Worldwide trends in underweight and obesity from 1990 to 2022: a pooled analysis of 3663 population-representative studies with 222 million children, adolescents, and adults

BACKGROUND

Underweight and obesity are associated with adverse health outcomes throughout the life course. We estimated the individual and combined prevalence of underweight or thinness and obesity, and their changes, from 1990 to 2022 for adults and school-aged children and adolescents in 200 countries and territories.

METHODS

We used data from 3663 population-based studies with 222 million participants that measured height and weight in representative samples of the general population. We used a Bayesian hierarchical model to estimate trends in the prevalence of different BMI categories, separately for adults (age ≥20 years) and school-aged children and adolescents (age 5-19 years), from 1990 to 2022 for 200 countries and territories. For adults, we report the individual and combined prevalence of underweight (BMI <18·5 kg/m2) and obesity (BMI ≥30 kg/m2). For school-aged children and adolescents, we report thinness (BMI <2 SD below the median of the WHO growth reference) and obesity (BMI >2 SD above the median).

FINDINGS

From 1990 to 2022, the combined prevalence of underweight and obesity in adults decreased in 11 countries (6%) for women and 17 (9%) for men with a posterior probability of at least 0·80 that the observed changes were true decreases. The combined prevalence increased in 162 countries (81%) for women and 140 countries (70%) for men with a posterior probability of at least 0·80. In 2022, the combined prevalence of underweight and obesity was highest in island nations in the Caribbean and Polynesia and Micronesia, and countries in the Middle East and north Africa. Obesity prevalence was higher than underweight with posterior probability of at least 0·80 in 177 countries (89%) for women and 145 (73%) for men in 2022, whereas the converse was true in 16 countries (8%) for women, and 39 (20%) for men. From 1990 to 2022, the combined prevalence of thinness and obesity decreased among girls in five countries (3%) and among boys in 15 countries (8%) with a posterior probability of at least 0·80, and increased among girls in 140 countries (70%) and boys in 137 countries (69%) with a posterior probability of at least 0·80. The countries with highest combined prevalence of thinness and obesity in school-aged children and adolescents in 2022 were in Polynesia and Micronesia and the Caribbean for both sexes, and Chile and Qatar for boys. Combined prevalence was also high in some countries in south Asia, such as India and Pakistan, where thinness remained prevalent despite having declined. In 2022, obesity in school-aged children and adolescents was more prevalent than thinness with a posterior probability of at least 0·80 among girls in 133 countries (67%) and boys in 125 countries (63%), whereas the converse was true in 35 countries (18%) and 42 countries (21%), respectively. In almost all countries for both adults and school-aged children and adolescents, the increases in double burden were driven by increases in obesity, and decreases in double burden by declining underweight or thinness.

INTERPRETATION

The combined burden of underweight and obesity has increased in most countries, driven by an increase in obesity, while underweight and thinness remain prevalent in south Asia and parts of Africa. A healthy nutrition transition that enhances access to nutritious foods is needed to address the remaining burden of underweight while curbing and reversing the increase in obesity.

FUNDING

UK Medical Research Council, UK Research and Innovation (Research England), UK Research and Innovation (Innovate UK), and European Union.

Assessment of the reliability of YouTube™ videos about zirconia crowns in pediatric dentistry

PURPOSE

To evaluate the reliability of YouTube™ videos on zirconia crowns in pediatric dentistry.

METHODS

On January 4, 2022, a search was performed using the term "pediatric zirconia crown". The first 100 videos on the subject were included. Non-English videos, duplicates, and off-topic videos were excluded. For each video, an examiner recorded the number of views, likes, comments, channel followers, upload date, duration, and category rating. Two examiners assessed the reliability of the information presented in the videos using DISCERN, a brief questionnaire and scale score used to assess in a valid and reliable way the quality of information on treatment choices for health problems. Descriptive and inferential analyses were performed (p < 0.05).

RESULTS

Of the initial 100 videos, 72 were excluded because of language, duplication, and subject matter. The 28 remaining videos had an average of 3.5 comments, 8,896.18 channel followers, 5,614.00 views, 19.14 likes, and a duration of 840.32 s. The average view rate was 7.54 per day ± 10,206.81. There was a statistically significant difference between the number of views and comments (p < 0.001), likes and comments (p < 0.001), and likes and views (p = 0.006). According to the DISCERN, none of the videos received the maximum grade to be considered very good. Two were considered good, nine fair, fourteen poor, and three very poor.

CONCLUSION

Given that the majority of YouTube™ videos currently available on zirconia crowns in pediatric dentistry were deemed unreliable according to the DISCERN questionnaire, caution should be exercised when using the information presented.

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.

Obesogenic behavior clusters associated with weight status among Brazilian students: a latent class analysis

This study aimed to examine the association between clusters of physical activity (PA), diet, and television viewing (TV) with weight status among a representative sample of Brazilian students. Data from the National Health School-based Survey (PeNSE) 2015 were analyzed (n = 16,521; mean age 14.8, standard deviation 0.03 year). PA (minutes/week spent in leisure-time, and commuting to/from school), TV (hours/day), and weekly consumption of deep-fried empanadas, candies, sodas, ultra-processed foods, fast foods, green salads or vegetables, and fruits were self-reported on the validated PeNSE questionnaire. Latent class analysis defined behavior classes, and binary logistic regression assessed the association between clustering and weight status. Six classes' types with positive and negative behaviors were identified. Adolescents belonging to the "low TV time and high healthy diet" class had higher chances of being overweight (including obesity) compared to their peers in the "moderate PA and mixed diet" class. No associations were found in the other clusters. Mixed classes with healthy and unhealthy behaviors characterized adolescents' lifestyles and these profiles were related to weight status.

Physical Education for Health Among School-Aged Children and Adolescents: A Scoping Review of Reviews

BACKGROUND

Physical education (PE) classes in schools are considered relevant to implement interventions, especially focused on physical activity. However, evidence overviews on how PE classes contribute to general health (physical, social, affective, and cognitive domains) are still needed. Thus, we summarized evidence synthesis (eg, systematic reviews) that addressed the contribution of PE classes to the health of school-aged children and adolescents.

METHODS

We performed a scoping review with searches in 8 databases and institutional websites to find systematic reviews or meta-analyses that answered this review's research question. Data charting form included the identification of the study, health outcomes, and PE classes' strategies (policies and environment, curriculum, appropriate instructions, and evaluation). An interactive process was performed to build the evidence summary.

