Bidirectional Daily Associations Between Accelerometer-Measured Sleep and Physical Activity in Brazilian High School Students.

PURPOSE: This study analyzed day-to-day estimates of bidirectional associations between sleep parameters and intensity-specific physical activity and assessed whether the timing of physical activity influences these relationships. METHODS: The sample was comprised of 651 high school students (51.2% female, 16.33 [1.0] y old) from southern Brazil. Physical activity and sleep were measured using accelerometers. Multilevel models were applied to test associations of nocturnal total sleep time, onset, and efficiency with moderate to vigorous and light (LPA) physical activity. RESULTS: Higher engagement in moderate to vigorous physical activity and LPA was associated with increased total sleep time, and this effect was greater when physical activity was performed in the morning. Morning and evening LPA were associated with increased sleep efficiency and reduced total sleep time, respectively. Practice of LPA in the morning leads to early sleep onset, whereas evening LPA was associated with later onset. Higher total sleep time and later sleep onset were associated with lower moderate to vigorous physical activity and LPA on the following day. However, higher sleep efficiency was associated with increased LPA. CONCLUSION: The relationship between sleep parameters and physical activity is bidirectional and dependent on physical activity intensity and timing.

Clustering of Physical Activity, Sleep, Diet, and Screen-Based Device Use Associated with Self-Rated Health in Adolescents.

BACKGROUND: Little is known about how the interplay among health-related behaviors impacts self-rated health (SRH). We examined the clustering of physical activity (PA), sleep, diet, and specific screen-based device use, and the associations between the emergent clusters and SRH among Brazilian adolescents. METHOD: The data used in this cross-sectional study were from the baseline of the Movimente Program. Self-reported data were analyzed. SRH was recorded as a 5-point scale (from poor to excellent). Daily duration of exposure to the computer, the television, the cell phone, and games; PA; sleep; and weekly consumption of fruits and vegetables and ultra-processed foods were included in a Two-Step cluster analysis. Multilevel ordered logistic regressions assessed the associations between the clusters and SRH. RESULTS: The data of 750 students (girls: 52.8%, 13.1 ± 1.0 years) were analyzed. Good SRH was more prevalent (52.8%). Three clusters were identified: the Phubbers (50.53%; characterized by the longest cell phone use duration, shortest gaming and computer use, lowest PA levels, and low consumption of fruits and vegetables), the Gamers (22.80%; longest gaming and computer use duration, PA < sample average, highest intake of ultra-processed foods), and a Healthier cluster (26.67%; physically active, use of all screen-based devices < sample average, and healthier dietary patterns). For both Gamers (-0.85; 95% CI -1.24, -0.46) and Phubbers (-0.71; 95% CI -1.04, -0.38), it was found a decrease in the log-odds of being in a higher SRH category compared with the Healthier cluster. CONCLUSION: Specific clusters represent increased health-related risk. Assuming the interdependence of health-related behaviors is indispensable for accurately managing health promotion actions for distinguishable groups.

Psychometric analysis of the Brazilian-version Kidscreen-27 questionnaire.

BACKGROUND: The objective of this study was to verify the reliability, discriminatory power and construct validity of the Kidscreen-27 questionnaire in Brazilian adolescents. METHODS: Adolescents that participated of the pilot study (210 adolescents; 52.9% boys; 13.7 years old) and of the baseline (816 participants; 52.7% girls; 13.1 years old) of the Movimente Project in 2016/2017 composed the sample of the present study. This project was carried out in six public schools in the city of Florianópolis, Santa Catarina, Brazil. Test-retest reproducibility was assessed by the intraclass correlation coefficient and Gwet coefficient; internal consistency through McDonald's Omega; Hankins' Delta G coefficient verified the scale's discriminatory power and; confirmatory factor analysis to assess construct validity. RESULTS: Reproducibility values ranged from 0.71 to 0.78 for the dimensions (ICC), and ranged from 0.60 to 0.83 for the items (Gwet). McDonald's Ômega (0.82-0.91) for internal consistency measures. Discriminatory power ranging from 0.94 for the dimension Social Support and Friends to 0.98 for Psychological Well-Being. The factorial loads were > 0.40, except for item 19 (0.36). The fit quality indicators of the model were adequate (X2[df] = 1022.89 [311], p < 0.001; RMSEA = 0.053 (0.049-0.087); CFI = 0.988; TLI = 0.987), confirming the five-factor structure originally proposed. CONCLUSIONS: The Brazilian-version Kidscreen-27 achieved good levels of reproducibility, internal consistency, discriminatory power and construct validity. Its use is adequate to measure the health-related quality of life of adolescents in the Brazilian context.

