The bidirectional longitudinal association between academic performance and cardiovascular disease risk factors in adolescents.

INTRODUCTION: The limited prior research examining the association between academic performance and cardiovascular disease (CVD) risk factors in youth did not explore the reciprocal association between these constructs, and analyzed CVD risk factors individually. Thus, the aim of the present study was to explore the bidirectional longitudinal association between clustered CVD risk score and academic performance in adolescents over a 24-month interval. METHODS: A total of 237 adolescents (45.6% girls), aged 13.9 ± 0.3 years old at baseline, from DADOS (Deporte, ADOlescencia y Salud) study were included in this study. A clustered CVD risk score was created by calculating the mean age- and gender-standardized z-scores of waist circumference, systolic blood pressure, total cholesterol to high-density lipoprotein cholesterol ratio, triglycerides, homeostatic model assessment of insulin resistance, and cardiorespiratory fitness (inversed). Academic performance was assessed through the final academic grades and the test of educational abilities. RESULTS: Our results showed that the clustered CVD risk score at baseline was not associated with academic performance 24 months later (all p > .05). Nevertheless, except for physical education, academic grades at baseline were inversely associated with clustered CVD risk score at follow-up in adolescents (ß ranged from -0.140 to -0.102; all p < .05). No associations were found between academic abilities at baseline and clustered CVD risk score at follow-up (all p > .05). CONCLUSION: Academic grades could help predict CVD risk 24 months later during adolescence. Education professionals should foster adolescents' academic performance not only to improve academic results but also to maximize future cardiovascular health benefits.

Mediating role of physical fitness on the association between diet and health-related quality of life in adolescents.

Objective: The aim of this study was to analyse whether the association between adherence to the Mediterranean diet and health-related quality of life (HRQoL) is mediated by physical fitness components (i.e., cardiorespiratory fitness, lower-limb strength, upper-limb strength and motor competence) in adolescents. Methods: This is a cross-sectional study including mediation analyses. This study involved 181 adolescents (86 girls) aged 15.8 ± 0.3 years recruited from secondary schools and sport clubs located in Castellon (Spain). Adherence to the Mediterranean diet was evaluated using the KIDMED questionnaire. HRQoL was assessed with the KIDSCREEN-10 questionnaire. Cardiorespiratory fitness was assessed using the 20-m shuttle run test. Lower-limb strength was assessed through the standing broad jump test. Upper-limb strength was evaluated using a handgrip dynamometer. Motor competence was assessed using the 4 × 10 m shuttle run test. Mediation analyses were performed for each physical fitness component in order to assess its mediating effect on the association between adherence to the Mediterranean diet and HRQoL. Indirect effects (IE) with confidence intervals (CI) not including zero were interpreted as statistically significant. Results: Cardiorespiratory fitness and lower-limb strength had a mediating effect on the positive association between adherence to the Mediterranean diet and HRQoL (IE = 0.11, 95 % CI = 0.01; 0.27 and IE = 0.07, 95 % CI = 0.01; 0.19). Upper-limb strength and motor competence did not act as mediators in the association between adherence to the Mediterranean diet and HRQoL (IE = 0.00, 95 % CI = -0.04; 0.07 and IE = 0.01, 95 % CI = -0.03; 0.07, respectively). Conclusion: Our findings showed that the positive association of adherence to the Mediterranean diet on adolescents' HRQoL was mediated by physical fitness. Educational and public health strategies aiming to improve Spanish adolescents' HRQoL should focus on diet and physical fitness.

Bidirectional longitudinal associations of mental health with academic performance in adolescents: DADOS study.