RESULTS

An initial search yielded 2264 titles, and 49 systematic reviews (including 11 with meta-analysis) were included in this review. Most documents reported the main benefits of PE classes on physical domain outcomes (eg, physical activity, cardiorespiratory fitness, body mass index, and fundamental motor skills). However, evidence on the benefits of PE classes in affective (eg, enjoyment, motivation, and autonomy); social (eg, cooperation, problem-solving, and making friends); and cognitive (eg, memory, attention, concentration, and decision making) domains were found. Strategies on PE classes for health benefits were highlighted.

CONCLUSIONS

These elements were detailed in the evidence summary, which may be considered to guide researchers, teachers, and practitioners to define research and practice priorities on PE class interventions for health in the school context.

National policies on physical activity from 64 countries with different economies: a scoping review with thematic analysis

In 2018, the World Health Organization (WHO) launched a Global Action Plan on Physical Activity (PA), which included 20 policy actions for creating active societies, environments, people, and systems The objective of this scoping review was to summarize the themes/contents of national PA policies/plans conforming to the WHO's proposals and the country's economy. This review followed PRISMA guidelines for scoping reviews. A systematic search of electronic databases (Web of Science, Medline/PubMed, LILACS, PsycINFO, Scopus, and SPORTDiscus) and 441 government documents/websites from 215 countries/territories was conducted (February 2021). Documents on national-level policies, published in English, Spanish, and Portuguese since 2000 were eligible. The information on content and structure was systematically extracted and summarized into dimensions WHO's: active societies, environments, people, and systems The search identified 888 article references and 586 potentially relevant documents. After screening, 84 policy documents from 64 countries were eligible. Most documents(n = 46) provided detailed PA policies/plans amid other health topics (e.g. noncommunicable diseases, named 'general documents'), and 38 were PA-specific. The content analysis merged 54 visions, 65 missions, 108 principles, 119 objectives, 53 priorities, 105 targets, 126 indicators, and 1780 actions/strategies from 38 PA-specific and 46 general documents. Among the PA-specific documents, the active system's dimension was the most contemplated in the principles(n = 43), priorities(n = 51), and action/strategies(n = 530) elements. At the same time, the objectives(n = 39), targets(n = 52), and indicators(n = 58) presented contents more frequently related to the active people dimension. For the general documents, all principles(n = 4), objectives(n = 14), and priorities(n = 7) were related to the dimension of active people, while target(n = 51), indicator(n = 53), and actions/strategies(n = 292) elements presented content related to all dimensions. The increase in countries with national PA policies/plans should be followed by improving the current ones because important dimensions seem to be not considered in these documents. This will facilitate a global PA agenda that considers the complexity and multidimensionality of PA promotion.

A systematic review of the clustering and correlates of physical activity and sedentary behavior among boys and girls

Identifying the clustering and correlates of physical activity (PA) and sedentary behavior (SB) is very important for developing appropriate lifestyle interventions for children and adolescents. This systematic review (Prospero CRD42018094826) aimed to identify PA and SB cluster patterns and their correlates among boys and girls (0-19 years). The search was carried out in five electronic databases. Cluster characteristics were extracted in accordance with authors' descriptions by two independent reviewers and a third resolved any disagreements. Seventeen studies met the inclusion criteria and the population age ranged from six to 18 years old. Nine, twelve, and ten cluster types were identified for mixed-sex samples, boys, and girls, respectively. While girls were in clusters characterized by "Low PA Low SB" and "Low PA High SB", the majority of boys were in clusters defined by "High PA High SB" and "High PA Low SB". Few associations were found between sociodemographic variables and all cluster types. Boys and girls in "High PA High SB" clusters had higher BMI and obesity in most of the tested associations. In contrast, those in the "High PA Low SB" clusters presented lower BMI, waist circumference, and overweight and obesity. Different cluster patterns of PA and SB were observed in boys and girls. However, in both sexes, a better adiposity profile was found among children and adolescents in "High PA Low SB" clusters. Our results suggest that it is not enough to increase PA to manage the adiposity correlates, it is also necessary to reduce SB in this population.

Association of High Blood Pressure With Physical Activity, Screen-Based Sedentary Time, and Sedentary Breaks in a 2-Year Cohort of Community Dwelling Adults

Objective: This study analyzed the association of high blood pressure (HBP) with physical activity, sedentary behavior, and sedentary breaks in 2-year follow-up.

Methods: A sample of 331 middle-aged and older adults (mean age of 59.6 ± 17.3 years) was randomly selected and assessed at baseline and after 2 years of follow-up. HBP was considered as ≥140/90 mmHg values of systolic and diastolic blood pressure. Physical activity, sedentary behavior, and sedentary breaks were assessed by questionnaire. Age, sex, socioeconomic status, and body mass index were covariates.

Results: Continuous HBP was observed in 26.3% of sample between baseline and follow-up. Adults who reported continuously high sedentary breaks at leisure activities were less likely to have HBP (OR = 0.34, p = 0.011), as well as those who remained high physically active (OR = 0.41, p = 0.016), even after mutual adjustment. No association was observed between high sedentary behavior and HBP at follow-up.

Conclusion: Community dwelling adults who were high active and performed frequent sedentary breaks were less likely to have HBP in 2-year follow-up. Strategies for HBP control should considered both physical activities and leisure sedentary breaks in adult population.

Results from Brazil's 2022 Report Card on Physical Activity for Children and Adolescents

This research aims to summarize the process and results of the 2022 Report Card on Physical Activity for Brazilian children and adolescents. A group of experts led by 10 PhD researchers gathered the best possible evidence on physical activity indicators. The Report Card Brazil 2022 included the top 10 indicators of physical activity and sleep, obesity, and poor mental health variables, which made up four dimensions: (I) Daily Behaviors; (II) Settings and Sources of Influence; (III) Government Strategies and Investments; and (IV) Health Outcomes. Comprehensive searches, including peer-reviewed and gray literature searches, were performed for each indicator. Data were considered from systematic reviews, local and national surveys, websites, and official information from the Brazilian Federal Government. Grades from the indicators ranged from F (Active Play) to B (School). In addition, the results found for each indicator were Overall Physical Activity (D), Organized Sport Participation (C-), Active Transportation (C), Sedentary Behaviors (D), Sleep (C), Family and Peers (C-), Community and Environment (C), Government (D+), Physical Fitness (D+), Obesity (11.7%), and Poor Mental Health (37.8%). Successfully strategies for increasing physical activity among Brazilian children and adolescents should look at the different indicators presented in this report.

