A network analysis involving mental difficulties, cognition, physical fitness, 24-hour movement components, fatness, and sociodemographic factors in children.

Background: Evidence supports the beneficial linear influence of diverse lifestyle behaviors on brain health since childhood; however, multiple behaviors -and not only one-simultaneously affect such outcomes. Therefore, the aim was to explore the multivariate relationship through a network analysis among mental difficulty and cognitive function with physical fitness (PF), 24-h movement components, fatness, and sociodemographic factors in children. Methods: Cross-sectional study involved 226 children (52.2 % boys) aged between six and 11 years. Mental difficulties were evaluated through the Strengths and Difficulties Questionnaire and cognitive function by the Raven's Colored Progressive Matrices Test. The body mass index and PF were assessed according to the procedures suggested by the Proesp-Br, while moderate-to vigorous-intensity physical activity (MVPA) using accelerometry. The socioeconomic level, sleep, and screen time were evaluated by questionnaires. A network analysis was carried out to evaluate the associations among variables and establish centrality measures. Results: Age and PF moderated the negative relationship between cognitive function and MVPA. Furthermore, the direct and inverse relationship between cognitive function and mental difficulties appears to be affected by the 24-h movement components. Finally, age, PF, and screen time are the nodes with higher values of expected influence, indicating more sensitivity to interventions for decreasing mental difficulty and improving cognitive function. Conclusion: Mental health and cognitive function were moderated by the multivariate interaction among age, PF, and the three 24-h movement components. Nonetheless, centrality measures from the network analysis suggest that PF, MVPA, and screen time are crucial nodes in order to implement future interventions.

Sedentary time play a moderator role in the relationship between physical fitness and brain-derived neurotrophic factor in children. A pilot study.

Aim: Despite some advances, there are many controversies concerning brain-derived neurotrophic factor (BDNF) and its relationships with variables related to physical fitness and sedentary time, especially in children. The aim of the study was to explore the moderating role of sedentary time on the association between physical fitness and BDNF. Therefore, this study will add to the perspective of understanding how much time children may spend being sedentary with no deleterious influence on the positive association between physical fitness and BDNF. Methods: This cross-sectional study included 44 children aged between 6 and 11 years (9.02 ± 1.43) from a public school in Porto Alegre, Brazil. Cardiorespiratory fitness (CRF) was determined by the 6-min walk/run test, and muscular strength was determined through the lower limb strength test (LLS). Sedentary time was assessed through accelerometers, and blood samples were collected to determine serum BDNF levels (z score). Moderation analysis was performed using the PROCESS macro adjusted for sex, age, somatic maturation, waist circumference, and socioeconomic level. Results: Sedentary time moderates the relationship between CRF and BDNF, such that children should spend less than 511 minutes per day sedentary to achieve the benefits of CRF in BDNF concentrations. Conclusion: Sedentary time plays a significant moderating role in the relationship between CRF and BDNF. Therefore, to promote brain health in children, both increasing physical fitness and reducing sedentary time might be encouraged.

The genetic predisposition to obesity has no influence on waist circumference when screen time and sleep duration are adequate in children and adolescents.

The aim of the present study was to verify whether the amount of sleep duration, screen time, and physical activity moderate the relationship between FTO rs9939609 polymorphism and waist circumference (WC) in children and adolescents. This is a cross-sectional study conducted with 1338 children and adolescents, aged between 6 and 17 years. Lifestyle habits were assessed through self-reported questionnaire. WC was measured on the narrowest part of the trunk between the last rib and the iliac crest. FTO rs9939609 polymorphism was genotyped by real time polymerase chain reaction. The PROCESS macro for the SPSS was used for moderation analyses, through multiple linear regression models. Results indicated significant interactions were found between sleep duration and screen time X FTO rs9939609, showing that these lifestyle behaviours are moderators in the relationship between a genetic predisposition for obesity and higher WC. For physical activity, there was no significant interaction. Therefore, sleeping more than 564 min a day (i.e. 9.4 h) and spending no more than 233 min in front of screen may counteract the genetic predisposition to obesity in children and adolescents.Highlights A healthy lifestyle may counteract the genetic predisposition to central obesity;Children and adolescents should sleep more than approximately 9 h (564 min) per day and spend less than approximately 4 h (233 min) per day in front of screens in order to counteract the genetic predisposition to central obesity conferred by the FTO gene variant.It is fundamental to promote actions for the adoption of a healthy lifestyle, including the importance of presenting adequate sleep habits and low screen time for a better cardiometabolic health and reduction of obesity.