BACKGROUND: The dual-factor model of mental health (i.e., the presence of psychological well-being along with the absence of distress) and its association with academic performance over time has been barely studied in the adolescent population, as most of the prior research focuses on psychological well-being or distress indicators in isolation. The current study analyzed the bidirectional longitudinal association between the dual-factor model of mental health and academic performance in adolescents, comprising a longitudinal assessment 2 years apart. METHODS: A total of 266 secondary school students (13.9 ± 0.3 years at baseline) from Deporte, ADOlescencia y Salud study were assessed. Mental health was assessed through the Behavior Assessment System for Children and Adolescents. Academic performance was assessed through academic grades and the Test of Educational Abilities. A cross-lagged modeling approach was used to examine the bidirectional longitudinal association between mental health and academic performance. RESULTS: Higher academic performance at baseline was associated with better mental health over time, but not vice versa, since this association was not bidirectional. CONCLUSION: Results suggest that academic performance is an important target for developing educational interventions, as it shapes adolescents' mental health at 2 years of follow-up. IMPACT: The overall picture of students' mental health and academic performance was analyzed. Academic performance may be a predictor of adolescents' mental health status. Mental health may not be a predictor of adolescents' academic performance. Good mental health should be promoted among youth with low academic performance.

The bidirectional longitudinal association between health-related quality of life and academic performance in adolescents: DADOS study.

PURPOSE: Although previous evidence has suggested a relationship between health-related quality of life (HRQoL) and academic performance, the directionality of this association is understudied and remains to be clarified. Thus, the primary objective of this study was to explore the bidirectional association between HRQoL and academic performance in adolescents between two timepoints with a 24-month interval. A secondary aim was to analyze whether this association varies between boys and girls. METHODS: This is a bidirectional longitudinal analysis with 257 adolescents (13.9 ± 0.3 years at baseline) from the DADOS study. HRQoL was measured using the KIDSCREEN-10 questionnaire. Academic performance was assessed through academic grades and the Spanish version of the Science Research Associates Test of Educational Ability. RESULTS: Cross-lagged analyses revealed that HRQoL at baseline was not associated with academic performance 24 months later, while all the academic grades and the overall score of academic abilities at baseline were positively associated with HRQoL at follow-up in adolescents. Results of the stratified analyses by sex were largely similar. Specifically, in girls, math, language, physical education, and grade point average at baseline were positively associated with HRQoL 24 months later, while in boys, all the academic grades indicators (except physical education), numeric ability, and the overall score of academic abilities at baseline were positively associated with HRQoL at follow-up. CONCLUSION: These findings suggest that academic performance in early adolescence may predict HRQoL 24 months later. Health and education professionals could benefit from collaborating to achieve both improved academic performance and HRQoL in youth.

Risk of depression mediates the association between cardiorespiratory fitness and academic performance in adolescent boys and girls: DADOS study.

This study aims to analyze the mediating role of risk of depression in the association between cardiorespiratory fitness and academic performance in a sample of adolescents and to test the moderation effect of sex. A total of 263 adolescents (125 girls, 13.9 ± 0.3 years) from the DADOS (Deporte, ADOlescencia y Salud) study were included in the analysis. Cardiorespiratory fitness was assessed by the 20-m shuttle run test. Academic performance was assessed through the final academic grades and the test of educational abilities. Risk of depression was evaluated through the Behavior Assessment System for Children and Adolescents. Mediation analyses were performed to determine the direct and indirect associations between cardiorespiratory fitness, risk of depression, and academic performance. Indirect effects with confidence intervals not including zero were interpreted as statistically significant, and percentages of mediation were calculated in order to know how much of the association was explained by the mediation. Our findings indicated a significant mediating effect of risk of depression in the association between cardiorespiratory fitness with final grades in math, language, and grade point average (percentages of mediation: 26%, 53%, and 29%, respectively). These analyses were not moderated by sex (all confidence intervals included 0). CONCLUSION: Risk of depression acts as a possible underlying mechanism in the association between cardiorespiratory fitness and academic grades in adolescents. Educational and health institutions could benefit from our findings since the promotion of higher cardiorespiratory fitness levels might reduce the risk of depression with potential benefits on adolescents' academic performance. WHAT IS KNOWN: • Cardiorespiratory fitness is positively associated with academic performance in adolescents. Nevertheless, the psychological mechanisms underlying this association are poorly understood. WHAT IS NEW: • Risk of depression mediates the association between cardiorespiratory fitness and academic performance in adolescents, independently of sex. • Our findings may improve the efficacy of mental health and educational programs by promoting the enhancement of cardiorespiratory fitness levels, which may reduce risk of depression with potential benefits on academic performance.

