Incorporating missingness for estimation of marginal regression models with multiple source predictors

Braun

et al. 2017

Environmental Research

Polybrominated diphenyl ethers (PBDEs) are associated with impaired visual spatial abilities in toxicological studies, but no epidemiologic study has investigated PBDEs and visual spatial abilities in children. The Health Outcomes and Measures of the Environment Study, a prospective birth cohort (2003–2006, Cincinnati, OH), was used to examine prenatal and childhood PBDEs and visual spatial abilities in 199 children. PBDEs were measured at 16±3 weeks gestation and at 1, 2, 3, 5, and 8 years using gas chromatography/isotope dilution high-resolution mass spectrometry. We used the Virtual Morris Water Maze to measure visual spatial abilities at 8 years. In covariate-adjusted models, 10-fold increases in BDE-47, −99, and −100 at 5 years were associated with shorter completion times by 5.2 (95% Confidence Interval [CI] −9.3, −1.1), 4.5 (95% CI −8.1, −0.9), and 4.7 seconds (95% CI −9.0, −0.3), respectively. However, children with higher BDE-153 at 3 years had longer completion times (β=5.4 seconds, 95% CI −0.3, 11.1). Prenatal PBDEs were associated with improved visual spatial memory retention, with children spending a higher percentage of their search path in the correct quadrant. Child sex modified some associations between PBDEs and visual spatial learning. Longer path lengths were observed among males with increased BDE-47 at 2 and 3 years, while females had shorter paths. In conclusion, prenatal and postnatal BDE-28, −47, −99, and −100 at 5 and 8 years were associated with improved visual spatial abilities, whereas a pattern of impairments in visual spatial learning was noted with early childhood BDE-153 concentrations.

Section: Methodsmentioning

confidence: 99%

Prenatal and postnatal polybrominated diphenyl ether exposure and visual spatial abilities in children

Braun

et al. 2017

Environmental Research

“…We investigated associations between log 10 -transformed child serum PBDEs and FSIQ and Externalizing Problems at 8 years with multiple informant models (Horton et al, 1999; Litman et al, 2007), which are non-standard versions of generalized estimating equations that allow for repeated environmental chemical measurements (Sanchez et al, 2011). This method allows us to identify windows of susceptibility for PBDE neurotoxicity by including interaction terms between child age and PBDE concentrations.…”

Section: Methodsmentioning

confidence: 99%

Childhood polybrominated diphenyl ether (PBDE) exposure and neurobehavior in children at 8 years

Xie

et al. 2017

Environmental Research

Background Prenatal polybrominated diphenyl ether (PBDE) exposure has been associated with decrements in IQ and increased attention deficit/hyperactivity disorder related behaviors in children; however, data are limited for the role of postnatal exposures. Objectives We investigated the association between a series of childhood PBDE concentrations and Full-Scale Intelligence Quotient (FSIQ) and externalizing problems at 8 years. Methods We used data from 208 children in the Health Outcomes and Measures of the Environment (HOME) Study, a prospective pregnancy and birth cohort. Child serum PBDEs were measured at 1, 2, 3, 5, and 8 years; missing serum PBDE concentrations were estimated via multiple imputation. The Wechsler Intelligence Scales for Children-IV and the Behavior Assessment System for Children-2 was used to assess intelligence and externalizing behavior, respectively, in children at 8 years. We used multiple informant models to estimate associations between repeated lipid-adjusted PBDEs and child neurobehavior and to test for windows of susceptibility. Results Postnatal exposure to PBDE congeners (-28, -47, -99, -100, and -153) at multiple ages was inversely associated with FSIQ at 8 years. For instance, a 10-fold increase in BDE-153 concentrations at 2, 3, 5, and 8 years were all related to lower FSIQ at age 8 (β for 3 years: −7.7-points, 95% CI −12.5, −2.9; β for 8 years: −5.6-points, 95% CI −10.8, −0.4). Multiple PBDE congeners at 8 years were associated with increased hyperactivity and aggressive behaviors at 8 years. Conclusions Postnatal PBDE exposure was associated with decrements in FSIQ and increases in hyperactivity and aggressive behaviors.

“…Multiple informant models were used to estimate βs and 95% confidence intervals (CIs) between log 10 -transformed lipid-adjusted prenatal and postnatal PBDE concentrations (BDE-28, −47, −99, −100, −153, and ΣPBDEs) and continuous CPT-II measures at 8 years in each of the 100 imputed datasets (Horton et al, 1999; Litman et al, 2007). These models allow for repeated PBDE concentrations throughout childhood to be included within one model and therefore allowed us to examine PBDE neurotoxicity at different exposure time points, spanning from in utero to school-age.…”

Section: Methodsmentioning

confidence: 99%

Prenatal and postnatal polybrominated diphenyl ether (PBDE) exposure and measures of inattention and impulsivity in children

Neurotoxicology and Teratology

Poston

et al. 2017

Exposure to polybrominated diphenyl ethers (PBDEs) during fetal development may be associated with deficits in attention and impulse control. However, studies examining postnatal PBDE exposures and inattention and impulsivity have been inconsistent. Using data from 214 children in the Health Outcomes and Measures of the Environment (HOME) Study, a prospective pregnancy and birth cohort with enrollment from 2003–2006 in the Greater Cincinnati Area, we investigated the relationship of both prenatal and postnatal PBDE exposures with attention and impulse control. Serum PBDEs were measured at 16±3 weeks of gestation and during childhood at 1, 2, 3, 5, and 8 years. We assessed children’s attention and impulse control using the Conners’ Continuous Performance Test-Second Edition (CPT-II) at 8 years. We used multiple informant models to estimate associations of repeated PBDE measures with inattention and impulsivity. There was a pattern of associations between PBDEs and poorer performance on CPT-II measures of attention. For BDE-153, adverse associations extended to exposures at preschool and kindergarten ages; ten-fold increases in exposure were associated with higher omission errors (BDE-153 at 3 years: β=4.0 [95% CI: −2.4, 10.4]; at 5 years: β=4.6 [95% CI: −2.8, 12.0]; at 8 years: β=4.1 [95% CI: −3.4, 11.5]). Longer hit reaction times, indicated by the exponential part of the hit reaction curve, were also observed with 10-fold increases in BDE-153 during the prenatal period and throughout childhood (Prenatal: β=15.0 milliseconds (ms) [95% CI: −15.8, 45.8]; 5 years: β=20.6 ms [95% CI: −20.8, 61.9]; 8 years: β=28.6 ms [95% CI: −12.1, 69.4]). Significant impairment in discriminability, as indicated by detectability (d′), between targets and non-targets was also noted with 5 and 8-year PBDE concentrations. Associations between PBDEs and inattention significantly differed by child sex, with males performing more poorly than females with regard to omission errors and measures of reaction times. Collectively, these results do not strongly support that PBDEs are associated with poorer impulse and attention control among 8 year old children. However, there may be a possible relationship between prenatal and concurrent PBDEs and inattention, which requires additional research.