Fitness, body composition, and metabolic risk scores in children and adolescents: the UP&DOWN study.

We aimed to analyse the longitudinal association between physical fitness (PF) and body composition (BC) with a metabolic risk score (Met4) in children and adolescents and to elucidate whether the association between PF and Met4 differs when using relativized or absolute fitness variables. A total of 188 children (86 females) and 195 adolescents (97 females) were included. Cardiorespiratory fitness (CRF) was determined by the 20-m shuttle run test, and muscular fitness (MF) was determined by hand grip and standing long jump tests. Height and weight were measured, and the body mass index (Kg/m2) was calculated. Triceps and subscapular skinfolds were assessed to compute body fat percentage. Met4 was computed from systolic blood pressure, triglycerides, high-density lipoprotein cholesterol, and glucose levels. Relative CRF was longitudinally and negatively associated with Met4 in female children (ß = -0.031, p = 0.025), while absolute CRF was positively associated with Met4 in male children and adolescents (ß = 0.000, p < 0.05). Relative upper and lower-body MF were longitudinally and negatively associated with Met4 in female adolescents (ß = -1.347, ß = -0.005, p < 0.05), while absolute lower-body MF was positively associated with Met4 in male children (ß = 0.000, p = 0.019). BC was longitudinally and positively associated with Met4 in male children (ß-ranging from 0.011 to 0.055, all p < 0.05) and male adolescents (ß-ranging from 0.011 to 0.046, all p < 0.05).  Conclusion: BC is more strongly associated with Met4 than PF in children and adolescents. An optimal body weight status should be considered the main objective of health-promoting programs at childhood and adolescence. Furthermore, the way of expressing the fitness variables determines the direction of the association with Met4. What is Known: • Physical fitness is an important health indicator in children and adolescents, with great amount of previous evidence supporting the preventive role of maintaining optimal levels of both cardiorespiratory and muscular fitness for future cardiometabolic issues. What is New: • The way of reporting physical fitness variables can affect the associations between physical fitness features and cardiometabolic outcomes. Since body composition variables have a great impact on both physical fitness and cardiometabolic health, relativizing physical fitness performance by body composition could lead to erroneous conclusions.

Objective measured physical activity and metabolic syndrome score in children and adolescents: The UP&DOWN longitudinal study.

INTRODUCTION: We aimed to analyze the cross-sectional and longitudinal association of physical activity (PA) levels and PA patterns with metabolic syndrome score (MetS) in children and adolescents. METHODS: A total of 175 children (82 females) and 188 adolescents (95 females) were included. Objective PA levels and patterns were determined by accelerometry. MetS was computed from waist circumference, systolic blood pressure, triglycerides, high-density lipoprotein cholesterol, and glucose levels. Different linear regression models were implemented to examine the associations of PA with MetS. RESULTS: Vigorous PA, moderate-vigorous PA, number of bouts per day in 10 min (N10), and total time in bouts per day in 10 min (T10) were negatively associated with MetS in male children and adolescents at cross-sectional level (ß ranging from -0.005 to -0.164, all p < 0.05). Total time in bouts per day in 20 min in male children, and vigorous PA and N10 in female children were longitudinally and negatively associated with MetS (ß ranging from -0.011 to -0.247, all p < 0.05). CONCLUSIONS: Associations of PA and MetS were observed at cross-sectional level in males and longitudinally in female children. The associations in PA patterns were found when patterns were grouped into bouts of 10 min. Therefore, for future studies of PA with health markers in the pediatric population, it would be advisable to choose bouts of shorter duration.

European fitness landscape for children and adolescents: updated reference values, fitness maps and country rankings based on nearly 8 million test results from 34 countries gathered by the FitBack network.

