763 research outputs found
Early-life Phthalate Exposures and Adolescent Obesity and Cardiometabolic Health
Background: Phthalates may act as metabolic disruptors, altering body composition and glucose and lipid metabolism. Phthalate exposure is ubiquitous among pregnant women and young children who may be more susceptible to adverse health effects. Previous studies are primarily cross-sectional or do not evaluate cardiometabolic outcomes during adolescence.
Objectives: Investigate associations of repeated urinary phthalate metabolite concentrations during gestation and childhood with 1) body composition, 2) insulin resistance, and 3) lipid levels at 12 years of age.
Methods: We used data from a prospective pregnancy and birth cohort that enrolled pregnant women from Cincinnati, OH from 2003-2006. We measured nine phthalate metabolites in spot urine samples collected twice from mothers during pregnancy and up to seven times from children at 1, 2, 3, 4, 5, 8, and 12 years. At age 12 years, we assessed: 1) fat and lean mass of the whole body, android and gynoid sub regions, and visceral fat area with dual x-ray absorptiometry, and calculated android to gynoid %fat ratio and age- and sex-standardized fat and lean mass index z-scores (N=206), 2) insulin and glucose from fasting serum samples and calculated homeostatic model assessment of insulin resistance (HOMA-IR) (N=183), and 3) triglycerides, high-density (HDL), and low-density (LDL) lipoprotein cholesterol in fasting serum samples (N=183). Using a multiple informant model, we estimated covariate-adjusted associations between urinary phthalate biomarker concentrations at each time period and outcomes at age 12 years.
Results: In Specific Aim 1, prenatal and later childhood urinary concentrations of mono-n-butyl (MnBP), mono-isobutyl (MiBP), and mono-benzyl (MBzP) phthalate were associated with lower whole-body fat and lean body mass index z-scores. In Specific Aim 2, most early-life phthalate biomarkers were not associated with 12-year measures of insulin resistance. In Specific Aim 3, some urinary phthalate biomarkers, particularly low-molecular weight phthalates, were inversely associated with lipid levels at age 12 years.
Conclusions: Prenatal and childhood phthalate exposures may be associated with body composition, particularly lean mass, and lipid levels at 12-years age, with exposure-period and sex-specific differences
Prenatal urinary triclosan concentrations and child neurobehavior
Background: Exposure to triclosan, an antimicrobial chemical, is ubiquitous among pregnant women and may
reduce thyroid hormone levels that are important for fetal neurodevelopment. Few studies have examined the
association between prenatal triclosan exposure and children's neurobehavior.
Objective: We investigated the relationship of prenatal urinary triclosan concentrations with children's behavior
and cognitive abilities at age three years in a prospective pregnancy and birth cohort in Canada.
Methods: We measured triclosan in urine samples collected at ~12 weeks of gestation in 794 Canadian women
enrolled in a prospective pregnancy and birth cohort study (MIREC) from 2008 to 2011. Around age 3 years, we
assessed children's cognitive abilities using the Wechsler Primary and Preschool Scale of Intelligence-III (WPPSIIII), and two scales of the Behavior Rating Inventory of Executive Function-Preschool (BRIEF-P). Parents reported children's problem and reciprocal social behaviors using the Behavior Assessment System for Children-2
(BASC-2) and Social Responsiveness Scale-2 (SRS-2), respectively.
Results: After adjusting for confounders using multivariable linear regression, triclosan was not associated with
most of the 30 examined neurobehavioral scales. Each 10-fold increase in triclosan was associated with better
WPPSI-III picture completion scores (β: 0.2; 95% CI: 0,0.5) and BASC-2 externalizing (β: â0.5; 95% CI: â1.1, 0)
and hyperactivity (β: â0.6; 95% CI: â1.2, â0.1) scores, suggesting less externalizing and hyperactive behaviors. Child sex did not modify these associations.
Conclusions: In this cohort, urinary triclosan concentrations measured once in early pregnancy were not associated with most assessed aspects of neurobehavior and weakly associated with a few others, but not in the
hypothesized direction
Upper Limits on a Stochastic Background of Gravitational Waves
The Laser Interferometer Gravitational-Wave Observatory has performed a third science run with much improved sensitivities of all three interferometers. We present an analysis of approximately 200 hours of data acquired during this run, used to search for a stochastic background of gravitational radiation. We place upper bounds on the energy density stored as gravitational radiation for three different spectral power laws. For the flat spectrum, our limit of Ί_0<8.4Ă10^(-4) in the 69â156 Hz band is ~10^5 times lower than the previous result in this frequency range
Search for Gravitational-wave Inspiral Signals Associated with Short Gamma-ray Bursts During LIGO's Fifth and Virgo's First Science Run
Progenitor scenarios for short gamma-ray bursts (short GRBs) include coalescenses of two neutron stars or a neutron star and black hole, which would necessarily be accompanied by the emission of strong gravitational waves. We present a search for these known gravitational-wave signatures in temporal and directional coincidence with 22 GRBs that had sufficient gravitational-wave data available in multiple instruments during LIGO's fifth science run, S5, and Virgo's first science run, VSR1. We find no statistically significant gravitational-wave candidates within a [ â 5, + 1) s window around the trigger time of any GRB. Using the Wilcoxon-Mann-Whitney U-test, we find no evidence for an excess of weak gravitational-wave signals in our sample of GRBs. We exclude neutron star-black hole progenitors to a median 90% confidence exclusion distance of 6.7 Mpc
First search for gravitational waves from the youngest known neutron star
We present a search for periodic gravitational waves from the neutron star in the supernova remnant Cassiopeia
A. The search coherently analyzes data in a 12 day interval taken from the fifth science run of the Laser
Interferometer Gravitational-Wave Observatory. It searches gravitational-wave frequencies from 100 to 300 Hz
and covers a wide range of first and second frequency derivatives appropriate for the age of the remnant and
for different spin-down mechanisms. No gravitational-wave signal was detected. Within the range of search
frequencies, we set 95% confidence upper limits of (0.7â1.2) Ă 10^(â24) on the intrinsic gravitational-wave
strain, (0.4â4) Ă 10^(â4) on the equatorial ellipticity of the neutron star, and 0.005â0.14 on the amplitude of
r-mode oscillations of the neutron star. These direct upper limits beat indirect limits derived from energy
conservation and enter the range of theoretical predictions involving crystalline exotic matter or runaway r-modes.
This paper is also the first gravitational-wave search to present upper limits on the r-mode amplitude
- âŚ