Familial psychosocial risk classes and preschooler body mass index: The moderating effect of caregiver feeding style

BACKGROUND

Early child weight gain predicts adolescent and adult obesity, underscoring the need to determine early risk factors affecting weight status and how risk factors might be mitigated. Socioeconomic status, food insecurity, caregiver depressive symptomology, single parenthood, and dysfunctional parenting each have been linked to early childhood weight status. However, the associations between these risk factors and children's weight status may be moderated by caregiver feeding styles (CFS). Examining modifiable factors buffering risk could provide key information to guide early obesity intervention efforts.

METHODS

This analysis used baseline data from the Growing Healthy project that recruited caregivers/child dyads (N = 626) from Michigan Head Start programs. Caregivers were primarily non-Hispanic white (62%) and African American (30%). After using latent class analysis to identify classes of familial psychosocial risk, CFS was tested as a moderator of the association between familial psychosocial risk class and child body mass index (BMI) z-score.

RESULTS

Latent class analysis identified three familial psychosocial risk classes: (1) poor, food insecure and depressed families; (2) poor, single parent families; and (3) low risk families. Interactive effects for uninvolved feeding styles and risk group indicated that children in poor, food insecure, and depressed families had higher BMI z-scores compared to children in the low risk group. Authoritative feeding styles in low risk and poor, food insecure, and depressed families showed lower child BMI z-scores relative to poor, single parent families with authoritative feeding styles.

CONCLUSIONS

Uninvolved feeding styles intensified the risk and an authoritative feeding style muted the risk conferred by living in a poor, food-insecure, and depressed family. Interventions that promote responsive feeding practices could help decrease the associations of familial psychosocial risks with early child weight outcomes.

Behavioral Associations with Overweight in Low-Income Children

OBJECTIVE

Food reinforcement (relative reinforcement value [RRV]), self-control (the ability to delay gratification [ATDG]), and eating outside of homeostatic need (eating in the absence of hunger [EAH]) are associated with overweight/obesity. These constructs have typically been studied in isolation in children, and little is known about how they interrelate and whether these associations differ by sex. The objective of this study is to investigate these associations by sex.

METHODS

In a low-income sample of 230 7- to 10-year-old children, RRV, ATDG, and EAH were assessed. The model showing that elevated RRV, lower ATDG, and greater EAH are each independent, direct predictors of overweight in middle childhood was separately tested by sex. It was predicted that greater RRV and less ATDG would also have indirect effects on overweight through EAH. The association between RRV and ATDG was investigated.

RESULTS

For girls, higher RRV was indirectly associated with overweight through EAH. For boys, no associations of RRV, ATDG, or EAH with overweight were significant. Finally, for girls, RRV and ATDG were significantly positively associated.

CONCLUSIONS

In girls, higher food reinforcement appears to be an important contributor to overweight. During middle childhood, ATDG may be assessing food reinforcement rather than self-control. Future studies are needed to identify the mechanisms underlying childhood overweight in boys.

Externalizing behavior is prospectively associated with intake of added sugar and sodium among low socioeconomic status preschoolers in a sex-specific manner

BACKGROUND

High intake of added sugar and sodium is a public health concern for preschool-aged children living in the US. Externalizing behavior may predict higher consumption of added sugar and/or sodium; however, previous studies have mostly been cross-sectional. The aim was to evaluate whether externalizing behavior is prospectively related to added sugar and intake in a sex-specific manner among preschoolers.

METHODS

This was a secondary analysis of 524 preschool children (48% male) from Michigan who participated in an obesity prevention trial that occurred during one school year from 2011 to 2015. Teacher-assessed externalizing behaviors and three 24-h dietary recalls were completed at baseline and follow-up. We used linear mixed effects regression to evaluate the association between externalizing behavior at baseline and added sugar (% of total Calories) and sodium intake (mg/1000 Calories) at follow-up. In adjusted analysis, we included baseline income-to-needs ratio, child race/ethnicity, and baseline overweight status. All models were adjusted for total energy intake and accounted for clustering by classroom.

RESULTS

Baseline externalizing behavior was positively associated with added sugar intake at follow-up among boys; after adjustment for confounders, every 5 points lower externalizing T-score (corresponding to higher externalizing behavior) was associated with a 0.6 higher percentage of added sugar per total Calories (95% CI 0.2 to 1.1; P value = 0.004). In contrast, girls with higher levels of externalizing behavior had lower consumption of added sugars; after confounder adjustment, every 5 points lower externalizing T-score was related to 0.6 lower percentage intake (95% CI -1.0 to -0.1; P value = 0.01). Baseline externalizing behavior was inversely associated with sodium intake at follow-up among boys. After potential confounder adjustment, for every 5 points lower externalizing behavior T-score, there was a 22 mg/1000 Cal lower sodium intake (95% CI -45 to 1; P value = 0.06). In contrast, after adjustment for confounders, every 5 points lower externalizing T-score among girls was related to 24 mg/1000 Cal higher sodium intake (95% CI 1 to 46; P value = 0.04).

