Physical activity (PA) and sedentary behaviour (SED) have been linked to the mental health of children and adolescents, yet the timing of behaviours may play a role in this relationship and ...clarifying this could inform interventions. We explored cross-sectional associations of PA and SED in varying time segments throughout the school day with the mental health of school-aged children and adolescents from rural Northeastern Ontario, Canada. A total of 161 students (56% female, M = 10.3 years old) wore accelerometers for 8 days (7 nights) and completed a self-report survey (parent reported for children younger than 11). Mental health was measured using the Strengths and Difficulties Questionnaire. Accelerometer-measured SED, light PA (LPA), and moderate and vigorous PA (MVPA) were estimated in the time-segments before school (06:00–08:44), school time (08:45–15:04), after school (15:05–16:59), and evenings (17:00–21:59). Associations were tested with multilevel linear regressions while adjusting for confounding factors. Students spent 72.6 min in MVPA, 209.0 min in LPA, and 621.0 min in SED per day. Daily SED was associated with less conduct problems (
β
= −0.27,
p
< 0.05). Evening LPA was inversely associated with hyperactivity (
β
= −1.45,
p
< 0.05), while SED was associated with hyperactivity and with peer problems before school (
β
= 1.70 and
β
= 1.01, respectively,
p
< 0.05), and during school (
β
= −0.83 and
β
= −0.57, respectively,
p
< 0.05). No associations were observed for MVPA, emotional symptoms, or prosocial behaviour. In conclusion, displacing SED with LPA in some specific periods of the day may benefit the mental health of students; taking this into account could strengthen interventions.
The brain is a key target of ethanol teratogenicity, in which ethanol can produce neurodegeneration in selected areas, including the hippocampus and cerebellum. The research objective was to test the ...hypothesis that chronic prenatal ethanol exposure, via maternal ethanol administration, produces differential time course of decreased linear density of hippocampal CA1 pyramidal cells and cerebellar Purkinje cells. Timed pregnant guinea pigs received chronic oral administration of ethanol, isocaloric-sucrose/pair-feeding, or water throughout gestation (term, about gestational day (GD) 68), and the offspring were studied at GD 62 (near-term fetus), postnatal day (PD) 1 (neonate), PD 5, and PD 12 (early postnatal life). Ethanol treatment, compared with isocaloric-sucrose/pair-feeding and water treatments, decreased brain, hippocampal, and cerebellar weights at GD 62, PD 1, PD 5, and PD 12. Hippocampal CA1 pyramidal cell linear density and cerebellar Purkinje cell linear density were unaffected at GD 62. Ethanol treatment produced 25, 30, and 30% decreases in linear density of hippocampal CA1 pyramidal cells at PD 1, PD 5, and PD 12, respectively, and a 30% decrease in linear density of cerebellar Purkinje cells at PD 12 only. At PD 5, Purkinje cell profile linear density remained unaffected; however, ethanol treatment appeared to increase linear density of apoptotic Purkinje cell nuclei, as determined by a modified TUNEL method. The data demonstrate that chronic prenatal ethanol exposure produces apparent differential time course of decreased linear density of hippocampal CA1 pyramidal cells and cerebellar Purkinje cells in the developing guinea pig.Key words: prenatal ethanol exposure, hippocampal CA1 pyramidal cells, cerebellar Purkinje cells, decreased linear density, differential time course, guinea pig.
Abstract Context Existing reviews of physical activity (PA) interventions designed to increase PA behavior exclusively in children (ages 5 to 11 years) focus primarily on the efficacy (e.g., internal ...validity) of the interventions without addressing the applicability of the results in terms of generalizability and translatability (e.g., external validity). Objective This review used the RE-AIM (Reach, Efficacy/Effectiveness, Adoption, Implementation, Maintenance) framework to measure the degree to which randomized and non-randomized PA interventions in children report on internal and external validity factors. Methods and results A systematic search for controlled interventions conducted within the past 12 years identified 78 studies that met the inclusion criteria. Based on the RE-AIM criteria, most of the studies focused on elements of internal validity (e.g., sample size, intervention location and efficacy/effectiveness) with minimal reporting of external validity indicators (e.g., representativeness of participants, start-up costs, protocol fidelity and sustainability). Conclusions Results of this RE-AIM review emphasize the need for future PA interventions in children to report on real-world challenges and limitations, and to highlight considerations for translating evidence-based results into health promotion practice.