Role of physical activity and health-related fitness on self-confidence and interpersonal relations in 14-year-old adolescents from secondary school settings: DADOS study.

BACKGROUND: The effect of physical activity (PA) and physical fitness (PF) on self-confidence and interpersonal relations in adolescents is uncertain. AIM: To analyzed the associations of PA and PF with self-confidence and interpersonal relations in adolescents. SAMPLE: A total of 268 (138 boys) adolescents (13.9 ± 0.3 years) from the DADOS study were included in the analysis. METHODS: PA was evaluated using GENEActiv accelerometers and the health-related PF components by the ALPHA health-related fitness test battery. The levels of self-confidence and interpersonal relations were determined by the Behavior Assessment System for Children Level 3. RESULTS: The associations of PA levels and PF components with self-confidence reported positive associations of moderate-vigorous PA (MVPA), standing long jump, and 20-m shuttle run (shuttle run test) tests (all p < 0.05), and negative association of 4 × 10-m shuttle run test (4 × 10-m test), but only the 4 × 10-m test remained significant in the adjusted model for the whole sample and only in boys (p ≤ 0.01) when analyzed by sex. Regarding interpersonal relations, positive associations of standing long jump and shuttle run test (all p < 0.05), and negative association of 4 × 10-m test were found in all the adolescents. The shuttle run test was associated with interpersonal relations in boys independently of confounders. PA levels were not associated with interpersonal relations. CONCLUSION: A higher level of lower-limb muscle strength, speed-agility, and cardiorespiratory fitness might improve self-confidence and interpersonal relations in adolescents, but these relationships seem to be influenced by sex, body mass index, and pubertal status. Speed-agility and cardiorespiratory fitness seem to have a stronger impact on boys. MVPA may improve self-confidence in adolescents.

Is higher physical fitness associated with better psychological health in young pediatric cancer survivors? A cross-sectional study from the iBoneFIT project.

OBJECTIVE: To examine the associations of self-perceived and objectively-measured physical fitness with psychological well-being and distress indicators in young pediatric cancer survivors. MATERIALS AND METHODS: A total of 116 participants (12.1 ± 3.3 years, 56.9% boys) from the iBoneFIT project participated in this cross-sectional study. Objectively-measured physical fitness (muscular fitness) was obtained by handgrip strength and standing long jump tests for the upper and lower body, respectively. Self-perceived physical fitness was obtained by the International Fitness Scale (IFIS). Positive and negative affect were assessed by the positive affect schedule for children (PANAS-C), happiness by Subjective Happiness Scale (SHS), optimism by Life Orientation Test-Revised (LOT-R), self-esteem by the Rosenberg Self-Esteem Scale (RSE), anxiety by State-Trait Anxiety Inventory for Children (STAIC-R), and depression by Children Depression Inventory (CDI). Multiple linear regressions adjusted by key covariates were performed to analyze associations. RESULTS: No associations were found between objectively-measured muscular fitness and any of the psychological well-being and distress indicators (p > 0.05). Self-perceived overall fitness and flexibility were positively associated with positive affect (ß ≥ 0.258, p < 0.05). Self-perceived cardiorespiratory fitness, speed/agility, and flexibility were negatively associated with depression (ß ≥ -0.222, p < 0.05). Finally, self-perceived cardiorespiratory fitness was also negatively associated with anxiety and negative affect (ß ≥ -0.264, p < 0.05). CONCLUSIONS: Perceived physical fitness, but not objectively physical fitness, seems to be inversely related to psychological distress variables and to less extent positively related to psychological well-being. The findings from this study highlight the importance of promoting self-perceived fitness in the pediatric oncology population.

Observational longitudinal association between waking movement behaviours and psychological distress among adolescents using isotemporal analysis: DADOS study.

