Scientific sinkhole: estimating the cost of peer review based on survey data with snowball sampling.

BACKGROUND: There are a variety of costs associated with publication of scientific findings. The purpose of this work was to estimate the cost of peer review in scientific publishing per reviewer, per year and for the entire scientific community. METHODS: Internet-based self-report, cross-sectional survey, live between June 28, 2021 and August 2, 2021 was used. Participants were recruited via snowball sampling. No restrictions were placed on geographic location or field of study. Respondents who were asked to act as a peer-reviewer for at least one manuscript submitted to a scientific journal in 2020 were eligible. The primary outcome measure was the cost of peer review per person, per year (calculated as wage-cost x number of initial reviews and number of re-reviews per year). The secondary outcome was the cost of peer review globally (calculated as the number of peer-reviewed papers in Scopus x median wage-cost of initial review and re-review). RESULTS: A total of 354 participants completed at least one question of the survey, and information necessary to calculate the cost of peer-review was available for 308 participants from 33 countries (44% from Canada). The cost of peer review was estimated at $US1,272 per person, per year ($US1,015 for initial review and $US256 for re-review), or US$1.1-1.7 billion for the scientific community per year. The global cost of peer-review was estimated at US$6 billion in 2020 when relying on the Dimensions database and taking into account reviewed-but-rejected manuscripts. CONCLUSIONS: Peer review represents an important financial piece of scientific publishing. Our results may not represent all countries or fields of study, but are consistent with previous estimates and provide additional context from peer reviewers themselves. Researchers and scientists have long provided peer review as a contribution to the scientific community. Recognizing the importance of peer-review, institutions should acknowledge these costs in job descriptions, performance measurement, promotion packages, and funding applications. Journals should develop methods to compensate reviewers for their time and improve transparency while maintaining the integrity of the peer-review process.

Active Healthy Kids Global Alliance Global Matrix 4.0-A Resource for Physical Activity Researchers.

BACKGROUND: This brief report provides an overview of the Active Healthy Kids Global Alliance (AHKGA); an introduction to the Global Matrix 4.0; an explanation of the value and opportunities that the AHKGA efforts and assets provide to the physical activity research, policy, practice, and advocacy community; an outline of the series of papers related to the Global Matrix 4.0 in this issue of the Journal of Physical Activity and Health; and an invitation for future involvement. METHODS: The AHKGA was formed to help power the global movement to get kids moving. In 2019-2021, we recruited countries to participate in the Global Matrix 4.0, a worldwide initiative to assess, compare, and contrast the physical activity of children and adolescents. RESULTS: A total of 57 countries/jurisdictions (hereafter referred to as countries for simplicity) were recruited. The current activities of the AHKGA are summarized. The overall findings of the Global Matrix 4.0 are presented in a series of papers in this issue of the Journal of Physical Activity and Health. CONCLUSIONS: The Global Matrix 4.0 and other assets of the AHKGA are publicly available, and physical activity researchers, practitioners, policy makers, and advocates are encouraged to exploit these resources to further their efforts.

Global Matrix 4.0 Physical Activity Report Card Grades for Children and Adolescents: Results and Analyses From 57 Countries.

BACKGROUND: The Global Matrix 4.0 on physical activity (PA) for children and adolescents was developed to achieve a comprehensive understanding of the global variation in children's and adolescents' (5-17 y) PA, related measures, and key sources of influence. The objectives of this article were (1) to summarize the findings from the Global Matrix 4.0 Report Cards, (2) to compare indicators across countries, and (3) to explore trends related to the Human Development Index and geo-cultural regions. METHODS: A total of 57 Report Card teams followed a harmonized process to grade the 10 common PA indicators. An online survey was conducted to collect Report Card Leaders' top 3 priorities for each PA indicator and their opinions on how the COVID-19 pandemic impacted child and adolescent PA indicators in their country. RESULTS: Overall Physical Activity was the indicator with the lowest global average grade (D), while School and Community and Environment were the indicators with the highest global average grade (C+). An overview of the global situation in terms of surveillance and prevalence is provided for all 10 common PA indicators, followed by priorities and examples to support the development of strategies and policies internationally. CONCLUSIONS: The Global Matrix 4.0 represents the largest compilation of children's and adolescents' PA indicators to date. While variation in data sources informing the grades across countries was observed, this initiative highlighted low PA levels in children and adolescents globally. Measures to contain the COVID-19 pandemic, local/international conflicts, climate change, and economic change threaten to worsen this situation.

