Organochlorines are environmentally persistent contaminants that readily cross the placenta, posing a potential risk to the developing fetus. Evidence for neurodevelopmental effects at low levels of ...these compounds is growing, though few studies have focused on behavioral outcomes. The authors investigated the association between prenatal polychlorinated biphenyl (PCB) and p,p′-dichlorodiphenyl dichloroethylene (p,p′-DDE) levels and behaviors associated with attention deficit hyperactivity disorder (ADHD), measured with the Conners’ Rating Scale for Teachers (CRS-T), in a cohort of 607 children aged 7–11 years (median age, 8.2 years) born in 1993–1998 to mothers residing near a PCB-contaminated harbor in New Bedford, Massachusetts. The median umbilical cord serum level of the sum of 4 prevalent PCB congeners (118, 138, 153, and 180) was 0.19 ng/g serum (range, 0.01–4.41 ng/g serum). The authors found higher risk for ADHD-like behaviors assessed with the CRS-T at higher levels of PCBs and p,p′-DDE. For example, the authors found higher risk of atypical behavior on the Conners’ ADHD Index for the highest quartile of the sum of 4 PCB congeners versus the lowest quartile (risk ratio = 1.76, 95% confidence interval: 1.06, 2.92) and a similar relation for p,p′-DDE. These results support an association between low-level prenatal organochlorine exposure and ADHD-like behaviors in childhood.
•No studies have explored peripubertal serum organochlorine pesticides and semen parameters.•Selected peripubertal organochlorine pesticides were related to lower volume and progressive motility.•No ...associations were found with sperm concentration and total count.
Epidemiologic literature on the relation of organochlorine pesticides (OCPs) with semen quality among adult men has been inconclusive, and no studies have prospectively explored the association between peripubertal serum OCPs and semen parameters in young men.
To evaluate prospective associations of peripubertal serum concentrations of hexachlorobenzene (HCB), β-hexachlorocylohexane (β-HCH), and p,p′-dichlorodiphenyldichloroethylene (p,p′-DDE) with semen parameters among young Russian men.
This prospective cohort study included 152 young men who enrolled in the Russian Children’s Study (2003–2005) at age 8–9 years and were followed annually until young adulthood. HCB, β-HCH, and p,p′-DDE concentrations were measured at the CDC by mass spectrometry in serum collected at enrollment. Between 18 and 23 years, semen samples (n = 298) were provided for analysis of volume, concentration, and progressive motility; we also calculated total sperm count and total progressive motile count. Linear mixed models were used to examine the longitudinal associations of quartiles of serum HCB, β-HCH and p,p′-DDE with semen parameters, adjusting for total serum lipids, body mass index, smoking, abstinence time and baseline dietary macronutrient intake.
Lipid-adjusted medians (IQR) for serum HCB, βHCH and p,ṕ-DDE, respectively, were 150 ng/g lipid (102–243), 172 ng/g lipid (120–257) and 275 ng/g lipid (190–465). In adjusted models, we observed lower ejaculated volume with higher serum concentrations of HCB and βHCH, along with reduced progressive motility with higher concentrations of βHCH andp,ṕ-DDE. Men in the highest quartile of serum HCB had a mean (95% Confidence Interval, CI) ejaculated volume of 2.25 mL (1.89, 2.60), as compared to those in the lowest quartile with a mean (95% CI) of 2.97 mL (2.46, 3.49) (p = 0.03). Also, men in the highest quartile of serum p,ṕ-DDE had a mean (95% CI) progressive motility of 51.1% (48.6, 53.7), as compared to those in the lowest quartile with a mean (95% CI) of 55.1% (51.7, 58.5) (p = 0.07).
In this longitudinal Russian cohort study, peripubertal serum concentrations of selected OCPs were associated with lower ejaculated volume and progressive motility highlighting the importance of the peripubertal window when evaluating chemical exposures in relation to semen quality.
Studies suggest that exposure to endocrine disrupting chemicals (EDCs), including phthalates, phenols, and parabens may influence childhood behavior, but the relationship during adolescence has not ...been assessed.
We investigated the association between urinary biomarker concentrations of potential EDCs, including some phthalate and bisphenol A replacement chemicals, and behavior in adolescents.