OBJECTIVES: (1) To develop reference values for health-related fitness in European children and adolescents aged 6-18 years that are the foundation for the web-based, open-access and multilanguage fitness platform (FitBack); (2) to provide comparisons across European countries. METHODS: This study builds on a previous large fitness reference study in European youth by (1) widening the age demographic, (2) identifying the most recent and representative country-level data and (3) including national data from existing fitness surveillance and monitoring systems. We used the Assessing Levels of PHysical Activity and fitness at population level (ALPHA) test battery as it comprises tests with the highest test-retest reliability, criterion/construct validity and health-related predictive validity: the 20 m shuttle run (cardiorespiratory fitness); handgrip strength and standing long jump (muscular strength); and body height, body mass, body mass index and waist circumference (anthropometry). Percentile values were obtained using the generalised additive models for location, scale and shape method. RESULTS: A total of 7 966 693 test results from 34 countries (106 datasets) were used to develop sex-specific and age-specific percentile values. In addition, country-level rankings based on mean percentiles are provided for each fitness test, as well as an overall fitness ranking. Finally, an interactive fitness platform, including individual and group reporting and European fitness maps, is provided and freely available online (www.fitbackeurope.eu). CONCLUSION: This study discusses the major implications of fitness assessment in youth from health, educational and sport perspectives, and how the FitBack reference values and interactive web-based platform contribute to it. Fitness testing can be conducted in school and/or sport settings, and the interpreted results be integrated in the healthcare systems across Europe.

Family-reported barriers and predictors of short-term attendance in a multidisciplinary intervention for managing childhood obesity: A psycho-family-system based randomised controlled trial (ENTREN-F).

OBJECTIVE: This study was aimed to examine patient enrolment in the pre-intervention stage, family-reported barriers, attendance rates and underlying predictors of short-term attendance in a family-system-based randomised controlled trial for managing childhood obesity in children aged 8-12-years-old (ENTREN-F). METHOD: Psychosocial and anthropometric measures were collected through primary health referral. The data were used for descriptive analyses of sample characteristics and linear regression analyses. RESULTS: Low enrolment rates and several family-reported barriers were observed in the pre-intervention stage. Logistical barriers were the most frequent family-reported reason for attrition in the different stages of the study. Having a first face-to-face orientation session with the families and the use of motivational interviewing helped to improve adherence in the initial phases of the study. After 6 months of intervention, family based treatments (FBTs) under consideration achieve greater adherence compared with the standard intervention. Moreover, family involvement was a predictor of success for better treatment adherence rates. By contrast, participants who attended a brief standard intervention, mothers with primary education, greater body mass index, higher levels of depressive symptomatology and more critical comments towards their children, children with higher weight status and lower levels of self-reported depressive symptoms at baseline attended interventions less frequently. CONCLUSIONS: In future programmes a comprehensive screening of modifiable factors related to family and their setting characteristics is paramount prior to intervention, identifying key barriers related to drop-out, especially in the case of less-advantaged families.

Objectively measured physical activity and academic performance in school-aged youth: The UP&DOWN longitudinal study.

To examine the longitudinal relationships between objectively measured total volume and specific intensities of physical activity (PA) with academic performance in a large sample of youth aged 6-18 years. A longitudinal study of 1046 youth (10.04 ± 3.10 years) from Spain was followed over 2 years. PA (volume and intensity) was measured by accelerometry. Academic performance was assessed through grades reported on the transcript at the end of the academic year (Mathematics, Language, an average of these two core subjects, and grade point average [GPA]). Longitudinal relationships between PA and four indicators of academic performance were examined using covariance and regression analyses, adjusted for a variety of confounders. Youth Quartile 2 for PA volume at baseline obtained better scores than those who participated in Quartiles 1 or 4 volumes of PA in GPA 2 years later (p = 0.006). There were generally no longitudinal associations between specific PA intensities and any of the academic performance indicators (all p > 0.170). However, a change in light PA over 2 years was inversely associated with three academic indicators in youth (ßrange , -.103 to - 090; all P < 040). Findings suggest that participants in Quartile 2 volume of PA had a better GPA in comparison with Quartiles 1 and 4 volumes of PA during youth, but there was no association with changes in PA volume over time. PA intensity was generally unrelated to academic performance during youth. However, there was an inverted u-shape relationship between light PA changes and GPA.

Correlates of dual trajectories of physical activity and sedentary time in youth: The UP & DOWN longitudinal study.