CONCLUSIONS

Externalizing behavior among preschool-aged children was prospectively related to added sugar and sodium intake in a sex-dependent manner.

TRIAL REGISTRATION

NCT01398358 Registered 19 July 2011.

Prenatal naled and chlorpyrifos exposure is associated with deficits in infant motor function in a cohort of Chinese infants

BACKGROUND

Organophosphate insecticides (OPs) are used worldwide, yet despite nearly ubiquitous exposure in the general population, few have been studied outside the laboratory. Fetal brains undergo rapid growth and development, leaving them susceptible to long-term effects of neurotoxic OPs. The objective here was to investigate the extent to which prenatal exposure to OPs affects infant motor development.

METHODS

30 OPs were measured in umbilical cord blood using gas chromatography tandem mass spectrometry in a cohort of Chinese infants. Motor function was assessed at 6-weeks and 9-months using Peabody Developmental Motor Scales 2nd edition (PDMS-2) (n=199). Outcomes included subtest scores: reflexes, stationary, locomotion, grasping, visual-motor integration (V-M), composite scores: gross (GM), fine (FM), total motor (TM), and standardized motor quotients: gross (GMQ), fine (FMQ), total motor (TMQ).

RESULTS

Naled, methamidophos, trichlorfon, chlorpyrifos, and phorate were detected in ≥10% of samples. Prenatal naled and chlorpyrifos were associated with decreased 9-month motor function. Scores were 0.55, 0.85, and 0.90 points lower per 1ng/mL increase in log-naled, for V-M (p=0.04), FM (p=0.04), and FMQ (p=0.08), respectively. For chlorpyrifos, scores were 0.50, 1.98, 0.80, 1.91, 3.49, 2.71, 6.29, 2.56, 2.04, and 2.59 points lower for exposed versus unexposed infants, for reflexes (p=0.04), locomotion (p=0.02), grasping (p=0.05), V-M (p<0.001), GM (p=0.007), FM (p=0.002), TM (p<0.001), GMQ (p=0.01), FMQ (p=0.07), and TMQ (p=0.008), respectively. Girls appeared to be more sensitive to the negative effects of OPs on 9-month motor function than boys.

CONCLUSIONS

We found deficits in 9-month motor function in infants with prenatal exposure to naled and chlorpyrifos. Naled is being aerially sprayed to combat mosquitoes carrying Zika virus, yet this is the first non-occupational human study of its health effects. Delays in early-motor skill acquisition may be detrimental for downstream development and cognition.

Improving Self-Regulation for Obesity Prevention in Head Start: A Randomized Controlled Trial

OBJECTIVES

To determine the effect of an intervention to improve emotional and behavioral self-regulation in combination with an obesity-prevention program on the prevalence of obesity and obesity-related behaviors in preschoolers.

METHODS

This was a cluster-randomized intervention trial in Head Start (HS) classrooms conducted in each of 4 academic years from 2011 to 2015. Participants (697 children; 49% boys; mean age: 4.1 ± 0.5 years; 48% white, 30% African American, 12% Hispanic) were randomly assigned by classroom to 1 of 3 intervention arms: (1) HS + Preschool Obesity Prevention Series (POPS) + Incredible Years Series (IYS) (HS enhanced by the POPS [program targeting evidence-based obesity-prevention behaviors] and the IYS [program to improve children's self-regulation]), (2) HS+POPS, or (3) HS. Primary outcomes were changes in prevalence of obesity, overweight/obesity, BMI z score, and teacher-reported child emotional and behavioral self-regulation; secondary outcomes were dietary intake, outdoor play, screen time, and parent nutrition knowledge and nutrition self-efficacy.

RESULTS

HS+POPS+IYS improved teacher-reported self-regulation compared with HS+POPS (P < .001) and HS (P < .001), but there was no effect on the prevalence of obesity (16.4% preintervention to 14.3% postintervention in HS+POPS+IYS versus 17.3% to 14.4% in HS+POPS [P = .54] versus 12.2% to 13.0% in HS [P = .33]). There was no effect of HS+POPS compared with HS alone (P = .16). There was no effect on other outcomes except for sugar-sweetened beverage intake (HS+POPS+IYS resulted in a greater decline than HS; P = .005).

CONCLUSIONS

An intervention for parents and children to improve HS preschoolers' emotional and behavioral self-regulation in combination with an obesity-prevention curriculum did not reduce obesity prevalence or most obesity-related behaviors.

