Early life growth trajectories and future risk for overweight

Prenatal exposure to metal mixtures, body mass index trajectories in early life and effect modifiers: Insights from a prospective birth cohort study

Current scientific knowledge is insufficient on the effects of metal mixtures on early life growth trajectories. This study included 7118 mother-infant pairs from a Chinese birth cohort. Concentrations of 18 maternal urinary metals were quantified, and growth trajectories were conducted based on standardized body mass index (BMI) for up to eight times from 0 to 2 years. A three-phase analytical framework was applied to explore the risk ratios (RR) and 95 % confidence intervals (95 % CI) of co-exposure to metals on dynamic growth, along with potential modifiers. Five growth trajectory groups were identified. Exposure to metal mixtures driven by thallium (Tl, 34.8 %) and aluminum (Al, 16.2 %) was associated with an increased risk of low-rising trajectory (RR=1.58, 95 % CI: 1.25, 2.00); however, exposure to mixtures driven by strontium (Sr, 49.5 %) exhibited an inverse correlation (RR = 0.81, 95 % CI: 0.67, 0.97). Furthermore, infants with varying levels of Tl, Al and Sr, as well as modifiers including pre-pregnancy BMI and infant sex faced distinct risks of low-rising trajectory. Our findings highlighted the Tl, Al, and Sr as key metals in relation to the low-rising trajectory in early life characterized as catch-up growth, with pre-pregnancy BMI and infant sex exerting as potential modifiers.

Exposure to organophosphate esters and maternal-child health

Organophosphate esters (OPEs) are a class of chemicals now widely used as flame retardants and plasticizers after the phase-out of polybrominated diphenyl ethers (PBDEs). However, OPEs carry their own risk of developmental toxicity, which poses concern for recent birth cohorts as they have become ubiquitous in the environment. In this review, we summarize the literature evaluating the association between OPE exposure and maternal, perinatal, and child health outcomes. We included original articles investigating associations of OPE exposure with any health outcome on pregnant women, newborns, children, and adolescents. We found 48 articles on this topic. Of these, five addressed maternal health and pregnancy outcomes, 24 evaluated prenatal OPE exposure and child health, 18 evaluated childhood OPE exposure and child/adolescent health, and one article evaluated both prenatal and childhood OPE exposure. These studies suggest that OPE exposure is possibly associated with a wide range of adverse health outcomes, including pregnancy loss, altered gestational duration and smaller birthweight, maternal and neonatal thyroid dysfunction, child metabolic dysregulation and abnormal growth, impaired neurodevelopment, and changes in immune response. Many of the reported outcomes associated with OPE exposure varied by child sex. Findings also varied substantially by OPE metabolite and exposure time. The OPEs most frequently measured, detected, and found to be associated with health outcomes were triphenyl phosphate (TPHP, metabolized to DPHP) and tris(1,3-dichloro-2-propyl) phosphate (TDCIPP, metabolized to BDCIPP). The extensive range of health outcomes associated with OPEs raises concern about their growing use in consumer products; however, these findings should be interpreted considering the limitations of these epidemiological studies, such as possible exposure misclassification, lack of generalizability, insufficient adjustment for covariates, and failure to consider chemical exposures as a mixture.

Ethnoracial disparities in childhood growth trajectories in Brazil: a longitudinal nationwide study of four million children

BACKGROUND

The literature contains scarce data on inequalities in growth trajectories among children born to mothers of diverse ethnoracial background in the first 5 years of life.

OBJECTIVE

We aimed to investigate child growth according to maternal ethnoracial group using a nationwide Brazilian database.

METHODS

A population-based retrospective cohort study employed linked data from the CIDACS Birth Cohort and the Brazilian Food and Nutrition Surveillance System (SISVAN). Children born at term, aged 5 years or younger who presented two or more measurements of length/height (cm) and weight (kg) were followed up between 2008 and 2017. Prevalence of stunting, underweight, wasting, and thinness were estimated. Nonlinear mixed effect models were used to estimate childhood growth trajectories, among different maternal ethnoracial groups (White, Asian descent, Black, Pardo, and Indigenous), using the raw measures of weight (kg) and height (cm) and the length/height-for-age (L/HAZ) and weight-for-age z-scores (WAZ). The analyses were also adjusted for mother's age, educational level, and marital status.

RESULTS

A total of 4,090,271 children were included in the study. Children of Indigenous mothers exhibited higher rates of stunting (26.74%) and underweight (5.90%). Wasting and thinness were more prevalent among children of Pardo, Asian, Black, and Indigenous mothers than those of White mothers. Regarding children's weight (kg) and length/height (cm), those of Indigenous, Pardo, Black, and Asian descent mothers were on average shorter and weighted less than White ones. Regarding WAZ and L/HAZ growth trajectories, a sharp decline in average z-scores was evidenced in the first weeks of life, followed by a period of recovery. Over time, z-scores for most of the subgroups analyzed trended below zero. Children of mother in greater social vulnerability showed less favorable growth.

CONCLUSION

We observed racial disparities in nutritional status and childhood growth trajectories, with children of Indigenous mothers presenting less favorable outcomes compared to their White counterparts. The strengthening of policies aimed at protecting Indigenous children should be urgently undertaken to address systematic ethnoracial health inequalities.

Prenatal and postnatal exposure to NO2 and rapid infant weight gain - A population-based cohort study

BACKGROUND

Childhood overweight and obesity is a global public health problem. Rapid infant weight gain is predictive of childhood overweight. Studies found that exposure to ambient air pollution is associated with childhood overweight, and have linked prenatal exposure to air pollution with rapid infant weight gain.

OBJECTIVES

To examine the association between prenatal and postnatal ambient NO2 exposure, a traffic-related marker, with rapid weight gain in infants.

METHODS

We carried out a population-based historical cohort study using data from the Israeli national network of maternal and child health clinics. The study included 474,136 infants born at term with birthweight ≥2500 g in 2011-2019 in central Israel. Weekly averages of NO2 concentration throughout pregnancy (prenatal) and the first 4 weeks of life (postnatal) were assessed using an optimized dispersion model and were linked to geocoded home addresses. We modelled weight gain velocity throughout infancy using the SuperImposition by Translation and Rotation (SITAR) method, a mixed-effects nonlinear model specialized for modelling growth curves, and defined rapid weight gain as the highest velocity tertile. Distributed-lag models were used to assess critical periods of risk and to measure relative risks for rapid weight gain. Adjustments were made for socioeconomic status, population group, subdistrict, month and year of birth, and the alternate exposure period - prenatal or postnatal.

