Prenatal exposure to polybrominated diphenyl ethers and child attention problems at 3-7 years.

INTRODUCTION: Polybrominated diphenyl ethers (PBDEs) comprise a class of halogenated compounds used extensively as flame retardant chemicals in consumer products resulting in nearly ubiquitous human exposure. Mounting evidence suggests that PBDEs are developmental neurotoxicants; however, associations between early life exposure and child behavior have been largely limited to a single developmental time point. METHODS: The study population consists primarily of white, black and Chinese women who were pregnant on 11 September 2001 and delivered at 1 of 3 downtown New York City hospitals. Maternal-child pairs were followed through age 7 years. Cord blood was collected at delivery and PBDE plasma levels for 210 samples were analyzed by the U.S. Centers for Disease Control and Prevention. The Child Behavior Checklist, a validated maternal-report instrument used for assessing child behavior, was administered annually between the ages of 3 and 7 years. We analyzed the association between natural log-transformed and dichotomized (low vs. high) PBDEs and attention problems using multivariable adjusted negative binomial regression. RESULTS: We detected 4 PBDE congeners in more than 50% of samples, with concentrations highest for BDE-47 (median±IQR: 11.2±19.6 ng/g). In adjusted analyses, we detected associations between BDE-47 (1.21, 95% CI: 1.00, 1.47), and BDE-153 (1.18, 95% CI: 1.00, 1.39) in cord plasma and increased attention problems among children at age 4 (n=109) but not 6 (n=107) years. CONCLUSIONS: Our findings demonstrate a positive trend between prenatal PBDE exposure and early childhood attention problems, and are consistent with previous research reporting associations between prenatal PBDE exposure and disrupted child behaviors.

The Pattern of Gestational Weight Gain is Associated with Changes in Maternal Body Composition and Neonatal Size.

OBJECTIVES: The pattern of gestational weight gain (GWG) reflects general nutrient availability to support growing fetal and maternal compartments and may contribute to later health, but how it relates to changes in maternal body composition is unknown. We evaluated how the pattern of GWG related to changes in maternal body composition during pregnancy and infant size at birth. METHODS: A prospective, multi-ethnic cohort of 156 pregnant women and their infants was studied in New York City. Prenatal weights were used to estimate total and rate (kg/week) of GWG by trimester. Linear regression models evaluated the association between trimester-specific GWG group (low, medium, high GWG) [total (low ≤25, high ≥75 percentile) or rate (defined by tertiles)] and infant weight, length and maternal body composition changes from 14 to 37 weeks, adjusting for covariates. RESULTS: Compared to the low gain group, medium/high rate of GWG in the second trimester and high rate of GWG in the third trimester were associated with larger gains in maternal fat mass (ß range for fat Δ = 2.86-5.29 kg, all p < 0.01). For infant outcomes, high rate of GWG in the second trimester was associated with higher birth weight (ß = 356 g, p = 0.001) and length (ß = 0.85 cm, p = 0.002). First and third trimester GWG were not associated with neonatal size. CONCLUSIONS: The trimester specific pattern and rate of GWG reflect changes in maternal body fat and body water, and are associated with neonatal size, which supports the importance of monitoring trimester-specific GWG.

Predictors and consequences of global DNA methylation in cord blood and at three years.

DNA methylation changes have been implicated in many common chronic diseases leading to the hypothesis that environmental and age-related DNA methylation changes within individuals are involved in disease etiology. Few studies have examined DNA methylation changes within an individual over time and all of these studies have been conducted in adults. Here, we aim to characterize how global DNA methylation changes from birth to age three within a longitudinal birth cohort study and to determine whether there are consistent predictors of DNA methylation levels measured three years apart. We measured global DNA methylation in the same children at birth (cord blood) and again at three years of age among 165 children, using an immunoassay. We found that on average, DNA methylation was significantly higher in blood at age 3-years than in cord blood (p<0.01). However, for any individual child, the difference was less than would be expected by chance. We found that pre-pregnancy BMI was negatively predictive of both cord and three-year DNA methylation, even after statistical adjustment to account for the correlation between cord blood and three-year DNA methylation. The biologic implications of small changes in global DNA methylation are unknown. However, the observation that global DNA methylation levels persist within an individual from birth to age three supports the belief that factors that influence global DNA methylation, including pre-pregnancy BMI, may confer long-term effects.

Dynamic energy-balance model predicting gestational weight gain.

