This survey study examines data from the National Survey of Children's Health to determine which sociodemographic factors might modify the association between neurodevelopmental disorders and being bullied.

Background: Accumulating evidence suggests that prenatal chemical exposure triggers epigenetic modifications that could influence health outcomes later in life. In this study, we investigated whether DNA methylation (DNAm) levels at the glutamate ionotropic receptor NMDA type subunit 2B (GRIN2B) gene underlies the association between prenatal exposure to an endocrine disrupting chemical (EDC), bisphenol F (BPF), and lower cognitive functions in 7-year-old children. Methods: Data from 799 children participating in the Swedish Environmental Longitudinal Mother and child Asthma and allergy (SELMA) pregnancy cohort was analyzed. Prenatal BPF exposure was assessed by measuring BPF levels in maternal urine. At age 7, DNAm of three CpG sites in a regulatory region of the GRIN2B gene was analyzed from buccal swabs using bisulfite-Pyrosequencing. Cognitive functions, including full-scale IQ and four subscales, were evaluated using the Wechsler Intelligence Scale for Children (WISC-IV). Associations between prenatal BPF exposure and GRIN2B DNAm, as well as between GRIN2B DNAm and cognitive functions, were determined using regression models adjusted for potential confounders. Generalized structural equation models (gSEM) were used to evaluate if GRIN2B DNAm mediates the association between prenatal BPF exposure and cognitive functions at 7 years of age. Results: Prenatal BPF exposure was positively associated with GRIN2B DNAm levels at the third CpG site (CpG3), while CpG3 methylation was inversely associated with cognitive test scores. Mediation analyses showed that CpG3 methylation exerted 6–9% of the association between BPF exposure and full-scale IQ, as well as verbal comprehension and perceptual reasoning in boys, while not significant in girls. Conclusions: This study is the first to identify locus-specific DNAm as a mediating factor underlying an epidemiological association between prenatal EDC exposure and cognitive functions in childhood. It also confirms previous findings, that GRIN2B DNAm is responsive to environmental exposures.

Aim

We examined the association between the number of words used at age 2.5 years and deficits in intellectual functioning at age 7 years, in 549 children, and whether such association is confirmed by parental concern about the child's development.

Methods

Parental reports of how many words their children used at age 2.5 years were analysed for the association to intellectual functioning (assessed with Wechsler Intelligence Scale for Children - Fourth Edition,WISC-IV) at age 7 years using linear regression, adjusting for sex, maternal education level, parental IQ and smoking during pregnancy. Parental concern at age 7 years was examined with the Early Symptomatic Syndromes Eliciting Neurodevelopmental Clinical Examinations-Questionnaire (ESSENCE-Q).

Results

Adjusted linear regression showed that use of 50 words or fewer at age 2.5 years, relative to use of more than 50 words, was associated with lower scores of Full-scale IQ (B = 7.27, p = 0.001), verbal comprehension (B = 8.53, p < 0.001), working memory (B = 9.04, p < 0.001) and perceptual reasoning (B = 4.21, p = 0.045), in the WISC-IV, at age 7 years. Parental concern was more common in the group that used 50 words or fewer (Mann-Whitney U test, p = 0.011).

Conclusion

This easily accessible measure of number of words seems to be a valuable marker for intellectual functioning later in life.

DNA methylation (DNAm) profiles in central airway epithelial cells (AECs) may play a key role in pathological processes in asthma. The goal of the current study is to compare the diagnostic performance of DNAm markers across three tissues: AECs, nasal epithelial cells (NECs), and peripheral blood mononuclear cells (PBMCs). Additionally, we focused on the results using the machine learning algorithm in the context of multi-locus effects to evaluate the diagnostic performance of the optimal subset of CpG sites. We obtained 74 subjects with asthma and 41 controls from AECs, 15 subjects with asthma and 14 controls from NECs, 697 subjects with asthma and 97 controls from PBMCs. Epigenome-wide DNA methylation levels in AECs, NECs and PBMCs were measured using the Infinium Human Methylation 450K BeadChip. Overlap analysis across the three different sample sources at the locus and pathway levels were studied to investigate shared or unique pathophysiological processes of asthma across tissues. Using the top 100 asthma-associated methylation markers as classifiers from each dataset, we found that both AEC- and NEC-based DNAm signatures exerted a lower classification error than the PBMC-based DNAm markers (p-value = 0.0002). The area-under-the-curve (AUC) analysis based on out-of-bag errors using the random forest classification algorithm revealed that PBMC-, NEC-, and AEC-based methylation data yielded 31 loci (AUC: 0.87), 8 loci (AUC: 0.99), and 4 loci (AUC: 0.97) from each optimal subset of tissue-specific markers, respectively. We also discovered the locus-locus interaction of DNAm levels of the CDH6 gene and RAPGEF3 gene might interact with each other to jointly predict the risk of asthma - which suggests the pivotal role of cell-cell junction in the pathological changes of asthma. Both AECs and NECs might provide better diagnostic accuracy and efficacy levels than PBMCs. Further research is warranted to evaluate how these tissue-specific DNAm markers classify and predict asthma risk.