RESULTS

The cumulative adjusted relative risk for rapid weight gain of NO2 exposure was 1.02 (95% confidence intereval [CI] 1.00, 1.04) for exposure throughout pregnancy and 1.02 (95% CI 1.01, 1.04) for exposure during the first four postnatal weeks per NO2 interquartile range increase (7.3 ppb). An examination of weekly associations revealed that the critical period of risk for the prenatal exposure was from mid-pregnancy to birth.

CONCLUSIONS

Prenatal and postnatal exposures to higher concentrations of traffic-related air pollution are each independently associated with rapid infant weight gain, a risk factor for childhood overweight and obesity.

Gestational exposure to organophosphate esters and adiposity measures of children up to 6 years: Effect modification by breastfeeding

Organophosphate esters (OPEs) are synthetic chemicals used in various commercial products. Accumulating evidence has shown that they may act as metabolic disruptors. However, no study has investigated the long-term effects of gestational OPEs exposure on childhood adiposity. Breast milk represents the optimal nutritional form of feeding for infants and may protect against the adverse effects of gestational OPEs exposure on offspring development. Using data from the Shanghai-Minhang birth cohort study, we investigated the associations of gestational OPEs exposure with adiposity measures in children up to 6 years of age, and whether breastfeeding could modify these associations. A total of 733 mother-child pairs with available data on OPE concentrations and child anthropometry were included. Eight OPE metabolites were assessed in maternal urine samples collected at 12-16 weeks of pregnancy. Information on children's weight, height, arm circumference, and waist circumference was collected at birth and 0.5, 1, 4, and 6 years of age. Weight-for-age and body mass index-for-age z scores were calculated. The duration of children's breastfeeding was categorized as ≤4 months or >4 months. The generalized estimate equation and Bayesian Kernel Machine Regression models were used to examine the associations of OPEs exposure with children's adiposity measures. Selected OPEs exposure was associated with higher children's adiposity measures. Particularly, we found stronger associations of bis(1-chloro-2-propyl) phosphate (BCIPP), bis(2-chloroethyl) phosphate (BCEP), bis(1,3-dichloro-2-propyl) phosphate (BDCPP), and di-o-cresyl phosphate and di-p-cresyl phosphate (DCP) with higher adiposity measures in children breastfed for ≤4 months, while little evidence of associations was found among those breastfed for >4 months. Our study suggested that gestational OPEs exposure could alter children's adiposity measures, but the potential effects were attenuated if children were breastfed for >4 months.

Changes in the Incidence of Childhood Obesity

OBJECTIVES

Examine childhood obesity incidence across recent cohorts.

METHODS

We examined obesity incidence and prevalence across 2 cohorts of children in the United States 12 years apart using the Early Childhood Longitudinal Studies, parallel data sets following the kindergarten cohorts of 1998 and 2010 with direct anthropometric measurements at multiple time points through fifth grade in 2004 and 2016, respectively. We investigated annualized incidence rate and cumulative incidence proportion of obesity (BMI z-score ≥95th percentile based on Centers for Disease Control and Prevention weight-for-age z-scores).

RESULTS

Among children who did not have obesity at kindergarten entry, there was a 4.5% relative increase in cumulative incidence of new obesity cases by end of fifth grade across cohorts (15.5% [14.1%-16.9%] vs 16.2% [15.0%-17.3%]), though annual incidence did not change substantially. The risk of incident obesity for children who had normal BMI at kindergarten entry stayed the same, but the risk of incident obesity among overweight kindergartners increased slightly. Social disparities in obesity incidence expanded: incidence of new cases during primary school among non-Hispanic Black children increased by 29% (95% confidence interval, 25%-34%), whereas risk for other race-ethnic groups plateaued or decreased. Children from the most socioeconomically disadvantaged households experienced 15% higher cumulative incidence across primary school in 2010 than 1998.

CONCLUSIONS

Incidence of childhood obesity was higher, occurred at younger ages, and was more severe than 12 years previous; thus, more youths may now be at risk for health consequences associated with early onset of obesity.

Longitudinal association between the timing of adiposity peak and rebound and overweight at seven years of age

Background

The timing of adiposity peak (AP) or adiposity rebound (AR) is a determinant of overweight or obesity in adolescence and adulthood. However, limited studies have reported the association in young school-age children. We aimed to evaluate this association and explore the role of health behaviours in it.

Methods

Routinely collected, sequential, anthropometric data from the 1st to 80th months of age were used to estimate AP and AR timings in 2330 children born in Shanghai between 2010 and 2013. Multivariate regression analyses were applied to identify the associations between the AP or AR timings and the risk of developing overweight or obesity in first-grade school children. The roles of health behaviours, including dietary patterns, physical activity level, sleep and snacking habits, and screen time, were also evaluated.

Results

Children with a late AP or an early AR were at higher risk of overweight but not obesity or central obesity in their first grade. A high physical activity level was associated with a lower risk of having overweight in children with a late AP, and limited screen time was associated with a decreased risk of having overweight or obesity in children with an early AR. The absence of a late-night snacking habit in children with a non-early AR indicated a decreased risk of having overweight. However, this association was not observed among children with an early AR.

Conclusion

The timings of AP and AR are tied to overweight in middle childhood. Prevention strategies are suggested to move forward to control late AP and early AR.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-022-03190-9.

Adherence to index-based dietary patterns in childhood and BMI trajectory during the transition to adolescence: the EPOCH study

BACKGROUND

In the United States, one in five adolescents are obese. Index-based dietary patterns are measures of the overall diet that have the potential to serve as valuable obesity risk stratification tools. However, little is known about the association between adherence to index-based dietary patterns in childhood and BMI during the transition from childhood to adolescence.

OBJECTIVE

To prospectively examine the relationship between adherence to three index-based dietary patterns in childhood and BMI trajectory during the transition to adolescence.

METHODS

The study included 581 children enrolled in a Colorado prospective cohort study conducted between 2006 and 2015. Dietary intake was assessed with the Block Kids Food Frequency Questionnaire at age 10 years. Scores were calculated for the Healthy Eating Index-2010 (HEI-2010), the alternate Mediterranean (aMED) diet, and the Dietary Approaches to Stop Hypertension (DASH) diet. Weight and height were assessed via anthropometry at two research visits (ages 10 and 16 years), with interim clinical measurements extracted from Kaiser Permanente medical records. Separate mixed models were used to assess the association between each diet index score and BMI over a 6-year period. Models were stratified by sex and adjusted for age, race/ethnicity, income, and exposure to gestational diabetes.