Associations between stress biology indicators and overweight across toddlerhood

Biological stress responses are proposed as a pathway through which stress exposure can "get under the skin" and lead to health problems, specifically obesity. Yet, it is not clear when such associations may emerge or whether they are bidirectional. Cortisol and salivary alpha amylase (sAA) were considered indicators of the biological stress response. We tested the longitudinal association between cortisol and sAA and weight in 215 low-income children at ages 21, 27, and 33 months (52% male; 46% non-Hispanic white). sAA and cortisol intercept and slope (representing morning level and rate of change across the day) were calculated for each age point using random effect models. Children were weighed and length measured and categorized as overweight versus normal weight (overweight defined as weight-for-length z-score ≥85th percentile for age and sex). Cross-lagged models stratified by sex and controlling for birthweight z-score tested the concurrent and cross-lagged associations between each of 4 indices of stress biology individually (cortisol and sAA intercept and slope) and overweight. Overweight status was correlated across time. Cortisol and sAA were correlated across occasions of measurement, though somewhat less strongly in boys. There were no concurrent associations between stress indicators and overweight. sAA at 27 months predicted greater risk of overweight at 33 months in girls, such that both lower sAA intercept and more rapidly increasing sAA at 27 months predicted greater risk of overweight at 33 months (β=-0.64, p<0.05 and β=1.09, p<0.05, respectively). For boys only, overweight at 21 months predicted lower sAA intercept at 27 months (β=-0.35, p<0.05). Findings suggest that longitudinal associations of stress biology and weight status may be present only on a limited basis very early in the lifespan.

Longitudinal associations between maternal feeding and overweight in low-income toddlers

Maternal feeding is a frequent intervention target for the prevention of early childhood obesity but longitudinal associations between feeding and child overweight are poorly understood. This observational cohort study sought to examine the cross-lagged associations between maternal feeding and overweight across ages 21, 27, and 33 months. Feeding was measured by maternal self-report (n = 222) at each age. Child weight and length were measured. Cross-lagged analysis was used to evaluate longitudinal associations between feeding and overweight, adjusting for infant birth weight, maternal body mass index, maternal education, and maternal depressive symptoms. The sample was 50.5% white, 52.3% male and 37.8% of mothers had a high school education or less. A total of 30.6%, 29.2%, and 26.3% of the sample was overweight at each age, respectively. Pressuring to Finish, Restrictive with regard to Amount, Restrictive with regard to Diet Quality, Laissez-Faire with regard to Diet Quality, Responsiveness to Satiety, Indulgent Permissive, Indulgent Coaxing, Indulgent Soothing, and Indulgent Pampering each tracked strongly across toddlerhood. There were no significant associations between maternal feeding and child overweight either in cross-sectional or cross-lagged associations. Our results do not support a strong causal role for feeding in childhood overweight. Future work longitudinal work should consider alternative approaches to conceptualizing feeding and alternative measurement approaches.

Effectiveness of differing levels of support for family meals on obesity prevention among head start preschoolers: the simply dinner study

Background

Despite slight decreases in obesity prevalence in children, nearly 25% of preschool-aged children are overweight or obese. Most interventions focused on promoting family meals as an obesity-prevention strategy target meal planning skills, knowledge and modeling of healthy eating without addressing the practical resources that enable implementation of family meals. There is a striking lack of evidence about what level of resources low-income parents need to implement family meals. This study will identify resources most effective in promoting family meals and, subsequently, test associations among the frequency of family meals, dietary quality and children’s adiposity indices among children enrolled in Head Start.

Methods

The Multiphase Optimization Strategy, employed in this study, is a cutting-edge approach to maximizing resources in behavioral interventions by identifying the most effective intervention components. We are currently testing the main, additive and interactive effects of 6 intervention components, thought to support family meals, on family meal frequency and dietary quality (Primary Outcomes) as compared to Usual Head Start Exposure in a Screening Phase (N = 512 low-income families). Components yielding the most robust effects will be bundled and evaluated in a two-group randomized controlled trial (intervention and Usual Head Start Exposure) in the Confirming Phase (N = 250), testing the effects of the bundled intervention on children’s adiposity indices (Primary Outcomes; body mass index and skinfolds). The current intervention components include: (1) home delivery of pre-made healthy family meals; (2) home delivery of healthy meal ingredients; (3) community kitchens in which parents make healthy meals to cook at home; (4) healthy eating classes; (5) cooking demonstrations; and (6) cookware/flatware delivery. Secondary outcomes include cooking self-efficacy and family mealtime barriers. Moderators of the intervention include family functioning and food security. Process evaluation data includes fidelity, attendance/use of supports, and satisfaction.

Discussion

Results will advance fundamental science and translational research by generating new knowledge of effective intervention components more rapidly and efficiently than the standard randomized controlled trial approach evaluating a bundled intervention alone. Study results will have implications for funding decisions within public programs to implement and disseminate effective interventions to prevent obesity in children.

Trial registration

Clincaltrials.gov Identifier NCT02487251; Registered June 26, 2015.

Breastfeeding, Mixed, or Formula Feeding at 9 Months of Age and the Prevalence of Iron Deficiency and Iron Deficiency Anemia in Two Cohorts of Infants in China

OBJECTIVE

To assess associations between breastfeeding and iron status at 9 months of age in 2 samples of Chinese infants.