Participants were from the New Bedford Cohort (NBC), a prospective birth cohort of residents near the New Bedford Harbor Superfund site in Massachusetts. We measured urinary concentrations of 16 phthalate metabolites or replacements, 8 phenols, and 4 parabens in 205 NBC adolescents and estimated associations between select EDCs and adolescent behavior assessed with the Behavior Assessment System for Children, Second Edition -Teacher Rating Scale (BASC-2). Of note, up to 32 of the 205 in our assessment had missing outcome information imputed.
Increased urinary concentrations of the sum of 11 antiandrogenic phthalate metabolites were associated with an increase in maladaptive behaviors (Externalizing Behavior, Behavioral Symptoms Index, and Developmental Social Disorders or DSD), and a decrease in Adaptive Skills. For example, a doubling of urinary concentrations of antiandrogenic phthalate metabolites was associated with an increased risk of Externalizing Behavior (RR=1.04; 95% CI: 1.01–1.08). While associations were generally stronger in males, sex differences were not statistically significant. Urine concentrations of phenols and parabens were not associated with adverse behavior.
Our findings support the importance of exposure to antiandrogenic phthalates during adolescence as a potential correlate of maladaptive behaviors including Externalizing Behavior, DSD behaviors, and decrements in Adaptive Skills.
•Antiandrogenic phthalate exposure in teens correlated with maladaptive behavior.•Suggestive evidence of stronger phthalate exposure-behavior correlates in males.•No evidence that phenol exposure in teens correlated with maladaptive behavior.
Background: We previously reported associations between organochlorines and behaviors related to attention deficit hyperactivity disorder among boys and girls at 8 years of age using a teacher's ...rating scale for a birth cohort in New Bedford, Massachusetts (USA). Objectives: Our goal was to corroborate these findings using neuropsychological measures of inattentive and impulsive behaviors. Methods: We investigated the association between cord serum polychlorinated biphenyls (PCBs) and p,p'-dichlorodiphenyl dichloroethylene (p,p'-DDE) and attention and impulse control using a Continuous Performance Test (CPT) and components of the Wechsler Intelligence Scale for Children, 3rd edition (WISC-III). Participants came from a prospective cohort of children born during 1993–1998 to mothers residing near a PCB-contaminated harbor in New Bedford. Median (range) cord serum levels for the sum of four prevalent PCBs congeners 118, 138, 153, and 180 (ΣPCB₄) and p,p'-DDE were 0.19 (0.01–2.59) and 0.31 (0–14.93) ng/g serum, respectively. Results: We detected associations between PCBs and neuropsychological deficits for 578 and 584 children with CPT and WISC-III measures, respectively, but only among boys. For example, boys with higher exposure to ΣPCB₄ had a higher rate of CPT errors of omission rate ratio for the exposure interquartile range (IQR) = 1.12; 95% confidence interval (CI): 0.98, 1.27 and slower WISC-III Processing Speed (change in score for the IQR = –2.0; 95% CI: –3.5, –0.4). Weaker associations were found for p,p'-DDE. For girls, associations were in the opposite direction for the CPT and null for the WISC-III. Conclusions: These results support an association between organochlorines (mainly PCBs) and neuropsychological measures of attention among boys only. Sex-specific effects should be considered in studies of organochlorines and neurodevelopment.
Rice is an important dietary source for methylmercury; however, rice does not contain the same beneficial nutrients as fish. Our main objective was to assess associations of prenatal methylmercury ...exposure through rice ingestion with child neurodevelopment in rural China.
Eligible peripartum women were enrolled (n = 391), provided peripartum hair samples, and children's neurodevelopment was assessed at 12 months (n = 264, 68%) and 36 months (n = 190, 48%) using the Bayley Scales of Infant Development, 2nd Edition, including the Mental Developmental Index (MDI) and the Psychomotor Developmental Index (PDI). Associations between prenatal methylmercury exposure during the third trimester log
maternal hair total mercury (THg) and child's neurodevelopment were assessed using linear mixed models for repeated measures.
In adjusted models, a doubling in maternal hair THg corresponded to a 1.3-point decrement in the MDI score 95% confidence interval (CI): - 2.6, - 0.14, and a 1.2-point decrement in the PDI score (95% CI: - 2.6, 0.14). Overall, adverse associations between maternal hair THg and MDI scores attenuated over time. However, associations were robust and stable over time among children whose primary caregiver was their parent(s). During the study follow-up, an increasing proportion of children were raised by grandparents (12 months: 9% versus 36 months: 27%), a trend associated with rural-to-urban parental migration for work.