Association between sociodemographic, dietary, and substance use factors and accelerometer-measured 24-hour movement behaviours in Brazilian adolescents.

Sociodemographic factors and lifestyle behaviours were evidenced as correlates of self-reported 24-hour movement behaviours in high-income settings. However, it is unclear how these relations occur in a middle-income country setting, with unique cultural and social characteristics. This study aimed to examine the association between sociodemographic, dietary, and substance use factors with accelerometer-measured 24-hour movement behaviours in Brazilian adolescents. Information on sex, age, socioeconomic status (SES), family structure, dietary behaviours, and history of substance use were collected by a questionnaire. Sleep duration, sedentary behaviour, and light- and moderate-to-vigorous physical activity (LPA and MVPA) were measured using wrist-worn accelerometers. On average, females slept more (ß = 21.09, 95%CI 13.18; 28.98), engaged in more LPA (ß = 17.60, 95%CI 8.50; 27.13), and engaged in less sedentary behaviour (ß = -16.82, 95%CI -30.01; -4.30) and MVPA (ß = -4.76, 95%CI -7.48; -1.96) than males. Age and sedentary behaviour were positively associated (ß = 8.60, 95%CI 2.53; 14.64). Unprocessed foods were positively related to LPA (ß = 2.21, 95%CI 0.55; 3.92), whereas processed foods were positively related to sedentary behaviour (ß = 3.73, 95%CI 0.03; 7.38) and inversely related to MVPA (ß = -0.89, 95%CI -1.68; -0.10). Family structure, SES, and substance use factors were not significantly associated with any 24-hour movement behaviour.Conclusions: Sex, age, and dietary behaviours, unlike SES or substance use, were associated with 24-hour movement behaviours in this sample of Brazilian adolescents and are important factors to consider in interventions, policies, and practice. What is Known: • The 24-hour movement behaviours are composed of sleep, sedentary behaviour, and physical activity and are important determinants of health. • Most adolescents do not engage in adequate levels of physical activity, sedentary behaviour, and sleep, and there is a need to better understand factors related to these behaviours. What is New: • Sex, age, and dietary behaviours were associated with the 24-hour movement behaviours. • No associations were found between socioeconomic status and substance use with the 24-hour movement behaviours.

Effectiveness and moderators of a multicomponent school-based intervention on screen time devices: the Movimente cluster-randomized controlled trial.

BACKGROUND: Interventions targeting reduce screen time in adolescents are urgently needed, mainly in low and middle-income countries because of the lack of evidence. Thus, the aims of the study were to examine the effect of a cluster-randomized controlled trial on screen time (ST) devices among Brazilian adolescents and to identify possible moderators. METHODS: Movimente was a multicomponent school-based intervention that was performed in 2017 and consisted of teacher training, education curriculum, and environmental improvements. Baseline and post-intervention assessments (over one academic year) were conducted with students aged 10-16 years at baseline (baseline n = 921, [n = 538 intervention group; n = 383 control group]). A self-report questionnaire was used to measure daily minutes of device specific screen time (TV, computer, video games and smartphone) and demographic variables. Linear mixed models were used to examine intervention effects and an exploratory moderation analysis (sex, grade and socioeconomic status) was performed. RESULTS: The intervention had no significant effects on TV time (ß = - 6.4, 95% CI: - 6.1;13.4), game time (ß = - 8.2, 95% CI: - 7.2;10.8), computer time (ß = 1.1, 95% CI: - 6.3;18.5), smartphone time (ß = - 10.2, 95% CI: - 32.5;12.1), screen time (ß = - 12.8, 95% CI: - 50.5;24.8), meeting screen time guidelines (OR: 1.29, 95% CI: 0.65,2.57) and meeting screen time guidelines with smartphone (OR: 1.66, 95% CI: 0.37,7.40). There was a significant intervention effect on reducing TV time (ß = - 37.1, 95% CI: - 73.0, - 1.3) among 8th grade students only. CONCLUSIONS: The Movimente intervention was effective only for TV time among 8th grade students. Understanding how school-based interventions can improve adolescents' device specific screen time across age groups is needed. Future strategies should cover all screen-based devices. Further, there is a need for more studies in low- and-middle income countries to assist in the development of effective strategies. TRIAL REGISTRATION: Clinicaltrials.gov identifier NCT02944318 (25/10/2016).