Association between simultaneity of health-risk behaviours and self-rated health in Brazilian adolescents

Introduction

This study examined the association between simultaneity of four health-risk behaviours, namely, low levels of moderate-to-vigorous physical activity (insufficient MVPA: <420 min/week), tobacco use, alcohol consumption, and excessive television (TV)–(>2 h/d of TV viewing) and self-rated health (SRH) in Brazilian adolescents.

Methods

We used data of 100,551 adolescents from the National School Health Survey, a national cross-sectional study carried out in 2015. Association between simultaneity of health risk behaviours (i.e. the ratio between observed and expected prevalence rates) and SRH was examined using logistic regression models.

Results

The majority of the participants were female (51.9%) and 14 years of age (50.6%), and 26% of the participants’ SRH ranged from ’average’ to ’extremely poor’. Those who engaged in the following combinations of health-risk behaviours had higher odds of worse SRH than their healthier counterparts: insufficient MVPA and tobacco use (odds ratio—OR: 2.0, 95% confidence interval [CI]: 1.4 to 3.0); insufficient MVPA and alcohol consumption (OR: 1.6, 95%CI: 1.3 to 1.9); insufficient MVPA and >2 h/day of TV viewing (OR: 1.3, 95%CI: 1.1 to 1.6); insufficient MVPA, tobacco use and alcohol consumption (OR: 2.1, 95%CI: 1.7, to 2.7); and insufficient MVPA, alcohol consumption and >2 h/day of TV viewing (OR: 1.6, 95%CI: 1.4 to 2.0).

Conclusions

Insufficient MVPA, alcohol consumption, and other health-risk behaviours were associated with worse SRH in Brazilian adolescents.

Mapping recommended strategies to promote active and healthy lifestyles through physical education classes: a scoping review

Background

Understanding which strategies have been recommended for the promotion of active and healthy lifestyles through physical education (PE) classes can guide PE policies and practice. Therefore, we summarized worldwide recommendations regarding strategies for PE classes that have aimed to promote active and healthy lifestyles among school-aged children and adolescents.

Methods

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) guidelines were utilized. A literature search was carried out in June 2020 in eight peer-reviewed literature databases, in addition to searches in institutional and personal libraries. The eligibility criteria included any online document that included recommendations targeting any dimension of PE classes (e.g., policy and environment, curriculum, appropriate instruction, student assessment, and strategies that interact with PE) published since 2000.

Results

In total, 2,408 potentially eligible documents were screened. Of these, 63 were included in the final analysis. The recommended strategies were as follows: six referred to policy and environment (valuing PE, higher frequency and duration of classes, inclusive PE classes, mandatory daily classes, evaluation of PE classes, and qualified teachers), five to curriculum (structure, type of content, cross-cutting themes, and components that improve PE classes), four to appropriate instruction (promotion of physical activities, inclusion of social issues, employment of the use of innovative technologies, and organization of the teaching–learning process), and three to student assessment (understanding human movement concepts, evaluation of contents, and assessment methods to develop an active and healthy lifestyle).

Conclusion

Twenty-one strategies recommended for PE classes linked to five dimensions aimed at different target populations were identified. Over half were linked to the dimensions of policy and environment and appropriate instruction. PE is recommended to be mandatory and valued at all educational levels, with weekly frequency that contributes to an active and healthy lifestyle. This review shows that guaranteeing different experiences beyond sports, improving social inclusion, using innovative technologies, and providing adequate materials and spaces to be important challenges and ways to guide policies, programs, and new research in this field of knowledge.

Open Science Framework Registration: https://osf.io/harwq/

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 ± 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.

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.

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 (β = 21.09, 95%CI 13.18; 28.98), engaged in more LPA (β = 17.60, 95%CI 8.50; 27.13), and engaged in less sedentary behaviour (β = -16.82, 95%CI -30.01; -4.30) and MVPA (β = -4.76, 95%CI -7.48; -1.96) than males. Age and sedentary behaviour were positively associated (β = 8.60, 95%CI 2.53; 14.64). Unprocessed foods were positively related to LPA (β = 2.21, 95%CI 0.55; 3.92), whereas processed foods were positively related to sedentary behaviour (β = 3.73, 95%CI 0.03; 7.38) and inversely related to MVPA (β = -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.

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.

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 (β = − 6.4, 95% CI: − 6.1;13.4), game time (β = − 8.2, 95% CI: − 7.2;10.8), computer time (β = 1.1, 95% CI: − 6.3;18.5), smartphone time (β = − 10.2, 95% CI: − 32.5;12.1), screen time (β = − 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 (β = − 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).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-021-11895-2.

Scoping Review on Interventions for Physical Activity and Physical Literacy Components in Brazilian School-Aged Children and Adolescents

This scoping review mapped the existing evidence on interventions to promote physical activity (PA) and/or components of physical literacy (PL) in Brazilian school-aged children and adolescents. Nine electronic databases and gray literature were consulted in May 2020, with no limit on year or language. School-based intervention studies (6 to 18 years old, primarily) that assessed PA or PL components (PA-related factors or attributes) were eligible. The studies were stratified by children (<12 years of age) and adolescents (≥12 years of age). A total of 63 documents were included, which refer to 42 different intervention studies. Twenty-five interventions focused on adolescents and 17 on children. The most-used strategies in the interventions were changes in physical and environmental education classes, extracurricular PA sessions, and health education. No study has analyzed all components of PL or evaluated PL using specific protocols or instruments. PA attributes were the most studied components (30 studies). This review identified the need to conduct interventions with strategies that target all components of PL, representing important elements for a research agenda that underlies school interventions that contribute to an active lifestyle.

Implementation of a school-based physical activity intervention for Brazilian adolescents: a mixed-methods evaluation

The effectiveness of physical activity interventions can be improved through examining the aspects related to their implementation. However, little such evidence has been collected, particularly in low- and middle-income countries. This study aimed to evaluate the implementation of a school-based physical activity intervention with qualitative and quantitative data from different actors (students, teachers and parents) involved in developing the program. The program was conducted in 2017 with three main components: (i) teacher training, (ii) environmental changes and (iii) educational actions. Mixed-method evaluation was performed by an independent evaluation team using a validated indicator matrix for the implementation process, including the self-reported information of students, teachers and parents, as well as interviews with teachers. In the 3 eligible schools, 350 adolescents (51% girls) answered the implementation questionnaire, as did 45 parents (84% mothers), and 47 teachers (70% female). In the qualitative analysis, 18 teachers participated. Categorical analysis found that the intervention was considered feasible by teachers. In general, teachers had a more positive perception of the implementation than did students. The lack of engagement from the school community and parents and the busy schedule of teachers were indicated to be the main difficulties. In conclusion, despite the teachers' motivation, some barriers prevented the successful implementation of the program.