STUDY DESIGN

Associations between feeding at 9 months of age (breastfed as sole milk source, mixed fed, or formula fed) and iron deficiency anemia (IDA), iron deficiency, and iron sufficiency were determined in infants from Zhejiang (n = 142) and Hebei (n= 813) provinces. Iron deficiency was defined as body iron < 0 mg/kg, and IDA as iron deficiency + hemoglobin < 110 g/L. Multiple logistic regression assessed associations between feeding pattern and iron status.

RESULTS

Breastfeeding was associated with iron status (P < .001). In Zhejiang, 27.5% of breastfed infants had IDA compared with 0% of formula-fed infants. The odds of iron deficiency/IDA were increased in breastfed and mixed-fed infants compared with formula-fed infants: breastfed vs formula-fed OR, 28.8 (95% CI, 3.7-226.4) and mixed-fed vs formula-fed OR, 11.0 (95% CI, 1.2-103.2). In Hebei, 44.0% of breastfed infants had IDA compared with 2.8% of formula-fed infants. With covariable adjustment, odds of IDA were increased in breastfed and mixed-fed groups: breastfed vs formula-fed OR, 78.8 (95% CI, 27.2-228.1) and mixed-fed vs formula-fed OR, 21.0 (95% CI, 7.3-60.9).

CONCLUSIONS

In both cohorts, the odds of iron deficiency/IDA at 9 months of age were increased in breastfed and mixed-fed infants, and iron deficiency/IDA was common. Although the benefits of breastfeeding are indisputable, these findings add to the evidence that breastfeeding in later infancy identifies infants at risk for iron deficiency/IDA in many settings. Protocols for detecting and preventing iron deficiency/IDA in breastfed infants are needed.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT00642863 and NCT00613717.

Early Childhood Risk Factors for Mealtime TV Exposure and Engagement in Low-Income Families

OBJECTIVE

To identify whether child and mother characteristics in early childhood predict TV exposure and engagement during mealtime in middle childhood.

METHODS

A total of 220 low-income mother-child dyads participated. Children were 4.26 years old (SD = 0.51) at baseline and 5.94 years (SD = 0.68) at 2-year follow-up. Mothers completed baseline measures of child negative emotionality and parenting practices. Family mealtimes were video recorded and coded for background TV exposure and child TV engagement. Multinomial logistic regression tested whether child emotionality and parenting practices during early childhood predicted risk of child TV exposure or engagement during mealtime, relative to no TV use, 2 years later.

RESULTS

Children with greater negative emotionality in early childhood were more likely to engage with TV during mealtime than to have no TV. Similarly, early parenting disciplinary practices characterized by over-reactivity and laxness increased the risk for child TV engagement versus no TV during mealtime approximately 2 years later.

CONCLUSIONS

We identified 2 factors that associated with an increased risk for TV viewing during meals. Helping parents manage child negative emotionality using positive parenting strategies might reduce later child TV engagement and improve the quality of family mealtimes.

Child cortisol moderates the association between family routines and emotion regulation in low-income children

Biological and social influences both shape emotion regulation. In 380 low-income children, we tested whether biological stress profile (cortisol) moderated the association among positive and negative home environment factors (routines; chaos) and emotion regulation (negative lability; positive regulation). Children (M age = 50.6, SD = 6.4 months) provided saliva samples to assess diurnal cortisol parameters across 3 days. Parents reported on home environment and child emotion regulation. Structural equation modeling was used to test whether cortisol parameters moderated associations between home environment and child emotion regulation. Results showed that home chaos was negatively associated with emotion regulation outcomes; cortisol did not moderate the association. Child cortisol level moderated the routines-emotion regulation association such that lack of routine was most strongly associated with poor emotion regulation among children with lower cortisol output. Findings suggest that underlying child stress biology may shape response to environmental influences.

Gestational Age and Kindergarten School Readiness in a National Sample of Preterm Infants

OBJECTIVE

To examine the association of gestational age with school readiness in kindergarten reading and math skills. We hypothesized that compared with infants born at 39-41 weeks, infants born at lower gestational ages would have poorer school readiness.

STUDY DESIGN

The study sample comprised 5250 children from the Early Childhood Longitudinal Study, Birth Cohort, assessed with specialized reading and math assessments at kindergarten. Poor school readiness was characterized by reading and math theta scores ≥1.5 SD below the sample mean. The aOR and 95% CI of poor school readiness were estimated using multivariate logistic regression, examining gestational age continuously and categorically (very preterm [VPT], moderate/late preterm [M/LPT], early term [ET], and term). Pairwise comparisons were performed to test for differences by gestational age category.

RESULTS

There was an association between gestational age and poor school readiness for reading and math, with the suggestion of a threshold effect in children born at ≥32 weeks gestation. In adjusted models, in VPT infants, the aORs of poor school readiness in reading and math were 2.58 (95% CI, 1.29-5.15) and 3.38 (95% CI, 1.66-6.91), respectively. For infants born M/LPT and ET, the odds of poor school readiness in reading did not differ from those of children born full-term, however.