This study aimed to examine the impact of reallocating time spent in waking movement behaviours at baseline on indicators of psychological distress at 24-month follow-up using isotemporal substitution regression models among a sample of Spanish adolescents. The DADOS (Deporte, ADOlescencia y Salud) study is a 3-year longitudinal observational research project carried out between years 2015-2017. The analyses included 197 adolescents (91 girls) aged 13.9 ± 0.3 years at baseline. Waking movement behaviours were assessed by a wrist-worn GENEActiv triaxial accelerometer and expressed as minutes/day of light physical activity (LPA), moderate-vigorous physical activity (MVPA) and time spent in sedentary behaviour (SB). The Behaviour Assessment System for Children and Adolescents (level 3 for adolescents) was used to assess psychological distress indicators (i.e., anxiety, social stress, and risk of depression). Results showed significant associations only for girls. The substitution of 10 min/day of SB or LPA at baseline with 10 min/day of MVPA was associated with lower levels of anxiety (both p ≤ 0.01) and social stress (both p < 0.05) at follow-up. The substitution of 10 min/day of SB with 10 min/day of LPA was associated with higher levels of anxiety at follow-up (p = 0.01). These findings highlight the need of specific physical activity recommendations for mental health paying special attention to sex-differences.

Health-related quality of life in adolescents: individual and combined impact of health-related behaviors (DADOS study).

PURPOSE: To investigate the individual and combined effect of physical activity, adherence to the Mediterranean diet, sleep quality, sleep duration, and screen time on health-related quality of life (HRQoL) in adolescents. METHODS: This is a cross-sectional analysis with 262 adolescents (13.9 ± 0.3 years) from DADOS (Deporte, ADOlescencia y Salud) study. Physical activity was assessed with a wrist-worn GENEActiv triaxial accelerometer. Adherence to the Mediterranean diet was evaluated by the KIDMED questionnaire. Sleep patterns were self-reported through the Spanish version of Pittsburgh Sleep Quality Index questionnaire. Screen time was assessed through the HELENA sedentary behavior questionnaire. HRQoL was measured using the KIDSCREEN-10 questionnaire. Scores were categorized into low and high using a normative cut-off used to identify factors associated with being in a high HRQoL group. A healthy lifestyle index was created including positive scores for each individual behavior, and five categories of achievement were established (0, 1, 2, 3, ≥ 4). RESULTS: Sleep patterns and screen time revealed a significant individual relationship with HRQoL (p < 0.05). Adolescents achieving ≥ 3 positive health-related behaviors showed higher HRQoL levels compared to those fulfilling none (p < 0.05). Logistic regression analysis revealed an increased likelihood of high HRQoL according to the number of positive health-related behaviors achieved (p < 0.05). CONCLUSIONS: Our results reveal higher levels of HRQoL in those adolescents achieving ≥ 3 health-related behaviors compared to their peers achieving none. Moreover, our findings show a cumulative effect of health-related behaviors on HRQoL. These findings underline the key role of promoting a healthy lifestyle in order to improve adolescents' health and well-being.

Active commuting to school among 36,781 Spanish children and adolescents: A temporal trend study.

This study examines trends in the rates of active commuting to school (ACS) in Spanish children (n = 18 343; 8.93 ± 1.68) and adolescents (n = 18 438; 14.11 ± 1.58) aged 6-18 years from 2010 to 2017. Given the study period included the economic crisis in Spain (2008-2013), the second aim of this study was to compare ACS rates during and after the economic crisis. Data were obtained from 28 studies conducted across Spain. The overall trends in ACS were evaluated using multilevel logistic regression analysis. Among Spanish children and adolescents, the rates of ACS to school ranged around 60% between 2010 and 2017. The rates of ACS in Spanish youth did not change significantly during the 2010-2017 period, except a sporadic increase in the rate of ACS in adolescents in 2012-2013. No significant association between the ACS and the economic crisis time period in youth was found. As conclusion, the ACS remains stable in Spain during the last decade, which is a promising result regarding the evidenced decreasing trend in many countries. Further educational and policy strategies are important to continue promoting this behavior in children and adolescents in the long term.

Independent and combined influence of physical fitness components on self-esteem in adolescents: DADOS study.