RESULTS

Median (IQR) number of BMI assessments was 14 (10-18). Among girls, for every ten-unit increase in HEI-2010 score, there was an average 0.64 kg/m² decrease (p = 0.007) in BMI over time, after adjustment for covariates. Among girls, there was no association between BMI and aMED (β = -0.19, p = 0.24) or DASH (β = 0.28, p = 0.38). Among boys, there was no statistically significant association between BMI and HEI-2010 (0.06, p = 0.83), aMED (0.07, p = 0.70), or DASH (0.42, p = 0.06).

CONCLUSIONS

Efforts to prevent adolescent obesity could benefit from considering the degree of adherence to federal dietary guidance, as assessed by the HEI, in the period preceding adolescence, especially among girls.

The Effect of Growth Rate during Infancy on the Risk of Developing Obesity in Childhood: A Systematic Literature Review

The prevalence of childhood obesity has been trending upwards over the last few decades. Recent evidence suggests that infant growth rate has the potential to increase the risk of obesity development during childhood. This systematic literature review aimed to summarise the existing evidence on the relationship between infant growth rate and subsequent childhood obesity. Studies were sought for that assessed the effect of infant growth rate on outcomes of overweight, obesity, BMI, waist circumference or body composition measures among a population group of children aged 2 to 12 years old. Data sources included PubMed, CINAHL, Web of Science and MedLine. Twenty-four studies were identified as eligible and included in this review, out of 2302 publications. The ADA Quality Checklist was used to assess the quality of individual studies. Ten studies received a positive result and 14 studies a neutral result. A narrative synthesis was completed to present study characteristics and results. Several independent positive associations were determined between rapid growth at different stages during infancy and overweight, obesity, BMI, waist circumference and body composition in childhood. Further investigation is required to determine if a specific period of infancy carries greater associations of risk with childhood outcomes. Determining an ideal rate of infants' growth as a means to minimise the future risk of childhood obesity should be the focus of future research that will also inform early life obesity prevention strategies. Registration no.: CRD42021244029.

Maternal Oxidative Stress Biomarkers in Pregnancy and Child Growth from Birth to Age 6

CONTEXT

Maternal oxidative stress in pregnancy can arise through a multitude of sources and may have lifelong consequences for the child. Animal studies suggest that prenatal oxidative stress may contribute to metabolic dysfunction and excessive weight gain in the offspring. However, this relationship has been studied minimally in humans.

OBJECTIVE

Determine the association between prenatal oxidative stress biomarkers and child weight and body mass index (BMI) z-scores from birth to age 6.

METHODS

Within The Infant Development and the Environment Study (TIDES) prospective pregnancy cohort, we calculated age- and sex-specific Z-scores for child weight and BMI, measured between birth and age 6 (N = 736). Three oxidative stress biomarkers were quantified in third-trimester urine, including 8-iso-prostaglandin F2α (8-iso-PGF2α), its primary metabolite, and prostaglandin F2α (PGF2α). We examined associations between each biomarker and Z-scores using linear regression as well as group-based trajectory modeling.

RESULTS

Prenatal 8-iso-PGF2α and its metabolite were associated with lower birth weight and higher weight at age 4. For example, an ln-unit increase in 8-iso-PGF2α was associated with 0.17 SD higher weight at age 4 (95% CI 0.01, 0.33). These biomarkers were also associated with higher BMI at age 4. Finally, within 4 unique weight trajectories (low, normal, high, and low-high), children of mothers with higher 8-iso-PGF2α were 2.56 times more likely (95% CI 1.22, 5.41) to be in the low-high trajectory than children in the normal group.

CONCLUSION

We observed associations between third-trimester oxidative stress and lower birth weight as well as higher early childhood weight and BMI. These findings have important implications for understanding the developmental origins of childhood weight gain and metabolic disease.

Differential classification of infants in United States neonatal intensive care units for weight, length, and head circumference by United States and international growth curves

BACKGROUND

Clinicians and researchers use a variety of intrauterine growth curves to classify NICU infants as small (SGA), appropriate (AGA), or large for gestational age (LGA). Since curve creation methods and samples vary, SGA/AGA/LGA cut-offs and resulting subgroups of infants vary among curves and impact outcome study findings - limiting generalisability.

AIM

Determine how two international and two US-specific curves classified US NICU infants.

SUBJECTS AND METHODS

Classified 192,888 infants from US NICUs (2013-2016) as SGA or LGA for birthweight, length, and head circumference, using the international Fenton and INTERGROWTH-21st curves and US-specific Olsen and Lubchenco (historical) curves.

RESULTS

Modern curves classified approximately 10% of infants as SGA up to 32 weeks, but older infants had increased variability. The INTERGROWTH-21st curves consistently had rates above 10% for LGA after 32 weeks.

CONCLUSIONS

While Olsen and Fenton both fit, the Olsen curves had overall best-fit for our sample of US NICU infants. The INTERGROWTH-21st curves fit the definitions for SGA and LGA for younger ages, but inferences outside of these definitions are unwarranted due to limited sample size. The INTERGROWTH-21st sample used for 33 weeks and older infants was physically smaller at the upper percentiles than our sample of US infants.

Maternal urinary concentrations of organophosphate ester metabolites: associations with gestational weight gain, early life anthropometry, and infant eating behaviors among mothers-infant pairs in Rhode Island

BACKGROUND

Organophosphate esters (OPEs)-used as flame retardants and plasticizers-are associated with adverse pregnancy outcomes such as reduced fecundity and live births and increased preterm delivery. OPEs may interfere with growth and metabolism via endocrine-disruption, but few studies have investigated endocrine-related outcomes. The objective of this pilot study (n = 56 mother-infant pairs) was to evaluate associations of OPEs with gestational weight gain (GWG), gestational age at delivery, infant anthropometry, and infant feeding behaviors.

METHODS

We quantified OPE metabolites (bis-2-chloroethyl phosphate [BCEP], bis (1,3-dichloro-2-propyl) phosphate [BDCPP], diphenyl phosphate [DPHP]) in pooled maternal spot urine collected throughout pregnancy (~ 12, 28, and 35 weeks' gestation). We obtained maternal sociodemographic characteristics from questionnaires administered at enrollment and perinatal characteristics from medical record abstraction. Trained research assistants measured infant weight, length, head and abdominal circumferences, and skinfold thicknesses at birth and 6 weeks postpartum. Mothers reported infant feeding behavior via the Baby Eating Behavior Questionnaire (BEBQ). Using multiple linear regression, we assessed associations of log2-transformed maternal urinary OPE metabolites with GWG, gestational age at delivery, infant anthropometry at birth, weekly growth rate, and BEBQ scores at 6 weeks postpartum. We used linear mixed effects (LME) models to analyze overall infant anthropometry during the first 6 weeks of life. Additionally, we considered effect modification by infant sex.