CONCLUSIONS

Compared with term infants, the highest odds of poor school readiness in reading and math were seen in VPT infants, with lower odds of poor school readiness in children born at ≥32 weeks gestation. Ongoing developmental surveillance before kindergarten is indicated for VPT infants.

Low-income mothers' feeding goals predict observed home mealtime and child feeding practices

BACKGROUND

Mothers' goals are important for health behavior change, and engagement in child obesity interventions. It is unknown if maternal feeding goals are associated with observed home mealtime or feeding practices. The objective of this study was to examine the association of four common feeding goals (restrict junk food, promote fruit or vegetable intake, promote autonomy in eating and prevent obesity) with mothers' observed home mealtime and feeding practices.

METHODS

Low-income mothers (N = 265) of children (mean child age 70.8 months) participated in a semi-structured interview about child feeding. A coding scheme was developed and reliably applied to identify mothers' feeding goals from transcripts. Mothers' observed home mealtime and feeding practices were reliably coded from home mealtimes and a laboratory eating protocol. Mothers completed a questionnaire and reported demographics. Participant weights and heights were obtained. Regression models were used to test the association of each feeding goal with observed maternal practices, controlling for covariates.

RESULTS

The goal of restricting junk food was associated with the child always eating at a table (OR 2.87, 95% CI (1.39-5.96) p = 0.005), but not with the mother restricting junk food. The goal of promoting fruit or vegetable intake was associated with observationally promoting vegetables (OR 1.41, 95% CI (1.09-1.84), p = 0.01). The goals of promoting autonomy and preventing obesity were not associated with any observed maternal home mealtime or feeding practices.

CONCLUSIONS

While mothers' goals to restrict junk food and promote fruit or vegetable intake were associated with observed home mealtime and feeding practices, promoting autonomy and preventing obesity were not. Increased understanding of why low-income mothers may not translate certain feeding goals into practices may inform childhood obesity interventions.

Developmental Outcomes of Late Preterm Infants From Infancy to Kindergarten

OBJECTIVE

To compare developmental outcomes of late preterm infants (34-36 weeks' gestation) with infants born at early term (37-38 weeks' gestation) and term (39-41 weeks' gestation), from infancy through kindergarten.

METHODS

Sample included 1000 late preterm, 1800 early term, and 3200 term infants ascertained from the Early Childhood Longitudinal Study, Birth Cohort. Direct assessments of development were performed at 9 and 24 months by using the Bayley Short Form-Research Edition T-scores and at preschool and kindergarten using the Early Childhood Longitudinal Study, Birth Cohort reading and mathematics θ scores. Maternal and infant characteristics were obtained from birth certificate data and parent questionnaires. After controlling for covariates, we compared mean developmental outcomes between late preterm and full-term groups in serial cross-sectional analyses at each timepoint using multilinear regression, with pairwise comparisons testing for group differences by gestational age categories.

RESULTS

With covariates controlled at all timepoints, at 9 months late preterm infants demonstrated less optimal developmental outcomes (T = 47.31) compared with infants born early term (T = 49.12) and term (T = 50.09) (P < .0001). This association was not seen at 24 months, (P = .66) but reemerged at preschool. Late preterm infants demonstrated less optimal scores in preschool reading (P = .0006), preschool mathematics (P = .0014), and kindergarten reading (P = .0007) compared with infants born at term gestation.

CONCLUSIONS

Although late preterm infants demonstrate comparable developmental outcomes to full-term infants (early term and full-term gestation) at 24 months, they demonstrate less optimal reading outcomes at preschool and kindergarten timepoints. Ongoing developmental surveillance for late preterm infants is warranted into preschool and kindergarten.

Low-level prenatal lead exposure and infant sensory function

BACKGROUND

Lead is a pervasive neurotoxicant that has been associated with poorer cognitive, behavioral, and motor outcomes in children. The effects of lead on sensory function have not been well characterized. The aim of this study was to assess the effects of prenatal lead exposure on infant sensory function, as measured by auditory brainstem response (ABR) and grating visual acuity (VA).

METHODS

Lead was measured in maternal blood in mid- and late-pregnancy (mean gestational age = 15.5 and 39.0 weeks, respectively) and umbilical cord blood in a cohort of full-term infants in rural northeastern China. ABR latencies (peaks I, III, V) were measured in newborns during unsedated sleep (n = 315). The ABR central-to-peripheral (C-P) ratio was calculated as the ratio between the III-V and I-III interpeak intervals. VA was measured in 6-week-olds using Teller Acuity Cards (n = 1019) and assigned as the narrowest grid the infant fixated on. Multivariate linear regression was used to evaluate relationships between tertiles of mid-pregnancy, late-pregnancy, or cord lead and newborn ABR or 6-week VA.

