Sidsel Louise Domazet

Associations of Adiposity and Aerobic Fitness with Executive Function and Math Performance in Danish Adolescents

OBJECTIVE To examine the associations of adiposity and aerobic fitness with executive function and math performance in Danish adolescents. STUDY DESIGN Cross-sectional analyses were conducted with data on 525 adolescents attending sixth and seventh grades from 14 schools in the 5 main regions of Denmark. A modified Eriksen flanker task was used to assess inhibitory control, a key aspect of executive function. Academic performance was assessed by a customized math test. Aerobic fitness was assessed by an intermittent shuttle-run test (Andersen test). RESULTS Body mass index (BMI) was negatively associated with accuracy on incongruent trials during the flanker task (P = .005). A higher BMI was associated with a larger accuracy interference score (P = .01). Similarly, waist circumference (WC) was negatively associated with accuracy on incongruent trials (P = .008). A higher WC was associated with a larger reaction time (RT) interference score (P = .02) and accuracy interference score (P = .009). Higher aerobic fitness was associated with a faster RT on congruent trials (P = .009) and incongruent trials (P = .003). Higher aerobic fitness was associated with a smaller RT interference score (P = .04). Aerobic fitness was positively associated with math score (P < .001). BMI and WC were not associated with math score (P > .05). CONCLUSIONS These results suggest that aerobic fitness is positively associated with both inhibitory control and math performance in adolescents. Adiposity is negatively associated with inhibitory control in adolescents. Adiposity is not associated with math performance.

Effectiveness of a School-Based Physical Activity Intervention on Cognitive Performance in Danish Adolescents: LCoMotion-Learning, Cognition and Motion: A Cluster Randomized Controlled Trial

Background Physical activity is associated not only with health-related parameters, but also with cognitive and academic performance. However, no large scale school-based physical activity interventions have investigated effects on cognitive performance in adolescents. The aim of this study was to describe the effectiveness of a school-based physical activity intervention in enhancing cognitive performance in 12–14 years old adolescents. Methods A 20 week cluster randomized controlled trial was conducted including seven intervention and seven control schools. A total of 632 students (mean (SD) age: 12.9 (0.6) years) completed the trial with baseline and follow-up data on primary or secondary outcomes (74% of randomized subjects). The intervention targeted physical activity during academic subjects, recess, school transportation and leisure-time. Cognitive performance was assessed using an executive functions test of inhibition (flanker task) with the primary outcomes being accuracy and reaction time on congruent and incongruent trials. Secondary outcomes included mathematics performance, physical activity levels, body-mass index, waist-circumference and cardiorespiratory fitness. Results No significant difference in change, comparing the intervention group to the control group, was observed on the primary outcomes (p’s>0.05) or mathematics skills (p>0.05). An intervention effect was found for cardiorespiratory fitness in girls (21 meters (95% CI: 4.4–38.6) and body-mass index in boys (-0.22 kg/m2 (95% CI: -0.39–0.05). Contrary to our predictions, a significantly larger change in interference control for reaction time was found in favor of the control group (5.0 milliseconds (95% CI: 0–9). Baseline to mid-intervention changes in physical activity levels did not differ significantly between groups (all p’s>0.05). Conclusions No evidence was found for effectiveness of a 20-week multi-faceted school-based physical activity intervention for enhancing executive functioning or mathematics skills compared to a control group, but low implementation fidelity precludes interpretation of the causal relationship. Trial Registration www.ClinicalTrials.gov NCT02012881

Longitudinal Associations of Exposure to Perfluoroalkylated Substances in Childhood and Adolescence and Indicators of Adiposity and Glucose Metabolism 6 and 12 Years Later: The European Youth Heart Study.

OBJECTIVE To investigate the long-term association of exposure to perfluoroalkylated substances, including perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA), during childhood (9 years) and adolescence (15 years) on indicators of adiposity and glucose metabolism in adolescence (15 years) and young adulthood (21 years). Secondarily, we aim to clarify the degree of tracking of exposure from childhood into young adulthood. RESEARCH DESIGN AND METHODS Data derived from a large multicenter prospective cohort study, in which the same participants have been observed from childhood (N = 590), during adolescence (N = 444), and into young adulthood (N = 369). Stored plasma samples were analyzed for PFOS and PFOA. Indicators of adiposity comprising body height, body weight, sum of four skinfolds, and waist circumference, as well as indicators of glucose metabolism, comprising fasting blood glucose, triglyceride, and insulin levels, β-cell function, and insulin resistance, have been collected at all study waves. Multiple linear regression was applied in order to model earlier exposure on later outcome while controlling for baseline outcome levels, sex, age, and socioeconomic factors. RESULTS Childhood exposure to PFOS was associated with indicators of adiposity at 15 years of age that are displayed in elevated BMI, skinfold thickness, and waist circumference, as well as increased skinfold thickness and waist circumference at 21 years of age. PFOA exposure in childhood was associated with decreased β-cell function at 15 years of age. We did not observe associations between exposure during adolescence and indicators of adiposity and glucose metabolism in young adulthood. CONCLUSIONS This study found evidence for childhood exposure to PFOS and PFOA predicting adiposity at 15 and 21 years of age and impaired β-cell function at 15 years of age, respectively.