RESULTS

We observed weak positive associations between all OPE metabolites and GWG. In LME models, BDCPP was associated with increased infant length (β = 0.44 cm, 95%CI = 0.01, 0.87) and weight in males (β = 0.14 kg, 95%CI = 0.03, 0.24). BDCPP was also associated with increased food responsiveness (β = 0.23, 95%CI = 0.06, 0.40). DPHP was inversely associated with infant abdominal circumference (β = - 0.50 cm, 95%CI = - 0.86, - 0.14) and female weight (β = - 0.19 kg, 95%CI = - 0.36, - 0.02), but positively associated with weekly growth in iliac skinfold thickness (β = 0.10 mm/wk., 95%CI = 0.02, 0.19). Further, DPHP was weakly associated with increased feeding speed. BCEP was associated with greater infant thigh skinfold thickness (β = 0.34 mm, 95%CI = 0.16, 0.52) and subscapular skinfold thickness in males (β = 0.14 mm, 95%CI = 0.002, 0.28).

CONCLUSIONS

Collectively, these findings suggest that select OPEs may affect infant anthropometry and feeding behavior, with the most compelling evidence for BDCPP and DPHP.

Metabolite Profiles of the Relationship between Body Mass Index (BMI) Milestones and Metabolic Risk during Early Adolescence

Early growth is associated with future metabolic risk; however, little is known of the underlying biological pathways. In this prospective study of 249 boys and 227 girls, we sought to identify sex-specific metabolite profiles that mark the relationship between age and magnitude of the infancy body mass index (BMI) peak, and the childhood BMI rebound with a metabolic syndrome z-score (MetS z-score) during early adolescence (median age 12.8 years). Thirteen consensus metabolite networks were generated between male and female adolescents using weighted correlation network analysis. In girls, none of the networks were related to BMI milestones after false discovery rate (FDR) correction at 5%. In boys, age and/or magnitude of BMI at rebound were associated with three metabolite eigenvector (ME) networks comprising androgen hormones (ME7), lysophospholipids (ME8), and diacylglycerols (ME11) after FDR correction. These networks were also associated with MetS z-score in boys after accounting for age and race/ethnicity: ME7 (1.43 [95% CI: 0.52, 2.34] units higher MetS z-score per 1 unit of ME7), ME8 (-1.01 [95% CI: -1.96, -0.07]), and ME11 (2.88 [95% CI: 2.06, 3.70]). These findings suggest that alterations in sex steroid hormone and lipid metabolism are involved in the relationship of early growth with future metabolic risk in males.

Family Spirit Nurture (FSN) - a randomized controlled trial to prevent early childhood obesity in American Indian populations: trial rationale and study protocol

BACKGROUND

Childhood overweight and obesity is a persistent public health issue in the US. Risk for obesity and obesity-related morbidity throughout the life course begins in utero. Native Americans suffer the greatest disparities in the US in childhood overweight and obesity status of any racial or ethnic group. Existing early childhood home-visiting interventions provide an opportunity for addressing obesity during the first 1000 days. However, to date, no evidence-based model has been specifically designed to comprehensively target early childhood obesity prevention.

METHODS

This study is a randomized controlled trial to test the efficacy of home-visiting intervention, called Family Spirit Nurture, on reducing early childhood obesity in Native American children. Participants are expectant Native American mothers ages 14-24 and their child, enrolled from pregnancy to 24 months postpartum and randomized 1:1 to receive the Family Spirit Nurture intervention or a control condition. The intervention includes 36 lessons delivered one-on-one by locally-hired Native American Family Health Coaches to participating mothers from pregnancy until 18 months postpartum. A mixed methods assessment includes maternal self-reports, maternal and child observations, and physical and biological data collected at 11 time points from 32 weeks gestation to 2 years postpartum to measure the intervention's primary impact on maternal feeding behaviors; children's healthy diet and physical activity; children's weight status. Secondary measures include maternal psychosocial factors; household food and water security; infant sleep and temperament; and maternal and child metabolic status.

DISCUSSION

None of the 20 current federally-endorsed home-visiting models have demonstrated impacts on preventing early childhood obesity. The original Family Spirit program, upon which Family Spirit Nurture is based, demonstrated effect on maternal and child behavioral health, not including obesity related risk factors. This trial has potential to inform the effectiveness of home-visiting intervention to reduce obesity risk for tribal communities and other vulnerable populations and expand public health solutions for the world's obesity crisis.

TRIAL REGISTRATION

Clinicaltrials.gov (Identifier: NCT03334266 - Preventing Early Childhood Obesity, Part 2: Family Spirit Nurture, Prenatal - 18 Months; Retrospectively registered on 07 November 2017).

BAYESIAN ANALYSIS OF INFANT'S GROWTH DYNAMICS WITH IN UTERO EXPOSURE TO ENVIRONMENTAL TOXICANTS

Early infancy from at-birth to 3 years is critical for cognitive, emotional and social development of infants. During this period, infant's developmental tempo and outcomes are potentially impacted by in utero exposure to endocrine disrupting compounds (EDCs), such as bisphenol A (BPA) and phthalates. We investigate effects of ten ubiquitous EDCs on the infant growth dynamics of body mass index (BMI) in a birth cohort study.Modeling growth acceleration is proposed to understand the "force of growth" through a class of semiparametric stochastic velocity models. The great flexibility of such a dynamic model enables us to capture subject-specific dynamics of growth trajectories and to assess effects of the EDCs on potential delay of growth. We adopted a Bayesian method with the Ornstein-Uhlenbeck process as the prior for the growth rate function, in which the World Health Organization global infant's growth curves were integrated into our analysis. We found that BPA and most of phthalates exposed during the first trimester of pregnancy were inversely associated with BMI growth acceleration, resulting in a delayed achievement of infant BMI peak. Such early growth deficiency has been reported as a profound impact on health outcomes in puberty (e.g., timing of sexual maturation) and adulthood.