Profiles of mental health and their association with negative impacts and suicidal ideation during the COVID-19 pandemic: A Canadian perspective.

Background: Mental health among Canadians has worsened since the start of the COVID-19 pandemic. The purpose of this study was to identify profiles of mental health difficulties and to quantify the relationships between mental health profiles, negative impacts related to the pandemic and suicidal ideation. Data and methods: Participants were 22,721 adults (18 years and older) from the 2020 and 2021 Survey on COVID-19 and Mental Health. Latent profile analysis was used to identify patterns of anxiety, depression and psychological distress. The relationships between mental health profiles, negative impacts and suicidal ideation were examined using logistic regression models. Results: Three mental health profiles were identified. Individuals were classified as having no mental health difficulties (Profile 1, 65.70%), low-to-moderate mental health difficulties (Profile 2, 25.52%) and severe mental health difficulties (Profile 3, 8.78%). Individuals in Profiles 2 and 3 were at greater odds than individuals in Profile 1 of experiencing emotional distress; the death of a family member, friend or colleague; difficulty in meeting financial obligations or essential needs; the loss of a job or income; feelings of loneliness or isolation; physical health problems; challenges in personal relationships with household members; and other impacts. Individuals in Profile 2 (4.27%, odds ratio (OR) = 24.30) and Profile 3 (19.09%, odds ratio (OR) = 115.75) were considerably more likely to have contemplated suicide since the onset of the pandemic compared with those in Profile 1 (0.16%). Interpretation: Individuals who experienced high levels of anxiety, depression and psychological distress were most vulnerable to negative impacts related to the pandemic and suicidal ideation.

Associations between organized sport participation and mental health difficulties: Data from over 11,000 US children and adolescents.

The purpose of this study was to explore the association between participation in organized sport and a broad array of mental health difficulties among US children and adolescents. The data (cross-sectional) were from Data Release 3.0 (one-year follow-up visits on the full cohort) of the Adolescent Brain Cognitive Development (ABCD) study-a broadly representative sample of 11,235 US children and adolescents aged 9 to 13 years. Parents/guardians provided self-reports of their child's mental health difficulties using the Child Behavior Checklist. To assess participation in organized sport, children and adolescents were categorized into one of four groups: 1) participation in team sport, 2) participation in individual sport, 3) participation in team and individual sport, and 4) non-sport participation. Participation in team sport compared to non-sport participation was associated with 10% lower anxious/depressed scores, 19% lower withdrawn/depressed scores, 17% lower social problems scores, 17% lower thought problems scores, and 12% lower attention problems scores. Participation in team sport compared to non-sport participation was also associated with 20% lower rule-breaking behavior scores for females (compared to males). Conversely, participation in individual sport compared to non-sport participation was associated with 16% higher anxious/depressed scores, 14% higher withdrawn/depressed scores, 12% higher social problems scores, and 14% higher attention problems scores. Participation in both team and individual sport compared to non-sport participation was associated with 17% lower rule-breaking behavior scores for females (compared to males). Results indicate that team sport participation was associated with fewer mental health difficulties, whereas individual sport participation was associated with greater mental health difficulties. The findings complement previous research suggesting that team sport participation may be a vehicle to support child and adolescent mental health. Additional research is needed to determine to what extent, and under what circumstances, participation in individual sport may be problematic for younger cohorts.

Parental psychological problems were associated with higher screen time and the use of mature-rated media in children.

AIM: Parents' psychological problems may affect children's screen time, but research has been scarce. We examined the association between parental psychological problems and children's screen media behaviours in a nationally representative sample. METHODS: The participants were from the Adolescent Brain Cognitive Development study, recruited by probability sampling from the USA population. Children reported their use of TV, videos, video games, social media and mature-rated media. The parents (85% mothers) reported psychological problems using the Adult Self-Report questionnaire. RESULTS: In 10,650 children (5112 girls, 5538 boys) aged 9.9 ± 0.6 years, the presence of parental psychological problems was associated with children spending more daily time on screen media and with meeting the recommendation of ≤2 daily hours less often than children whose parents did not have psychological problems. Parental psychological problems were associated with children's TV watching, video watching and gaming but not with using social media. Parental internalising problems were associated with children watching mature-rated movies (odds ratio [OR] = 1.14, 95% confidence interval [CI] = 1.00, 1.30) and playing mature-rated games (OR = 1.27, 95% CI = 1.11, 1.45). CONCLUSION: Presence of parental psychological problems is associated with higher screen time and use of mature-rated media in children. This cross-sectional study was not able to examine causal associations.

