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.

Relevance of the anterior cingulate cortex volume and personality in motivated physical activity behaviors.

Some recent theories about the origins and maintenance of regular physical activity focus on the rewards of the properties of practicing this activity. Animal and human studies have demonstrated that mesolimbic dopamine plays a crucial role in the involvement in voluntary physical activity. Here, we test this possible role in a sample of 66 right-handed healthy young adults by studying the influence of personality and the volume of reward-related brain areas on individual differences in voluntary physical activity, objectively measured by accelerometer and subjectively self-reported by questionnaire. Our results show that a smaller volume of the right anterior cingulate cortex and lower scores on reward sensitivity contributed to explaining low levels of daily physical activity. Moreover, the volume of the right anterior cingulate cortex correlates positively with self-reported total physical activity. Results are discussed by highlighting the need to use objective measures of daily physical activity, as well as the important role of the anterior cingulate cortex and personality in promoting effortful and invigorating actions to obtain rewards.

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.

Individual and combined impact of physical fitness on health-related quality of life during adolescence: DADOS Study.

The purpose of the present study was to investigate the individual and combined impact of physical fitness components at baseline on health-related quality of life (HRQoL) at 24-month follow-up in adolescents. This longitudinal research included 199 adolescents (13.9 ± 0.3 years at baseline) from the DADOS study. Cardiorespiratory fitness was assessed using the 20-m shuttle run test. Muscular strength was assessed using the standing broad jump test. Motor competence was assessed using the 4 × 10-m shuttle run test. A physical fitness z-score was calculated as the mean of the z-scores values of each fitness test. A fitness index ranging from 0 to 3 was created according to the number of physical fitness components in which participants achieved high levels according to normative values. HRQoL was evaluated by the KIDSCREEN-10 questionnaire. Linear regression analyses showed that cardiorespiratory fitness, muscular strength, and the physical fitness z-score at baseline were individually associated with HRQoL at follow-up (ß ranging from 0.123 to 0.183; all p < 0.05). Moreover, logistic regression analysis revealed that adolescents with a fitness index ≥1 at baseline were more likely to achieve high HRQoL at 24-month follow-up, compared with their peers with an index of 0 (OR ranging from 3.554 to 9.087; all p < 0.05). Our results revealed an individual and cumulative positive impact of physical fitness at baseline on HRQoL at 24-month follow-up. These findings underline the key role of promoting the enhancement of overall physical fitness components in order to improve adolescents' health and well-being.Highlights Adolescents with high levels of cardiorespiratory fitness, muscular strength and motor competence will benefit from a greater physical and mental well-being over the time.The more physical fitness components with optimal levels, the greater likelihood of reaching better HRQoL over the time.Public health authorities should focus on the promotion of multiple physical fitness components to increase adolescent's likelihood of achieving greater HRQoL over the time.

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.

Physical activity and diabetes mortality in people with type 2 diabetes: a prospective cohort study of 0.5 million US people.

AIM: To examine the association between physical activity and the cause of death with the greatest risk related to type 2 diabetes mellitus (T2DM) in a large population-based cohort representative of the general US adult population. METHODS: A total of 41,726 adults suffering from T2DM (age 62 ± 14 years) and 459,660 adults without diabetes (age 46 ± 18 years) who participated in the National Health Interview Survey from 1997 to 2014 were included in this prospective cohort study. Self-reported moderate-to-vigorous physical activity (MVPA) was categorized into inactive, insufficiently active, active and very active. Mortality data was obtained from the National Death Index. Cox regression models adjusted for potential confounders were performed to estimate hazard ratio (HR) and 95% confidence interval (CI). RESULTS: Diabetes mortality cause showed the highest relative risk of death among adults with T2DM compared to adults without diabetes (HR 5.72 [3.15;10.39]). There was a non-linear inverse dose-response association between MVPA and diabetes mortality among adults with T2DM, up to a plateau in risk reduction at approximately 500 min/week. Any level of activity was inversely associated with a significantly lower risk of diabetes mortality compared with being inactive (insufficiently active HR 0.71[0.54;0.97], active HR 0.68 [0.49;0.95], very active HR 0.44 [0.32;0.60]). Compared to adults without diabetes, the risk of diabetes mortality decreased from HR 7.38 [4.00;13.58] for inactive people with T2DM to HR 3.34 [1.76;6.32] for very active people with T2DM. CONCLUSIONS: Higher levels of MVPA were associated with lower risk of diabetes mortality among adults with T2DM.

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.

Association between classic and specific bioimpedance vector analysis and sarcopenia in older adults: a cross-sectional study.