Trajectories of physical activity and sedentary time (SED) may differ between subgroups of youth. The aim of this study was to identify group-based dual trajectories of physical activity and SED and explore individual, social, and environmental correlates of these trajectories. Longitudinal data (three time points, baseline 2011-2012) of Spanish youth (n = 1597, mean age = 11.94 ± 2.52, 50.9% boys) were used. Moderate-to-vigorous physical activity (MVPA) and SED were assessed objectively at each time point, and 21 potential correlates were self-reported at baseline. Parallel process growth mixture models identified shared categorical latent groups, adjusting for school and age. Multinomial logistic regression models identified baseline correlates of a given trajectory. Four shared categorical latent groups were identified: (1) stable MVPA and decreasing SED (4%); (2) stable MVPA and increasing SED (3%); (3) consistently higher MVPA (18%); and (4) stable low MVPA and slight increase in SED (75%). Multinomial logistic regression models with group 3 as reference found: negative affect (RRR = 0.90, 95% CI 0.84-0.97), parental screen-time rules (RRR = 1.15, 95% CI 1.00-1.33), and household media equipment (RRR = 1.17, 95% CI 1.05-1.30) predicted likelihood of group 1 membership; cons of reducing SED (RRR = 2.70, 95% CI 1.77-4.10) predicted likelihood of group 2 membership; and co-participation in physical activity with friends (RRR = 0.80, 95% CI 0.69-0.94), fathers' modeling of TV viewing (RRR = 1.22, 95% CI 1.02-1.47), and household media equipment (RRR = 1.16, 95% CI 1.02-1.31) predicted likelihood of group 4 membership. Results suggest that strategies to improve MVPA and SED behaviors among youth may need to be multifaceted, targeting all levels of influence.

Longitudinal associations of physical fitness and body mass index with academic performance.

No studies have analyzed the longitudinal associations of change in physical fitness components and obesity with academic performance. The aim of the study was to examine longitudinal associations of changes in physical fitness components and body mass index with academic performance among youth, and whether the physical fitness components are moderators of the longitudinal association between obesity and academic performance in youth. Longitudinal analyses (2 years) included 1802 youths. Physical fitness components were assessed following the ALPHA health-related fitness test battery. Academic performance was assessed via school records. Youth in the persistently high cardiorespiratory fitness and motor ability categories (ie, fit at baseline and at 2-year follow-up) had higher academic performance at follow-up than those in the persistently low category. Further, youth with normal weight at baseline and overweight/obesity at follow-up had lower academic performance scores at follow-up compared to those with normal weight. Also, cardiorespiratory fitness may ameliorate the negative influence of excess body mass index on academic performance at follow-up. Promoting physical activity programs at school that include both aerobic exercise and motor tasks to improve physical fitness and reduce body mass index may not only improve physical health, but also contribute toward successful academic development.

A cross-sectional association of physical fitness with positive and negative affect in children and adolescents: the up & down study.

BACKGROUND: Affect and physical fitness play an important role in psychological and physical health; however, the association between those variables in youth remains unknown. The aim of the present study was to examine the influence of physical fitness on positive and negative affect in Spanish children and adolescents. METHOD: Healthy young Spanish people (n = 1,490) were recruited for the present study: 542 children (n = 272 girls; mean age 9.6 years) and 948 adolescents (n = 454 girls; mean age 14.1 years) with complete baseline data on health-related fitness tests (20 m shuttle run test, 4 × 10 m test, muscular fitness index, and physical fitness index), and positive and negative affect (Positive and Negative Affect Schedule). RESULTS: Higher performance on physical fitness components was associated with positive affect (ß = -0.176-0.118, all P < 0.05). There was no association between all physical fitness components and negative affect (ß = -0.100-0.15, all P > 0.05). There were differences on positive affect between the lowest and the highest quartile of the physical fitness index in boys (P = 0.037, Cohen's d 0.60) and girls (P = 0.004, Cohen's d = 0.69), and between the lowest and the highest quartile of muscular fitness index in girls (P < 0.001, Cohen's d = 0.76). CONCLUSIONS: Promoting physical activity during the school years, including strength exercises to increase muscular fitness, could improve positive affect levels and thus psychological health.

Bidirectional longitudinal associations of fatness with physical fitness in adolescents with Down syndrome. The UP&DOWN Longitudinal study.

BACKGROUND: The aim of this study was to examine the bidirectional longitudinal associations of several markers of fatness and physical fitness in adolescents with Down syndrome. METHODS: This study comprised a total of 111 adolescents (41 females), aged from 11 to 20 years with complete data at the baseline. We had a drop-out of <10% from the baseline to the 2-year follow-up. The ALPHA health-related fitness test battery for youth was used. RESULTS: Our results show that all fatness variables at the baseline were associated with a 2-year change in cardiorespiratory fitness (ß ranging from -0.32 to -0.38; all p < .05), but not with muscular and motor fitness (p > .05). However, no associations were found between physical fitness components as predictors and fatness indicators (p > .05). CONCLUSIONS: Results suggest that reducing fatness during adolescence might represent a modifiable factor to improve cardiorespiratory fitness at the 2-year follow-up, but not vice versa since associations were not bidirectional.