Cardiorespiratory Fitness and Muscular Strength Moderates the Relationship between FNDC5 Polymorphism and Adiposity in Children and Adolescents.

The human locus FNDC5 rs16835198 contributes positively to anthropometric phenotypes in children and adolescents. However, the role of specific components of physical fitness in this relationship is not known. The present study aimed to verify the moderator role of cardiorespiratory fitness (CRF) and muscular strength in the relationship between rs16835198 polymorphism FNDC5 and adiposity in children and adolescents. This cross-sectional study was carried out by genotyping the rs16835198 FNDC5 polymorphism in 1701 children and adolescents (mean age 11.73 ± 2.75 years). Obesity was assessed using waist circumference and body mass index (BMI) z-scores. To evaluate CRF and muscular strength, the 6 min run/walk test and lower limb strength (LLS) were used. Linear regression models were applied, and all analyses were adjusted for age, sex, skin color, living area, and school type. A significant interaction term for CRF (p = 0.038) and LLS (p = 0.040) × rs16835198 FNDC5 with WC was identified. Regarding BMI, a significant interaction term for CRF (p = 0.007) and LLS (p = 0.044) × rs16835198 FNDC5 was observed. Moreover, medium and high CRF and LLS levels protected against higher WC and BMI. In conclusion, adiposity levels of children and adolescents with a genetic predisposition to obesity might be modified by improving CRF and muscular strength.

Sleep-related problems and eating habits during COVID-19 lockdown in a southern Brazilian youth sample.

The pandemic has affected children's behaviors and this fact has an effect on their healthy habits, such as sleep and diet. The aim of the current study was to determinate the prevalence of sleep-related problems and its relationship with eating habits in children from the south of Brazil during the pandemic. Parents/legal guardians of 3-17 years old participants responded to a online survey distributed using the snowball sampling strategy in Brazil. The survey was conducted in April, 2020. Participants were asked for their sleep duration and sleep-related problems, as well as for their eating habits. Logistic regressions were performed to analyze the relationship between sleep-related problems and eating habits. 495 participants were included in the analysis. 48.8% of participants reported sleep-related problems with 12.3% not meeting the sleep guidelines. Moreover, participants reported eating fruits or vegetables and sweets over four and three per week, respectively. Different associations were found between varibles of sleep and eating habits. Those participants with healthy eating habits showed a lower prevalence of sleep-related problems.

Muscular fitness, Southern European Atlantic Diet and inflammation in adolescents. Azorean Physical Activity and Health Study II.

High muscular fitness (MF) and high adherence to the Southern European Atlantic Diet (the SEADiet) have been associated with several positive metabolic outcomes. The purpose of the present study was two-fold: (i) to explore the independent associations between MF and C-reactive protein (CRP) levels; and (ii) to investigate the combined impact of MF and SEADiet on the CRP levels in a sample of adolescents. A cross-sectional school-based study was conducted on 463 adolescents (272 girls) aged 15-18 years, from the Portuguese Azorean Archipelago. Anthropometric indicators (stature, body mass, waist circumference (WC)) were measured by standardized protocols and pubertal stages were assessed by Tanner criteria. Blood samples were taken after an overnight fast. MF was assessed by the curl-up and push-up tests (from the Fitnessgram test battery). Adherence to the SEADiet was assessed with a semi-quantitative food frequency questionnaire. Linear regression models showed that MF was inversely associated with hs-CRP (unstandardized B = -0.127; p < .009), after adjustments for age, sex, and pubertal stage, adherence of SEADiet, total energy intake and low-energy reporter and WC. Analysis of covariance (ANCOVA) showed a significant difference between the low adherence of SEADiet with low MF group and those with a high adherence of SEADiet and high MF (p < .05) (F(5, 453) = 2.238, p = .040). Our results showed that MF is inversely associated with hs-CRP. In addition, the adolescents with Low adherence of SEADiet/Low MF group had high levels of hs-CRP compared those who with high adherence of SEADiet/high MF group.