Cord blood DNA methylation of DNMT3A mediates the association between in utero arsenic exposure and birth outcomes: Results from a prospective birth cohort in Bangladesh.

BACKGROUND: Fetal epigenetic programming plays a critical role in development. DNA methyltransferase 3 alpha (DNMT3A), which is involved in de novo DNA methylation (DNAm), is a prime candidate gene as a mediator between prenatal exposures and birth outcomes. We evaluated the relationships between in utero arsenic (As) exposure, birth outcomes, and DNMT3A DNAm. METHODS: In a prospective Bangladeshi birth cohort, cord blood DNAm of three DNMT3A CpGs was measured using bisulfite pyrosequencing. Maternal toenail As concentrations at birth were measured to estimate in utero exposure. Among vaginal births (N = 413), structural equation models (SEMs) were used to evaluate relationships between DNMT3A methylation, log2 (toenail As), birth weight, and gestational age. RESULTS: In an adjusted SEM including birth weight and gestational age, maternal toenail As levels were associated with DNMT3A DNAm (B = 0.40; 95% CI: 0.15, 0.66) and gestational age (B = -0.19 weeks; 95% CI: 0.36, -0.03). DNMT3A DNAm was associated with gestational age (B = -0.10 weeks; 95% CI: 0.16, -0.04) and birth weight (B = -11.0 g; 95% CI: 21.5, 0.4). There was an indirect effect of As on gestational age mediated through DNMT3A DNAm (B = -0.04; 95% CI: 0.08, -0.01), and there were indirect effects of maternal toenail As levels on birth weight through pathways including gestational age (B = -14.4 g; 95% CI: 29.2, -1.9), DNMT3A DNAm and gestational age (B = -3.1 g; 95% CI: 6.6, -0.8), and maternal weight gain and gestational age (B = -5.1 g; 95% CI: 9.6, -1.5). The total effect of a doubling in maternal toenail As concentration is a decrease in gestational age of 2.1 days (95% CI: 0.9, 3.3) and a decrease in birth weight of 29 g (95% CI: 14, 46). CONCLUSIONS: DNMT3A plays a critical role in fetal epigenetic programming. In utero arsenic exposure was associated with greater methylation of CpGs in DNMT3A which partially mediated associations between prenatal As exposure and birth outcomes. Additional studies are needed to verify this finding.

An observational study of recess quality and physical activity in urban primary schools.

BACKGROUND: To date, there is scant literature that examines the recess context concurrent with, but separate from, levels of physical activity. The primary purpose of the current study was to examine how recess quality impacted physical activity levels, and how this was moderated by gender. A secondary purpose was to examine if differences in children's engagement in activities occurred between recess sessions scored as low- or high- quality. METHODS: This was an observational study of children at 13 urban elementary schools in the U.S. Across the 13 schools, data were collected at 55 recess sessions, with 3419 child-level observations (n = 1696 boys; n = 1723 girls). Physical activity data were collected using Fitbit accelerometers, recess quality data were collected using the Great Recess Framework - Observational Tool (GRF-OT), recess engagement data were collected using the Observation of Playground Play (OPP), and basic psychological need satisfaction (BPNS) data were collected using a modified version of the BPNS for recess physical activity survey. Primary analyses were conducted using Hierarchical Linear Modeling (HLM) with children nested within recess sessions. RESULTS: Gender moderated the relationship between adult engagement and moderate-to-vigorous physical activity (MVPA) (b = .012; 95% CI .001, .024), student behavior and MVPA (b = -.014; 95% CI -.021, -.007), and student behaviors and light physical activity (b = .009, 95% CI .003, .015). Both boys and girls engaged in more play during recess sessions scored as high quality on the GRF-OT. Children reported higher levels of basic psychological need satisfaction at recesses sessions scored as high quality on the GRF-OT. CONCLUSIONS: Results of the current study showed that the quality of the recess environment, and the interactions of both adults and students in that environment, need to be taken into consideration in future school-based recess studies.

Recess Quality and Social and Behavioral Health in Elementary School Students.

BACKGROUND: A majority of research findings have focused on recess as instrumental to achieving minutes of physical activity rather than focusing on the psycho-social benefits associated with a high-quality recess environment. The purpose of the current study was to examine the relationship between recess quality and teacher-reported social, emotional, and behavioral outcomes in children. METHODS: Data were collected from 26 schools in 4 different regions of the United States. Teachers (N = 113) completed behavioral assessments for randomly selected children in their classrooms (N = 352). Data assessors conducted live observations of recess using the Great Recess Framework-Observational Tool. A series of 2-level regression models were fit in Mplus v. 8.2 to assess how recess quality was associated with indicators of children's social, emotional, and behavioral health. RESULTS: Recess quality significantly predicted executive functioning problems (b = -.360, p = .021), resilience (b = .369, p = .016), emotional self-control (b = -.367, p = .016), and a composite of adaptive classroom behaviors (b = .321, p = .030). CONCLUSION: Results of the present study demonstrate that recess quality impacts child developmental outcomes. Schools should ensure there is adequate training and resources to facilitate a positive and meaningful recess for students.