Is early activity resumption after paediatric concussion safe and does it reduce symptom burden at 2 weeks post injury? The Pediatric Concussion Assessment of Rest and Exertion (PedCARE) multicentre randomised clinical trial.

OBJECTIVE: Investigate whether resuming physical activity (PA) at 72 hours post concussion is safe and reduces symptoms at 2 weeks, compared with resting until asymptomatic. METHODS: Real-life conditions, multicentre, single-blinded randomised clinical trial, conducted in three Canadian paediatric emergency departments (ED). Children/youth aged 10-<18 years with acute concussion were recruited between March 2017 and December 2019, and randomly assigned to a 4-week stepwise return-to-PA protocol at 72 hours post concussion even if symptomatic (experimental group (EG)) or to a return-to-PA once asymptomatic protocol (control group (CG)). The primary outcome was self-reported symptoms at 2 weeks using the Health and Behaviour Inventory. Adherence was measured using accelerometers worn 24 hours/day for 14 days post injury. Adverse events (AE) (worsening of symptoms requiring unscheduled ED or primary care visit) were monitored. Multivariable intention-to-treat (ITT) and per-protocol analyses adjusting for prognostically important covariates were examined. Missing data were imputed for the ITT analysis. RESULTS: 456 randomised participants (EG: N=227; mean (SD) age=13.3 (2.1) years; 44.5% women; CG: N=229; mean (SD) age=13.3 (2.2) years; 43.7% women) were analysed. No AE were identified. ITT analysis showed no strong evidence of a group difference at 2 weeks (adjusted mean difference=-1.3 (95% CI:-3.6 to 1.1)). In adherent participants, initiating PA 72 hours post injury significantly reduced symptoms 2 weeks post injury, compared with rest (adjusted mean difference=-4.3 (95% CI:-8.4 to -0.2)). CONCLUSION: Symptoms at 2 weeks did not differ significantly between children/youth randomised to initiate PA 72 hours post injury versus resting until asymptomatic; however, many were non-adherent to the intervention. Among adherent participants, early PA was associated with reduced symptoms at 2 weeks. Resumption of PA is safe and may be associated with milder symptoms at 2 weeks. LEVEL OF EVIDENCE: 1b. TRIAL REGISTRATION NUMBER: NCT02893969. REGISTRY NAME: Pediatric Concussion Assessment of Rest and Exertion (PedCARE).

Gender differences in physical activity and sedentary behavior: Results from over 200,000 Latin-American children and adolescents.

More physical activity and less sedentary behavior is beneficial for children and adolescents. Worldwide, gender differences are >8% favorable for men and the Latin-American region presents an even higher level of insufficient physical activity among women, with a lack of information in young population. Thus, the aim of the current study was to describe the gender differences in physical activity and recreational sedentary behavior in children and adolescents from Latin-American countries. The targeted age range was 5 to 17 years and included 219,803 participants (106,698 boys and 113,105 girls) from 33 out of 47 Latin-American countries identified. Physical activity guidelines from the World Health Organization (≥60 minutes of moderate-to-vigorous physical activity seven days of the week) and <3 hours recreational sedentary behavior daily were the references. In general, boys showed a higher prevalence of meeting physical activity guidelines in comparison with girls. A higher proportion of girls met the <3 hours recreational sedentary behavior cut-point in only ten countries. Thirty percent of the identified countries had no available data. The majority had data from the Global School-based Student Health Survey with data principally on adolescents and only 11/33 countries reported data in the last 5-year period. In conclusion, gender differences in the compliance with physical activity guidelines and the <3 hours recreational sedentary behavior cut-point are evident among children and adolescents from Latin-American countries, with boys being more active than girls.

An R Package for Computing Canadian Assessment of Physical Literacy (CAPL) scores and interpretations from raw data.

