and monthly family income. Newborn information included birth weight, gender and birth order.

RESULTS

A total of 5414 full-term singleton births were included. Of these, 15.1% were low birth weight, 73.6% were normal birth weight, and 11.3% were high birth weight. Bivariate analysis of variance revealed that low mean birth weight was associated with female gender, first-born babies, higher maternal age (>35 years), lower educational level and lower income (<500 JD). Multivariate analysis of variance revealed that mean birth weight was lower in female infants, first-born infants, infants of less educated mothers, higher age and low monthly income.

LIMITATIONS

The findings can be generalized to full-term singleton pregnancies in countries who share similar cultural and traditional values.

CONCLUSION

Education of mothers is a modifiable variable that can positively influence birth weight, particularly in the case of female and first-born infants.

IMPLICATION FOR NURSING AND HEALTH POLICY

The findings inform our understanding of some social factors affecting birth weights of neonates in Jordan and development of effective public health interventions that could reduce the adverse effects of such factors on newborn birth weight. Preconception and antenatal care is also important for early detection of such possible risk and targeting mothers who require early interventions and support.

Caesarean delivery, caesarean delivery on maternal request and childhood overweight: a Chinese birth cohort study of 181 380 children

What is already known about this subject Both rates of caesarean section and childhood overweight have been steadily increasing over the past decade in many parts of the world. Caesarean delivery on maternal request contributes remarkably to the rising trend of caesarean births. A few small-scale studies suggest that caesarean section may be associated with later overweight and obesity, whereas little is known about the impact of caesarean delivery on maternal request. What this study adds Caesarean section is associated with an increased risk of childhood overweight. Children born by caesarean delivery on maternal request are also more likely to be overweight. The strength of the caesarean-overweight association is modest.

OBJECTIVES

To assess the impact of caesarean delivery including non-medically indicated maternal request caesarean delivery on childhood overweight.

METHODS

We conducted a prospective investigation of a Chinese birth cohort involving 181 380 children, who were born during 1993-1996 to mothers registered in a perinatal care surveillance system and whose weight and height were measured in 2000. Information on delivery mode and covariates was obtained from the surveillance system. Overweight was defined according to the International Obesity Task Force body mass index (BMI) cutoffs. Multivariable logistic regression was used to estimate adjusted odds ratios. Stratified analyses were done to test whether the association between caesarean section and overweight persisted across subgroups.

RESULTS

The adjusted odds ratio of overweight for children born by caesarean compared with vaginal delivery was 1.13 [95% confidence interval {CI}: 1.08, 1.18]. The association persisted in subgroups stratified by gender, maternal education, maternal BMI, weight gain during pregnancy and child birthweight (all P values for interaction test ≥0.30). The adjusted odds ratio of overweight for children born by non-medically indicated caesarean delivery compared with vaginal delivery was 1.18 (95% CI: 1.00, 1.41).

CONCLUSION

Caesarean delivery including non-medically indicated maternal request caesarean delivery compared with vaginal delivery modestly increases childhood overweight risk.

Systematic review and meta-analyses of risk factors for childhood overweight identifiable during infancy

OBJECTIVE

To determine risk factors for childhood overweight that can be identified during the first year of life to facilitate early identification and targeted intervention.

DESIGN

Systematic review and meta-analysis.

SEARCH STRATEGY

Electronic database search of MEDLINE, EMBASE, PubMed and CAB Abstracts.

ELIGIBILITY CRITERIA

Prospective observational studies following up children from birth for at least 2 years.

RESULTS

Thirty prospective studies were identified. Significant and strong independent associations with childhood overweight were identified for maternal pre-pregnancy overweight, high infant birth weight and rapid weight gain during the first year of life. Meta-analysis comparing breastfed with non-breastfed infants found a 15% decrease (95% CI 0.74 to 0.99; I(2)=73.3%; n=10) in the odds of childhood overweight. For children of mothers smoking during pregnancy there was a 47% increase (95% CI 1.26 to 1.73; I(2)=47.5%; n=7) in the odds of childhood overweight. There was some evidence associating early introduction of solid foods and childhood overweight. There was conflicting evidence for duration of breastfeeding, socioeconomic status at birth, parity and maternal marital status at birth. No association with childhood overweight was found for maternal age or education at birth, maternal depression or infant ethnicity. There was inconclusive evidence for delivery type, gestational weight gain, maternal postpartum weight loss and 'fussy' infant temperament due to the limited number of studies.

CONCLUSIONS

Several risk factors for both overweight and obesity in childhood are identifiable during infancy. Future research needs to focus on whether it is clinically feasible for healthcare professionals to identify infants at greatest risk.

Relationship between breastfeeding and obesity in childhood

A cross-sectional study was conducted to investigate the weight status and the relationship of infant-feeding variables, birthweight and birth order with BMI in a group of Iranian children. Five hundred and eleven students of both sexes at the first grade in elementary schools (aged 7 years) were recruited randomly from all 19 educational districts of Tehran. Weights and heights of children and their mothers were measured. Data on breastfeeding (BF), formula-feeding, the timing of introduction of complementary foods (CF), birthweight, and birth order were collected from the mothers. The 2007 WHO reference value was used for determining child's weight status. Regression analysis in single and a 2-level linear regression models was used for examining the independent relationships of infant-feeding variables, birthweight and birth order with childhood BMI. The prevalence of underweight and overweight in this group of children was 7.6% and 19.7%, respectively. Total time of BF and duration of exclusive BF were not associated with childhood BMI. The timing of introduction of CF was inversely related to childhood BMI after controlling for other variables (beta:-0.34; 95% CI:-0.58,-0.10). Children with an early introduction of CF had significantly higher mean BMI (p for linear trend=0.012). Birth order and birthweight were related to childhood BMI significantly. These data suggest that overweight and obesity are nutritional problems among 7 years old Teharani children. The timing of introduction of CF, birth order, and birthweight were independent predictors of childhood BMI. Neither total time of BF nor duration of exclusive breastfeeding was associated with adiposity in children.