For young children living in rural China, a biomarker of prenatal methylmercury exposure was associated with decrements in cognitive function assessed between 12 and 36 months of age. Changes in the family structure over the study follow-up time interval potentially impacted children's sensitivity to prenatal methylmercury exposure.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Prenatal exposures are associated with childhood asthma, and risk may increase with simultaneous exposures. Pregnant women living in lower-income communities tend to have elevated exposures to a ...range of potential asthma risk factors, which may interact in complex ways. We examined the association between prenatal exposures and the risk of childhood asthma acute care clinical encounters (hospitalization, emergency department visit, observational stay) using conditional logistic regression with a multivariable smooth to model the interaction between continuous variables, adjusted for maternal characteristics, and stratified by sex. All births near the New Bedford Harbor (NBH) Superfund site (2000-2006) were followed through 2011 using the Massachusetts Pregnancy to Early Life Longitudinal data system to identify children ages 5-11 with asthma acute care clinical encounters (265 cases among 7,787 with follow-up). Hazard ratios (HRs) were higher for children living closer to the NBH with higher cord blood Pb levels than children living further away from the NBH with lower Pb levels (P<0.001). HRs were highest for girls (HR=4.17, 95% CI: 3.60, 4.82) compared to boys (HR=1.72, 95% CI: 1.46, 2.02). Our results suggest that prenatal Pb exposure in combination with residential proximity to the NBH is associated with childhood asthma acute care clinical encounters.
A link between the gut microbiome and behavior is hypothesized, but most previous studies are cross-sectional or in animal models. The modifying role of host sex is poorly characterized. We aimed to ...identify sex-specific prospective associations between the early-life gut microbiome and preschool-age neurobehavior.
In a prospective cohort, gut microbiome diversity and taxa were estimated with 16S rRNA sequencing at 6 weeks, 1 year, and 2 years. Species and gene pathways were inferred from metagenomic sequencing at 6 weeks and 1 year. When subjects were 3 years old, parents completed the Behavioral Assessment System for Children, second edition (BASC-2). A total of 260 children contributed 523 16S rRNA and 234 metagenomics samples to analysis. Models adjusted for sociodemographic characteristics.
Higher diversity at 6 weeks was associated with better internalizing problems among boys, but not girls β
= -1.86 points/SD Shannon diversity; 95% CI (-3.29, -0.42), p
= 0.01, β
= 0.22 (-1.43, 1.87), p
= 0.8, p
= 0.06. Among other taxa-specific associations, Bifidobacterium at 6 weeks was associated with Adaptive Skills scores in a sex-specific manner. We observed relationships between functional features and BASC-2 scores, including vitamin B6 biosynthesis pathways and better Depression scores.
This study advances our understanding of microbe-host interactions with implications for childhood behavioral health.
This is one of the first studies to examine the early-life microbiome and neurobehavior, and the first to examine prospective sex-specific associations. Infant and early-childhood microbiomes relate to neurobehavior including anxiety, depression, hyperactivity, and social behaviors in a time- and sex-specific manner. Our findings suggest future studies should evaluate whether host sex impacts the relationship between the gut microbiome and behavioral health outcomes.
The hypothesized link between gut bacteria and autism spectrum disorder (ASD) has been explored through animal models and human studies with microbiome assessment after ASD presentation. We aimed to ...prospectively characterize the association between the infant/toddler gut microbiome and ASD-related social behaviors at age 3 years. As part of an ongoing birth cohort gut bacterial diversity, structure, taxa, and function at 6 weeks (n = 166), 1 year (n = 158), 2 years (n = 129), and 3 years (n = 140) were quantified with 16S rRNA gene and shotgun metagenomic sequencing (n = 101 six weeks, n = 103 one year). ASD-related social behavior was assessed at age 3 years using Social Responsiveness Scale (SRS-2) T-scores. Covariate-adjusted linear and permutation-based models were implemented. Microbiome structure at 1 year was associated with SRS-2 total T-scores (p = 0.01). Several taxa at 1, 2, and 3 years were associated with SRS-2 performance, including many in the Lachnospiraceae family. Higher relative abundance of Adlercreutzia equolifaciens and Ruminococcus torques at 1 year related to poorer SRS-2 performance. Two functional pathways, L-ornithine and vitamin B6 biosynthesis, were associated with better social skills at 3 years. Our results support potential associations between early-childhood gut microbiome and social behaviors. Future mechanistic studies are warranted to pinpoint sensitive targets for intervention.