The Canadian Assessment of Physical Literacy (CAPL) is the first comprehensive protocol designed to assess a child's level of physical literacy. Current approaches to analyzing CAPL-2 raw data are tedious, inefficient, and/or can lead to computation errors. In this paper we introduce the capl R package (open source), designed to compute and visualize CAPL-2 scores and interpretations from raw data. The capl package takes advantage of the R environment to provide users with a fast, efficient, and reliable approach to analyzing their CAPL-2 raw data and a "quiet" user experience, whereby "noisy" error messages are suppressed via validation. We begin by discussing several preparatory steps that are required prior to using the capl package. These steps include preparing, formatting, and importing CAPL-2 raw data. We then use demo data to show that computing the CAPL-2 scores and interpretations is as simple as executing one line of code. This one line of code uses the main function in the capl package (get_capl()) to compute 40 variables within a matter of seconds. Next, we showcase the helper functions that are called within the main function to compute individual variables and scores for each test element within the four domains as well as an overall physical literacy score. Finally, we show how to visualize CAPL-2 results using the ggplot2 R package.

Typologies of Family Functioning and 24-h Movement Behaviors.

Research on the importance of the family environment on children's health behaviors is ubiquitous, yet critical gaps in the literature exist. Many studies have focused on one family characteristic and have relied on variable-centered approaches as opposed to person-centered approaches (e.g., latent profile analysis). The purpose of the current study was to use latent profile analysis to identify family typologies characterized by parental acceptance, parental monitoring, and family conflict, and to examine whether such typologies are associated with the number of movement behavior recommendations (i.e., physical activity, screen time, and sleep) met by children. Data for this cross-sectional observational study were part of the baseline data from the Adolescent Brain Cognitive Development (ABCD) study. Data were collected across 21 study sites in the United States. Participants included 10,712 children (female = 5143, males = 5578) aged 9 and 10 years (M = 9.91, SD = 0.62). Results showed that children were meaningfully classified into one of five family typologies. Children from families with high acceptance, medium monitoring, and medium conflict (P2; OR = 0.54; 95% CI, 0.39-0.76); high acceptance, medium monitoring, and high conflict (P3; OR = 0.28; 95% CI, 0.20, 0.40); low acceptance, low monitoring, and medium conflict (P4; OR = 0.24; 95% CI, 0.16, 0.36); and medium acceptance, low monitoring, and high conflict (P5; OR = 0.19; 95% CI, 0.12-0.29) were less likely to meet all three movement behavior recommendations compared to children from families with high acceptance, high monitoring, and low conflict (P1). These findings highlight the importance of the family environment for promoting healthy movement behaviors among children.

Home Team (Dis)Advantage Patterns in the National Hockey League: Changes Through Increased Emphasis on Individual Performance With the 3-on-3 Overtime Rule.

Past research examining National Hockey League (professional ice hockey; NHL) data from the 4-on-4 overtime era (seasons between 2005-06 and 2013-14) revealed an inconsistent home team (dis)advantage pattern such that home teams that were superior to their visiting counterparts had slightly greater odds of winning during regulation play compared to overtime (demonstrating home crowd advantages for team performance during regulation); in contrast, home teams experienced lower odds of winning in the shootout period than in overtime regardless of team quality (thereby demonstrating risks for individual choking from home crowd pressures). In this study, we explored the NHL home (dis)advantage pattern during four more recent seasons (2015-16 through 2018-19) in which the league instituted 3-on-3 play during overtime (perhaps increasing individual pressure for athletes competing in the 3-on-3 overtime period). We used archival data from the regular season (N=5,002 games) to compare home teams' odds of winning in regulation (with 5-on-5 skaters per team) to overtime (with 3-on-3) and in the shootout, adjusting for the quality of home and visiting teams. We conducted fixed-effects and multi-level logistic regression modeling. Evenly matched home teams were 1.66 times more likely to win than inferior home teams when games concluded in regulation versus overtime. Superior home teams were 4.24 times more likely to win than inferior home teams when games concluded in regulation rather than overtime. Thus, it is apparently more difficult for superior and evenly matched home teams to win in overtime than during regulation, suggesting that such home teams may be susceptible to choking in overtime. In contrast to the earlier 4-on-4 overtime era, home teams did not have lower odds of winning in the shootout compared to overtime. These results may have implications for NHL coaches' and players' tactical decision-making.

24-Hour Movement Behaviors and Internalizing and Externalizing Behaviors Among Youth.

