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.

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.

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.

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.

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.

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.

The conception, content validation, and test-retest reliability of the Questionnaire for Screen Time of Adolescents (QueST).

OBJECTIVE: To analyze the content validity and the test-retest reliability of the Questionnaire for Screen Time of Adolescents (QueST). METHODS: A study was conducted with high school adolescents from Southern Brazil enrolled in public education (2019). The QueST measures screen time across five constructs: studying, working/internship-related activities, watching videos, playing games, using social media/chat applications. Content validation involved consulting with experts and adolescents to evaluate whether the five constructs were clear and representing screen time behaviors, all ratings were quantified. The experts' evaluation provided Content Validity Indexes (CVI) for clarity and representativeness of the questionnaire. Students answered the QueST twice (1-week apart), and differences between applications were verified. Test-retest reliability was assessed using Intraclass Correlation Coefficients (ICC) and Bland-Altman analyses. RESULTS: Among the experts, the CVI indicated 94% and 98% of clarity and representativeness, respectively. All items were highly clear for at least 70% of the students. Test-retest reliability was assessed with 104 students (16.3 ±â€¯1.02 years; 66.3% girls). The ICC ranged from 0.41 (95%CI 0.24-0.56) for videos to 0.76 (95%CI 0.66-0.83) for social media/chat applications on weekdays; and from 0.24 (95%CI 0.04-0.41) for videos to 0.67 (95%CI 0.54-0.77) for social media/chat applications on weekends. The lowest mean difference was -4.6 min for working on weekdays, while the highest was 40.6 min for videos on weekends. CONCLUSIONS: The QueST proved to be fair to excellent for measuring different screen time constructs. However, the item of videos (weekends) showed poor stability. The QueST demonstrates satisfactory content validity attested by the experts and adolescents.

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.

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.

Is knowledge of screen time guidelines associated with stages of behavior change for television viewing among adolescents?

It is unknown whether knowledge of guidelines for television (TV) viewing translate into behavior change for TV time among adolescents. The purpose of the present study is to verify whether knowledge of TV recommendations (spending <2 hr/day watching TV) is associated with the stages of behavior change related to TV viewing among adolescents. Schoolchildren (11-16 years) from six schools were recruited. Their knowledge of TV guidelines (correct [<2 hr/day], overestimated [<1 hr/day or never watch TV], underestimated [<3hr/day or watch TV whenever they wanted], and do not know [response option]) and stages of behavior change related to TV (precontemplation, contemplation, preparation, action, and maintenance) were assessed by a questionnaire. Multinomial logistic regression was used to test the association between knowledge and stages of behavior change. A total of 792 adolescents (53% girls) participated, of whom 45% were in the precontemplation stage, while 35% underestimated and 18% did not know the TV guidelines. Those who overestimated the guidelines had higher odds of being in the maintenance stage than did those who knew the recommendations correctly (odds ratio [OR] 2.06), while those who underestimated the guidelines had lower odds of being in the maintenance (OR 0.22) and any other stage compared to those who were aware of the recommendations (the precontemplation stage was the reference). Underestimating the guidelines was associated with being in the precontemplation stage, while overestimating them was associated with the maintenance stage. Interventions should test whether increasing knowledge can help shifting those in the precontemplation and contemplation toward action and maintenance.

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.

Are adolescents really being sedentary or inactive when at school? An analysis of sedentary behaviour and physical activity bouts.

This study analysed physical activity (PA) and sedentary behaviour (SB) performed in bouts during schooltime. Adolescents of two schools answered a questionnaire, had their height and weight measured and wore accelerometers during schooltime. Moderate-to-vigorous intensity PA was estimated in bouts of 2, 5 and 10 min, and SB in bouts of 5, 10, 30 and 60 min. Body mass index was calculated, and adolescents were classified as overweight or normal weight. Frequency, duration and volume of PA and SB were calculated for the whole sample and for those who performed at least one bout weekly. PA and SB differences between gender and weight status were tested using Mann-Whitney and t tests. A total of 415 adolescents (54% girls, 12.3 ± 1.3 years old, 34.6% overweight) performed 0.1 (± 0.2), 0.2 (± 0.5) and 0.4 (± 0.6) bouts of 10, 5 and 2 min of PA, and 10.6 (± 2.0), 6.0 (± 1.3), 1.1 (± 0.9) and 0.4 (± 0.5) bouts/day of 5, 10, 30 and 60 min of SB, respectively. Boys accumulated less SB and more PA in bouts. No differences were found for weight status.Conclusion: Adolescents hardly engaged in bouted PA and accumulated more SB in smaller bouts during schooltime. Bouted PA and SB were not associated with weight status. What is Known: • Adolescents are not engaging in enough PA and are accumulating large volumes of SB, which might negatively impact their health. • Schools play an important role in daily overall PA, with opportunities such as PE classes and recesses. But most classes are still undertaken in seated positions. What is New: • Adolescents hardly engage in bouted (> 10 m) PA when at school., and most SB is accumulated in short bouts (≤ 10m). • Weight status was not associated with bouted PA or SB at school.