Higher blood lead levels (BLLs) have been linked to neurologic deficits and impaired growth, but few studies have evaluated their association with timing of sexual maturity or pubertal progression in ...boys.
In a longitudinal cohort of Russian boys enrolled at age 8–9 and followed to adulthood, BLLs were measured at study entry, and pubertal staging (genitalia and pubic hair) and testicular volume (TV) measurements were obtained annually. We used interval-censored regression models to estimate differences between boys with higher BLL (≥5 μg/dL) and lower BLL in mean ages at sexual maturity (genitalia stage 5, pubic hair stage 5, or TV ≥ 20 mL) and duration of pubertal progression (onset to maturity), adjusting for potential confounders. Mediation analyses were conducted to quantify the percent of lead's effect attributable to its association with reduced somatic growth.
Among 481 evaluable boys, 28% had BLL ≥ 5 μg/dL. Adjusted mean ages at sexual maturity were 14.7 years for genitalia, 16.1 for pubic hair, and 13.9 for TV. In adjusted models, boys with BLLs ≥5 μg/dL had later maturity than those with lower levels by 4–5 months depending on pubertal indicator. In mediation analyses, height and body mass index at age 11 accounted for 40–71% of the shift in age at maturity for boys with higher compared to lower BLLs. Higher BLLs were not associated with pace of pubertal progression.
Higher lead levels were associated with later attainment of sexual maturity in males, but not with the duration of pubertal progression. A high proportion of the delay in sexual maturity for boys with higher as compared to lower BLL was shown to be attributable to mediating effects of BLL on reduced growth.
•Higher blood lead has been linked to impaired growth and delayed pubertal onset.•Few studies have addressed the effects of blood lead on age at male sexual maturity.•We found significant delays in maturity among Russian boys with higher lead levels.•This delay was partly due to reduced growth among boys with higher lead levels.•Higher blood lead did not appear to slow pubertal progression.
Although prenatal chemical exposures influence neurobehavior, joint exposures are not well explored as risk factors for internalizing disorders through adolescence.
To evaluate associations of ...prenatal organochlorine and metal exposures, considered individually and as a mixture, with mid-childhood and adolescent internalizing symptoms.
Participants were 468 children from a prospective cohort recruited at birth (1993–1998) in New Bedford, Massachusetts. Organochlorines (hexachlorobenzene, p,p'-dichlorodiphenyl dichloroethylene, polychlorinated biphenyls) and metals (lead, manganese) were analyzed in cord blood. Internalizing symptoms (anxiety, depressive, somatic) were assessed via multiple informants on the Conners' Rating Scale (CRS) at 8-years and Behavior Assessment System for Children, Second Edition (BASC-2) at 15-years; higher T-scores indicate greater symptoms. Overall and sex-specific covariate-adjusted associations were evaluated using Bayesian Kernel Machine Regression (BKMR) and five-chemical linear regression models.
The cohort was socioeconomically diverse (35% household income <$20,000; 55% maternal ≤ high school education at birth). Most chemical concentrations were consistent with background levels e.g., median (range) cord blood lead: 1.1 (0–9.4) μg/dL. BKMR suggested linear associations and no interactions between chemicals. The overall mixture was positively associated with Conners’ Parent Rating Scale (CPRS) and BASC-2 Self Report of Personality (SRP) anxiety and depressive symptoms, and negatively with somatic symptoms. Prenatal lead was positively associated with adolescent anxiety symptoms 1.56 (95% CI: 0.50, 2.61) BASC-2 SRP Anxiety score increase per doubling lead. For CRPS and BASC-2 SRP, a doubling of cord blood manganese was positively associated with internalizing symptoms for girls e.g., 3.26 (95% CI: 0.27, 6.25) BASC-2 SRP Depression score increase, but not boys. Organochlorine exposures were not adversely associated with internalizing symptoms.
Low-level prenatal lead exposure was positively associated with adolescent anxiety symptoms, and prenatal manganese exposure was positively associated with internalizing symptoms for girls from mid-childhood through adolescence. In utero neurotoxicant metal exposures may contribute to the emergence of anxiety and depression.
•Examined prenatal chemicals and internalizing symptoms in childhood/adolescence.•Prenatal lead exposure positively associated with adolescent anxiety symptoms.•Persistent association of prenatal manganese and internalizing symptoms for girls.•Prenatal organochlorines not adversely associated with internalizing symptoms.
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