BACKGROUND: To verify (1) the association between classic and specific bioelectrical impedance vector analysis (BIVA) with body composition, hydration, and physical performance in older adults with and without sarcopenia; (2) which BIVA most accurately distinguishes sarcopenia. METHODS: A sample of 94 older adults with and without sarcopenia (29 men and 65 women, 60-85 years) was evaluated. The classic and specific BIVA procedures, Dual energy X-ray absorptiometry (DXA), and deuterium dilution were performed. Sarcopenia was defined by muscle weakness and low skeletal muscle index, while severity was indicated by low physical performance. RESULTS: The BIVA's potential to monitor hydration and muscle mass loss in older adults seems feasible. Classic and specific BIVA were able to distinguish sarcopenia in women (p < 0.001), but not in men. When the sarcopenia criteria were individually analyzed, both classic and specific BIVA were able to distinguish low skeletal muscle index in women, while only classic BIVA did for men. For the criterion of slow physical performance, only the classic BIVA showed severity differences for women. The vectors of adults without sarcopenia of both sexes tended to be positioned in the left region of the ellipses, revealing a predominance of soft tissues. CONCLUSIONS: Classic BIVA has a distinct sarcopenic association with body composition, hydration, and physical performance in older adults, while specific BIVA was similar between groups. Both BIVAs are sensible to detect female morphological changes (skeletal muscle index) but not for functional (handgrip, 6-min walk test) sarcopenia criteria. These procedures are promising tools for monitoring sarcopenia risks during aging.

Longitudinal Associations of Healthy Behaviors on Fitness in Adolescents: DADOS Study.

INTRODUCTION: This study aims to investigate the individual and combined associations of physical activity, sedentary time, diet, and sleep at baseline on cardiorespiratory fitness at 24-month follow-up in adolescents. METHODS: The DADOS (Deporte, ADOlescencia y Salud) prospective cohort study was performed between 2015 and 2017. Analyses were conducted in 2020 and included 189 adolescents aged 13.9 (SD=0.3) years at baseline. Vigorous physical activity, total sedentary time, and sleep duration were evaluated by GENEActiv accelerometer. Sleep quality and adherence to a Mediterranean diet were evaluated by questionnaires. Cardiorespiratory fitness was assessed by the 20-meter shuttle run test. A healthy lifestyle index was created by including positive scores for each individual behavior, and 3 categories of achievement (≤1, 2, ≥3) were established. RESULTS: Performing high vigorous physical activity and low screen time at baseline were individually associated with the likelihood of achieving high cardiorespiratory fitness at follow-up (OR=3.33 and 3.09, respectively). ANCOVA indicated that adolescents with a healthy lifestyle index ≥3 at baseline showed higher cardiorespiratory fitness at follow-up than those with a healthy lifestyle index of 2 and ≤1 (74.4 [SE=1.5] vs 68.9 [SE=1.4] and 67.8 [SE=1.5] laps, respectively; p<0.01). Adolescents with a healthy lifestyle index ≥3 at baseline were more likely to have high cardiorespiratory fitness at follow-up (OR=3.10) than their peers with ≤1. CONCLUSIONS: The results showed a cumulative impact of baseline health-related behaviors on cardiorespiratory fitness at 24-month follow-up in adolescents. These findings underline the key role of promoting a healthy lifestyle to improve adolescents' health.

An examination of the association between risk of depression and academic performance according to weight status in adolescents: DADOS study.

BACKGROUND: The early identification of emotional and psychological problems during adolescence seems helpful to improve academic performance (AP). However, the association between risk of depression and AP, as well as the role of health-related factors in this association remain to be elucidated. Therefore, the aims of this study were to analyze the association between risk of depression and AP in adolescents; to examine this association according to weight status; and to test the mediating role of weight status in this association. METHODS: A sample of 265 adolescents (125 girls) aged 13.9 ± 0.3 years old from the DADOS (Deporte, ADOlescencia y Salud) study was included in the analyses. Risk of depression was self-reported through the Behavior Assessment System for Children and Adolescents. AP was assessed through academic grades and the Spanish version of the Science Research Associates Test of Educational Ability. Weight status was assessed by body mass index (BMI) (kg/m2) and dichotomized according to the international age- and sex-specific BMI cut-offs (non-overweight vs. overweight). RESULTS: Linear regression analyses showed an inverse association between risk of depression and academic grades (all p<0.05). Further linear regressions analyzing risk of depression and AP (dependent variable) stratified by weight status showed stronger associations among overweight adolescents. Additionally, mediation analyses revealed that weight status acted as a mediator of this association. LIMITATIONS: The cross-sectional design prevents from interfering causal relationships. CONCLUSIONS: Educational institutions should promote the early identification of depression as well as the promotion of healthy weight status as strategies to enhance AP in adolescents.