PURPOSE: The Canadian 24-Hour Movement Guidelines for Children and Youth (≥60 minutes of moderate-to-vigorous physical activity per day, ≤2 hours of recreational screen time per day, and 9-11 hours of sleep per night for 5-13 years old) are associated with better physical health, but less is known about how these behaviors are related to mental health. This study examined the association of meeting these guideline recommendations with internalizing and externalizing behaviors among youth. METHODS: A large and broadly representative cross-sectional sample of 9- to 11-year-old U.S. youth (N = 11,875) from the Adolescent Brain and Cognitive Development study was analyzed. Internalizing and externalizing behaviors were measured using the Child Behaviour Checklist. Associations were examined using negative binomial regression adjusted for several confounders. RESULTS: Compared to meeting none of the recommendations, meeting recommendations for screen time and sleep but not physical activity was associated with a lower prevalence ratio of total, internalizing, and externalizing behaviors. Meeting two or all three recommendations was more strongly associated with these outcomes than meeting one recommendation or none. The prevalence ratio of the group meeting all three recommendations was .77 (95% confidence interval [CI]: .68-.86) for total problem scores, .78 (95% CI: .68-.89) for internalizing problem scores, and .79 (95% CI: .68-.91) for externalizing problem scores. CONCLUSIONS: Meeting the 24-hour movement guidelines was associated with a lower risk of internalizing and externalizing behaviors in youth. These associations were mainly explained by meeting the screen time and sleep duration recommendations.

Profiles of Active Transportation among Children and Adolescents in the Global Matrix 3.0 Initiative: A 49-Country Comparison.

This article aims to compare the prevalence of active transportation among children and adolescents from 49 countries at different levels of development. The data was extracted from the Report Cards on Physical Activity for Children and Youth from the 49 countries that participated in the Global Matrix 3.0 initiative. Descriptive statistics and a latent profile analysis with active transportation, Human Development Index and Gini index as latent variables were conducted. The global average grade was a "C", indicating that countries are succeeding with about half of children and youth (47-53%). There is wide variability in the prevalence and in the definition of active transportation globally. Three different profiles of countries were identified based on active transportation grades, Human Development Index (HDI) and income inequalities. The first profile grouped very high HDI countries with low prevalence of active transport and low inequalities. The second profile grouped low and middle HDI countries with high prevalence of active transportation and higher inequalities. And the third profile was characterized by the relatively high prevalence of active transportation and more variability in the socioeconomic variables. Promising policies from countries under each profile were identified. A unified definition of active transportation and contextualized methods for its assessment are needed to advance in surveillance and practice.

Evaluation of the process and outcomes of the Global Matrix 3.0 of physical activity grades for children and youth.

BACKGROUND/OBJECTIVE: Participation in the Active Healthy Kids Global Alliance (AHKGA) Global Matrix initiative represents a significant work and resource investment for Report Card teams. The objective of this paper was to evaluate the process and findings of the Global Matrix 3.0 and formulate recommendations for improvement. METHODS: The evaluation of the Global Matrix 3.0 was planned prior to its development and a list of potential process, impact, and outcome indicators were pre-identified. These indicators were informed by online surveys, direct reports, MailChimp's statistics, Google Analytics of the AHKGA website, and emails sent to the AHKGA Board of Directors. RESULTS: Five online surveys were completed by 88%-100% of the targeted respondents. High satisfaction ratings were observed for most of the Global Matrix 3.0 methods, key steps, concepts, and the resources (e-blasts and website) provided by the AHKGA. A total of 496 open-ended comments were provided in the five surveys, including 199 comments reporting issue(s), and 38 reporting both positive feedback and issue(s). The participating Report Card teams successfully assigned a grade to each physical activity indicator, produced a Report Card document, and wrote a short Report Card article. CONCLUSION: This evaluation process allowed for the identification of needed improvements and the formulation of recommendations for future Global Matrix initiatives. This work highlighted the need for the development of physical activity behavior assessment tools that would be internationally adopted and culturally adaptable to varying contexts to improve the standardization of physical activity surveillance at the global scale.

Relationships Among Children's Independent Mobility, Active Transportation, and Physical Activity: A Multisite Cross-Sectional Study.