Mediating role of screen media use on adolescents' total sleep time: A cluster-randomized controlled trial for physical activity and sedentary behaviour.

BACKGROUND: The present study aimed to analyse the effect of an intervention for increasing physical activity (PA) and reducing sedentary time on adolescents' total sleep time (TST) and to examine whether the effect on adolescents' TST was mediated by the intervention changes on screen-based sedentary time. METHODS: This study was a school-based cluster-randomized controlled trial conducted with Brazilian adolescents in Grades 7 to 9 (in 2017). Three schools participated in each of the intervention group (IG) and control group (CG). The intervention involved the following three strategies designed to increase PA and reduce sedentary time: (a) teacher training, (b) environmental improvements, and (c) health educational component. TST and screen-based sedentary time (television use, cell phone use, playing on computer/video game, and computer use that is not for gaming purposes) on weekdays and weekends were assessed using a standardized questionnaire. Generalized linear mixed models were conducted to verify the effect of the intervention on TST. Mediation analyses were used to examine the mediator role of changes in screen-based sedentary time in the relationship between the intervention and TST. RESULTS: Overall, 597 students participated in this study (mean age: 13.0 ± 1.0 years; IG: n = 351; CG: n = 246). The intervention had no effect on TST on weekdays and weekends. Adolescents in the IG were more likely to report ≤2 hr of television viewing per day on weekdays at follow-up. Mediated effects by screen media use were not significant. CONCLUSIONS: The school-based intervention for increasing PA and reducing sedentary time had no effect on adolescents' TST.

Modulating the Spin Seebeck Effect in Co2FeAl Heusler Alloy for Sensor Applications.

The thermoelectric conversion technique has been explored in a broad range of heat-flow sensors. In this context, the Spin Seebeck Effect emerges as an attractive candidate for biosensor applications, not only for the sensibility improvement but also for the power-saving electronic devices development. Here, we investigate the Longitudinal Spin Seebeck Effect in films with a Co 2 FeAl/W bilayer structure grown onto GaAs (100) substrate, systems having induced uniaxial magnetic anisotropy combined with cubic magnetic anisotropy. From numerical calculations, we address the magnetic behavior and thermoelectric response of the films. By comparing experiment and theory, we explore the possibility of modulating a thermoelectric effect by magnetic anisotropy. We show that the thermoelectric voltage curves may be modulated by the association of magnetic anisotropy induction and experimental parameters employed in the LSSE experiment.

Sociodemographic factors and lifestyle behaviours associated with bullying victimization and perpetration in a sample of Brazilian adolescents.

This article aims to identify the association of sociodemographic factors and lifestyle behaviours with bullying perpetration and victimization among high school students. The adolescents (n=852) answered a questionnaire about bullying (victims and perpetrators), sociodemographic factors (sex, age, maternal education, and participant's work status), tobacco use, alcohol use, illicit drug experimentation, physical activity, screen time, and sleep duration. Multilevel logistic regression models were performed. Older adolescents were less likely to be victims of bullying. Females were less likely to be perpetrators or victims of bullying. Adolescents who were working were more likely to be involved in bullying in both forms. Participation in non-sport activities and alcohol consumption were associated with higher odds of bullying victimization. We have identified specific populational subgroups that are more susceptible to being victims and/or perpetrators of bullying, which could support tailor-specific interventions to prevent bullying.

Screen Time Correlates of Bullying Perpetration and Victimization in Brazilian Adolescents.

