Predictors and health consequences of screen-time change during adolescence--1993 Pelotas (Brazil) birth cohort study

Effect of COVID-19 pandemic on eating habits and lifestyle of college students in Tabriz, Iran: a cross-sectional study

Background

The pandemic of coronavirus disease (COVID-19) has influenced lifestyle behaviors and the health of populations worldwide. The purpose of this study was to determine the effects of the COVID-19 pandemic on the eating habits and lifestyle behaviors of Tabriz University of Medical Sciences students in Tabriz, Iran.

Methods

This cross-sectional study was conducted on 220 college students selected using a convenience sampling method in May-June 2022. Data were collected by the questionnaire, which included information on eating habits, physical activity, smoking, watching television, social media use, sleep, anxiety and stress, and smoking before and during the pandemic. The Chi-square test was used to analyze the association of COVID-19 with lifestyle behaviors.

Results

The median age of participants was 22.00 (IQR: 3.00) years old. The median BMI was 21.69 (IQR: 3.82) kg/m2, and 74.5% of participants had a BMI of 18.5 to 25 kg/m2. Around 34.5% of participants reported a weight gain during the pandemic. During the pandemic, students' eating habits improved by maintaining a regular meal pattern, eating a balanced diet, consuming 2-3 servings of milk or its products, consuming one or more servings of pulses, eggs, or meat per day, decreasing consumption of fast food, fried, and junk foods, adding less sugar to meals and beverages, and consuming fewer sugar-sweetened beverages and foods with high sugar (all p = 0.000). They also reported less physical activity and more sitting and screen time. Sleep time and poorer quality of sleep increased during the pandemic (p = 0.000). Feeling stress or anxiety in a day increased, and 2.2% of our participants decided to smoke. The biggest reasons for eating habits changes were less eating out, fear of coronavirus spreading through food, preferring home-cooked food, and improved knowledge about nutrition.

Conclusion

The results indicated that the eating habits of university students improved; however, participants stated increased weight gain, screen, sitting, and sleep time, declined physical activity, worse sleep quality, and feeling stress or anxiety during the COVID-19 pandemic. The findings can help to develop nutritional and behavioral recommendations for maintaining adults' health during and after the pandemic.

Correlates of Sedentary Time Among Children and Adolescents in Ethiopia: A Cross-Sectional Study

PURPOSE

To assess the correlates of sedentary time among children and adolescents in Ethiopia.

METHODS

The study was conducted in representative samples of children and adolescents in the capital city of Ethiopia, Addis Ababa. Multivariable logistic regression models were used to determine associations of sedentary time and predictor variables.

RESULTS

The mean sedentary time was 4.61 (95% confidence interval [CI], 4.35-4.86) hours per day. Overall, the prevalence of high sedentary time (>3 h/d) was 68.2% (95% CI, 64.2-72.2). Results of multivariable logistic regression analyses showed a statistically significant association between high sedentary time and female household head (adjusted odds ratio [AOR] = 0.50; 95% CI, 0.32-0.80), literate mothers (AOR = 1.98; 95% CI, 1.26-3.11), child attending public school (AOR = 1.79; 95% CI, 1.12-2.85), children who belonged to the poor and rich household wealth tertiles compared with medium wealth tertile (AOR = 2.30; 95% CI, 1.42-3.72 and AOR = 2.04; 95% CI, 1.14-3.65, respectively), and those families that did not have adequate indoor play space for children (AOR = 0.45; 95% CI, 0.29-0.72).

CONCLUSION

The study found that time spent sedentary was high in the study area as compared with other studies of similar settings. Several modifiable factors were identified that can be targeted in interventions to reduce sedentary time in the study setting.

Body mass index, eating habits, and various lifestyle changes in young adults during the two years of the coronavirus disease 2019 (COVID-19) pandemic

BACKGROUND

The aim of this study was to find out the perceived impact of 2 years of coronavirus disease 2019 (COVID-19) pandemic on various lifestyle behaviors (LSBs) and changes and their effect on body mass index (BMI) of young Saudi adults.

MATERIALS AND METHODS

This was a descriptive exploratory study conducted in January 2022 on 1724 students (aged 16-21 years) from multiple colleges of Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia. The main tools of the study were: BMI and an online 30-item LSB and changes structured questionnaire, which assessed LSB and perceived changes, 1 month immediately preceding and 2 years after the COVID-19 outbreak.

RESULTS

Our study results showed that 48% of the subjects gained weight after the pandemic. Screen time (ST) increased from 6.8 h before pandemic to 9.2 h/24 h after pandemic outbreak (P < 0.0001). However, no significant association was observed between excessive ST and increased BMI. A significant decrease in physical activity was seen after the outbreak (P < 0.001), which was positively but insignificantly associated with increased BMI (P = 0.3). A significant increase in the frequency of food intake was observed; 18.7% of the subjects reported taking ≥ 4 meals/day before the epidemic compared to 32.1% during the pandemic (P = 0.001). Decreased intake of homemade food, increased intake of junk food, and increased number of the meals/day were significantly related with increased BMI (P < 0.05). The strongest risk factor for increased BMI after the outbreak of the pandemic was ≥4 meals/day (OR=1.6; P = 0.048).