BACKGROUND: Self-esteem is a common indicator of psychological well-being, but its relationship with physical fitness components during adolescence is not fully understood. AIMS: The aims of this study were to analyse the association of physical fitness components (low vs. high) with self-esteem in adolescents, and to examine the combined influence of physical fitness on self-esteem. SUBJECTS AND METHODS: A total of 225 participants (44% girls), aged 13.9 ± 0.3 years, from the DADOS (Deporte, ADOlescencia y Salud) study were included in the analyses. ALPHA-Fitness Test Battery was used to evaluate physical fitness components. The Spanish version of the Behaviour Assessment System for Children-3 questionnaire was used to assess self-esteem. RESULTS: Our results showed differences on self-esteem between groups of cardiorespiratory fitness (low = 49.51 ± 12.03 vs. high = 55.01 ± 4.46; p < 0.05) and upper limb muscular strength (low = 53.87 ± 7.38 vs. high = 54.29 ± 5.99; p < 0.05). Lower limb muscular strength and speed-agility groups did not show statistical differences. Significant differences on self-esteem were found when comparing adolescents with a physical fitness index of ≤1 vs. 4 (52.66 vs. 55.28; p < 0.05). CONCLUSION: These findings suggest that cardiorespiratory fitness and upper limb muscular strength are positively related with self-esteem. Moreover, our results revealed a combined influence of physical fitness on the self-esteem of adolescents.

The relative age effect on physical fitness in preschool children.

The aim of the present study was to investigate the existence of a relative age effect (RAE) on physical fitness of preschoolers. Anthropometry and physical fitness were assessed in 3147 children (3-5 years old) using the PREFIT battery. Based on the birth year, participants were divided into 3year groups (3-, 4- and 5-years). Within each year group, 4quarter groups were created: quarter 1, preschoolers born from January to March; quarter 2, from April to June; quarter 3, from July to September; quarter 4, from October to December. The MANCOVA analysis revealed a main effect of year group (Wilks' λ = 0.383; F10,5996 = 369.64; p < 0.001, ηp 2 = 0.381) and of quarter (Wilks' λ = 0.874; F15,8276.6 = 27.67; p < 0.001; ηp 2 = 0.044) over the whole battery of tests. To the best of our knowledge, this is the first study to report the existence of RAE at the preschool stage. In general, performance improved as the relative age increased (i.e., those born in quarter 1 performed better than those in the other quarters). Individualization strategies should be addressed within the same academic year not only in elementary or secondary years but also in preschoolers.

Inflammatory biomarkers and brain health indicators in children with overweight and obesity: The ActiveBrains project.

INTRODUCTION: Chronic inflammation plays an important role on the pathogenesis of several cardiovascular and metabolic diseases, as well as on brain function and behaviour. The aim of the present study was to examine the associations between inflammatory biomarkers and a wide range of brain health indicators (i.e., academic performance, executive function, behavioural and emotional functioning, and brain volume) in children with overweight/obesity. METHODS: A total of 107 children (10.0 ±â€¯1.1 years, 41% girls) from the ActiveBrains project were included in the analysis. Five inflammatory biomarkers were analysed in plasma: white blood cell (WBC) count, interleukin-6 (IL-6), interleukin-1ß, tumor necrosis factor-α (TNF-α), and C-reactive protein (CRP). Academic performance was assessed by Woodcock-Muñoz Tests of Achievement. Executive function was assessed through the Design Fluency Test for cognitive flexibility, the Stroop test for cognitive inhibition, and the Delayed Non-Match-to-Sample task for working memory. Behavioural and emotional functioning was evaluated through the Behavior Assessment System for Children (BASC) questionnaire. Total and regional brain volume was assessed by magnetic resonance imaging. RESULTS: IL-6 was inversely associated with adaptive skills (ß = -0.228; p = 0.030), while TNF-α was related to mathematics (ß = -0.198; p = 0.034). In addition, CRP was positively associated with externalizing (ß = 0.246; p = 0.046) and internalizing problems (ß = 0.234; p = 0.039), as well as the behavioural symptoms index (ß = 0.236; p = 0.047). However, these significant associations disappeared after multiple comparisons correction. Inflammatory biomarkers were not associated with executive function and total brain volumes. Regarding regional brain analyses, WBC was positively associated with gray matter volume in the left middle temporal gyrus (ß = 0.387; p < 0.001, k = 44), and CRP was positively associated with gray matter volume in the right superior temporal gyrus (ß = 0.439; p < 0.001, k = 29). Additionally, when adjusting by total brain volume, CRP was positively associated with gray matter volume in the right supplementary motor cortex (ß = 0.453; p < 0.001, k = 51). Moreover, both, IL-6 (ß = 0.366; p < 0.001, k = 81) and TNF-α (ß = 0.368; p < 0.001, k = 62) were positively associated with white matter volume around the right inferior frontal gyrus pars opercularis, while CRP was inversely associated with white matter volume around the left superior frontal gyrus (ß = -0.482; p < 0.001, k = 82). After adjusting by total brain volume, CRP was also inversely associated with white matter volume in 3 additional clusters (ß ranging from -0.473 to -0.404; p < 0.001, k = 87). CONCLUSIONS: Inflammation was slightly associated with brain health (i.e., academic performance, behavioural and emotional functioning and regional brain volume) in children with overweight or obesity. Further larger longitudinal and interventional studies are warranted to elucidate the short-term and long-term effect of systemic low-grade inflammation on children's brain health.

