Characterization of fetal exposure to multiple metals among an urban population: A case study of New York City.

INTRODUCTION: Metals and metalloids are ubiquitous and persistent in urban areas and are generally released into the environment as mixtures. OBJECTIVES: The purpose of this study was to establish baseline concentrations of selected elements in meconium samples among a large urban population in the US and understand the spatial variability in concentrations. The association of metal mixtures on birth weight was also assessed. METHODS: This cross-sectional study was conducted across five public hospitals located in New York City, NY (NYC) in four boroughs. We collected meconium sample from 116 infants during the first 24 h after delivery and quantified 11 metals using ICP-MS. Principal component analysis was used to determine metal mixtures and their association with birth weight. Spatial hot spots of each metal were calculated using the Getis-Ord (GI*). RESULTS: Essential elements were detected in all samples with Zn in the greatest abundance (median = 274.5 µg/g) and Mo in the least (median = 0.1845 µg/g). Pb was detected in all but two samples (median = 0.0222 µg/g), while Cd levels were detected in approximately half of the samples (median = 0.0019 µg/g). Co-located hot spots were detected for Cu, Zn, and Fe in southeast Brooklyn; Cd, Cr, and Ni in eastern Queens; and Al and Mo in south Queens. There was a significant inverse relationship between Pb concentrations (beta = -1935.7; p = 0.006) and the mixture of Cr, Cu, Mo, Zn (beta = -157.7; p = 0.045) and birth weight. CONCLUSIONS: Our findings indicate that meconium is an effective biomarker for measuring metal exposures among an urban population. We were able to quantify detectable levels of ten of the eleven metals measured in the study and characterize nutritionally necessary trace elements and metals derived from anthropogenic sources without biologic need in a cohort of NYC newborns. Further research needs to establish the change point from necessary to toxic, for the essential elements.

Early Postnatal Growth in a Subset of Convalescing Extremely-Low-Birth-Weight Neonates: Approximating the "Index Fetus" Ex Utero.

OBJECTIVES: The aim of the study was to evaluate whether a subset of noncritically ill, convalescing extremely-low-birth-weight neonates who were managed using a standardized nutritional protocol could achieve the growth rate of the index fetus. We hypothesized that an aggressive nutritional protocol applied to noncritically ill, convalescing premature neonates could achieve the growth rate of the index fetus. METHODS: This was a retrospective review of a subset of 21 premature neonates defined by 4 criteria: inborn or transferred-in within 24 hours of birth, gestational age < 30 weeks and birth weight ≤1000 g, hospitalized >35 postnatal days, and discharged between 34 and 42 weeks postconceptual age. Optimal growth at discharge was defined as weight and head circumference >10th percentile compared with comparable gestational age fetal parameters. RESULTS: Protein intake of ≥1.4 g ·â€Škg ·â€Šday and energy ≥30 kcal ·â€Škg ·â€Šday were provided as of the first postnatal day. Proteins ≥3 g ·â€Škg ·â€Šday and >80 kcal ·â€Škg ·â€Šday were established ≥10th postnatal day. Birth weight was regained by postnatal day 10 ±â€Š5 day (mean + standard deviation). Nutrition was predominantly enteral (ie, >50% of all calories) after the 11th postnatal day. At discharge, 71% (15/21) by weight and 76% (16/21) by head circumference were >10th percentile. After 30 weeks postconceptual age, the cohort exceeded the weight gain rate (g/wk) of a 10th-percentile fetus. CONCLUSIONS: In a selected subset of noncritically ill, convalescing extremely-low-birth-weight neonates, after a brief period of unavoidable postnatal weight loss and body water adjustment, adequate nutrition from birth can enable a more homeostatic pattern of growth that approximates growth of the index fetus.