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.

The mediating role of adiposity in the longitudinal association between cardiorespiratory fitness and blood pressure in adolescents: LabMed cohort study.

BACKGROUND: The aim of this prospective cohort study was to examine whether the association between the cardiorespiratory fitness (CRF) at baseline and blood pressure (BP) at follow-up is mediated by adiposity in adolescents. MATERIALS AND METHODS: The sample comprised 734 adolescents (349 girls) aged 12-18 years from the LabMed Physical Activity Cohort Study. The variables of interest were measured in 2011 (baseline) and in 2013 (2-year follow-up). CRF was assessed by the 20-m shuttle run test. Body mass index, waist circumference, body fat percentage, pubertal status and resting BP were assessed according to standard procedures. Boot-strapped mediation procedures were performed, and indirect effects (IE) with confidence intervals (CI) not including zero were considered statistically significant. RESULTS: After adjusting for potential confounders, body mass index acted as a mediator of the relationship between CRF and systolic BP (IE = -0. 023; CI = -0.039; -0.009), pulse pressure (IE = -0.023; CI = -0.034; -0.012) and rate product pressure (IE = -2.839; CI = -5.329; -0.340). Similar results were obtained for waist circumference as mediator for systolic BP (IE = -0.019; CI = -0.033; -0.005), pulse pressure (IE = -0.017; CI = -0.028; -0.007) and rate product pressure (IE = -3.793; CI = -6.097; -1.689). Likewise, body fat percentage mediated the association for: systolic BP (IE = -0.029; CI = -0.048; -0.010), pulse pressure (IE = -0.027; CI = -0.041; -0.013) and rate product pressure (IE = -4.280; CI = -7.488; -1.264). CONCLUSIONS: Adiposity mediated the association between CRF and BP in adolescents. Therefore, both optimal CRF and adiposity levels are important to maintain normal BP ranges throughout adolescence.

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.

Circulating inflammatory biomarkers and academic performance in adolescents: DADOS study.

OBJECTIVE: The present study aimed (1) to examine the association between circulating inflammatory biomarkers and academic performance in adolescents, and (2) to identify the ability of circulating inflammatory biomarkers to predict low academic performance. METHODS: A total of 244 adolescents (13.9±0.3 years, 112 girls) from the DADOS study were included in the analysis. Four inflammatory biomarkers were quantified: white blood cell (WBC) count, interleukin-6, tumor necrosis factor-α (TNF-α), and C-reactive protein (CRP). Academic performance was assessed through academic grades and the Spanish version of the Science Research Associates Test of Educational Abilities. RESULTS: TNF-α was inversely associated with math, Spanish and grade point average (ß ranging from -0.166 to -0.124; all p<0.05), while CRP was inversely associated with verbal ability (ß = -0.128; p<0.05). Overall, receiver operating characteristic (ROC) curves analyses showed discriminatory ability of WBC and TNF-α in identifying low academic performance (all p<0.05). Moreover, logistic regression analyses indicated that students with levels of WBC and TNF-α above the ROC cut-offs values showed between 78% to 87% increased likelihood of lower academic performance (p<0.05). CONCLUSIONS: Our findings suggested that some circulating inflammatory biomarkers were associated with academic performance in adolescents. Further larger longitudinal and interventional studies are needed to clarify the short-term and long-term relationship between inflammation and academic performance in youths.

Association between Health-Related Physical Fitness and Self-Rated Risk of Depression in Adolescents: Dados Study.

Depression is the most common mental disorder, affecting around 5% of adolescents. Physical fitness is considered a powerful marker of physical and mental health. The scientific results on the relationship between physical fitness and depression in the adolescent population are mixed. Therefore, the aim of the current study was to analyse the association between objectively assessed physical fitness and self-rated risk of depression in a group of adolescents. A total of 225 participants (44% girls), aged 13.9 ± 0.3 years, from the Deporte, ADOlescencia y Salud (DADOS) study were included in the analyses. Field-based Assessing Levels of Physical fitness and Health in Adolescents (ALPHA) health-related fitness test battery was used to objectively assess physical fitness components. The Behavior Assessment System for Children (BASC) level 3 was used to evaluate self-rated risk of depression. Our results showed that self-rated risk of depression was inversely associated with cardiorespiratory fitness (ß = -0.172), as well as positively associated with body mass index (ß = 0.146) and waist circumference (ß = 0.137) (all p < 0.05). Adolescents with low levels of cardiorespiratory fitness had significantly higher odds of self-rated risk of depression (OR = 7.17; 95% CI, 1.51-33.95). These findings suggest that health-related physical fitness, particularly cardiorespiratory fitness and body composition, is associated with depression in adolescents.