RESULTS

Higher late-pregnancy lead levels were associated with higher ABR C-P ratios and lower VA. In covariate-adjusted analyses, mean C-P ratios were 4.6 and 3.2 % higher in infants whose mothers had lead > 3.8 μg/dL and lead = 2-3.8 μg/dL, respectively, than for infants whose mothers had lead < 2 μg/dL (p-trend =0.002). In adjusted analyses for VA, mean scores were 8.5 and 7.2 % lower for maternal lead > 3.8 μg/dL and lead = 2-3.8 μg/dL, respectively, compared to lead < 2 μg/dL (p-trend =0.009).

CONCLUSION

Auditory and visual systems maturation appears delayed in infants with higher prenatal lead exposure during late-pregnancy, even at relatively low levels. Both systems start myelinating in late gestation and mature rapidly in infancy. Higher ABR C-P ratio and lower grating VA scores suggest effects of low-level lead exposure on sensory system myelination.

Effect of Sibling Birth on BMI Trajectory in the First 6 Years of Life

BACKGROUND AND OBJECTIVE

This study examined the longitudinal association between birth of a sibling and changes in body mass index z-score (BMIz) trajectory during the first 6 years of life.

METHODS

Children (n = 697) were recruited across 10 sites in the United States at the time of birth. Sibship composition was assessed every 3 months. Anthropometry was completed when the child was age 15 months, 24 months, 36 months, 54 months, and in first grade. Children were classified based on the timing of their sibling's birth. A piecewise quadratic regression model adjusted for potential confounders examined the association of the birth of a sibling with subsequent BMIz trajectory.

RESULTS

Children whose sibling was born when they were 24 to 36 months or 36 to 54 months old, compared with children who did not experience the birth of a sibling by first grade, had a lower subsequent BMIz trajectory and a significantly lower BMIz at first grade (0.27 vs 0.51, P value = 0.04 and 0.26 vs 0.51, P value = 0.03, respectively). Children who did not experience the birth of a sibling by the time they were in first grade had 2.94 greater odds of obesity (P value = 0.046) at first grade compared with children who experienced the birth of a sibling when they were between 36 to 54 months old.

CONCLUSIONS

A birth of a sibling when the child is 24 to 54 months old is associated with a healthier BMIz trajectory. Identifying the underlying mechanism of association can help inform intervention programs.

Iron Supplementation in Pregnancy or Infancy and Motor Development: A Randomized Controlled Trial

BACKGROUND AND OBJECTIVE

Insufficient iron levels for optimal fetal and infant development is a concern during pregnancy and infancy. The goal of this study was to assess the effects of iron supplementation in pregnancy and/or infancy on motor development at 9 months.

METHODS

The study was a randomized controlled trial (RCT) of infancy iron supplementation linked to an RCT of pregnancy iron supplementation, conducted in Hebei, China. A total of 1482 infants were randomly assigned to receive placebo (n = 730) or supplemental iron (n = 752) from 6 weeks to 9 months. Gross motor development (assessed by using the Peabody Developmental Motor Scale, Second Edition, instrument) was the primary outcome. Neurologic integrity and motor quality were secondary outcomes.

RESULTS

Motor outcome was available for 1196 infants, divided into 4 supplementation period groups: (1) placebo in pregnancy/placebo in infancy (n = 288); (2) placebo in pregnancy/iron in infancy (n = 305); (3) iron in pregnancy/placebo in infancy (n = 298); and (4) iron in pregnancy/iron in infancy (n = 305). Using the Peabody Developmental Motor Scale, instrument, iron supplementation in infancy but not pregnancy improved gross motor scores: overall, P < .001; reflexes, P = .03; stationary, P < .001; and locomotion, P < .001. Iron supplementation in infancy improved motor scores by 0.3 SD compared with no supplementation or supplementation during pregnancy alone. Effects of iron supplementation in infancy alone were similar to effects with iron in both pregnancy and infancy.

CONCLUSIONS

The RCT design supports the causal inference that iron supplementation in infancy, with or without iron supplementation in pregnancy, improved gross motor test scores at 9 months.

Adipose tissue fibrosis, hypertrophy, and hyperplasia: Correlations with diabetes in human obesity

OBJECTIVE

The relationship between adipose tissue fibrosis, adipocyte hypertrophy, and preadipocyte hyperplasia in the context of obesity and the correlation of these tissue-based phenomena with systemic metabolic disease are poorly defined. The goal of this study was to clarify the relationship between adipose tissue fibrosis, adipocyte hypertrophy, and preadipocyte hyperplasia in human obesity and determine the correlation of these adipose-tissue based phenomena with diabetes.

METHODS

Visceral and subcutaneous adipose tissues from humans with obesity collected during bariatric surgery were studied with QRTPCR, immunohistochemistry, and flow cytometry for expression of collagens and fibrosis-related proteins, adipocyte size, and preadipocyte frequency. Results were correlated with clinical characteristics including diabetes status.