Independent and combined influence of healthy lifestyle factors on academic performance in adolescents: DADOS Study.

BACKGROUND: Few studies have analyzed the combined effect of lifestyle factors on academic performance (AP) in adolescents. The aim of this study was to analyze the independent and combined effects of weight status, screen time, sleep quality, daily meal frequency, cardiorespiratory fitness, and physical activity (PA) on AP in adolescents. METHODS: A total of 262 adolescents (13.9 ± 0.3 years) from the DADOS study were included in the analysis. Weight status was assessed through body mass index (kg/m2). Participants completed questionnaires to evaluate screen time, sleep quality, and daily meal frequency. Cardiorespiratory fitness was assessed by the 20-m shuttle run test. PA was evaluated by a wrist-worn GENEActiv accelerometer. AP was assessed through the final academic grades and a validated questionnaire. RESULTS: Non-overweight status, low screen time, good sleep quality, and proper meal frequency showed independent, positive influence on AP. Moreover, adolescents achieving at least three healthy lifestyles were more likely to be in the high-performance group for academic grades than those achieving ≤1 (math OR: 3.02-9.51, language OR: 3.51-6.76, and grade point average OR: 4.22-9.36). CONCLUSIONS: Although individual healthy lifestyles are independently and positively associated with AP, the cumulative effect of multiple healthy lifestyles have a stronger impact.

Associations between objectively measured and self-reported sleep with academic and cognitive performance in adolescents: DADOS study.

Adequate sleep has been positively related with health and school achievement outcomes during adolescence. The aim of this study was to investigate the associations of objectively measured and self-reported sleep duration and quality with academic and cognitive performance in adolescents. This study was conducted with 257 adolescents (13.9 ±â€…0.3 years) from the DADOS study (Deporte, ADOlescencia y Salud). Objectively measured and self-reported sleep duration and quality were obtained by a wrist-worn GENEActiv accelerometer and the Spanish version of Pittsburgh Sleep Quality Index questionnaire, respectively. Academic performance was analysed through school records using four indicators: math, language, science and grade point average score. Cognitive performance was measured using the Spanish version of the "SRA Test of Educational Ability". After Benjamini-Hochberg correction for the false discovery rate, objectively measured sleep duration was negatively associated with verbal ability (ß = -0.179, p = .004), whilst self-reported sleep quality was positively associated with academic performance (ß ranging from 0.209 to 0.273; all p < .001). These associations remained significant after further controlling for physical fitness and physical activity. Conversely, there were no associations between self-reported sleep duration and objective sleep quality with academic and cognitive performance. Our findings fit in line with previous research showing that sleep quality may play an important role on adolescents' academic performance. Further interventional research is needed to clarify the mechanisms by which sleep is related to academic performance in youth.