Body mass index growth trajectories from birth through 24 months in Iranian infants of mothers with gestational diabetes mellitus

AIMS

Child growth is one of the important health indicators in pediatric care. Few studies focused on the impact of prenatal exposure to gestational diabetes mellitus (GDM) on growth trajectories particular in early years of childhood. The aim of this study was identifying growth pattern of GDM exposed offspring's, comparison with new WHO child growth standards.

METHODS AND MATERIALS

In a population-based Longitudinal study 438 infants exposed to gestational diabetes in utero, aged 0-24 months, born between 2014 and 2016 with at least 9 visits in first 2 years of life were enrolled. Twenty health centers of Ahvaz city (Capital of Khuzestan province, located in south western of Iran) and two referral centers for neonatal hypothyroidism involved the study.

RESULTS

Of 438 GDM exposed infants, 54.6% were boys. Incidence of low birth weight and macrosomia were 4.6% and 8.7% respectively.

RESULTS

4.6% had birth weight less than 2500gr and 8.7% was rate of macrosomia. Boys had higher weight and BMI than girls. Peak of BMI was 17.8 (±2.07) at 6 months after Gender was significant factor in predicted of BMI growth trajectories in GDM exposed children (p = 0.001). BMI in GDM exposed infants, in first 2 years of life was higher than WHO growth standards 2006 (P < 0.01).

CONCLUSION

Medians of BMI in GDM exposed infants in all measures was higher than WHO reference data 2006 (P < 0.01). Obesity prevention programs must be priority in GDM exposed infants.

Longitudinal BMI Growth Curves for Surviving Preterm NICU Infants Based on a Large US Sample

BACKGROUND

Longitudinal growth curves, based on repeated measurements from the same group of infants, exist for preterm infant weight and length but not for BMI. Our existing BMI (weight divided by length squared) curves are based on cross-sectional birth data obtained from a different group of infants at each gestational age (GA).

METHODS

We calculated BMI over time for 68 693 preterm infants between 24 and 36 weeks GA. Stratifying infants by sex, GA at birth, and quintiles based on birth BMI, we created longitudinal median curves using R and validated the resulting curves for empirical fit, proper classification, and normality of z scores.

RESULTS

We created 2 sets of BMI growth charts. The first set displays fitted median curves for all 5 percentile groups in each GA group by sex. The second set displays fitted median curves with their corresponding third and 97th percentiles by percentile group, GA, and sex. In the validation analysis, percentage of daily observations below the median curve approximated the expected 50th percentile after the initial 3 days. Unlike the cross-sectional curves, the longitudinal curves reveal the pattern of change corresponding to nadir; postnadir, these curves remained consistently below the cross-sectional curves and varied by GA and sex as expected. The percentage of observations falling below the 50th percentile for cross-sectional curves (revealing optimal growth) was generally much higher than for longitudinal curves (revealing actual growth).

CONCLUSIONS

These new longitudinal curves provide clinicians data on how premature infants' body proportionality changes over time.

Associations of the infancy body mass index peak with anthropometry and cardiometabolic risk in Mexican adolescents

BACKGROUND

Early-life growth dynamics are associated with future health. Little is known regarding timing and magnitude of the infancy body mass index (BMI) peak with adiposity and metabolic biomarkers during adolescence.

AIM

To examine associations of the infancy BMI peak with anthropometry and cardiometabolic risk during peripuberty.

METHODS

Among 163 ELEMENT participants, this study estimated age and magnitude of the infancy BMI peak from eight anthropometric measurements from birth-36 months using Newton's Growth Models, an acceleration-based process model. Associations were examined of the infancy milestones with anthropometry and cardiometabolic risk at 8-14 years using linear regression models that accounted for maternal calcium supplementation and age; child's birthweight, sex, and age; and the other infancy milestone.

RESULTS

Median age at the infancy BMI peak was 9.6 months, and median peak BMI was 16.5 kg/m2. Later age and larger magnitude of the peak predicted higher BMI z-score, waist circumference, and skinfold thicknesses; i.e. each 1 month of age at peak and each 1 kg/m2 of peak BMI corresponded with 0.04 (0.01-0.07) and 0.33 (0.17-0.48) units of higher BMI z-score, respectively. Later age at peak was also a determinant of worse glycaemia and higher blood pressure.

CONCLUSION

Later age and larger magnitude of the infancy BMI peak are associated with higher adiposity at 8-14 years of age. Later age but not magnitude of the BMI peak are related to a worse cardiometabolic profile during peripuberty.

Maternal caffeine intake during pregnancy and childhood growth and overweight: results from a large Norwegian prospective observational cohort study

OBJECTIVES

To study the association between maternal caffeine intake during pregnancy and the child's weight gain and overweight risk up to 8 years.

DESIGN

Prospective nationwide pregnancy cohort.

SETTING

The Norwegian Mother and Child Cohort Study.

PARTICIPANTS

A total of 50 943 mothers recruited from 2002 to 2008 and their children, after singleton pregnancies, with information about average caffeine intake assessed at mid-pregnancy.

OUTCOME MEASURE

Child's body size information at 11 age points from 6 weeks to 8 years. We defined excess growth in infancy as a WHO weight gain z-score of >0.67 from birth to age 1 year, and overweight according to the International Obesity Task Force. We used a growth model to assess individual growth trajectories.

RESULTS

Compared with pregnant women with low caffeine intake (<50 mg/day, 46%), women with average (50-199 mg/day, 44%), high (≥200-299 mg/day, 7%) and very high (≥300 mg/day, 3%) caffeine intakes had an increased risk of their child experiencing excess growth in infancy, after adjustment for confounders (OR=1.15, 95% CI 1.09 to 1.22, OR=1.30, 95% CI 1.16 to 1.45, OR=1.66, 95% CI 1.42 to 1.93, respectively). In utero exposure to any caffeine was associated with higher risk of overweight at age 3 years and 5 years, while the association persisted at 8 years, only for very high exposures. Any caffeine intake was associated with increased body mass index from infancy to childhood. Children prenatally exposed to caffeine intake >200 mg/day had consistently higher weight. Very high caffeine exposures were associated with higher weight gain velocity from infancy to age 8 years.

CONCLUSION

Any caffeine consumption during pregnancy is associated with a higher risk of excess infant growth and of childhood overweight, mainly at preschool ages. Maternal caffeine intake may modify the overall weight growth trajectory of the child from birth to 8 years. This study adds supporting evidence for the current advice to reduce caffeine intake during pregnancy.

