Patterns of Active Commuting to School in Spanish Preschool Children and Its Associations with Socio-Economic Factors: The PREFIT Project.

The aims of this study were to describe patterns of active commuting to school (ACS) of preschool children, and to analyse the relationship between ACS and family socio-economic factors. A total of 2636 families of preschoolers (3-to-5 years old) were asked to complete a questionnaire at home about the mode of commuting to school of their children and marital status, educational level, and profession of both father and mother. Chi-square analyses were applied to compare ACS between school grades and gender of the children. To analyse the association of ACS with socio-economic factors, logistic regression analyses were performed. Almost 50% of participants reported ACS of their offspring, with a higher rate in 3rd preprimary grade (5 years old) than in 1st and 2nd preprimary grades (3- and 4-years old. All, p < 0.05). Those preschool children who had parents with lower educational level and no managerial work had higher odds to ACS than those who had parents with higher educational level and managerial work (all, p ≤ 0.001). Around half of the Spanish preschool children included in this study commuted actively to school and families with lower educational levels or worse employment situation were related to active commuting to school.

Fitness, waist circumference and their association with future blood pressure in youth: The UP&DOWN Longitudinal Study.

OBJECTIVES: The aim was to determine the independent associations of muscular fitness (MF), cardiorespiratory fitness (CRF) and waist circumference (WC) with blood pressure (BP) levels over 2 years in children and adolescents. METHODS: 1089 children (517 females) and 787 adolescents (378 females) with complete data on fitness, WC and BP (systolic [SBP] and diastolic [DBP]) were included. Upper MF was assessed through the handgrip strength test, and lower MF using the standing long jump test. The 20-m shuttle run test was used to assess CRF. WC was obtained following standardized methods. Different regression models were fitted by introducing fitness and WC at baseline and their changes as exposures and BP at follow-up and their changes as outcomes. RESULTS: WC at baseline was positively and independently associated with each BP variable at follow-up in children and adolescents (ß=0.094-0.260; p≤0.05), and CRF was negatively associated with DBP in adolescents (ß=-0.096; p=0.034). WC changes were associated with BP variables 2 years later in children (ß=0.121-0.142; p<0.01). In adolescents, changes in upper MF (ß=-0.116; p=0.001) and WC (ß=0.080-0.098; p<0.05) were associated with SBP at follow-up. WC changes were independently associated with changes in each BP variable in children (ß=0.111-0.145; all p<0.05) and SBP changes in adolescents (ß=0.103 to 0.117; all p<0.01). CONCLUSIONS: WC, but neither MF nor CRF, is independently associated with BP and its changes over 2 years. The attainment or maintenance of optimal fatness levels in the pediatric population should be highly encouraged for the prevention of future hypertension.

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.

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.

Independent and combined associations of physical fitness components with inflammatory biomarkers in children and adolescents.

BACKGROUND: We aimed to examine the independent and combined associations of cardiorespiratory fitness, muscular fitness, and motor ability with single and clustered inflammatory biomarkers in children and adolescents. METHODS: This study included 503 children and adolescents. Cardiorespiratory fitness, upper- and lower-muscular fitness, and motor ability were assessed using field-based tests. Fasting blood samples were obtained to determine the levels of a set of inflammatory biomarkers. Global physical fitness and clustered inflammatory biomarker scores were computed. Associations between physical fitness and inflammatory biomarkers were analyzed through linear regression. Differences in inflammatory biomarker levels between physical fitness tertiles were tested. RESULTS: Global physical fitness was inversely associated with single and clustered inflammatory biomarkers in children (p < 0.05); and with C-reactive protein, complement factor C4, leptin, and clustered inflammatory biomarkers in adolescents (p < 0.025). Cardiorespiratory fitness and upper-muscular fitness were negatively and independently associated with several single and clustered inflammatory biomarkers in children and adolescents (p < 0.05). Differences were found between the lowest and the highest tertiles of global physical fitness in clustered inflammatory biomarker levels (p < 0.010). CONCLUSION: Physical fitness was negatively associated with single and clustered inflammatory biomarkers, independently of body mass index. Increasing physical fitness levels in youth might contribute to reduce the cardiovascular risk.

Neck circumference and clustered cardiovascular risk factors in children and adolescents: cross-sectional study.