Changes in and the mediating role of physical activity in relation to active school transport, fitness and adiposity among Spanish youth: the UP&DOWN longitudinal study.

BACKGROUND: Longitudinal changes in child and adolescent active school transport (AST), and the mediating role of different intensities of daily physical activity (PA) levels in relation to AST and physical fitness and adiposity indicators is unclear. This study aimed to: 1) describe longitudinal changes in AST, light PA (LPA), moderate- to vigorous-intensity PA (MVPA), physical fitness and adiposity indicators over three time-points; and 2) investigate the mediating role of LPA and MVPA levels on associations between AST and physical fitness and adiposity indicators over three time-points among children and adolescents. METHODS: This longitudinal study comprised 1646 Spanish children and adolescents (48.8% girls, mean age 12.5 years ±2.5) at baseline, recruited from schools in Cádiz and Madrid. Mode of commuting to school was self-reported at baseline (T0, 2011-12), 1-year (T1) and 2-year follow-up (T2). PA was assessed using accelerometers. Handgrip strength, standing long jump and cardiorespiratory fitness (CRF) assessed physical fitness. Height, weight, body mass index, waist circumference, and triceps and subscapular skinfold thickness were measured. Multilevel linear regression analyses assessed changes in AST, PA levels, physical fitness and adiposity indicators over three time-points (T0-T1-T2). Additionally, longitudinal path analysis (n = 453; mean age [years] 12.6 ± 2.4) was used to test the mediating effects of LPA and MVPA levels on the association between AST and physical fitness and adiposity indicators. RESULTS: Multilevel analyses observed decreases in LPA between T0-T1 (ß = - 11.27; p < 0.001) and T0-T2 (ß = - 16.27; p < 0.001) and decreases in MVPA between T0-T2 (ß = - 4.51; p = 0.011). Moreover, changes over time showed increases in handgrip between T0-T1 (ß = 0.78; p = 0.028) and T0-T2 (ß = 0.81; p = 0.046). Path analyses showed that AST was directly positively associated with MVPA at T1 (all, ß ≈ 0.33; p < 0.001). MVPA at T1 mediated associations between AST and CRF at T2 (ß = 0.20; p = 0.040), but not the other outcomes. LPA did not mediate any associations. CONCLUSIONS: Results from longitudinal path analysis suggest that participation in more AST may help attenuate declines in MVPA that typically occur with age and improve CRF. Therefore, we encourage health authorities to promote AST, as a way to increase MVPA levels and CRF among youth.

Bidirectional associations between fitness and fatness in youth: A longitudinal study.

The aim was to examine the bidirectional association between cardiorespiratory fitness (CRF) and fatness in a 2-year longitudinal study conducted in young people. A total of 1082 children (512 females) and 727 adolescents (342 females) with complete data at baseline and follow-up were included. CRF was determined by the 20-m shuttle run test. Height and weight were measured, and body mass index and fat mass index (kg/m2 ) were calculated. Triceps and subscapular skinfolds were assessed to compute body fat percentage. Bidirectionality was tested by including CRF and each fatness index as exposures and outcomes, alternatively, in different regression models. CRF was prospectively associated with fatness index levels (ß from -0.186 to -0.528; P < .001), remaining significant in children after adjusting for baseline fatness indices. Fatness indices were prospectively associated with CRF (ß from -0.207 to -0.479; P < .001), with no substantial changes observed in children and female adolescents when baseline CRF was considered. Changes in CRF were prospectively associated with several fatness indices, regardless of body fatness at baseline (ß from -0.062 to -0.220; P < .05). Body fatness changes were associated with future CRF levels, independently of baseline CRF, especially in children of both sexes and male adolescents (ß from -0.079 to -0.260; P < .05). Overall, a bidirectional association was observed between CRF and fatness in children and adolescents. The attainment of optimal CRF and fatness levels in early ages should be promoted since it could result in favorable future fatness and CRF levels, respectively, which are two key determinants of health status.

Physical activity less than the recommended amount may prevent the onset of major biological risk factors for cardiovascular disease: a cohort study of 198 919 adults.