RESULTS

Fibrosis was decreased, hypertrophy was increased, and preadipocyte frequency and fibrotic gene expression were decreased in adipose tissues from diabetic subjects compared to non-diabetic subjects. These differences were greater in visceral compared to subcutaneous adipose tissue.

CONCLUSIONS

These data are consistent with the hypothesis that adipose tissue fibrosis in the context of human obesity limits adipocyte hypertrophy and is associated with a reciprocal increase in adipocyte hyperplasia, with beneficial effects on systemic metabolism. These findings suggest adipose tissue fibrosis as a potential target for manipulation of adipocyte metabolism.

Low-Dose Iron Supplementation in Infancy Modestly Increases Infant Iron Status at 9 Mo without Decreasing Growth or Increasing Illness in a Randomized Clinical Trial in Rural China

BACKGROUND

Previous trials of iron supplementation in infancy did not consider maternal iron supplementation.

OBJECTIVE

This study assessed effects of iron supplementation in infancy and/or pregnancy on infant iron status, illnesses, and growth at 9 mo.

METHODS

Enrollment occurred from December 2009 to June 2012 in Hebei, China. Infants born to women in a pregnancy iron supplementation trial were randomly assigned 1:1 to iron [∼1 mg Fe/(kg · d) as oral iron proteinsuccynilate] or placebo from 6 wk to 9 mo, excluding infants with cord ferritin <35 μg/L. Study groups were pregnancy placebo/infancy placebo (placebo/placebo), pregnancy placebo/infancy iron (placebo/iron), pregnancy iron/infancy placebo (iron/placebo), and pregnancy iron/infancy iron (iron/iron). The primary outcome was 9-mo iron status: iron deficiency (ID) by cutoff (≥2 abnormal iron measures) or body iron <0 mg/kg and ID + anemia (hemoglobin <110 g/L). Secondary outcomes were doctor visits or hospitalizations and weight or length gain from birth to 9 mo. Statistical analysis by intention to treat and dose-response (between number of iron bottles received and outcome) used logistic regression with concomitant RRs and general linear models, with covariate control as applicable.

RESULTS

Of 1482 infants randomly allocated, 1276 had 9-mo data (n = 312-327/group). Iron supplementation in infancy, but not pregnancy, reduced ID risk: RRs (95% CIs) were 0.89 (0.79, 0.998) for placebo/iron compared to placebo/placebo, 0.79 (0.63, 0.98) for placebo/iron compared to iron/placebo, 0.87 (0.77, 0.98) for iron/iron compared to placebo/placebo, and 0.86 (0.77, 0.97) for iron/iron compared to iron/placebo. However, >60% of infants still had ID at 9 mo. Receiving more bottles of iron in infancy was associated with better infant iron status at 9 mo but only among iron-supplemented infants whose mothers were also iron supplemented (i.e., the iron/iron group). There were no group differences in hospitalizations or illnesses and no adverse effects on growth overall or among infants who were iron sufficient at birth.

CONCLUSIONS

Iron supplementation in Chinese infants reduced ID at 9 mo without adverse effects on growth or illness. Effects of iron supplementation in pregnancy were observed only when higher amounts of iron were distributed in infancy. This trial was registered at clinicaltrials.gov as NCT00613717.

Timing of Puberty in Overweight Versus Obese Boys

BACKGROUND AND OBJECTIVE

Studies of the relationship of weight status with timing of puberty in boys have been mixed. This study examined whether overweight and obesity are associated with differences in the timing of puberty in US boys.

METHODS

We reanalyzed recent community-based pubertal data from the American Academy of Pediatrics' Pediatric Research in Office Settings study in which trained clinicians assessed boys 6 to 16 years for height, weight, Tanner stages, testicular volume (TV), and other pubertal variables. We classified children based on BMI as normal weight, overweight, or obese and compared median age at a given Tanner stage or greater by weight class using probit and ordinal probit models and a Bayesian approach.

RESULTS

Half of boys (49.9%, n = 1931) were white, 25.8% (n = 1000) were African American, and 24.3% (n = 941) were Hispanic. For genital development in white and African American boys across a variety of Tanner stages, we found earlier puberty in overweight compared with normal weight boys, and later puberty in obese compared with overweight, but no significant differences for Hispanics. For TV (≥3 mL or ≥4 mL), our findings support earlier puberty for overweight compared with normal weight white boys.

CONCLUSIONS

In a large, racially diverse, community-based sample of US boys, we found evidence of earlier puberty for overweight compared with normal or obese, and later puberty for obese boys compared with normal and overweight boys. Additional studies are needed to understand the possible relationships among race/ethnicity, gender, BMI, and the timing of pubertal development.

Birth order and sibship composition as predictors of overweight or obesity among low-income 4- to 8-year-old children

OBJECTIVE

This study aimed to examine the association of birth order and number and sex of siblings with overweight or obesity among 4- to 8-year-olds.