OBJECTIVE: Early detection of cardiovascular disease (CVD) risk factors, such as obesity, is crucial to prevent adverse long-term effects on individuals' health. Therefore, the aims were: (1) to explore the robustness of neck circumference (NC) as a predictor of CVD and examine its association with numerous anthropometric and body composition indices and (2) to release sex and age-specific NC cut-off values to classify youths as overweight/obese. DESIGN: Cross-sectional study. SETTING: 23 primary schools and 17 secondary schools from Spain. PARTICIPANTS: 2198 students (1060 girls), grades 1-4 and 7-10. MEASURES: Pubertal development, anthropometric and body composition indices, systolic and diastolic blood pressure (SBP and DBP, respectively), cardiorespiratory fitness, blood sampling triglycerides (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-c), low-density lipoprotein cholesterol (LDL-c), glucose and inflammatory markers. Homoeostasis model assessment (HOMA-IR) and cluster of CVD risk factors were calculated. RESULTS: NC was negatively associated with maximum oxygen consumption (R2=0.231, P<0.001 for boys; R2=0.018, P<0.001 for girls) and adiponectin (R2=0.049, P<0.001 for boys; R2=0.036, P<0.001 for girls); and positively associated with SBP, DBP, TC/HDL-c, TG, HOMA, complement factors C-3 and C-4, leptin and clustered CVD risk factor in both sexes (R2 from 0.035 to 0.353, P<0.01 for boys; R2 from 0.024 to 0.215, P<0.001 for girls). Moreover, NC was positively associated with serum C reactive protein and LDL-c only in boys (R2 from 0.013 to 0.055, P<0.05). CONCLUSION: NC is a simple, low-cost and practical screening tool of excess of upper body obesity and CVD risk factors in children and adolescents. Paediatricians can easily use it as a screening tool for overweight/obesity in children and adolescents. For this purpose, sex and age-specific thresholds to classify children and adolescents as normal weight or overweight/obese are provided.

Objectively Measured Physical Activity During Physical Education and School Recess and Their Associations With Academic Performance in Youth: The UP&DOWN Study.

BACKGROUND: This study examined the associations of objectively measured physical activity in Physical Education and recess with academic performance in youth. METHODS: This cross-sectional study was conducted with 1,780 participants aged 6 to 18 years (863 girls). Physical activity was objectively measured by accelerometry and was also classified according to sex- and agespecific quartiles of physical activity intensities. Academic performance was assessed through school records. RESULTS: Physical activity in physical education (PE) and recess was not associated with academic performance (ß ranging from -0.038 to -0.003; all P > .05). Youth in the lowest quartile of physical activity in PE engaged in an average of 1.40 min of moderate-to-vigorous physical activity and those in the highest quartile engaged in 21.60 min (for recess: lowest quartile, 2.20 min; highest quartile, 11.15 min). There were no differences in academic performance between quartiles of physical activity in Physical Education and recess. CONCLUSIONS: Time spent at different physical activity intensities during PE and recess does not impair academic performance in youth.

Perceived environment in relation to objective and self-reported physical activity in Spanish youth. The UP&DOWN study.

The aims of the present study were to assess the association of environmental perception with objective and self-reported physical activity (PA) and the relation between environmental perception and meeting PA recommendations on children and adolescents. A sample of 1520 youth (770 boys) aged 8-18 years (12.1 ± 2.5 years) from the UP&DOWN study were included in the data analyses. Environmental perception was assessed with the short adapted version of the ALPHA environmental questionnaire. PA was objectively (accelerometers) and self-reported measured (PA Questionnaire for Children, Patient-centered Assessment and Counseling for Exercise Questionnaire and Finnish PA Index). Linear regression models were used to assess the association of environmental perception with PA. Bivariate logistic regression models were used to assess differences between environmental perception and meeting PA recommendations. Environmental perception was positively associated with both objective and self-reported PA. Some differences were found in the association of environmental perception and PA between sex- and age-specific groups. Youth who perceived a more favourable environment were more likely to meet PA recommendations (at least 60 min · day(-1) of moderate to vigorous PA (MVPA)). Results suggest that environmental perceptions of children and adolescents may play an important role in achieving higher levels of PA.