The influence of adherence to the Mediterranean diet on academic performance is mediated by sleep quality in adolescents.

AIM: This study examined the association of adherence to the Mediterranean diet with academic performance and tested whether this association was mediated by sleep in Spanish adolescents. METHODS: We recruited 269 adolescents (52% boys) aged 13.9 ± 0.3 years from the Deporte, ADOlescencia y Salud study of 38 secondary schools and sport clubs in Castellon, Spain, between February and May 2015. Adherence to the Mediterranean diet was assessed by the KIDMED questionnaire, sleep quality was evaluated with the Pittsburgh Sleep Quality Index test and sleep duration was objectively computed using a wrist-worn accelerometer. Academic performance was assessed through final school grades and a validated test. RESULTS: Greater adherence to the Mediterranean diet was associated with higher scores in language, core subjects, grade point average and verbal ability (p < 0.05). Sleep quality acted as a significant mediator of the association between adherence to the Mediterranean diet and final grades in maths, language, core subjects and the grade point average. CONCLUSION: Our data show that the influence of adherence to the Mediterranean diet on academic performance was mediated by sleep quality in adolescents. Education and public health professionals should work together to achieve both improved health status and academic performance in adolescents.

Fitness and academic performance in adolescents. The mediating role of leptin: DADOS study.

We tested the mediating effect of leptin on the association between physical fitness (PF) components and academic performance indicators in healthy adolescents. A total of 263 adolescents (13.9 ± 0.3 years, 47.5% girls, 12.5% overweight) from the DADOS (Deporte, ADOlescencia y Salud) Study were included in the analysis. PF components were assessed by the handgrip test for upper-limb muscular strength, standing long jump test for lower-limb muscular strength, 4 × 10-m shuttle run test for speed-agility, and 20-m shuttle run test for cardiorespiratory fitness. Plasma leptin concentration was assessed from antecubital vein blood after an overnight fast using a sensitive ELISA kit. Academic performance indicators were assessed through final school grades and through the Spanish version of the SRA Test of Educational Ability. Body composition was assessed by body mass index and skinfold thicknesses. Boot-strapped mediation procedures were performed and indirect effects with confidence intervals not including zero were interpreted as statistically significant. Our findings suggest that the positive associations observed between cardiorespiratory fitness and lower-limb muscular strength with academic performance indicators were mediated by leptin concentration after adjusting for sex, pubertal stage, socioeconomic status, and adiposity (percentage of mediation ranging from 54.61 to 82.02%). CONCLUSIONS: Improvements on PF components, particularly in cardiorespiratory fitness and lower-limb muscular strength, might reduce leptin concentration with potential benefits on academic performance in adolescents, independently of adiposity. What is Known: • Academic performance is associated with physical fitness and leptin concentration in children and adolescents. • Fitness modulates leptin concentration levels, regardless of physical activity and adiposity. What is New: • Leptin concentration mediates the association of cardiorespiratory fitness and muscular strength with academic performance in adolescents. • Improvements in cardiorespiratory fitness and muscular strength might reduce leptin concentration levels enhancing academic performance.

Cardiorespiratory fitness and academic performance association is mediated by weight status in adolescents: DADOS study.