METHODS

This is a cross-sectional study involving 273 low-income mother-child dyads. Questionnaires and anthropometry were completed. Multiple logistic regression was used to examine the association of birth order, having younger siblings, having older siblings, having at least one brother and having at least one sister with odds of overweight or obesity. Analyses were repeated to additionally include non-biological siblings. Models were adjusted for potential confounders and intermediate variables.

RESULTS

Prevalence of child overweight or obesity was 42.5%. Adjusting for covariates, only children and youngest siblings had higher odds of overweight or obesity compared with oldest siblings (odds ratio [OR]: 4.18, 95% confidence interval [CI]: 1.67, 10.46 and OR: 3.21, 95% CI: 1.41, 7.33, respectively). Having one or more younger siblings and having at least one brother were associated with lower odds (OR: 0.38, 95% CI: 0.21, 0.69 and OR: 0.47, 95% CI: 0.28, 0.81, respectively). Including non-biological siblings did not meaningfully change the associations.

CONCLUSION

Birth order and sibship composition are associated with overweight or obesity among 4- to 8-year-olds. Future studies identifying the underlying behavioural mechanism can help inform family-based intervention programmes.

Iron deficiency (ID) at both birth and 9 months predicts right frontal EEG asymmetry in infancy

This study considered effects of timing and duration of iron deficiency (ID) on frontal EEG asymmetry in infancy. In healthy term Chinese infants, EEG was recorded at 9 months in three experimental conditions: baseline, peek-a-boo, and stranger approach. Eighty infants provided data for all conditions. Prenatal ID was defined as low cord ferritin or high ZPP/H. Postnatal ID was defined as ≥ two abnormal iron measures at 9 months. Study groups were pre- and postnatal ID, prenatal ID only, postnatal ID only, and not ID. GLM repeated measure analysis showed a main effect for iron group. The pre- and postnatal ID group had negative asymmetry scores, reflecting right frontal EEG asymmetry (mean ± SE: -.18 ± .07) versus prenatal ID only (.00 ± .04), postnatal ID only (.03 ± .04), and not ID (.02 ± .04). Thus, ID at both birth and 9 months was associated with right frontal EEG asymmetry, a neural correlate of behavioral withdrawal and negative emotions.

Sleep Hygiene Practices and Bedtime Resistance in Low-Income Preschoolers: Does Temperament Matter?

This study examined sleep hygiene practices and bedtime resistance and tested whether associations differed by child temperament. Parents of Head Start preschoolers (n = 374, 56% non-Hispanic white) completed the Going to Bed subscale of the Children's Sleep-Wake Scale (GTB; higher score reflects less bedtime resistance), Children's Sleep Hygiene Scale (CSHS; higher score reflects better sleep hygiene), and Child Behavior Questionnaire (Anger, Activity, Impulsivity subscales indicated difficult temperament). Monte Carlo simulation adjusted for demographic covariates tested associations of CSHS with GTB in children with more- vs. less-difficult temperaments. Children with more- vs. less-difficult temperaments experienced worse sleep hygiene (p < .0001) and had more bedtime resistance (p < .0001). Among children with more difficult temperaments, better sleep hygiene was linearly associated with less bedtime resistance (β = 1.28, 95% CI 0.77, 1.78). Among children with less difficult temperaments, the association followed a piecewise linear trend: sleep hygiene was not associated with bedtime resistance when CSHS scores were < 4.1 (β = 0.15, 95% CI -4.87, 3.13), but for CSHS scores ≥ 4.1, an increase in CSHS was associated with lower bedtime resistance (β = 1.33, 95% CI 1.00, 1.79). Consistent sleep hygiene is associated with less bedtime resistance and may be helpful in reducing bedtime resistance among children with more difficult temperaments.

Higher weight status of only and last-born children. Maternal feeding and child eating behaviors as underlying processes among 4-8 year olds

Birth order has been associated with childhood obesity. The objective of this cross-sectional study was to examine maternal feeding and child eating behaviors as underlying processes for increased weight status of only children and youngest siblings. Participants included 274 low-income 4-8 year old children and their mothers. The dyads completed a videotaped laboratory mealtime observation. Mothers completed the Caregiver's Feeding Styles Questionnaire and the Children's Eating Behavior Questionnaire. Child weight and height were measured using standardized procedures. Path analysis was used to examine associations of birth order, maternal feeding behavior, child eating behavior, and child overweight/obese status. The association between only child status and greater likelihood of overweight/obesity was fully mediated by higher maternal Verbal Discouragement to eat and lower maternal Praise (all p values < 0.05). The association between youngest sibling status and greater likelihood of overweight/obesity was partially mediated by lower maternal Praise and lower child Food Fussiness (all p values < 0.05). Results provide support for our hypothesis that maternal control and support and child food acceptance are underlying pathways for the association between birth order and weight status. Future findings can help inform family-based programs by guiding family counseling and tailoring of recommendations for family mealtime interactions.