This study is an investigation of the associations of time spent in different screen time activities with bullying among Brazilian adolescents. In this cross-sectional study, adolescents answered questions related to bullying in the past 30 days and reported the weekly volume of screen time spent studying, working, watching videos, playing video games, and using social media applications. Multilevel logistic regression models were used. Our results indicate that higher social media use was associated with higher odds of bullying victimization among males but not females. Excessive use of screen time for work and social media purposes was associated with a higher likelihood of bullying victimization.

The relationship between physical activity and depressive symptoms is domain-specific, age-dependent, and non-linear: An analysis of the Brazilian national health survey.

Although there is consistent evidence of the beneficial effects of leisure physical activity (PA) on mental health, the role of PA in the domestic, transport, and occupational domains is inconclusive. This study aimed to analyze the relationship between domain-specific PA and depressive symptoms and examine whether the association is moderated by age in a representative sample of the Brazilian population. Cross-sectional data of 89,923 (52.4% female) individuals aged ≥15 years were analyzed. Depressive symptoms were assessed using the Patient Health Questionnaire-9. Physical activity (min/week) performed in different domains (domestic, transport, occupation, and leisure) was self-reported. Generalized additive models with penalized splines were used to explore associations. Lower leisure-time PA and higher levels of PA in the domestic, occupational, and transport domains at distinct PA thresholds were associated with higher depressive symptoms. Leisure PA, even at lower levels, was associated with lower depressive symptoms compared to no PA at all. The increase in depressive symptoms as a function of occupational PA was observed only at PA levels higher than 40 h/week. Although non-leisure PA levels were related to higher depressive symptoms among the total sample, higher domestic and transport PA levels were related to lower depressive symptoms among older adults. This study provides insights into the non-linearity and age-group dependence of the relationship between domain-specific PA and depressive symptoms in a middle-income country. The evidence suggests that care should be taken on recommending PA regardless of context or domain.

Cross-Sectional Associations of Screen Time Activities With Alcohol and Tobacco Consumption Among Brazilian Adolescents.

Objectives: Little is known about the association between specific types of screen time and adolescents' substance use. Thus, this study aimed to investigate the associations between screen time for studying, working, watching movies, playing games, and using social media and frequency of alcohol and tobacco use. Methods: In this cross-sectional study, Brazilian adolescents answered survey questions related to frequency of tobacco and alcohol consumption, and reported their daily volume of five types of screen time. Multilevel ordered logistic regression models were performed. Results: Each 1-hour increase in ST for studying was associated with 26% lower odds of smoking (OR = 0.74; 95% CI: 0.61-0.90) and 17% lower odds of drinking alcohol (OR = 0.83; 95% CI: 0.76-0.91) in the past 30 days. The increase of 1 hour of social media use was associated with 10% greater odds of smoking (OR = 1.10; 95% CI: 1.02-1.18) and a 13% greater chance of consuming alcohol (OR = 1.13; 95% CI: 1.08-1.18) in the past 30 days. Conclusion: The association between screen time and substance use appears to be type-specific. Future longitudinal research is needed to explore causal relationships.

Movement behaviors and their association with depressive symptoms in Brazilian adolescents: A cross-sectional study.

BACKGROUND: Physical activity, sleep, and sedentary behaviors compose 24-h movement behaviors and have been independently associated with depressive symptoms. However, it is not clear whether it is the movement behavior itself or other contextual factors that are related to depressive symptoms. The objective of the present study was to examine the associations between self-reported and accelerometer-measured movement behaviors and depressive symptoms in adolescents. METHODS: Cross-sectional data from 610 adolescents (14-18 years old) were used. Adolescents answered questions from the Center for Epidemiological Studies Depression scale and reported time spent watching videos, playing videogames, using social media, time spent in various physical activities, and daytime sleepiness. Wrist-worn accelerometers were used to measure sleep duration, sleep efficiency, sedentary time, and physical activity. Mixed-effects logistic regressions were used. RESULTS: Almost half of the adolescents (48%) were classified as being at high risk for depression (score ≥20). No significant associations were found between depressive symptoms and accelerometer-measured movement behaviors, self-reported non-sport physical activity, watching videos, and playing videogames. However, higher levels of self-reported total physical activity (odd ratio (OR) = 0.92, 95% confidence interval (95%CI): 0.86-0.98) and volume of sports (OR = 0.88, 95%CI: 0.79-0.97), in minutes, were associated with a lower risk of depression, while using social media for either 2.0-3.9 h/day (OR = 1.77, 95%CI: 1.58-2.70) or >3.9 h/day (OR = 1.67, 95%CI: 1.10-2.54), as well as higher levels of daytime sleepiness (OR = 1.17, 95%CI: 1.12-1.22), were associated with a higher risk of depression. CONCLUSION: What adolescents do when they are active or sedentary may be more important than the time spent in the movement behaviors because it relates to depressive symptoms. Targeting daytime sleepiness, promoting sports, and limiting social media use may benefit adolescents.