Associations of Physical Activity, Sports Participation and Active Commuting on Mathematic Performance and Inhibitory Control in Adolescents

Objectives To examine objectively measured physical activity level, organized sports participation and active commuting to school in relation to mathematic performance and inhibitory control in adolescents. Methods The design was cross-sectional. A convenient sample of 869 sixth and seventh grade students (12–14 years) was invited to participate in the study. A total of 568 students fulfilled the inclusion criteria and comprised the final sample for this study. Mathematic performance was assessed by a customized test and inhibitory control was assessed by a modified Eriksen flanker task. Physical activity was assessed with GT3X and GT3X+ accelerometers presented in sex-specific quartiles of mean counts per minute and mean minutes per day in moderate-to-vigorous physical activity. Active commuting and sports participation was self-reported. Mixed model regression was applied. Total physical activity level was stratified by bicycling status in order to bypass measurement error subject to the accelerometer. Results Non-cyclists in the 2nd quartile of counts per minute displayed a higher mathematic score, so did cyclists in the 2nd and 3rd quartile of moderate-to-vigorous physical activity relative to the least active quartile. Non-cyclists in the 3rd quartile of counts per minute had an improved reaction time and cyclists in the 2nd quartile of counts per minute and moderate-to-vigorous physical activity displayed an improved accuracy, whereas non-cyclists in the 2nd quartile of counts per minute showed an inferior accuracy relative to the least active quartile. Bicycling to school and organized sports participation were positively associated with mathematic performance. Conclusions Sports participation and bicycling were positively associated with mathematic performance. Results regarding objectively measured physical activity were mixed. Although, no linear nor dose-response relationship was observed there was no indication of a higher activity level impairing the scholastic or cognitive performance.

Immediate and delayed effects of integrating physical activity into preschool children's learning of numeracy skills

A cluster-randomized controlled trial was conducted to examine the effects of a 4-week program that integrated movements into cognitive tasks related to numerical skills. Participants (N = 120, Mage = 4.70 years, SD = 0.49; 57 girls) were assigned to one of the following four conditions: performing integrated physical activity (task relevant), performing nonintegrated physical activity (task nonrelevant), observing integrated physical activity, or conventional sedentary teaching (without performing or observing physical activity). Results showed that children who performed task-relevant integrated physical activity performed better than children in all other conditions. In addition, children who performed physical activity, either integrated or nonintegrated, reported higher scores for enjoyment of the instructional method than the two sedentary learning conditions. Implications for educational theory and practice are discussed.

Reference values for cardiometabolic risk scores in children and adolescents: Suggesting a common standard

BACKGROUND AND AIMS International reference values for cardiometabolic risk variables, to allow for standardization of continuous risk scores in children, are not currently available. The aim of this study was to provide international age- and gender-specific reference values for cardiometabolic risk factors in children and adolescents. METHODS Cohorts of children sampled from different parts of Europe (North, South, Mid and Eastern) and from the United States were pooled. In total, 22,479 observations (48.7% European vs. 51.3% American), 11,234 from girls and 11,245 from boys, aged 6-18 years were included in the study. Linear mixed-model regression analysis was used to analyze the associations between age and each cardiometabolic risk factor. RESULTS Reference values for 14 of the most commonly used cardiometabolic risk variables in clustered risk scores were calculated and presented by age and gender: systolic blood pressure (SBP), diastolic blood pressure (DBP), waist circumference (WC), body mass index (BMI), sum of 4 skinfolds (sum4skin), triglycerides (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), TC:HDL-C ratio, glucose, insulin, homeostatic model assessment-score (HOMA-score), and cardiorespiratory fitness (CRF). CONCLUSIONS This study suggests a common standard to define cardiometabolic risk in children. Adapting this approach makes single risk factors and clustered cardiometabolic disease risk scores comparable to the reference material itself and comparable to cardiometabolic risk values in studies using the same strategy. This unified approach therefore increases the prospect to estimate and compare prevalence and trends of cardiometabolic risk in children when using continuous cardiometabolic risk scores.

Objectively measured physical activity in Danish after-school cares: Does sport certification matter?

Inactivity and more sedentary time predominate the daily activity level of many of todays children. In Denmark, certified sport after‐school cares have been established in order to increase childrens daily physical activity (PA) level. This cross‐sectional study aimed to investigate the activity level among participants in certified sport after‐school cares vs regular after‐school cares. The study was carried out in 2011 in 10 after‐school cares (5 sport/5 regular) throughout Denmark, whereof 475 children aged 5–11 years participated. PA level was assessed using Actigraph GT3X and GT3X+ activity monitors worn by the children for at least 8 consecutive days. Anthropometry and cardiorespiratory fitness were measured as well. A multivariate regression analysis was carried out to check for the differences in the PA level across the two care systems. However, there did not appear to be any differences in overall PA or in time‐specific day parts (e.g., during after‐school care). The activity levels were quite similar across after‐school cares and were mutually high during time spent in the care facility.