Reallocating time spent in physical activity intensities: Longitudinal associations with physical fitness (DADOS study).

OBJECTIVES: Firstly, to investigate the longitudinal associations between accelerometer-derived physical activity (PA) intensities and physical fitness (PF) at 24-month follow-up in adolescents. Secondly, to examine how substituting time spent in low or moderate PA intensities with vigorous PA at baseline was related to PF at 24-month follow-up. DESIGN: Longitudinal observational study METHOD: The DADOS (Deporte, ADOlescencia y Salud) study is a 3-year longitudinal research project carried out between years 2015-2017. The analyses included 189 adolescents (91girls) aged 13.9±0.3 years at baseline. PA was assessed by a wrist-worn GENEActiv triaxial accelerometer and expressed as minutes/day of light, moderate and vigorous PA. Cardiorespiratory, musculoskeletal and motor fitness were assessed by field tests and a global fitness z-score was calculated as the mean of the z-scores values of each fitness test. Association between PA intensities and PF were determined using linear regression. Isotemporal analyses estimating the association of reallocating PA intensities with PF were performed. RESULTS: Baseline vigorous PA was positively associated with cardiorespiratory fitness and global fitness score at follow-up in boys (ß=0.234;p=0.002, ß=0.340;p<0.001) and girls (ß=0.184;p=0.043, ß=0.213;p=0.004). In boys, baseline vigorous PA was also positively associated with musculoskeletal and motor fitness (ß=0.139;p=0.035, ß=0.195;p=0.021). The substitution of 10min/day of light PA or moderate PA with 10min/day of vigorous PA at baseline was positively associated with all PF components and global fitness score in boys (p<0.001), and with global fitness score girls (p<0.05). CONCLUSION: These findings highlight the need of promoting vigorous PA due to its specific influence on adolescent's PF.

Prevalence of severe/morbid obesity and other weight status and anthropometric reference standards in Spanish preschool children: The PREFIT project.

BACKGROUND: Childhood obesity has become a major health problem in children under the age of 5 years. Providing reference standards would help paediatricians to detect and/or prevent health problems related to both low and high levels of body mass and to central adiposity later in life. Therefore, the aim of this study was to examine the prevalence of different weight status categories and to provide sex- and age-specific anthropometry reference standards for Spanish preschool children. METHODS: A total of 3178 preschool children (4.59±0.87 years old) participated in this study. Prevalence of different degrees of obesity (mild, severe, and morbid) and other weight status categories were determined. RESULTS: Reference standards were obtained. Prevalence of overweight and obese preschool children in the Spanish population ranged from 21.4 to 34.8%. Specifically, the obesity prevalence was 3.5, 1.2, and 1.3% of these subjects were categorized as mild, severe, and morbid obese. Sex- and age-specific reference standards for anthropometric parameters are provided for every 0.25 years (i.e. every trimester of life). CONCLUSION: Our results show a high prevalence of overweight/obese preschoolers. The provided sex- and age-specific anthropometric reference standards could help paediatricians to track and monitor anthropometric changes at this early stage in order to prevent overweight/obesity.

Association Between Screen Media Use and Academic Performance Among Children and Adolescents: A Systematic Review and Meta-analysis.