PURPOSE: Children's independent mobility (IM) may facilitate both active transportation (AT) and physical activity (PA), but previous studies examining these associations were conducted in single regions that provided limited geographical variability. METHOD: We recruited 1699 children (55.0% girls) in 37 schools stratified by level of urbanization and socioeconomic status in 3 regions of Canada: Ottawa, Trois-Rivières, and Vancouver. Participants wore a SC-StepRx pedometer for 7 days and completed a validated questionnaire from which we derived a 6-point IM index, the number of AT trips over a week, and the volume of AT to/from school (in kilometer per week). We investigated relationships among measures of IM, AT, and PA employing linear mixed models or generalized linear mixed models adjusted for site, urbanization, and socioeconomic status. RESULTS: Each unit increase in IM was associated with 9% more AT trips, 19% higher AT volume, and 147 more steps per day, with consistent results across genders. Both measures of AT were associated with marginally higher PA when pooling boys' and girls' data. Children in Vancouver engaged in more AT. PA did not vary across site, urbanization, or socioeconomic status. CONCLUSION: IM was associated with more AT and PA regardless of where children lived, underscoring a need for IM interventions.

Testing validity of FitnessGram in two samples of US adolescents (12-15 years).

BACKGROUND: This study examined the validity of the FitnessGram® criterion-reference cut-points for cardiorespiratory fitness (CRF) based on two samples of US adolescents (aged 12-15 years). This study also established the CRF cut-points for metabolically healthy weight status based on a recent national fitness survey for the purposes of cross-validating with pre-existing cut-points including FitnessGram. METHODS: Two cross-sectional data from the 2003-2004 National Health and Nutrition Examination Survey (NHANES) (n = 378) and 2012 NHANES National Youth Fitness Survey (NNYFS) (n = 451) were used. CRF (estimated V ˙ O2max in mL/kg/min) was estimated from a submaximal exercise test. CRF categories based on FitnessGram cut-points, a clustered cardiometabolic risk factors score and weight status were used. A series of Receiver Operating Characteristic (ROC) curve analyses were conducted to identify age- and sex-specific CRF cut-points that were optimal for metabolically healthy weight status. RESULTS: Based on FitnessGram cut-points, having high risk CRF, but not low risk CRF, was associated with high cardiometabolic risk (OR = 3.17, 95% CI = 1.14-8.79) and unhealthy weight status (OR = 5.81, 95% CI = 3.49-9.68). The optimal CRF cut-points for 12-13-year-olds and 14-15-year-olds were 40 and 43 mL/kg/min in males and 39 and 34 mL/kg/min in females, respectively. Compared to meeting new CRF cut-points, not meeting new CRF cut-points was associated with higher odds of showing high cardiometabolic risk (OR = 2.91, 95% CI = 1.47-5.77) and metabolically unhealthy weight status (OR = 4.47, 95% CI = 2.83-7.05). CONCLUSION: FitnessGram CRF cut-point itself has rarely been scrutinized in previous literature. Our findings provide partial support for FitnessGram based on two samples of US adolescents. CRF cut-points established in this study supports international criterion-referenced cut-points as well as FitnessGram cut-points only for males. FitnessGram should be continuously monitored and scrutinized using different samples.

Prevalence and correlates of objectively measured weight status among urban and rural Mozambican primary schoolchildren: A cross-sectional study.

BACKGROUND: The coexistence of undernutrition (thinness) and overnutrition (overweight/obesity) among children and adolescents is a public health concern in low-middle-income countries. Accurate prevalence estimates of thinness and overweight/obesity among children and adolescents are unavailable in many low-middle-income countries due to lack of data. Here we describe the prevalences and examine correlates of objectively measured weight status among urban and rural schoolchildren in Mozambique. METHODS: A cross-sectional study design was applied to recruit 9-11-year-old schoolchildren (n = 683) from 17 urban and rural primary schools in Mozambique. Body mass index (BMI) was computed from objectively measured height and weight and participants' weight categories were determined using the World Health Organization cut-points. Actigraph GT3X + accelerometers were worn 24 hours per day for 7 days to assess movement behaviours. Multilevel multivariable modelling was conducted to estimate odds ratios and confidence intervals. RESULTS: Combined prevalence of overweight/obesity (11.4%) was significantly higher among urban participants compared to rural participants (5.7%; χ2 = 7.1; p = 0.008). Conversely, thinness was more prevalent among rural (6.3%) compared to urban (4.2%) participants. Passive school commute, not meeting daily moderate- to vigorous-intensity physical activity (MVPA) guidelines, and maternal BMI >25 kg/m2 were associated with overweight/obesity while possessing one or more functional cars at home, maternal BMI >25 kg/m2 and being an older participant were associated with thinness in the present sample. The proportion of total variance in the prevalences of obesity and/or thinness occurring at the school level was 8.7% and 8.3%, respectively. CONCLUSION: Prevalences of thinness, overweight/obesity and other key variables differ between urban and rural schoolchildren in Mozambique. MVPA, active transport and mother's BMI are important modifiable correlates of weight status among Mozambican schoolchildren. Results from this study demonstrate important differences between urban and rural schoolchildren that should not be ignored when designing interventions to manage malnutrition, formulating public health strategies, and interpreting findings.