Background: Perfluoroalkyl substances (PFASs) are widespread, bioaccumulating, and persistent and show placental transfer. Emerging research indicates associations between prenatal exposure and low birth weight. The aim of this study was to assess the associations between first trimester exposure to PFASs and birth weight (BW) in the Swedish Environmental, Longitudinal, Mother and child, Asthma and allergy (SELMA) study and examine whether associations differ between girls and boys. Methods: Eight PFASs were analyzed in maternal serum (median: 10 weeks of pregnancy). Associations between prenatal PFAS exposure and birth outcomes with BW, BW for gestational age, and birth small for gestational age (SGA) were assessed in 1533 infants, adjusted for potential confounders and stratified by sex. Results: Increased maternal perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), and perfluoroundecanoic acid (PFUnDA) were associated with lower BW, lower BW for gestational age, and SGA birth. Associations were significant only in girls, where prenatal exposure in the upper quartile was associated with a 93–142-g lower BW when compared with that of the lowest quartile exposure. The associations were not mediated by effects on gestational age. Conclusions: We found associations between prenatal exposure for five different PFASs and birth weight, with more pronounced associations in girls than in boys.

A multiple regression model was evaluated to predict pulp and handsheet properties including z-directional tensile strength (z-strength) and Scott bond values. One hypothesis that was central for the model evaluation was that the crill content, as measured with ultraviolet and infrared lights, would improve the statistical models. A chemi-thermomechanical pulp (CTMP) mill designed with two parallel primary refining lines and a reject refiner was the basis for this study, and all process data and pulp samples were gathered from the specific process. Pulp was extracted from the process for an extended period from a position after the latency chest (primary refined pulp) and from the pulp-stream exiting the mill to the board machine (accept pulp). The crill content was positively correlated to the z-strength of the accept pulp, explaining 55% of the variance with a linear regression model with the drill content as the sole predictor. The estimation model of the z-strength of accept pulp was based on a combination of the crill content, freeness, fibril perimeter for longer fibers, and mean kink angle, and resulted in an R-2 of 0.79. When applying cross-validation to determine the predictive model performance, the highest R-2 obtained was 0.67. This latter model included the crill content, fibril perimeter, and mean kink angle as predictors.

Background We are exposed to several chemicals such as persistent organic pollutants (POPs) in our everyday lives. Prior evidence has suggested that POPs may have adverse effects on reproductive function by disrupting hormone synthesis and metabolism. While there is age-related decline of fertility, the use of hormonal combined oral contraceptives (COCs) and its association to return of fertility remains controversial. The goal of this study is to investigate the association between exposure to POPs, both individually and as a mixture, and fecundability measured as time-to-pregnancy (TTP) according to pre-pregnancy use of COCs and age. Methods Using the SELMA (Swedish Environmental Longitudinal Mother and Child, Allergy and Asthma) study, we have identified 818 pregnant women aged 18-43 years (mean 29 years) with data on how long they tried to get pregnant and what was their most recently used contraceptive method. These data were collected at enrollment to the study (median week 10 of pregnancy). Concentrations of 22 POPs and cotinine were analyzed in the blood samples collected at the same time as the questions on TTP and pre-pregnancy use of contraceptive. Analyses were done on the association between POPs exposure and TTP measured as continuous (months) and binary (infertile for those with TTP > 12 months). To study the chemicals individually, Cox regression and logistic regression were used to estimate fecundability ratios (FRs) and odds ratios (ORs), respectively. Weighted quantile sum (WQS) regression was used to investigate the chemicals as a mixture where chemicals of concern were identified above the 7.6% threshold of equal weights. To perform the subgroup analysis, we stratified the sample according to use of COCs as the most recent pre-pregnancy contraception method and age (< 29 years, and >= 29 years). The models were adjusted for parity, regularity of menses, maternal body mass index (BMI) and smoking status, and stratified as described above. Results Prior to stratification, none of the POPs were associated with fecundability while increased exposure to HCB, PCB 74 and 118 had higher odds of infertility. Upon stratification, POP exposure was significantly associated with longer TTP in women aged >= 29 years who did not use COC. Specifically, PCBs 156, 180, 183, and 187 were associated with reduced fecundability while PCBs 99, 153, 156, 180, 183, and 187 had higher odds of infertility. As a mixture, we identified the chemicals of concern for a longer TTP include PCBs 118, 156, 183, and 187. Moreover, chemicals of concern identified with increased odds of infertility were PCB 74, 156, 183, 187, and transnonachlor. Conclusion Serum concentrations of selected POPs, both as individual chemicals and as a mixture, were significantly associated with lower fecundability and increased odds of infertility in women aged 29 years and above not using COC as their most recent pre-pregnancy contraceptive. Our findings suggest that pre-pregnancy use of oral contraceptive and age may modify the link between POPs and fecundability. The differences of specific chemicals in the individual analysis and as a mixture support the need to study combination effects of chemicals when evaluating reproductive outcomes.