Metrics of early childhood growth in recent epidemiological research: A scoping review

Metrics to quantify child growth vary across studies of the developmental origins of health and disease. We conducted a scoping review of child growth studies in which length/height, weight or body mass index (BMI) was measured at ≥ 2 time points. From a 10% random sample of eligible studies published between Jan 2010-Jun 2016, and all eligible studies from Oct 2015-June 2016, we classified growth metrics based on author-assigned labels (e.g., 'weight gain') and a 'content signature', a numeric code that summarized the metric's conceptual and statistical properties. Heterogeneity was assessed by the number of unique content signatures, and label-to-content concordance. In 122 studies, we found 40 unique metrics of childhood growth. The most common approach to quantifying growth in length, weight or BMI was the calculation of each child's change in z-score. Label-to-content discordance was common due to distinct content signatures carrying the same label, and because of instances in which the same content signature was assigned multiple different labels. In conclusion, the numerous distinct growth metrics and the lack of specificity in the application of metric labels challenge the integration of data and inferences from studies investigating the determinants or consequences of variations in childhood growth.

Early Life Growth Predictors of Childhood Adiposity Trajectories and Future Risk for Obesity: Birth to Twenty Cohort

BACKGROUND

There is growing evidence of variations in adiposity trajectories among individuals, but the influence of early life growth patterns on these trajectories is underresearched in low- and middle-income countries. Therefore, our aim was to examine the association between early life conditional weight gain and childhood adiposity trajectories.

METHODS

We previously identified distinct adiposity trajectories (four for girls and three for boys) in black South African children (boys = 877; girls = 947). The association between the trajectories and early life growth patterns, and future obesity risk was assessed by multivariate linear and multinomial logistic and logistic regressions. Conditional weight gain independent of height was computed for infancy (0-2 years) and early childhood (2-4 years).

RESULTS

Conditional weight gain before 5 years of age was significantly associated with early onset of obesity or overweight (excess weight) BMI trajectories in both boys and girls. In girls, greater conditional weight gain in infancy was associated with increased relative risk of being in the early-onset obese to morbid obese trajectory, with relative risk ratios of 2.03 (95% confidence interval: 1.17-3.52) compared to belonging to a BMI trajectory in the normal range. Boys and girls in the early-onset obesity or overweight BMI trajectories were more likely to be overweight or obese in early adulthood.

CONCLUSIONS

Excessive weight gain in infancy and early childhood, independent of linear growth, predicts childhood and adolescent BMI trajectories toward obesity. These results underscore the importance of early life factors in the development of obesity and other NCDs in later life.

Conditional random slope: A new approach for estimating individual child growth velocity in epidemiological research

Objectives

Conditioning child growth measures on baseline accounts for regression to the mean (RTM). Here, we present the “conditional random slope” (CRS) model, based on a linear‐mixed effects model that incorporates a baseline‐time interaction term that can accommodate multiple data points for a child while also directly accounting for RTM.

METHODS

In two birth cohorts, we applied five approaches to estimate child growth velocities from 0 to 12 months to assess the effect of increasing data density (number of measures per child) on the magnitude of RTM of unconditional estimates, and the correlation and concordance between the CRS and four alternative metrics. Further, we demonstrated the differential effect of the choice of velocity metric on the magnitude of the association between infant growth and stunting at 2 years.

RESULTS

RTM was minimally attenuated by increasing data density for unconditional growth modeling approaches. CRS and classical conditional models gave nearly identical estimates with two measures per child. Compared to the CRS estimates, unconditional metrics had moderate correlation (r = 0.65–0.91), but poor agreement in the classification of infants with relatively slow growth (kappa = 0.38–0.78). Estimates of the velocity‐stunting association were the same for CRS and classical conditional models but differed substantially between conditional versus unconditional metrics.

CONCLUSION

The CRS can leverage the flexibility of linear mixed models while addressing RTM in longitudinal analyses.

Higher neonatal growth rate and body condition score at 7 months are predictive factors of obesity in adult female Beagle dogs

Background

The risks during early growth on becoming overweight in adulthood are widely studied in humans. However, early-life predictive factors for canine adult overweight and obesity have not yet been studied.

To identify factors that may help explain the development of overweight and obesity at adulthood in dogs, a longitudinal study of 2 years was conducted in 24 female Beagle dogs of the same age, sexual status, and raised under identical environmental conditions. By means of a hierarchical classification on principal components with the following quantitative values: fat-free mass (FFM), percentage fat mass and pelvic circumference at 2 years of age, three groups of dogs were established and were nominally named: ideal weight (IW, n = 9), slightly overweight (OW1, n = 6) and overweight (OW2, n = 9). With the aim of identifying predictive factors of development of obesity at adulthood parental characteristics, growth pattern, energy balance and plasma factors were analysed by logistic regression analysis.

Results

At 24 months, the group compositions were in line with the body condition scores (BCS 1–9) values of the IW (5 or 6/9), the OW1 (6/9) and the OW2 (7 or 8/9) groups. Logistic regression analysis permitted the identification of neonatal growth rate during the first 2 weeks of life (GR_2W) and BCS at 7 months as predictors for the development of obesity at adulthood. Seventy percent of dogs with either GR_2W >125% or with BCS > 6/9 at 7 months belonged to the OW2 group. Results from energy intake and expenditure, corrected for FFM, showed that there was a greater positive energy imbalance between 7 and 10 months for the OW2, compared to the IW group.

Conclusion

This study expands the understanding of previously reported risk factors for being overweight or obese in dogs, establishing that (i) 15 out of 24 of the studied dogs became overweight and (ii) GR_2W and BCS at 7 months of age could be used as predictive factors as overweight adult dogs in the OW2 group had higher values compared the other groups of dogs.

Electronic supplementary material

The online version of this article (doi:10.1186/s12917-017-0994-7) contains supplementary material, which is available to authorized users.

Potential selection effects when estimating associations between the infancy peak or adiposity rebound and later body mass index in children

INTRODUCTION

This study aims to evaluate a potential selection effect caused by exclusion of children with non-identifiable infancy peak (IP) and adiposity rebound (AR) when estimating associations between age and body mass index (BMI) at IP and AR and later weight status.

SUBJECTS AND METHODS

In 4744 children with at least 4 repeated measurements of height and weight in the age interval from 0 to 8 years (37 998 measurements) participating in the IDEFICS (Identification and Prevention of Dietary- and Lifestyle-Induced Health Effects in Children and Infants)/I.Family cohort study, fractional polynomial multilevel models were used to derive individual BMI trajectories. Based on these trajectories, age and BMI at IP and AR, BMI values and growth velocities at selected ages as well as the area under the BMI curve were estimated. The BMI growth measures were standardized and related to later BMI z-scores (mean age at outcome assessment: 9.2 years).