Body mass index and movement behaviors among schoolchildren from 13 countries across a continuum of human development indices: A multinational cross-sectional study.

OBJECTIVE: This study describes the distributions of body mass index (BMI) and movement behaviors among schoolchildren from 13 countries across a continuum of human development. METHODS: Data were from a cross-sectional study of 9-11-year-old children (n = 8055) recruited from 269 urban schools in 13 countries, and an additional 7 rural schools in one of these countries (Mozambique). BMI was derived from objectively measured heights and weights. Moderate- to vigorous-intensity physical activity (MVPA), sedentary time (SED), and sleep duration were assessed by waist-worn Actigraph GT3X+ accelerometers. Linear models were used to describe the distributions of BMI z-scores, MVPA, SED, and sleep among sites across varying Human Development Indices (HDIs). RESULTS: Mean MVPA, SED, and sleep duration were 63.1 ± 27.3 minutes/day, 508.7 ± 72.4 minutes/day, and 8.8 ± 0.9 hours/night, respectively. Overall, 2.1% of the sample were thin, 19.5% overweight, and 11.7% were obese. Density curves (BMI z-scores and SED) for urban children in Mozambique showed significantly higher mean values compared with rural children. Boys had significantly higher mean MVPA compared with girls. Mean BMI z-scores were positively associated (ß = .02; P = .004) with HDI, mean daily MVPA minutes were negatively associated (ß = -.38; P = .025) with HDI, and mean SED time was positively associated with HDI (ß = 1.18; P = .049). No significant association (ß = .01; P = .29) was observed between sleep duration and HDI. CONCLUSION: Our findings show distinct differences in BMI and movement behavior profiles between urban and rural children in Mozambique. Mean BMI z-scores, MVPA, and SED differed by country HDI. These findings support the need to include both rural and urban participants in study samples.

Screen time and problem behaviors in children: exploring the mediating role of sleep duration.

BACKGROUND: Previous research examining the relationship between screen time (ST) and psychological health outcomes have primarily focused on one type of ST (i.e., television), while little research has considered other types of screens (e.g., videos, movies, social media), screen content (e.g., violent video games), or potential mediating variables. Therefore, the purpose of the present study was to assess ST types and content and their association with problem behaviors, and to determine whether these relationships were mediated by sleep duration. METHODS: Parents and children provided cross-sectional baseline data (2016-18) as part of the Adolescent Brain Cognitive Development study, a broadly US representative sample of 11,875 children aged 9 to 10 years. Parents self-reported their children's emotional and behavioral syndromes via the Child Behavior Checklist and sleep duration using one item from the Parent Sleep Disturbance Scale. Children self-reported their ST behavior, which comprised ST types (television/movies, videos, video games, and social media) and content (mature-rated video games and R-rated movies). RESULTS: Time spent in various ST types was positively associated with problem behaviors: watching television/movies was associated with a 5.9% increase in rule-breaking behavior (incidence rate ratio [IRR] = 1.059), 5% increase in social problems (IRR = 1.050), 4% increase in aggressive behavior (IRR = 1.040), and 3.7% increase in thought problems (IRR = 1.037). Greater time spent playing mature-rated video games was associated with greater somatic complaints (IRR = 1.041), aggressive behavior (IRR = 1.039), and reduced sleep duration (IRR = .938). Sleep duration mediated the relationship between ST (type and content) and problem behaviors, albeit the effect sizes were small. The largest effects were observed between sleep duration and all problem behaviors, with greater sleep duration predicting an 8.8-16.6% decrease in problem behaviors (IRRs ranging from .834 to .905). CONCLUSION: Greater time spent in ST behavior was associated with greater problem behaviors among children. There was strong evidence that longer sleep duration was associated with reduced problem behaviors. While sleep duration mediated the effects of ST on problem behaviors, other potential mediating variables need to be investigated in future research.