OBJECTIVES: We examined the dose-response relationship between physical activity (PA) and incidence of cardiovascular disease (CVD) risk factors in adults in Taiwan. METHODS: This study included 1 98 919 participants, aged 18-97 years, free of CVD, cancer and diabetes at baseline (1997-2013), who were followed until 2016. At baseline, participants were classified into five PA levels: inactive' (0 metabolic equivalent of task (MET)-h/week), 'lower insufficiently active' (0.1-3.75 MET-h/week), 'upper insufficiently active' (3.75-7.49 MET-h/week), 'active' (7.5-14.99 MET-h/week) and 'highly active' (≥15 MET-h/week]. CVD risk factors were assessed at baseline and at follow-up by physical examination and laboratory tests. Analyses were performed with Cox regression and adjusted for the main confounders. RESULTS: During a mean follow-up of 6.0±4.5 years (range 0.5-19 years), 20 447 individuals developed obesity, 19 619 hypertension, 21 592 hypercholesterolaemia, 14 164 atherogenic dyslipidaemia, 24 275 metabolic syndrome and 8548 type 2 diabetes. Compared with inactive participants, those in the upper insufficiently active (but not active) category had a lower risk of obesity (HR 0.92; 95% CI 0.88 to 0.95), atherogenic dyslipidaemia (0.96; 0.90 to 0.99), metabolic syndrome (0.95; 0.92 to 0.99) and type 2 diabetes (0.91; 0.86 to 0.97). Only highly active individuals showed a lower incidence of CVD risk factors than their upper insufficiently active counterparts. CONCLUSION: Compared with being inactive, doing half the recommended amount of PA is associated with a lower incidence of several common biological CVD risk factors. Given these benefits, half the recommended amount of PA is an evidence based target for inactive adults.

Does modality matter? A latent profile and transition analysis of sedentary behaviours among school-aged youth: The UP&DOWN study.

The aims of this study were to identify profiles of sedentary behaviour (SB) patterns, based on leisure-time self-reported SB modalities (screen, educative, social, and relaxing) and to evaluate changes in these profiles over 2 years among Spanish youth aged 8-18 years. Latent profile analysis (LPA), a data-driven analytic approach, was used to identify groups of boys and girls (n = 1553; 48% girls; mean±SD age: 12.56 ± 2.49 y) with distinct SB profiles using the SB modalities (time/d) as input variables. Latent transition analysis, an extension of LPA that uses longitudinal data, was used to analyse 2-year changes in these profiles. At baseline, four and three SB profiles were found among boys (labelled: screen, educative, social, and relaxing) and girls (labelled: screen/social, educative, and relaxing), respectively. Overall, more girls (range: 48%-67%) had the same profile over time, than boys (40%-52%). Participants with a screen or relaxing SB profile at baseline were more likely to have an educative profile after 2 years. Youth with a social and an educative SB profile at baseline were more likely to transition to profiles characterized by higher screen and social SB, respectively. Using a novel and person-centered approach, this study identified gender-specific SB profiles that were moderately stable over time.

[Family environment, physical activity and sedentarism in preadolescents with childhood obesity: ANOBAS case-control study]. / Ambiente familiar, actividad física y sedentarismo en preadolescentes con obesidad infantil: estudio ANOBAS de casos-controles.

OBJECTIVE: The aim of this study is to compare the levels of physical activity and sedentary behaviours in children with obesity and normal weight through accelerometer measures, and analyze the family environment related to physical activity. DESIGN: Case-control study. LOCATION: A health center and colleges of the Community of Madrid. PARTICIPANTS: A total of 50 obese children between 8 and 12 years of age (P > 97) and their mothers were matched by age, sex and socioeconomic status of their parents (1: 1) with 50 children with normopeso (GN; P < 85). MAIN MEASUREMENTS: Physical activity levels were measured by accelerometer (ActiGraph GT3X), levels of physical activity of the primary caregiver were measured through physical activity questionnaire (IPAQ) and the environment in relation to the physical activity was measured by the Home Environment Scale (HES-S). RESULTS: The group GO showed less vigorous physical activity than their peers in the GN group. Vigorous physical activity in the GO group was associated with modeling and parental policies regarding physical activity. A multiple regression analysis revealed that 21% of the variance of weight status of children was explained by sex, vigorous physical activity and maternal body mass index. CONCLUSIONS: The levels of vigorous physical activity and the family environment differ between children with obesity and normal weight. Therefore, it is important to continue working on the awareness of illness and the promotion of healthy habits from Primary Care and the school and institutional context.