The aim of our study was to examine the mediation effect of weight status on the association between cardiorespiratory fitness (CRF) and academic performance (AP). Two hundred sixty-nine adolescents (140 boys) aged 13.9 ± 0.3 years old from the DADOS study were included in this cross-sectional analysis. CRF was assessed by the 20-m shuttle run test and estimated maximum oxygen uptake was used in the analysis. AP was assessed through the final academic grades and the Science Research Associates Test of Educational Abilities for assessing reasoning, verbal, and numeric abilities. Weight status was assessed by body mass index (kg/m2). Boot-strapped mediation procedures were performed and indirect effects (IE) with confidence intervals (CI) not including zero were considered statistically significant. Mediation analysis revealed that weight status acted as a mediator of the relationship of CRF with reasoning ability (IE = 0.039; CI = 0.001; 0.091) and the final grades in Math (IE = 0.011; CI = 0.002; 0.025), Language (IE = 0.013; CI = 0.004; 0.027), and GPA (IE = 0.011; CI = 0.003; 0.023). CONCLUSIONS: Our data show that the influence of CRF on academic performance is mediated by weight status in adolescents. We suggest that our data could be considered by educators, families, and policy makers, so that active lifestyles might be promoted when designing programs aimed to improve AP among adolescents. What is Known: • Academic performance is associated with both, cardiorespiratory fitness and weight status. • The role of weight status in the association between cardiorespiratory fitness and academic performance is poorly understood. What is New: • We support the scarce research investigating the mediating role of weight status as mechanism in the association between fitness and academic performance in youth. • Previous knowledge is expanded by suggesting that cardiorespiratory fitness is related to weight status which in turn may positively influence academic performance in adolescents.

Regular Practice of Competitive Sports Does Not Impair Sleep in Adolescents: DADOS Study.

PURPOSE: To analyze differences in sleep quality and duration by athletic status and sex, and to examine the association between physical activity (PA) recommendation and sleep in adolescents. METHODS: A total of 267 adolescents [13.9 (0.3) y] from Deporte, ADOlescencia y Salud (DADOS) study (129 girls) were included in this cross-sectional analysis. Athletes competed regularly in organized sport events and trained ≥3 days per week, but nonathletes did not compete. PA was assessed by GENEActiv accelerometer. PA values were dichotomized into inactive (<60 min/d of moderate and vigorous PA) and active (≥60 min/d of moderate and vigorous PA). Sleep quality was evaluated with the Spanish version of the Pittsburgh Sleep Quality Index. Pittsburgh Sleep Quality Index values were dichotomized into >5 (poor quality) or ≤5 (good quality). Sleep duration was objectively measured by accelerometer. RESULTS: Sleep quality and duration were not statistically different between athletes [median (Mdn) = 4.0, interquartile range (IQR) = 3.0-6.0 and Mdn = 8.0, IQR = 7.4-8.6 h, respectively] and nonathletes (Mdn = 5.0, IQR = 3.0-7.0 and Mdn = 7.9; IQR = 7.3-8.6 h, respectively), P > .05. Nonathlete or inactive adolescents did not show higher risk for poor sleep quality or short sleep duration than athletes [odds ratio (OR) = 1.17; 95% confidence interval (CI), 0.68-2.00 and OR = 0.93; 95% CI, 0.56-1.55, respectively] or active peers (OR = 1.39; 95% CI, 0.66-2.89 and OR = 1.62; 95% CI, 0.78-3.37, respectively). CONCLUSIONS: In our group of adolescents, competitive sport practice did not alter sleep patterns. PA recommendations for adolescents may not discriminate between good and poor sleepers.

Impact of an endurance training program on exercise-induced cardiac biomarker release.

We evaluated the influence of a 14-wk endurance running program on the exercise-induced release of high-sensitivity cardiac troponin T (hs-cTnT) and NH2-terminal pro-brain natriuretic peptide (NT-proBNP). Fifty-eight untrained participants were randomized to supervised endurance exercise (14 wk, 3-4 days/wk, 120-240 min/wk, 65-85% of maximum heart rate) or a control group. At baseline and after the training program, hs-cTnT and NT-proBNP were assessed before and 5 min, 1 h, 3 h, 6 h, 12 h, and 24 h after a 60-min maximal running test. Before training, hs-cTnT was significantly elevated in both groups with acute exercise (P < 0.0001) with no between-group differences. There was considerable heterogeneity in peak hs-cTnT concentration with the upper reference limit exceeded in 71% of the exercise tests. After training, both baseline and postexercise hs-cTnT were significantly higher compared with pretraining and the response of the control group (P = 0.008). Acute exercise led to a small but significant increase in NT-proBNP, but this was not mediated by training (P = 0.121). In summary, a controlled endurance training intervention resulted in higher pre- and postexercise values of hs-cTnT with no changes in NT-proBNP.