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.

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.

Sedentary behavior in children and adolescents: an update of the systematic review of the Brazil’s Report Card

Abstract This review updated data on sedentary behavior in Brazilian children and adolescents for the Brazil’s Report Card 4.0. The searching was carried out in eight databases (PubMed, Scopus, Web of Science, LILACS, SPORTDiscus, BIREME, Scielo, and Google Scholar), based on the the following criteria: original research; samples including Brazilian children and adolescents; to be a observational survey with the prevalence of at least one component of sedentary behavior. In this updated review were included 118 studies (corresponding to 159 papers), being 71 studies (104 papers) previously reviewed in the Report Card 3.0 and 47 studies (55 papers) found in update from 2018 to 2019. Screen time (34.7%) and TV viewing (28.2%) remains the most investigated components, however, two studies investigated cell phone use, and there was an increase in other types of sedentary behavior such as sitting time (from 9% to 25.6%). We found only four studies involving pre-scholars, but four of them covered almost all age groups. Self-reported questionnaire was the instrument more used; however, increased the studies using accelerometers (from 2 to 8 studies). The cut-off point more frequent was 2 hours/day (47.5%), but the use of other measures doubled. Almost 70% of the studies reported that less than 50% (general range: 9.4% to 97.7%) of individuals had < 2 hours/day of sedentary behavior. The updated review found few studies with prescholars and children; using validated instruments; using accelerometers, with standardization of cutoff points, and prevalences very close to what was observed in the previous review.

Prevalence of global physical activity among young people: an updated systematic review for the Brazil’s Report Card

abstract This study aimed to update the review of Brazil’s Report Card on the prevalence of global physical activity (PA) among Brazilian children and adolescents. This systematic review included an electronic search of eight databases (PubMed, Scopus, Web of Science, LILACS, SPORTDiscus, BIREME, Scielo, and Google Scholar) and a manual search of the references of retrieved studies. Studies published in 2018 and 2019 that assessed global PA among Brazilian youth were included. A narrative approach to the results was adopted. The initial search retrieved 1,892 potentially relevant titles (1,244 titles after duplicate analysis), of which 62 (47 different studies) met all the inclusion criteria. Most updated studies were carried out in Southern (40.4%) and Southeastern (25.5%) Brazil. Six studies provided data from national surveys (12.8%), and one study included preschool children (< 5 years old). Ten studies objectively measured PA (accelerometer or pedometer devices). In the updated studies, the overall proportion of young people who were physically active ranged from 9.8% to 79.6%. Three national surveys reported the prevalence of physically active students, ranging from 18.4% to 78.8%. There was an increase of surveys that objectively measured PA and with children under 12 years of age in the 2018 and 2019 studies. However, important research gaps (e.g., variations in the measurement of global PA), even in the same study, should be considered to improve the monitoring and evaluation of global PA in Brazil.

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 (β = 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 (β = 1.19, 95%CI: 0.29; 2.08) was associated with better HRQoL, while processed food score (β = -0.45, 95%CI: -0.78; -0.13), working using screen devices for more than 4 h/day (β = -2.38, 95%CI: -4.52; -0.25), having experimented illicit drugs (β = -2.05, 95%CI: -3.20; -0.90), and sleeping less than 8 h/night (β = -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.

Protocol paper for the Movimente school-based program: A cluster-randomized controlled trial targeting physical activity and sedentary behavior among Brazilian adolescents

BACKGROUND

A better understanding of how multicomponent school-based interventions work and their effects on health and education outcomes are needed. This paper described the methods of the Movimente Program, a school-based intervention that aims to increase physical activity (PA) and decrease sedentary behavior (SB) among Brazilian students.

METHODS

This is a cluster randomized controlled trial with adolescents from 7th to 9th grade in public schools from Florianopolis, Southern Brazil. After agreement, 6 schools were randomly selected to intervention or control groups (3 schools each), and all eligible students were invited to the study. The Movimente intervention program was performed during a school year and included 3 main components: Teacher training (including face-to-face meeting, social media platform, and handbook with lesson plans); improvements in the PA environment in school; and educational strategies. Control schools continued with their traditional schedule. Baseline (March/April 2017), postintervention (November/December 2017), and maintenance (June/July 2018) evaluations included PA and SB as primary outcomes (assessed by self-report and accelerometry). Secondary outcomes included psychosocial factors related to PA and SB (e.g., social support and self-efficacy), as well as health (e.g., quality of life and nutritional status) and education (e.g., academic achievement) outcomes. A program evaluation was performed based on the RE-AIM framework. Participants, intervention staffs, and evaluators were not blinded to group assignment, but a standardized evaluation protocol was applied independently of the trial allocation.

RESULTS

Statistical analyses will include a multilevel approach for repeated measurements and mediation analysis. Any side effects of the intervention will be recorded. The sample size close to that expected (n = 1090) was reached (n = 999). The results of this trial will involve valuable information about the effect and the evaluation of a multicomponent intervention carried out in a middle-income country.

CONCLUSION

By creating opportunities for adolescents to be active at school using multicomponent strategies, the Movimente program has the potential to enhance students health and academic performance which may encourage the school community (e.g., teachers, principals) to adopt the program. Also, this trial will provide evidence for practitioners, policy makers, and researchers on how multicomponent program may be implemented in a school setting.

TRIAL REGISTRATION

The trial is registered at the Clinical Trial Registry (Trial ID: NCT02944318; date of registration: 18 October 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.

Clustering of obesogenic behaviors and association with body image among Brazilian adolescents in the national school-based health survey (PeNSE 2015)

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The co-occurrence of obesogenic behaviors is associated to body image indicators.

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Risk behaviors combined may set the adolescent at risk for psychological health.

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Adolescents in healthy clusters perceive themselves as having normal weight.

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Girls engaging in healthy clusters are less likely to use pills to control weight.