IMPORTANCE: The health consequences of excessive screen media use in children and adolescents are increasingly being recognized; however, the association between screen media use and academic performance remains to be elucidated. OBJECTIVES: To estimate the association of time spent on screen-based activities with specific academic performance areas in children and adolescents and to examine this association separately in these populations. DATA SOURCES: MEDLINE, Scopus, Web of Science, Cochrane Database of Systematic Reviews, and ERIC were searched from database inception through September 2018. STUDY SELECTION: Cross-sectional studies of the association between time or frequency of screen media use and academic performance in children and adolescents were independently screened by 2 researchers. A total of 5599 studies, published between 1958 and 2018 from 23 countries, were identified. DATA EXTRACTION AND SYNTHESIS: Data were processed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Random-effects models were used to estimate the pooled effect size (ES). MAIN OUTCOMES AND MEASURES: Academic performance areas included composite scores, language, and mathematics. Screen media measurements included time or frequency of computer, internet, mobile phone, television, video game, and overall screen media use. RESULTS: In total, 58 cross-sectional studies (1.0%) of 5599 articles were included in the systematic review, of which 30 (52%) were included in the meta-analysis. The systematic review studies involved 480 479 participants aged 4 to 18 years, ranging from 30 to 192 000 people per study, and the meta-analysis studies involved 106 653 total participants, ranging from 70 to 42 041 people per study. Across studies, the amount of time spent on overall screen media use was not associated with academic performance (ES = -0.29; 95% CI, -0.65 to 0.08). Individually, television viewing was inversely associated with composite academic performance scores (ES = -0.19; 95% CI, -0.29 to -0.09), language (ES = -0.18; 95% CI, -0.36 to -0.01), and mathematics (ES = -0.25; 95% CI, -0.33 to -0.16). Video game playing was inversely associated with composite scores (ES = -0.15; 95% CI, -0.22 to -0.08). Subgroup analyses found that television viewing was inversely associated with language only in children (ES = -0.20; 95% CI, -0.26 to -0.15), whereas both television viewing (ES = -0.19; 95% CI, -0.30 to -0.07) and video game playing (ES = -0.16; 95% CI, -0.24 to -0.09) were inversely associated with composite scores only in adolescents. CONCLUSIONS AND RELEVANCE: Findings from this study suggest that each screen-based activity should be analyzed individually for its association with academic performance, particularly television viewing and video game playing, which appeared to be the activities most negatively associated with academic outcomes. Education and public health professionals should consider supervision and reduction to improve the academic performance of children and adolescents exposed to these activities.

The effect of sleep quality on academic performance is mediated by Internet use time: DADOS study / O efeito da qualidade do sono no desempenho acadêmico é mediado pelo tempo de uso da internet: estudo DADOS

Abstract Objective: The aims of the present study were to analyze the association of sleep patterns with academic and cognitive performance in adolescents, and to test the potential mediating effect of different activities of screen media usage on this association. Methods: A sample of 269 adolescents (140 boys) aged 14 years from the baseline data of the Deporte, ADOlescencia y Salud study completed questionnaires about sleep quality, cognitive performance, and leisure-time sedentary behaviors. Sleep duration was objectively computed using a wrist-worn GENEActiv accelerometer and academic performance was analyzed through school records. Results: Sleep quality (but not sleep duration) was associated with all the academic performance indicators (all p < 0.05). Analysis of covariance revealed higher grades among adolescents with better sleep quality (PSQI ≤ 5; all p < 0.05). These analyses showed no differences regarding cognitive performance. Internet use time was revealed as a mediator of the association between sleep quality and academic performance, being significant for all academic performance indicators (PM ranging from 15.5% to 16.0%). Conclusions: The association between sleep quality and academic performance in adolescents is mediated by time of Internet use. Overall, reducing Internet use in adolescents could be an achievable intervention for improving sleep quality, with potentially positive effects on academic performance.

Resumo Objetivo: Analisar a associação dos padrões de sono com o desempenho acadêmico e cognitivo em adolescentes e testar o efeito mediador potencial de diferentes atividades com uso de dispositivos (mídias) com tela nessa associação. Métodos: Uma amostra de 269 adolescentes (140 meninos) de 14 anos, da linha de base do estudo DADOS (Deporte, ADOlescencia y Salud) preencheu uma série de questionários sobre qualidade do sono, desempenho cognitivo e comportamentos sedentários no lazer. A duração do sono foi calculada objetivamente com um acelerômetro de pulso GENEActiv e o desempenho acadêmico foi analisado por meio de registros escolares. Resultados: A qualidade do sono (mas não a duração do sono) foi associada a todos os indicadores de desempenho acadêmico (todos os valores de p < 0,05). A análise de covariância revelou notas mais altas nos adolescentes com melhor qualidade de sono (PSQI ≤ 5; todos os valores de p < 0,05). Essas análises não mostraram diferenças em relação ao desempenho cognitivo. O tempo de uso da Internet revelou-se como um mediador da associação entre qualidade do sono e desempenho acadêmico, foi significativo para todos os indicadores de desempenho acadêmico (PM variou de 15,5% a 16,0%). Conclusões: A associação entre qualidade do sono e desempenho acadêmico em adolescentes é mediada pelo tempo de uso da internet. No geral, reduzir o tempo de uso da internet pelos adolescentes pode ser uma intervenção viável para melhorar a qualidade do sono, com efeitos potencialmente positivos no desempenho acadêmico.