BACKGROUND: Gestational weight gains (GWGs) that exceed the 2009 Institute of Medicine recommended ranges increase risk of long-term postpartum weight retention; conversely, GWGs within the recommended ranges are more likely to result in positive maternal and fetal outcomes. Despite this evidence, recent epidemiologic studies have shown that the majority of pregnant women gain outside the target GWG ranges. A mathematical model that predicts GWG and energy intake could provide a clinical tool for setting precise goals during early pregnancy and continuous objective feedback throughout pregnancy. OBJECTIVE: The purpose of this study was to develop and validate a differential equation model for energy balance during pregnancy that predicts GWG that results from changes in energy intakes. DESIGN: A set of prepregnancy BMI-dependent mathematical models that predict GWG were developed by using data from a longitudinal study that measured gestational-changes in fat-free mass, fat mass, total body water, and total energy expenditure in 63 subjects. RESULTS: Mathematical models developed for women with low, normal, and high prepregnancy BMI were shown to fit the original data. In 2 independent studies used for validation, model predictions of fat-free mass, fat mass, and total body water matched actual measurements within 1 kg. CONCLUSIONS: Our energy-balance model provides plausible predictions of GWG that results from changes in energy intakes. Because the model was implemented as a Web-based applet, it can be widely used by pregnant women and their health care providers.

Prenatal exposure to PBDEs and neurodevelopment.

BACKGROUND: Polybrominated diphenyl ethers (PBDEs) are widely used flame retardant compounds that are persistent and bioaccumulative and therefore have become ubiquitous environment contaminants. Animal studies suggest that prenatal PBDE exposure may result in adverse neurodevelopmental effects. OBJECTIVE: In a longitudinal cohort initiated after 11 September 2001, including 329 mothers who delivered in one of three hospitals in lower Manhattan, New York, we examined prenatal PBDE exposure and neurodevelopment when their children were 12-48 and 72 months of age. METHODS: We analyzed 210 cord blood specimens for selected PBDE congeners and assessed neurodevelopmental effects in the children at 12-48 and 72 months of age; 118, 117, 114, 104, and 96 children with available cord PBDE measurements were assessed at 12, 24, 36, 48, and 72 months, respectively. We used multivariate regression analyses to evaluate the associations between concentrations of individual PBDE congeners and neurodevelopmental indices. RESULTS: Median cord blood concentrations of PBDE congeners 47, 99, and 100 were 11.2, 3.2, and 1.4 ng/g lipid, respectively. After adjustment for potential confounders, children with higher concentrations of BDEs 47, 99, or 100 scored lower on tests of mental and physical development at 12-48 and 72 months. Associations were significant for 12-month Psychomotor Development Index (BDE-47), 24-month Mental Development Index (MDI) (BDE-47, 99, and 100), 36-month MDI (BDE-100), 48-month full-scale and verbal IQ (BDE-47, 99, and 100) and performance IQ (BDE-100), and 72-month performance IQ (BDE-100). CONCLUSIONS: This epidemiologic study demonstrates neurodevelopmental effects in relation to cord blood PBDE concentrations. Confirmation is needed in other longitudinal studies.

Anthropometry and moderate malnutrition in preschool children.

OBJECTIVE: For years it has been shown that more children die from moderate malnutrition (MM) than severe. Till yet few studies deal specifically with identifying these children. This study attempts to statistically determine the appropriate anthropometric measures and cut-off points for diagnosing moderate malnutrition in preschool children. METHODS: Anthropometric measurements were obtained from 609 preschool children from the cities of Adigrat, Ethiopia; Janampet, India; San Paulo, Brazil. The values were used to determine the sensitivity, specificity, positive predictive value (PPV) and likelihood ratio (LR) of each index studied. The optimum cutoff point for each index was considered to be the cutoff point with the maximum Kappa coefficient for efficiency. The McNemar Test for the significance of changes was used to determine if these findings were in agreement when applied to this data. RESULTS: Weight for height (WFH) at each site had the highest PPV and LR of 4 but was not signficant by the McNemar Test. Mid-upper arm circumference (MUAC) in India had the same PPV (77%) as WFH but a LR of 2. MUAC in India, Brazil and Ethiopia tested significantly for the McNemar Test. The cut-off point for MUAC in India and Brazil was determined to be <15.5 cm in India and Brazil but was <15 cm in Ethiopia. Waist circumference in India tested a significantly PPV of 64%, and a LR of 2. CONCLUSION: These results show that WFH and MUAC could be used with WFA to identify the MM child. The cut-off points for MUAC may vary per location. WC positive data suggests further study is warranted. The McNemar findings yielded significant evidence that statistically determined indicators can be established to identify MM. With further study these methods may prove to be an important component in the efforts to improve child survival.