This study aimed to examine the association between clusters of obesogenic behaviors and body image indicators among a population-based sample of Brazilian adolescents. Data from a cross-sectional country representative survey of 9th grade students (N = 102,301) were analyzed. Physical activity (PA), sedentary behavior (SB) and body image indicators (i.e. satisfaction, perception, value, and weight control attitudes and behaviors) were self-reported. Three clusters were previously validated with two-steps cluster analysis: “Health-promoting SB and diet”, “Health-promoting PA and diet”, and “Health-risk”. Multinomial and binary logistic regression were used to associate clusters with body image indicators. Adolescents in the healthier clusters were more likely to be satisfied/very satisfied with body image and perceive themselves as having normal weight than those in the “Health-risk” cluster. Boys in both health-promoting clusters were more likely to consider body image as being important/very important and perceive themselves to be thin/very thin. Adolescents in the “Health-promoting PA and diet” cluster were more likely to be trying to lose or gain weight than those in the “Health-risk” cluster. Girls in the “Health-promoting SB and diet” cluster had lower odds of adopting unhealthy weight control behaviors than those in the “Health-risk” cluster. The effect of obesogenic behaviors on distinct aspects of body image was confirmed and found to vary according to different synergies between adolescents’ health-related behavior. These findings provide important insights on the understanding of behavioral profiles which can be targeted to prevent unhealthy weight control behaviors and weight related disorders, especially among girls.

Psychosocial mediators of screen time reduction after an intervention for students from schools in vulnerable areas: A cluster-randomized controlled trial

OBJECTIVES

To investigate whether psychosocial variables mediate the effect of a multicomponent intervention on screen time reduction among Brazilian students from schools located in vulnerable areas.

DESIGN

A cluster-randomized controlled trial with a 4-month follow-up.

METHODS

This study was conducted with 1085 students (548 in the intervention group and 537 in the control group), aged 11-17years. The intervention strategies focused on training teachers, increasing opportunities for physical activity at school, and reducing screen time, as well as health education. The questionnaire was administered before and after intervention with questions about the amount of time spent on TV and computer/video games on weekdays and weekend days (combined screen time). The potential psychosocial mediators (attitude, self-efficacy, family and school support) were measured through validated scales. Socioeconomic status was used as control variable. Multilevel mediation analyses were conducted using a product-of-coefficients test.

RESULTS

Psychosocial factors were not mediators of the effect of the intervention on screen time. The intervention significantly improved school support for both sexes (boys: 1.307; girls: 0.759; p<0.05) and older students (1.154; p<0.001). Attitude (boys: -0.228; 11-13years: -0.133; 14-17years: -0.152; p<0.05) and self-efficacy scales (boys: -0.040; girls: -0.104; 11-13years: -0.048; 14-17years: -0.100; p<0.05) were associated with reduced screen time.

CONCLUSIONS

The intervention produced a significant improvement of school support for both sexes, as well as older students. Enhancing attitude and self-efficacy may be a useful strategy for reducing screen time among boys and students of any age groups.

TRIAL REGISTRATION

ClinicalTrials.Gov: NCT02439827. Registration date: May 3, 2015.

[Assistance programs for physical activity in Brazilian schools: a review based on the RE-AIM model]

The analysis of physical activity (PA) assistance programs is of major importance to ensure progress in the area. The Reach, Efficacy, Adoption, Implementation and Maintenance (RE-AIM) tool has been broadly disseminated in the literature. This study set out to identify PA assistance programs among Brazilian students and analyze them using the RE-AIM tool. The search was conducted in the Lilacs, SportDiscus, SciELO, Scopus, Web of Science, EBSCOhot, PsycINFO and PubMed databases. After thoroughly researching titles, abstracts and studies, 15 articles (seven PA assistance programs) were included. The programs were conducted in the past decade at public schools in the South and Southeast of Brazil. Multicomponent (education and teacher training) strategies were used with positive results in the practice of PA. With respect to the results of the RE-AIM tool, it was found that the most reported dimensions were "reach" (74%), followed by "efficacy" (48%), "adoption" (43%), "implementation" (35%) and "maintenance" (5%). The indicators most frequently mentioned were those related to the internal validity of the program: demographic and behavioral information of the target population, method of identification of the target population, sample size, participation rate and number of organizational units involved.

Validity and reliability of an instrument to measure factors associated with screen time in Brazilian students

This study analyzed the validity and reliability of an instrument with scales measuring factors associated with screen time in adolescents. Two cross-sectional studies included students for analyses of validity and internal consistency (n=1138, 51.5% boys) and test-retest reproducibility (n=194, 56.2% boys). Individual (attitude, self-efficacy and expectations), social (behaviors, rules, beliefs and family support and support of school members) and physical environmental (home and bedroom equipment) factors of screen time were evaluated. All the scales of the instrument met the statistical criteria of the validity of the exploratory factorial analysis (p<0.001). The exploratory factorial analysis indicated five one-dimensional and three two-factor scales (self-efficacy, expectations and familiar behavior), with factorial loads of 0.56 to 0.88. There were significant correlations between the scores of almost all the scales and the reported screen time (p<0.05). Eight of nine scales/subscales showed Cronbach's α value being higher than 0.70, and ICC ranged from 0.63 to 0.83. In conclusion, the instrument presented scales with acceptable validity and reliability and can be used to measure factors associated with screen time in Brazilian students.

Clustering of diet, physical activity and sedentary behavior among Brazilian adolescents in the national school - based health survey (PeNSE 2015)

BACKGROUND

There is a lack of evidence regarding clusters of health-related behaviors among adolescents from low, lower-middle, and upper-middle income countries. This study aimed to identify clustering patterns of health-related behaviors (diet, physical activity [PA] and sedentary behavior [SB]) and association with sociodemographic variables among a population-based sample of Brazilian adolescents.

METHODS

Cross-sectional data from the 2015 National School-Based Health Survey (PeNSE). A total of 102,072 (females: 51.7%) students in ninth-grade (age: 14.3 ± 1.1 years-old) enrolled in public and private schools were investigated in this study. Healthy and unhealthy diet, PA and SB were measured using a validated questionnaire. Two-step cluster analysis was conducted to identify lifestyle patterns. The methodology for complex analysis and weighting was used to inferential statistical procedures. Multinomial logistic regression assessed associations between sociodemographic factors and the clusters.