Muscle Fitness Cut Points for Early Assessment of Cardiovascular Risk in Children and Adolescents.

OBJECTIVES: To study the cross-sectional and longitudinal (2-year follow-up) association between muscle fitness and cardiovascular disease (CVD) risk factors in youth; whether there are muscle fitness cut points associated with CVD risk (cross-sectional); and whether the health-related muscle fitness cut points identified at baseline are associated with CVD risk 2 years later. STUDY DESIGN: In total, 237 children (110 girls) aged 6-10 years and 274 adolescents (131 girls) aged 12-16 years with complete data were included in the study (10.3% drop out). The handgrip strength and the standing long jump tests were used to assess muscle fitness. CVD risk score was computed with sum of 2 skinfolds, systolic blood pressure, insulin, glucose, triglycerides, and total cholesterol/high density lipoprotein cholesterol. RESULTS: Muscle fitness at baseline was associated inversely with single CVD risk factors and CVD risk score at baseline and 2-year follow-up (all P < .05). Receiver operating characteristics curve analyses showed a significant discriminating accuracy of handgrip strength in identifying CVD risk in children and adolescents (boys: ≥ 0.367 and ≥0.473; girls: ≥ 0.306 and ≥0.423 kg/kg body mass, respectively, all P < .001). Similarly, the standing long jump cut points for children and adolescents were ≥104.5 and ≥140.5 in boys, and ≥81.5 and ≥120.5 cm in girls, respectively (all P < .05). These cut points were associated with CVD risk 2 years later (all P < .01). CONCLUSIONS: Muscle fitness is associated with present and future cardiovascular health in youth, and is independent of cardiorespiratory fitness. It should be monitored to identify youth at risk who could benefit from intervention programs.

Diet quality and well-being in children and adolescents: the UP&DOWN longitudinal study.

The present study examined the association between high-quality diet (using the Mediterranean diet (MD) as an example) and well-being cross-sectionally and prospectively in Spanish children and adolescents. Participants included 533 children and 987 adolescents at baseline and 527 children and 798 adolescents at 2-year follow-up, included in the UP&DOWN study (follow-up in schoolchildren and adolescents with and without Down's syndrome). The present study excluded participants with Down's syndrome. Adherence to an MD was assessed using the KIDMED index. Well-being was measured using the Positive and Negative Affect Schedule and the KIDSCREEN-10 questionnaire. Associations between MD adherence and well-being were assessed using multi-level, mixed-effects linear regression. At baseline, MD adherence was positively related to health-related quality of life in secondary school girls and boys (ß=0·41, se 0·10, P<0·001; ß=0·46, se 0·10, P<0·001, respectively) and to positive affect in secondary school girls and boys (ß=0·16, se 0·05, P=0·006; ß=0·20, se 0·05, P<0·001, respectively) and in primary school boys (ß=0·20, se 0·08, P=0·019). At 2-year follow-up, MD adherence was negatively related to negative affect in secondary school adolescent girls and boys (ß=-0·15, se 0·07, P=0·047; ß=-0·16, se 0·06, P=0·019, respectively), and MD adherence was associated with higher positive affect scores in secondary school girls (ß=0·30, se 0·06, P<0·001) and in primary school boys (ß=0·20, se 0·09, P=0·023). However, MD adherence at baseline did not predict well-being indicators at 2-year follow-up. In conclusion, higher MD adherence was found to behave as a protective factor for positive well-being in cross-sectional analysis.

The influence of cardiorespiratory fitness on clustered cardiovascular disease risk factors and the mediator role of body mass index in youth: The UP&DOWN Study.