Abstract Context An identified limitation of existing reviews of physical activity interventions in school-aged youth is the lack of reporting on issues related to the translatability of the research ...into health promotion practice. Objective This review used the Reach, Efficacy/Effectiveness, Adoption, Implementation and Maintenance framework to determine the extent to which intervention studies promoting physical activity in youth report on factors that inform generalizability across settings and populations. Methods and results A systematic search for controlled interventions conducted within the last ten years identified 50 studies that met the selection criteria. Based on Reach, Efficacy/Effectiveness, Adoption, Implementation and Maintenance criteria, most of these studies focused on statistically significant findings and internal validity rather than on issues of external validity. Due to this lack of information, it is difficult to determine whether or not reportedly successful interventions are feasible and sustainable in an uncontrolled, real-world setting. Conclusions Areas requiring further research include costs associated with recruitment and implementation, adoption rate, and representativeness of participants and settings. This review adds data to support recommendations that interventions promoting physical activity in youth should include assessment of adoption and implementation issues.
The Ontario Ministry of Education (OMOE) implemented the Daily Physical Activity (DPA) policy (OMOE, 2005), which mandates that children receive 20 minutes of sustained moderate to vigorous physical ...activity (PA) during instructional time daily. The purpose of this thesis was to describe how and to what extent the DPA policy is being implemented, and to generate strategic recommendations to optimize its delivery across Ontario. Two separate studies surveyed teachers (n = 66; Study 1) and parents (n = 172; Study 2) to characterize DPA implementation strategies and fidelity, and to identify associated facilitators, correlates, and barriers. Results indicate that the directives of the DPA policy are not being satisfied by teachers and are not being communicated to parents. Study 3 reviewed the internal and external validity of published PA interventions in children to identify effective strategies for PA behaviour change. Together, findings from the three studies identified modifiable predictors of DPA delivery and family-based support, and informed future research and recommendations.
Maternal consumption of ethanol during pregnancy can produce teratogenic effects in the offspring, including the fetal alcohol syndrome. The brain is a key target of ethanol teratogenesis, in which ...ethanol can produce neurodegeneration in selected areas, including the hippocampus and cerebellum. However, the time course of neuronal cell loss is not clearly understood. The research objective was to test the hypothesis that chronic prenatal ethanol exposure, via maternal ethanol administration, produces differential time course of loss of hippocampal CA1 pyramidal cells and cerebellar Purkinje cells. Timed pregnant guinea pigs received chronic oral administration of ethanol, isocaloric sucrose/pair feeding, or water throughout gestation (term, about gestational day (GD) 68), and the offspring were studied at GD 62 (near-term fetus), postnatal day (PD) 1 (neonate), PD 5 and PD 12 (early postnatal life). Ethanol treatment, compared with isocaloric-sucrose/pair-feeding and water treatments, decreased brain, hippocampal, and cerebellar weights at GD 62, PD 1, and PD 12. Only brain and hippocampal weights were decreased at PD 5. Hippocampal CA1 pyramidal and cerebellar Purkinje cell numbers were unaffected at GD 62. Ethanol treatment produced about a 25%, 30% and 30% loss of hippocampal CA1 pyramidal cells at PD 1, PD 5 and PD 12, respectively, and about a 30% loss of cerebellar Purkinje cells at PD 12 only. At PD 5, Purkinje cell number remained unaffected by ethanol treatment; however, the number of apoptotic Purkinje cell nuclei doubled, based on detection using the TUNEL® method. The data demonstrate that chronic prenatal ethanol exposure produces differential time course of loss of hippocampal CA1 pyramidal cells and cerebellar Purkinje cells in the developing guinea pig, involving apparent apoptotic neurodegeneration of the Purkinje cells.