RESULTS

Three reliable and meaningful clusters were identified and labelled as follows: (1) health-promoting SB and diet (32.6%); (2) health-promoting PA and diet (44.9%), and (3) health-risk (22.5%). Compared to boys, girls were less likely to be in clusters 1 (OR = 0.85; 95% CI = 0.78-0.93, p < 0.001) and 2 (OR = 0.43; 95% CI = 0.40-0.46, p < 0.001) than the health-risk cluster. Higher socioeconomic status was positively associated with health-promoting PA and diet, and negatively related to health-promoting SB and diet. Older adolescents were more likely to be in cluster 1 than in cluster 3, compared to younger adolescents.

CONCLUSION

Approximately one-quarter of the population (health-risk cluster) reported engaging in multiple risk behaviors. Interventions may need to be tailored to specific adolescent groups, especially considering sociodemographic differences.

Physical activity as part of daily living: Moving beyond quantitative recommendations

The purpose of this study is to discuss a paradigm shift towards a broader understanding of physical activity (PA) as part of daily living and, therefore, a different approach for PA guidelines, research, and promotion. To this aim, we centered the discussion in two topics: 1) PA: from a restricted view to a broader phenomenon; and 2) Recommendations for PA: moving beyond minutes and dose-response. A holistic understanding of PA and its relationship with health is not possible unless it is considered values, meanings, and symbols that impregnate the human behavior linked to the modes of living of a given people. If we do believe that PA is a behavior essential to human life, we must align our actions to our speech. However, current guidelines, as well as in most policies and programs of PA is largely portrayed as a way to attain longer life expectancy and less diseases, which runs against our consolidated understanding of PA as part of our everyday life. New guidelines could focus on how, when, why, where, and with whom we include PA in our daily lives, based on a day-long approach, instead of how much we should do in order to prevent non-communicable diseases.

Rationale and methods of a cluster-randomized controlled trial to promote active and healthy lifestyles among Brazilian students: the "Fortaleça sua Saúde" program

Background

Interventions on adolescents’ lifestyle are important, but the main mechanisms that explain the changes (mediating variables) on lifestyle are unclear. This paper presents the rationale and methods of an intervention program focused on promoting active and healthy lifestyles (especially physical activity [PA] practice and reducing screen time) among Brazilian students-the Fortaleça sua Saúde program (Portuguese for “strengthen your health”).

Methods/Design

This is a school-based cluster-randomized controlled trial. Three intervention and three control (no intervention) full-time public schools were randomly selected in Fortaleza, northeastern Brazil. Students (n = 1,272) from classes in Grades 7–9 were eligible, and 1,085 (548 in the intervention and 537 in control schools) completed the baseline and follow-up measures. The program duration was approximately four months and took place in 2014. Intervention strategies focused on teacher training, activities on health in the curriculum, active opportunities in the school environment (the availability of equipment for PA), and health education (health materials for students and parents). Data collection was undertaken before and immediately after the intervention. The primary variables included the practice of PA (weekly PA volume, PA behavior change stage and preference for PA during leisure-time) and screen time (TV and computer/video games). Potential intrapersonal, interpersonal and environmental mediators of PA and screen time were evaluated by a standardized questionnaire. Other lifestyle components (e.g., eating habits, substance use), psychological (e.g., self-rated health, body satisfaction) and biological (general and abdominal obesity) aspects, as well as academic performance were also evaluated in the total sample. Depressive symptoms, eating disorders, sleep quality, objectively-measured PA, and sedentary time were evaluated in obese students.

Discussion

If effective, this program will contribute to the development of public policies for the promotion of active and healthy lifestyles in youth, especially those from low- and middle-income countries. The main intrapersonal, interpersonal and/or environmental mediators of PA and screen time may also be indicated. Finally, we anticipate that the proposed strategies may be adaptable to public schools and may even be extended to the entire school system.

Trial registration

ClinicalTrials.Gov: NCT02439827. Registration date: May 3, 2015.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-015-2543-2) contains supplementary material, which is available to authorized users.

The association of HPV genotype with the regression, persistence or progression of low-grade squamous intraepithelial lesions

BACKGROUND

Human papillomavirus (HPV) is a highly prevalent sexually transmitted virus causing cytological alterations that precede cervical cancer. Approximately 130 genotypes have been sequenced. Low-grade squamous intraepithelial lesions (LSIL) are the most frequent cytological alteration and have an uncertain behavior.

OBJECTIVES

To analyze the frequency of HPV types in LSIL and their association with the regression, persistence or progression of these lesions.

METHODS

A cohort study of forty patients with LSIL cytology was conducted from December 2007 to March 2011. The follow-up lasted two years and included cytology and colposcopy. HPV detection was performed using PCR, and genotyping was performed using PCR-specific and RFLP techniques.

RESULTS

DNA-HPV was detected in 87% (35/40) of the cases, with oncogenic HPV accounting for 76%; type 16 in 32% (11/35) and type 18 in 20%. LSIL regression, persistence and progression rates at the end of the study were 60%, 23% and 17%, respectively. There was 50% regression in lesions in the high oncogenic risk group (types 16 and 18).

CONCLUSION

HPV 16 was the most frequent genotype found in LSIL. The persistence and progression of the LSIL were related to the persistence of oncogenic HPV. The longer the follow-up time, the lower the LSIL persistence rate and the higher its regression rate; the progression rate remained stable. In addition to the presence of oncogenic HPV, other factors are necessary for the progression of LSIL.

The Role of School Environment in Physical Activity among Brazilian Adolescents

Objective

To analyze the association of physical activity facilities and extracurricular sports activities in schools with physical activity among adolescents.

Methodology/Principal Findings

We used data collected for the National Survey of School Health in 2012. The national representative sample comprised 109,104 Brazilian students from 2,842 schools. We calculated the prevalence of participation in physical education classes, leisure-time physical activity, and total physical activity level. We also evaluated the following physical activity facilities: sports courts, running/athletics tracks, schoolyard with teacher-directed physical activities, swimming pools, locker rooms; and the offer of extracurricular sports activities. Schools with at least one physical activity facility had increased odds of participation in physical education (OR 1.59; 95% CI 1.20 to 2.10). However, in order to increase leisure-time physical activity (OR1.14; 95% CI 1.03 to 1.26) and total physical activity level (OR 1.15; 95% CI 1.06 to 1.24) at least four and two facilities, respectively, were necessary. Extracurricular sports activities in schools were positively associated with leisure-time physical activity and physical activity level. The number of sports courts and swimming pool in a school were associated with participation in physical education classes. Availability of sports courts, running/athletics tracks, and swimming pool in schools were associated with leisure-time physical activity. Total physical activity was associated with schools with sports courts, schoolyard with teacher-directed physical activities, and swimming pool.