BACKGROUND: The combined effect of cardiorespiratory fitness (CRF) and body mass index (BMI) on cardiovascular disease (CVD) risk in young people remains to be fully determined. We examined the individual and combined associations of CRF and BMI with clustered CVD risk factors, and the mediator role of BMI in the association between CRF and clustered CVD risk factors in children and adolescents. METHODS: 237 children (111 girls) and 260 adolescents (120 girls) were included in this cross-sectional study. Height and weight were assessed and BMI was calculated. A CVD risk factor index (CVDRF-I) was computed from: waist circumference, systolic blood pressure, triglycerides, high-density lipoprotein cholesterol and glucose. CRF was assessed using the 20-m shuttle run test. Regression analysis, analysis of covariance and mediation analysis (Baron and Kenny procedures) were used to test the independent and combined effect of CRF and BMI on CVDRF-I, and to test mediation hypothesis, respectively. RESULTS: CRF was negatively associated with CVDRF-I (all P < 0.05); however, after adjusting for BMI the associations were no longer significant in children and adolescents of both sex groups. Contrary, the association between BMI and CVDRF-I was independent of CRF (all P < 0.001). The effect of CRF on CVDRF-I was mediated by BMI. The percentage of the total effect of CRF on CVDRF-I mediated by BMI for boys and girls children and boys and girls adolescents were 79.5%, 100%, 81.2% and 55.7%, respectively. CONCLUSIONS: BMI is an independent predictor of CVDRF-I and a mediator of the association between CRF and CVDRF-I in children and adolescents. These results help to clarify the associations between CRF, weight status and cardiovascular health, suggesting that future CVD health would benefit from maintaining an optimal weight status.

Associations of total sedentary time, screen time and non-screen sedentary time with adiposity and physical fitness in youth: the mediating effect of physical activity.

The aims of the present study were: i) to examine the associations of total accelerometer-based sedentary time (ST) and specific-domain self-reported ST (i.e., screen-based, educational-based, social-based, and other-based ST) with adiposity and physical fitness in youth; and ii) to analyse the mediation effect of physical activity (PA) on associations. This study was conducted with 415 children (9.1 ± 0.4 years) and 853 adolescents (13.6 ± 1.6 years) in Spain during 2011-2012. Total ST and PA were assessed by accelerometry. Leisure-time spent in twelve sedentary behaviours was self-reported. Adiposity and physical fitness was measured following the ALPHA battery for youth. Total accelerometer-based ST was positively associated with global adiposity score in children, and negatively associated with global physical fitness score in children and adolescents; but relationships were not independent of PA. PA mediated all associations of accelerometer-based and self-reported ST with adiposity or physical fitness in children. Conversely, screen-, educational-, social-, and other-based ST were negatively related to physical fitness in adolescents, independently of PA. These findings give an impetus to developing effective strategies for specifically promoting PA in children and for increasing PA while reducing ST in adolescents in order to produce improvements on adiposity and physical fitness.

A longitudinal perspective of eating disorder risk in immigrant and Spanish native adolescents: The longitudinal up & down study.

OBJECTIVES: Previous research has postulated immigrant status as a relevant factor influencing eating disorder (ED) risk in adolescents. The present study assesses differences by sex in ED risk between Spanish native and immigrant adolescent populations residing in Spain and analyzes longitudinal differences in ED risk between immigrant and native adolescents over 2-year follow-up. METHOD: The study sample was 981 adolescents aged 11-19 years at baseline. ED risk was evaluated using the Spanish version of the SCOFF Questionnaire. Logistic regression was used to value associations between country of origin and ED risk prevalence by sex, as well as changes in ED risk at 2-year follow-up. RESULTS: Immigrant adolescent girls and boys presented greater ED risk than their Spanish counterparts. Prospective analyses showed that immigrant boys presented greater likelihood of acquiring ED risk over 2 years compared to Spanish adolescent boys. CONCLUSION: Immigrant adolescent populations, particularly boys, seem to be vulnerable to ED. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Interday Reliability of the IDEEA Activity Monitor for Measuring Movement and Nonmovement Behaviors in Older Adults.

The interday reliability of the Intelligent Device for Energy Expenditure and Activity (IDEEA) has not been studied to date. The study purpose was to examine the interday variability and reliability on two consecutive days collected with the IDEEA, as well as to predict the number of days needed to provide a reliable estimate of several movement (walking and climbing stairs) and nonmovement (lying, reclining, and sitting) behaviors and standing in older adults. The sample included 126 older adults (74 women) who wore the IDEEA for 48 hr. Results showed low variability between the 2 days, and the reliability was from moderate (intraclass coefficient correlation = .34) to high (.80) in most of movement and nonmovement behaviors analyzed. The Bland-Altman plots showed high-moderate agreement between days, and the Spearman-Brown formula estimated that 1.2 and 9.1 days of monitoring with the IDEEA are needed to achieve intraclass coefficient correlations ≥ .70 in older adults for sitting and climbing stairs, respectively.