Socioeconomics inequities associated with different domains of physical activity: results of the National Health Survey 2019, Brazil. / Iniquidades socioeconômicas associadas aos diferentes domínios da atividade física: resultados da Pesquisa Nacional de Saúde 2019.

OBJECTIVE: To examine the socioeconomic indicators associated with engagement in physical activity (PA) in the leisure-time, transportation, domestic and occupational domains, in Brazilian adults. METHODS: Cross-sectional study with secondary data from the National Health Survey (PNS), conducted in 2019. The factors associated with engagement in PA were analyzed using logistic regression. RESULTS: The study involved 88,500 Brazilian adults with mean age of 45 ± 17.5 years old. Longer working hours [odds ratio (OR) = 0.74; 95%CI 0.66;0.82; > 40h vs. ≥ 20h] and female sex (OR = 0.67; 95%CI 0.63;0.71) were associated with lower chances of engaging in leisure-time PA. Higher income (OR = 3.20; 95%CI 2.79;3.67; > 5 vs. ≥ minimum wage) and education level (OR = 3.01; 95%CI 2.74;3.32 - complete higher education vs. incomplete elementary school) were positively associated with leisure-time PA. CONCLUSION: Socioeconomic correlates were strongly related to engagement in PA in Brazilian adults, suggesting a pattern of inequity marked by the need for survival, which is socially reproduced.

Relationship between types of physical activity and depression among 88,522 adults.

BACKGROUND: Physical activity is associated with depression; however, the influence of physical activity type on this association remains poorly explored. We aimed to investigate the association between various types of leisure-time physical activity and depression among a large and representative sample. METHODS: Data from the 2019 Brazilian National Health Survey were used (n = 88,522 adults aged between 18 and 107 years, 53% female). Depression was measured using the Patient Health Questionnaire-9; participants' leisure-time physical activity types were self-reported. A four-step hierarchical regression was applied, and the analyses were adjusted for several confounders. RESULTS: Active individuals had lower odds of depression (odds ratio [OR], 0.71; 95% confidence interval [CI], 0.62-0.81); however, only outdoor walking/running (OR, 0.70; 95% CI, 0.60-0.82), cycling (OR, 0.50; 95% CI, 0.34-0.74), and team sports (OR, 0.52; 95% CI, 0.42-0.66) were associated with lower odds of depression than inactivity. CONCLUSIONS: Physical activity type may be associated with mental health. The qualitative mechanisms of some physical activities seem to have greater capability than others to reduce depression. Causal inferences could not be made, however, our findings suggest that specific physical activities types have additional benefits that can be used in promoting mental health in clinical intervention and at a population level.

Associations between Sociodemographic, Dietary, and Substance Use Factors with Self-Reported 24-Hour Movement Behaviors in a Sample of Brazilian Adolescents.