Conclusions

School-level characteristics have important potential to increase the possibility of engagement in physical activity in and out of school, and therefore have a fundamental role in promoting these practices.

Barriers associated with frequency of leisure-time physical activity among Brazilian adults of different income strata

This study aimed to estimate the prevalence of the main perceived barriers to leisure-time physical activity (LTPA) and their associations with the frequency of LTPA in a representative sample of industrial workers from Brazil (n = 47,477), according to their income strata (low income: ≤$US280, middle income: $US281-$US1400, and high income: ≥$US1401). Data were collected between 2006 and 2008 via questionnaires about the main perceived barrier to LTPA and the frequency of LTPA. Multinomial logistic regression was performed to evaluate differences among groups. There was a lower prevalence of regular practice of LTPA in the low- (15.8%) and middle-income strata (18.2%) than among the individuals of the high-income stratum (27.6%). A large proportion of workers who regularly participated in LTPA reported no barriers (low: 43.1%; middle: 46.8%; high: 51.6%). Additional obligations and fatigue were the two most common perceived barriers in all family income strata among participants who engaged in different frequencies of LTPA. The odds for all perceived barriers showed a positive trend related to frequency of LTPA (from regular to no LTPA), with higher values according to income. In summary, the ordering of the main perceived barriers to LTPA differed according to workers' income stratum and frequency of engaging in LTPA.

Time spent by Brazilian students in different modes of transport going to school: changes over a decade (2001-2011)

To examine changes in the time spent in each mode of transportation used for going to school by gender and age among adolescents from Santa Catarina State, Brazil. Two school-based surveys were performed in 2001 (N = 5,028) and 2011 (N = 6,529) in high school students (15-19 years old). The mode of transportation (on foot; by bicycle; by bus; car/motorcycle) and the time spent for commuting to school were assessed. Active commuting increased for short trips in both genders (male: 25.1% to 36.7%; female: 18.8% to 29.2%) and in all ages (15-16 years: 21% to 32.7%; 17-19 years: 21.9% to 32.4%), and declined for longer trips in males (30.5% to 21.9%) and in 15-16 years old students (25.7% to 34.7%). Car/motorcycle use has doubled for short trips in males (38.1% to 65.9%) and in 17-19 years old students (37.7% to 62.7%), while the use of buses remained stable in both genders. Our findings contribute to discussions on public policy focusing on the design of safe environments to promote active commuting to schools, particularly to decrease the use of motorized transport for short trips.

Overweight in Brazilian industry workers: Prevalence and association with demographic and socioeconomic factors and soft drink intake

Objective: To estimate the prevalence of overweight in industry workers and its association with demographic and socioeconomic factors and soft drink intake (including type). Methods: This is a nationwide cross-sectional cohort survey of "Lifestyle and leisure habits of industry workers" conducted between 2006 and 2008 in 24 Brazilian federate units. The participants answered a previously tested questionnaire and self-reported their weight and height. Statistical analyses consisted of crude and adjusted Poisson regression. Results: Males and females had overweight prevalences of 45.7% (95%CI=45.1; 46.2) and 28.1% (95%CI=27.4; 28.9) respectively. Older and married individuals and those working in medium-sized and large factories were more likely to be overweight. Males with higher education levels and gross family incomes were also more likely to be overweight, but not females. Finally, men (PR=1.24; 95%CI=1.13; 1.36) and women (PR=1.40; 95%CI=1.22; 1.61) who consumed diet/light soft drinks were also more likely to be overweight than those who did not consume soft drinks. Conclusion: More than one-third of the workers were overweight according to their self-reported weight and height, and the prevalence of overweight was higher in males. Demographic and socioeconomic variables and diet/light soft drink intake were associated with overweight. These data may be helpful for the development of actions that reduce the risk of overweight in this population.

Gender differences in the clustering patterns of risk behaviours associated with non-communicable diseases in Brazilian adolescents

OBJECTIVE

The aim of this study is to investigate gender differences in the clustering of risk behaviours associated with chronic non-communicable diseases in Brazilian adolescents.

METHODS

A cross-sectional survey was conducted in 2011 comprising 6529 adolescents aged 15-19years from Santa Catarina State, Brazil. Excessive screen-time, insufficient moderate to vigorous physical activity (MVPA), low fruit/vegetable intake and consumption of alcohol were investigated. Poisson regression was performed in the analysis of sociodemographic factors associated with the clustering of three or more risk behaviours.

RESULTS

Girls presented with higher insufficient MVPA (76.3%), while boys presented with lower fruit or vegetable intake (53.0%) and greater consumption of alcohol (40.8%). A total of 21.2% of the teenagers had one risk behaviour, 37.3% had two, 28.5% had three, and 8.0% had all of the measured risk behaviours. Adolescents who did not work and boys who lived in urban areas exhibited more risk behaviours, whereas girls aged 17-19years old and boys who had mothers with ≥12years of study exhibited fewer risk behaviours.

CONCLUSION

There was a difference between genders for individual risk behaviours, and a high degree of clustering in both genders. Prevention programs could focus on these behaviours in order to reduce negative health outcomes in adolescents.

Which social support and psychological factors are associated to active commuting to school?

OBJECTIVE

The aim of this study was to investigate the association between self-efficacy, enjoyment, and volitional control with active commuting, as well as to analyze the impact of social support from parents, friends, and teachers with active commuting to school.

METHODS

Participants in this cross-sectional study were 625 students (male: 46.3%) aged 10 to 15years from Porto, Portugal (2010/2011). A questionnaire was used to assess active commuting to/from school (walk/cycle), self-efficacy, enjoyment, volitional control and social support. Binary logistic regression was performed to identify significant associations between targeted variables and active commuting.

RESULTS

The results show positive associations in crude analyses for all variables, except for enjoyment for walk/cycle to school. In the adjusted model, higher likelihood of active commuting was found among students who reported having higher self-efficacy (OR=2.10; CI95%: 1.07; 4.11) to walk/cycle to school as well as among adolescents who reported being encouraged by their parents (OR=3.66; CI95%: 1.55; 8.69), and having the partnership of friends in active journeys (OR=4.31; CI95%: 1.79; 10.37).