CONCLUSION

After 2 years of the pandemic, 48% of the young adults perceived they had gained weight, which was strongly associated with self-reported increase in the number of meals/day (≥4). These observations could aid the development of nutritional recommendations to maintain the health of young adults during and after the COVID-19 pandemic.

Characterizing Changes in Screen Time During the COVID-19 Pandemic School Closures in Canada and Its Perceived Impact on Children With Autism Spectrum Disorder

The COVID-19 pandemic has led to an increase in screen time for children and families. Traditionally, screen time has been associated with negative physical and mental health outcomes, and children with autism spectrum disorder (ASD) are at increased risk of these outcomes. The primary objectives of this study were to (1) characterize the change in screen time during COVID-19 school closures for children with ASD, and (2) examine the parent perceived impact of screen time on mental health and quality of life of children and their families. Canadian parents and caregivers of children 19 years of age and younger were eligible to participate in an anonymous, online survey study. This survey was available in English, consisted of 28 questions, took ~10-min to complete, and was available for 6 weeks (May 22 through July 6, 2020). The total sample consisted of 414 responses (ASD: n = 127, mean age = 11.7 ± 4.06 years; community sample: n = 287, mean age = 9.4 ± 4.26 years). Seventy-one respondents were missing responses to our primary question and removed from the analyses (final sample n = 344). Compared to the community sample, the ASD group had a significantly higher screen time use before and during the COVID-19 pandemic school closures [weekdays: difference = 1.14 (SE = 0.18), t = 6.56, p < 0.0001; weekends: difference = 1.41 (SE = 0.20), t = 6.93, p < 0.0001]. Mean total screen time during the pandemic was 6.9 h (95% CI 6.49, 7.21) on weekdays and 6.3 h (95% CI 5.91, 6.63) on weekends for the ASD group, and 5.6 h (95% CI 5.28, 5.92) on weekdays and 5.0 h (95% CI 4.70, 5.34) on weekends for the community sample. There was a significant increase in screen time during the COVID-19 pandemic as compared to before the pandemic period in the ASD group [weekdays: mean difference = 3.8 h (95% CI 3.35-4.25), p < 0.0001; weekends: mean difference = 1.5 h (95% CI 1.17-1.92), p < 0.0001]. Gender was a significant predictor of parent perceived mental health and quality of life, with male gender associated with a higher likelihood of negative impact [quality of life (child/family) OR = 1.8 (95% CI 1.1-2.9), corrected p = 0.040; mental health OR = 1.9 (95% CI 1.1-3.1), corrected p = 0.0028]. Parents' most frequently endorsed emotions toward screen time were guilt, frustration, and worry. Results of this survey study revealed that children with ASD were less likely to benefit from screen time to cope with social isolation, and screen time resulted in significantly more lost time on social interactions than the community sample, which may exacerbate difficulties in social domains. Given the unprecedented circumstances of the COVID-19 pandemic and the novel context of technology use, the findings of this study highlight the need for revision of screen time recommendations to reflect the current needs of children and families.

Prospective association between dietary patterns and BMI Z-score in Brazilian adolescents

OBJECTIVE

To identify dietary patterns and prospectively evaluate their influence on the BMI Z-score of adolescents.

DESIGN

A longitudinal study, using data from the Longitudinal Study on Sedentary Behavior, Physical Activity, Eating Habits and Adolescent Health - LONCAAFS.

SETTING

To obtain data on food consumption, a 24-h recall survey was conducted; a second 24-h recall was applied to 30 % of the sample in all waves. Dietary patterns were identified by exploratory factor analysis using principal components. BMI Z-score was determined according to the recommendation of the WHO, based on the BMI for age and sex. Socio-economic data, sedentary behaviour and physical activity level were obtained. Associations between BMI Z-score and dietary patterns and between BMI Z-score and variables of interest were determined using generalised estimating equations.

PARTICIPANTS

Totally, 1431 adolescents were assessed in 2014, 1178 in 2015, 959 in 2016 and 773 in 2017, belonging to the public schools of João Pessoa, Northeast Brazil.

RESULTS

Three dietary patterns were identified throughout the study: 'traditional', 'snacks' and 'Western'. The 'Western' dietary pattern was positively associated with BMI Z-score (β = 0·025; 95 % CI 0·002, 0·048), regardless of sex and physical activity level, prospectively.

CONCLUSION

A dietary pattern composed of foods with high energy density, high fat and sugars, and low fibre influences the BMI Z-score of adolescents over time.