RESULTS

Age and BMI at IP and AR were not identifiable in 5.4% and 7.8% of the children, respectively. These groups of children showed a significantly higher BMI growth during infancy and childhood. In the remaining sample, BMI at IP correlated almost perfectly (r⩾0.99) with BMI at ages 0.5, 1 and 1.5 years, whereas BMI at AR correlated perfectly with BMI at ages 4-6 years (r⩾0.98). In the total study group, BMI values in infancy and childhood were positively associated with later BMI z-scores where associations increased with age. Associations between BMI velocities and later BMI z-scores were largest at ages 5 and 6 years. Results differed for children with non-identifiable IP and AR, demonstrating a selection effect.

CONCLUSIONS

IP and AR may not be estimable in children with higher-than-average BMI growth. Excluding these children from analyses may result in a selection bias that distorts effect estimates. BMI values at ages 1 and 5 years might be more appropriate to use as predictors for later weight status instead.

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.

Association between Prepregnancy Body Mass Index and Gestational Weight Gain with Size, Tempo, and Velocity of Infant Growth: Analysis of the Newborn Epigenetic Study Cohort

BACKGROUND

The first 1000 days of life is a critical period of infant growth that has been linked to future adult health. Understanding prenatal factors that contribute to variation in growth during this period could inform successful prevention strategies.

METHODS

Prenatal and maternal characteristics, including prepregnancy obesity and gestational weight gain were evaluated in relation to weight growth trajectories during the first 24 months of life using the SuperImposition by Translation and Rotation (SITAR) method, which provides estimates of infant size, timing to peak velocity, and growth velocity. The study sample included 704 mother-infant dyads from a multiethnic prebirth cohort from the Southeastern United States. The total number of weight measures was 8670 (median number per child = 14).

RESULTS

Several prenatal and maternal characteristics were linked with infant growth parameters. The primary findings show that compared to women with a prepregnancy BMI between 18 and 24.9, women with a prepregnancy BMI ≥40 had infants that were 8% larger during the first 24 months, a delayed tempo of around 9 days, and a slower velocity. Mothers who had greater than adequate gestational weight gain had infants that were 5% larger even after controlling for prepregnancy BMI and several other covariates.

CONCLUSIONS

The findings contribute new data on the associations between gestational weight gain and aspects of early growth using the SITAR method, and support a growing consensus in the literature that both prepregnancy BMI and gestational weight gain relate independently to risk for greater postnatal weight growth.

Gestational Weight Gain and Offspring Longitudinal Growth in Early Life

BACKGROUND

Excessive gestational weight gain (GWG) increases the risk of childhood obesity, but little is known about its association with infant growth patterns.

AIM

The aim of this study was to examine the association between GWG and infant growth patterns.

METHODS

Pregnant women (n = 743) self-reported GWG at delivery, which we classified as inadequate, adequate or excessive based on the current guidelines. Offspring weight-for-age z-score (WAZ), length-for-age z-score (LAZ (with height-for-age (HAZ) in place of length at 36 months)) and body mass index z-score (BMIZ) were calculated at birth, 8, 18 and 36 months using the 2006 World Health Organization growth standards. Linear mixed models estimated the change in z-score from birth to 36 months by GWG.

RESULTS

The mean (SD) WAZ was -0.22 (1.20) at birth. Overall, WAZ and BMIZ increased from birth to, approximately, 24 months and decreased from 24 to 36 months, while LAZ/HAZ decreased from birth through 36 months. Excessive GWG was associated with higher offspring WAZ and BMIZ at birth, 8 and 36 months, and higher HAZ at 36 months, compared with adequate GWG. Compared with the same referent, inadequate GWG was associated with smaller WAZ and BMIZ at birth and 8 months.

CONCLUSION

Excessive GWG may predispose infants to obesogenic growth patterns, while inadequate GWG may not have a lasting impact on infant growth.

Regression models for linking patterns of growth to a later outcome: infant growth and childhood overweight

Background

Regression models are widely used to link serial measures of anthropometric size or changes in size to a later outcome. Different parameterisations of these models enable one to target different questions about the effect of growth, however, their interpretation can be challenging. Our objective was to formulate and classify several sets of parameterisations by their underlying growth pattern contrast, and to discuss their utility using an expository example.

Methods

We describe and classify five sets of model parameterisations in accordance with their underlying growth pattern contrast (conditional growth; being bigger v being smaller; becoming bigger and staying bigger; growing faster v being bigger; becoming and staying bigger versus being bigger). The contrasts are estimated by including different sets of repeated measures of size and changes in size in a regression model. We illustrate these models in the setting of linking infant growth (measured on 6 occasions: birth, 6 weeks, 3, 6, 12 and 24 months) in weight-for-height-for-age z-scores to later childhood overweight at 8y using complete cases from the Norwegian Childhood Growth study (n = 900).

Results

In our expository example, conditional growth during all periods, becoming bigger in any interval and staying bigger through infancy, and being bigger from birth were all associated with higher odds of later overweight. The highest odds of later overweight occurred for individuals who experienced high conditional growth or became bigger in the 3 to 6 month period and stayed bigger, and those who were bigger from birth to 24 months. Comparisons between periods and between growth patterns require large sample sizes and need to consider how to scale associations to make comparisons fair; with respect to the latter, we show one approach.

Conclusion

Studies interested in detrimental growth patterns may gain extra insight from reporting several sets of growth pattern contrasts, and hence an approach that incorporates several sets of model parameterisations. Co-efficients from these models require careful interpretation, taking account of the other variables that are conditioned on.

Electronic supplementary material

The online version of this article (doi:10.1186/s12874-016-0143-1) contains supplementary material, which is available to authorized users.