CONCLUSION

Self-efficacy, encouragement from parents and companionship from friends were important indicators of active commuting to school among Portuguese adolescents. These findings provide support for further research to identify and understand factors that predict and explain the active commuting.

Changes in television viewing and computers/videogames use among high school students in Southern Brazil between 2001 and 2011

OBJECTIVES

To compare the prevalence of television (TV) watching and of computer/videogame use among high school students (15-19 years) from Southern Brazil between 2001 and 2011 and to identify associated socio-demographic factors.

METHODS

Panel studies were conducted with high school students in the state of Santa Catarina, Brazil, in 2001 (n = 5,028) and 2011 (n = 6,529). TV watching and computer/videogame use were collected using questionnaires.

RESULTS

Prevalence of ≥2 h/day of TV watching dropped from 76.8 to 61.5 % and ≥2 h/day of computer/videogame use increased from 37.9 to 60.6 %. In both surveys, those aged 15-16 and those who did not work had higher likelihoods of being exposed to ≥2 h/day of TV watching. Boys, those with higher family income, and those who were living in urban areas had higher likelihoods of ≥2 h/day of computer/videogame use. Older age, studying at night and not working were protective factors to these behaviors.

CONCLUSIONS

After a decade, there was a decrease in the prevalence of TV viewing and an increase in computer/videogame use. Socio-demographic factors were differently associated with these behaviors.

Clustering of unhealthy behaviors in a Brazilian population of industrial workers

OBJECTIVE

To analyze the clustering of four unhealthy behaviors (tobacco use, excessive alcohol consumption, physical inactivity and low consumption of fruits and vegetables) and their association with sociodemographic factors among adult industrial workers in Brazil.

METHODS

Data from 23 Brazilian states and the Federal District were collected via questionnaire from 2006 to 2008. Clustering of risk behaviors was identified using the ratio between the observed and expected percentages of each combination of unhealthy behaviors.

RESULTS

Among the 44,477 workers surveyed, 18.0% of men and 11.4% of women accumulated three or four unhealthy behaviors. The most frequent combination was physical inactivity and low consumption of fruits and vegetables. The concurrent presence of all four behaviors was 86% higher in men and 148% higher in women than would be predicted if the frequency of these behaviors were independent. Presence of one or more negative behaviors was more frequent in men, younger individuals and in those with lower levels of education and family income than subjects without these characteristics.

CONCLUSIONS

There was a strong tendency for unhealthy behaviors to assume combinatorial patterns, mainly in men, people with less education, income, and age, suggesting important disparities.

Prognosis of intraepithelial cervical lesion during adolescence in up to two years of follow-up

Our objective was to describe the evolution of cervical SIL within 24 months of the initial diagnosis, in a cohort study of 147 sexually active adolescents attending a public health service in Rio de Janeiro, between 1993 and 2006. The participants were divided in two groups, according to whether cervical biopsy was performed or not. The median of the interval between sexual debut and the atypical cytopathology was 12 months and in 8.2% of patients there was a diagnosis of HSIL at the first abnormal smear. After a two-year follow-up by cytology, the regression (ASCUS 91%, LSIL 63.6%, HSIL 50%) and progression (LSIL 6.1%) were verified. In the group undergoing biopsy, the final histological regression reached 59.4% for CIN1 and 71.4% for CIN2, while the progression from CIN1 to CIN 2/3 was 3.1%. Our results corroborate the recommendation for conservative management in compliant adolescents due to a high regression rate. However, there should be maintained a careful follow-up based on the possible evolution of the lesion.

[Normal neonatal cerebral ultrasonography in preterm infants - Is it possible to calm down the parents?]

OBJECTIVE: To verify the predictive values of neonatal cerebral ultrasonography for motor and cognitive development of very low birth weight preterm babies after twelve months correct age. METHODS: The population studied was a cohort of preterm babies with birth weight less than 1,500g, who had been admitted in the Neonatal Intensive Care Unit of Instituto Fernandes Figueira, and were followed to 12-30 months corrected age for prematurity. A cerebral ultrasonography was performed before discharge. The results were classified as normal and abnormal (parenchymal hemorrhage, porencephaly, periventricular leucomalacia, ventricular dilatation). The babies were followed in the Follow-up Clinic and between 12-30 months correct age they underwent a neurological assessment with observation of the acquisition of motor milestones and submitted to Bayley Scales of Development. RESULTS: We studied 83 babies. Cerebral ultrasonography was normal in 68 babies (81.9%) and abnormal in 15 (18.8%). With a mean age of 21 months, 63 children (75.9%) had normal motor development and 20 (24.0%) had motor abnormalities. The cognitive development was normal in 68 children (81.9%). The negative predictive value of the cerebral ultrasonography for motor development was 85.3%, and for cognitive development, 86.8%. The positive predictive value of the cerebral ultrasonography for motor development was 66.7% and for cognitive development, 42.9%. CONCLUSIONS: The negative predictive values were greater than the positive predictive values in both areas of development. The probability for children with normal neonatal ultrasonography to have normal motor and cognitive development is greater than 85%.

[The predictive value of neonatal neurological assessment and neonatal cranial ultrasonography with respect to the development of very low birth weight premature infants]

OBJECTIVE

To verify the predictive value of two tests (neurological assessment and ultrasonography) performed at the time of discharge, with respect to the neuromotor and cognitive development of premature infants.

METHODS

Seventy very low birth weight premature infants (below 1,500 g), admitted to the Neonatal Department between 1992 and 1994 were studied. The average birth weight and gestation age were, respectively, 1,185 g (SD: 180 g) and 32.2 weeks (SD: 1.4). At the term correct age, neurological assessment by the Dubowitz & Dubowitz method and cerebral ultrasonography were carried out. After discharge, the development was monitored at the follow up clinic.

RESULTS

At 21 months correct age (SD: 4.9), neuromotor and cognitive abnormalities were observed, respectively, in 25.7% and 20.3% of the infants evaluated. The neonatal neurological assessment was found to be more sensitive than those specific for neuromotor (sensibility: 77.7%, specificity: 57.6%) and cognitive (sensibility: 78.5%, specificity: 56.4%) abnormalities, and exhibited low predictive value for both neuromotor and cognitive abnormality. Ultrasonography exhibited high specificity with respect to both neuromotor and cognitive development. The cerebral ultrasonography has also a reasonable predictive value for neuromotor abnormality.

CONCLUSION

The combination of both tests yielded higher predictive values.