We aimed to identify sociodemographic, dietary, and substance use factors associated with self-reported sleep duration, physical activity (PA), and sedentary behavior (SB) indicators in a sample of Brazilian adolescents. Adolescents (n = 731, 51% female, mean age: 16.4 years) answered a questionnaire. The volume of total PA, sports, non-sports, total SB, leisure-time SB, involuntary SB, sleep duration, dietary behaviors, sociodemographic, and substance use indicators were self-reported. Multilevel linear models were fitted. Females engaged in less total PA, sports, total SB, and leisure-time SB, but in more involuntary SB than males. Age was positively associated with non-sports and involuntary SB. Socioeconomic status was positively associated with total PA. Adolescents who lived with the mother only practiced more sports compared to those living with two parents. Unprocessed food was positively associated with total PA and sports. Processed food was inversely associated with total PA and non-sports, and positively associated with total SB and leisure-time SB. Alcohol use was positively associated with total PA, and tobacco smoking was negatively associated with total PA. No associations were observed for sleep duration. In conclusion, sociodemographic, dietary, and substance use factors are associated with the 24 h movement behaviors among Brazilian adolescents, and some associations are type specific.

How do adolescents with short sleep duration spend their extra waking hours? A device-based analysis of physical activity and sedentary behaviour in a Brazilian sample.

OBJECTIVES: To compare sedentary behaviour and physical activity between short sleepers and adequate sleepers in a sample of Brazilian adolescents. MATERIAL AND METHODS: 688 adolescents wore accelerometers on the non-dominant wrist for seven days. Sleep duration, sedentary behaviour, light (LPA), moderate (MPA), and vigorous physical activity (VPA) were estimated. Participants were classified as short (<8h/night) or adequate sleepers (≥8h/night). The minutes and the percentage of time spent in each waking behaviour was compared between short and adequate sleepers. RESULTS: Participants were 16.3 years old, 50.4% were female, and 67.7% were short sleepers. Adequate sleepers engaged in less (min/day) sedentary behaviour (-53.46), LPA (-25.44), MPA (-4.27), and VPA (-0.63) compared to short sleepers. However, no differences were observed for the proportion of time (68% in sedentary behaviour, 28% in LPA, 3% in MPA, and <0.4% in VPA). CONCLUSION: Patterns of waking behaviours are similar between short and adequate sleepers.

Clustering of Physical Activity, Diet and Sedentary Behavior among Youth from Low-, Middle-, and High-Income Countries: A Scoping Review.

BACKGROUND: The interaction between physical activity (PA), diet, and sedentary behavior (SB) plays an important role on health-related outcomes. This scoping review (Prospero CRD42018094826) aims to identify and appraise clusters of PA, diet, and SB among youth (0-19 years) according to country income. METHODS: Five databases were searched. Fifty-seven articles met the inclusion criteria. RESULTS: Fifty-five cluster types were identified, with greater variety in high-income than lower income countries. The most prevalent profiles were "High SB and consumption of sugar, salt, and beverages (SSB)" (n = 17) and "High PA" (n = 13-5), both of which presented in all income countries. The healthiest profile, "High PA and fruit and vegetables (F&V); Low SB and SSB" (n = 12), was present in upper-middle and high-income countries, while the unhealthiest "Low PA and F&V; High SB and SSB" (n = 6) was present only in high-income countries. CONCLUSIONS: High SB and unhealthy diet (SSB) were more prevalent in clusters, mainly in high-income countries. The results support the need for multi-component actions targeting more than one behavior at the same time.

Efforts on Changing Lifestyle Behaviors May Not Be Enough to Improve Health-Related Quality of Life Among Adolescents: A Cluster-Randomized Controlled Trial.