WHO Child Growth Standards Are Often Incorrectly Applied to Children Born Preterm in Epidemiologic Research

In epidemiologic research, there is no standard approach for accounting for gestational age (GA) at birth when interpreting postnatal anthropometric data in analyses of cohorts that include children born preterm (CBP). A scoping review was conducted to describe analytical approaches to account for GA at birth when applying the WHO Growth Standards (WHO-GS) to anthropometric data in epidemiologic studies. We searched PubMed, Scopus, MEDLINE, Embase, and Web of Science for studies that applied WHO-GS, included CBP in the study population, had access to data within 1 mo of age, and were published between 2006 and 2015 in English. Of the 80 included studies that used the WHO-GS, 80% (64 of 80) included all children regardless of GA, whereas 20% (16 of 80) restricted analyses that used WHO-GS to term-born children. Among the 64 studies that included all children, 53 (83%) used chronological age and 11 (17%) used corrected age for CBP. Of the 53 studies that used chronological age, 12 (23%) excluded data that were likely contributed by CBP (e.g., very low birth weight or extremely low outlying z scores) and 19 (36%) adjusted for or stratified by GA at birth in regression analyses. In summary, researchers commonly apply WHO-GS to CBP, usually based on chronological age. Methodologic challenges of analyzing data from CBP in the application of WHO-GS were rarely explicitly addressed. Further efforts are required to establish acceptable approaches to account for heterogeneity in GA at birth in the analysis of post-term anthropometric data in epidemiologic research.

Detecting Associations between Early-Life DDT Exposures and Childhood Growth Patterns: A Novel Statistical Approach

It has been hypothesized that environmental exposures at key development periods such as in utero play a role in childhood growth and obesity. To investigate whether in utero exposure to endocrine-disrupting chemicals, dichlorodiphenyltrichloroethane (DDT) and its metabolite, dichlorodiphenyldichloroethane (DDE), is associated with childhood physical growth, we took a novel statistical approach to analyze data from the CHAMACOS cohort study. To model heterogeneity in the growth patterns, we used a finite mixture model in combination with a data transformation to characterize body mass index (BMI) with four groups and estimated the association between exposure and group membership. In boys, higher maternal concentrations of DDT and DDE during pregnancy are associated with a BMI growth pattern that is stable until about age five followed by increased growth through age nine. In contrast, higher maternal DDT exposure during pregnancy is associated with a flat, relatively stable growth pattern in girls. This study suggests that in utero exposure to DDT and DDE may be associated with childhood BMI growth patterns, not just BMI level, and both the magnitude of exposure and sex may impact the relationship.

Low birthweight or rapid catch-up growth: which is more associated with cardiovascular disease and its risk factors in later life? A systematic review and cryptanalysis

BACKGROUND

The effects of birthweight (the Barker hypothesis) and growth trajectory in early life on the incidence of cardiovascular disease (CVD) and its risk factors in later life have been investigated in a number of studies.

OBJECTIVE

To undertake a systematic review and cryptanalysis of the association of low birthweight (LBW) and the postnatal growth trajectory with CVD and its risk factors.

METHODS

English-language publications in PubMed, ISI Web of Science and Scopus were searched. Initially, two independent reviewers identified relevant papers in several steps and the quality of papers was then determined by a validated quality-appraisal checklist.

RESULTS

By applying maximum sensitivity, 7259 paper were identified, 382 of which were duplicates and 1273 were considered to be relevant to the topic. Then, after title and abstract review, 628 irrelevant papers were excluded; 26 papers were added after reference-checking. Then, 250 other papers were deleted after full text review. Finally, 39 relevant papers remained and were entered into the systematic review. Overall, 79·6% of all CVD risk factors reported in primary studies of the rapid catch-up growth hypothesis were statistically significant, whereas the corresponding figure was 58·5% for the effects of LBW (Barker hypothesis).

CONCLUSIONS

This systematic review highlights the importance of low birthweight in increasing the risk of CVD and its risk factors in later life. The results support rapid postnatal catch-up growth of LBW neonates as a more important factor than LBW alone in CVD and its risk factors.

Adiposity and Insulin Resistance in Children from a Rural Community in Mexico

BACKGROUND AND AIMS

The study of the incidence of overweight and obesity as well as body composition and insulin resistance in children from rural communities is scarce. The aims of the study were a) to characterize the adiposity and homeostasis model assessment of insulin resistance (HOMA-IR) in school-age children from a rural community and b) to determine factors associated with fat mass and HOMA-IR in this population.

METHODS

A total of 41 school-aged children (15 males and 26 females; 9.9 ± 2.5 years old) from a Mexican rural community was studied. Trained observers had previously assessed the children's nutritional status during the first 6 months of life. Anthropometry, energy intake, physical activity, body composition and biochemical parameters were measured.

RESULTS

The overall prevalence of overweight/obesity was 7.3%. The mean energy intake of children was below international recommendations (1,235 ± 400 kcal/day). A higher percentage of fat mass was observed in females (20.3 ± 8.5) than in males (14.1 ± 5.1) (p = 0.006). There were seven children with IR, but we did not observe a correlation between HOMA and BMI percentiles (Pearson's r = 0.09, p = 0.57). In a regression model, gender (females) was the primary factor associated with the percentage of fat mass. The growth velocity during the first 6 months of life was associated with HOMA-IR.

CONCLUSIONS

There is a low frequency of overweight and obesity in children from rural communities in Mexico. However, these children appear to have increased risk of adiposity and insulin resistance.

Postnatal growth velocity and overweight in early adolescents: a comparison of rural and urban African boys and girls

Objectives

To compare growth velocity of two African child cohorts and examine the relationship between postnatal growth velocity in infancy/early childhood and the risk of overweight/stunting in early adolescence.

Methods

The study used data from two child cohorts from urban (Birth to Twenty Cohort, South Africa) and rural (Lungwena Child Survival Study, Malawi) African settings. Mixed effect modelling was used to derive growth and peak growth velocities. T-tests were used to compare growth parameters and velocities between the two cohorts. Linear and logistic regression models were used to determine the relationship between growth velocity and early adolescent (ages 9–11 years) body mass index and odds of being overweight.

Results

Children in the BH cohort were significantly taller and heavier than those in the Lungwena cohort, and exhibited faster weight and height growth velocity especially in the first year of life (P < 0.05). No significant association was shown between baseline weight (α_w) and overweight in early adolescence (OR = 1.25, CI = 0.67, 2.34). The weight growth velocity parameter β_w was highly associated with odds of being overweight. Association between overweight in adolescence and weight velocity was stronger in infancy than in early childhood (OR at 3 months = 4.80, CI = 2.49, 9.26; OR at 5 years = 2.39, CI = 1.65, 3.47).

Conclusion

High weight and height growth velocity in infancy, independent of size at birth, is highly associated with overweight in early adolescence. However, the long term effects of rapid growth in infancy may be dependent on a particular population's socio-economic status and level of urbanization. Am. J. Hum. Biol. 26:643–651, 2014. © 2014 The Authors American Journal of Human Biology Published by Wiley Periodicals, Inc.