Schools have been the main context for physical activity (PA) and sedentary behavior (SB) interventions among adolescents, but there is inconsistent evidence on whether they also improve dimensions of the health-related quality of life (HRQoL). The aim of this study was to evaluate the effects of a school-based active lifestyle intervention on dimensions of HRQoL. A secondary aim was to verify whether sex, age, and HRQoL at baseline were moderators of the intervention effect. A cluster-randomized controlled trial was conducted at three control and three intervention schools in Florianopolis, Brazil. All students from 7th to 9th grade were invited to participate. A school year intervention, designed primarily to increase PA and reduce SB, included strategies focused on (i) teacher training on PA, SB, and nutrition, and availability of teaching materials related to these contents; (ii) environmental improvements (i.e., creation and revitalization of spaces for the practice of PA in school); and (iii) education strategies, with the availability of folders and posters regarding PA, SB, and nutrition. Participants and the research staffs were not blinded to group assignment, but a standardized evaluation protocol was applied at baseline and after the intervention (March and November 2017) using the KIDSCREEN-27 to assess HRQoL across five dimensions. Mixed linear models were performed to evaluate the effect of the Movimente intervention on the five HRQoL dimensions. Of the 921 students who answered the questionnaire at baseline, 300 and 434 completed the study in control and intervention groups, respectively (dropouts: 20%). The results revealed no significant effects of the intervention on any HRQoL dimensions. A reduction of the school environment dimension was observed in both the control (-2.44; 95% CI: -3.41 to -1.48) and intervention groups (-2.09; 95% CI: -2.89 to -1.30). Sensitivity analyses showed that students in the highest baseline tertiles of HRQoL in any dimension had a reduction in their respective scores from pre- to post-intervention in both school groups. In conclusion, our results demonstrated no intervention effect on HRQoL dimensions and those students with the highest levels of HRQoL at baseline on all dimensions reduced from pre to post-intervention. CLINICAL TRIAL REGISTRATION: The trial is registered at the Clinical Trial Registry (Trial ID: NCT02944318; date of registration: October 18, 2016).

Attitudes towards body weight dissatisfaction associated with adolescents' perceived health and sleep (PeNSE 2015).

This study aimed to investigate whether attitudes towards body weight dissatisfaction is associated with perceived health and impairments in sleep among a national population-based sample of Brazilian adolescents. This is a cross-sectional data from the 2015 National School-Based Health Survey (PeNSE). A total of 100.182 students (70.8% were between 14 to 15) in ninth-grade, enrolled in public and private schools were eligible for data analysis. Variables were measured using a questionnaire and binary logistic regression was used. There was association between attitudes towards body weight dissatisfaction and perceived health (not controlling weight = OR: 2.19, 95%CI: 2.00-2.40; trying to lose = OR: 1.90, 95%CI: 1.75-2.05; gain = OR: 2.22, 95%CI: 2.01-2.46; maintain = OR: 1.81, 95%CI: 1.54-2.14). Adolescents were also more likely to present impairments in sleep (not controlling weight = OR: 1.21, 95%CI: 1.11-1.32; trying to lose = OR: 1.16, 95%CI: 1.08-1.25; gain = OR: 1.43, 95%CI: 1.28-1.61; maintain = OR: 1.43, 95%CI: 1.22-2.68). Dissatisfaction is an additional concern in the daily life of adolescents, which is associated to depreciation of the quality of sleep and decrement of psychological well-being.

Association between Lifestyle Behaviors and Health-Related Quality of Life in a Sample of Brazilian Adolescents.

This study aimed to analyze the association between lifestyle behaviors and health-related quality of life (HRQoL) among Brazilian adolescents. We evaluated 739 adolescents (51.0% girls; mean age, 16.4 ± 1.0 years) from the mesoregion Grande Florianópolis, Brazil. Participants were asked to complete an online questionnaire and sex, age, mother's education, health-related quality of life, physical activity, screen time indicators, sleep duration, diet, cigarette smoking, alcohol drinking, and drug experimentation were retrieved. Health-related quality of life was assessed using the Kidscreen-10 instrument. Measures of body mass and height were taken by trained researchers. Mixed-effects linear regression models were used. Self-reported health-related quality of life was higher in males (ß = 3.68, 95%CI: 2.75; 4.61) compared to females, and no association was observed for age and mother's education level. Practicing sports (ß = 1.19, 95%CI: 0.29; 2.08) was associated with better HRQoL, while processed food score (ß = -0.45, 95%CI: -0.78; -0.13), working using screen devices for more than 4 h/day (ß = -2.38, 95%CI: -4.52; -0.25), having experimented illicit drugs (ß = -2.05, 95%CI: -3.20; -0.90), and sleeping less than 8 h/night (ß = -1.35, 95%CI: -2.27; -0.43) were unfavorably associated with HRQoL. Non-sport physical activities, unprocessed food, studying, watching videos, playing videogames, using social media, alcohol drinking, and smoking were not associated with health-related quality of life. These findings suggest that promoting sports and adequate sleep, and preventing excessive workloads and the use of drugs among adolescents may be effective strategies to improve HRQoL.