A systematic review of screen-time literature to inform educational policy and practice during COVID-19

There is an urgent need for consensus around the matter of screen time (ST) during the COVID-19 pandemic. Some governments announced restrictions for online schooling time per day to protect students from perceived risks of prolonged screen-use, but critics and an emerging body of research question such regulations. Our review of 52 empirical studies found (a) an overwhelming majority of literature shows effect sizes too small to be of practical or clinical significance, and (b) findings more specifically on educational ST are inconclusive and critically underrepresented. These facts, along with the undeniable benefits of online learning in the absence of brick-and-mortar schooling and the ominous forecasts of learning loss caused by prolonged school closure, inform our recommendations for a more moderate policy and practical stance on restrictions - one that is focused on responsibly leveraging the educational and social benefits of ST in a world still recovering from the COVID-19 pandemic.

Adolescents' healthy lifestyle

OBJECTIVE

Using a wide and representative sample of adolescents from 37 countries, this study aimed to analyze how age changes adolescents' healthy lifestyle.

METHODS

The study included 148,839 adolescents who participated in the Health Behavior in School-aged Children 2010 survey. A composite score of a healthy lifestyle was created using the combination of daily physical activity, daily fruit and vegetable consumption, <2h daily on screen-based behaviors, abstinence from alcohol, and abstinence from tobacco products. Healthy lifestyle measures were based on self-report.

RESULTS

4.7% of boys and 4.4% of girls aged 11 years, 3% of boys and 2% of girls aged 13 years, and 1.5% of boys and 0.8% of girls aged 15 scored perfectly on the healthy lifestyle score. As age increased, the prevalence of adolescents with a healthy lifestyle decreased. In 37 countries and regions, the prevalence of healthy behaviors decreased linearly between early adolescence and the age of 15 years.

CONCLUSIONS

In general, adolescents do not have a healthy lifestyle. Results from this study highlight that there is still much work to be done in promoting healthy lifestyles and to raise awareness among adolescents of the potential risk to their health status.

Behavioral, contextual and biological factors associated with obesity during adolescence: A systematic review

INTRODUCTION/OBJECTIVE

Adolescence is a critical period for the development of obesity. Obesity arises from a complex interaction between several factors, which are not yet fully understood. Therefore, the purpose of this review was to identify and assess the peer-reviewed scientific literature on the behavioral, contextual and biological factors associated with obesity in adolescents.

METHODS

PubMed and Scopus were systematically searched to identify prospective cohort studies concerning the relation between behavioral, contextual and biological factors and obesity in adolescents aged 10 to 18 years.

RESULTS

40 studies published between the year 2000 and 2018 were included. A positive consistent association between genetic factors and obesity during adolescence was found. Also, there is evidence to support the association between socioeconomic status and obesity. There was conflicting evidence for the contribution of dietary intake, physical activity, sedentary behavior, sleep, food store environment, school food environment. For the remaining factors no associations were found, or no conclusions could be drawn due to the limited number of studies identified.

CONCLUSIONS

Further prospective studies that assess multiple obesity determinants simultaneously and use state-of-art measures are warranted to aid in the development of effective strategies and interventions to prevent obesity during adolescence.

Screen time and moderate-to-vigorous physical activity changes and displacement in adolescence: A prospective cohort study

BACKGROUND

This paper determines longitudinal changes in the time Spanish adolescents devote to moderate-to-vigorous physical activity (MVPA) and screen media activity (SMA). Moreover, it examines the displacement hypothesis between time spent on SMA and MVPA.

METHODS

A cohort of 755 adolescents participated in a prospective cohort study over a three-year period. Repeated measures ANOVA to highlight interaction effects among all variables and Structural Equation Modeling (SEM) techniques were employed.

RESULTS

Age and gender-related variations in longitudinal changes in time spent on MVPA and SMA evolved in the inverse direction (decreased on MVPA/increased on SMA) according to the ANOVA. The potential displacement between time spent on SMA and MVPA from Wave I to Wave II was analysed via SEM. The first model, estimated in the overall sample, showed no evidence for the displacement hypothesis. Subsequently, a multigroup sequence of panel models was performed and a partial displacement was observed only in boys. Hence, boys who spent more time on SMA were more likely to devote less time to MVPA three years later.

CONCLUSION

This study confirms the opposite trend on the time spent on MVPA and SMA over a three-year period, being clearly higher in SMA. Further SEM analyses reveal a deferred displacement hypothesis between SMA and MVPA only in boys. This partial gendered displacement may be linked to the different uses adolescents make of screen media. The incursion of new technological devices (smartphones or tablets) and their wide range of possibilities for social networking or gaming could explain this displacement.

Perception of neighborhood safety and screen time in adolescents from Curitiba, Brazil

OBJECTIVE

To analyze the association between perceptions of neighborhood safety (PNS) and screen time among adolescents and to assess the moderating effects of sex, age and socioeconomic status.

METHODS

A cross-sectional study with school survey was conducted in Curitiba, Brazil. First, six schools (three public and three private) were intentionally selected. Next, one class within each educational level (from the sixth year of elementary school to the third year of high school) was randomly selected. PNS was assessed using a NEWS-Y scale, and daily screen time was defined as the time spent watching TV/videos/DVDs, playing video games and using the Internet. Multinomial logistic regression models were used to test the association between PNS and screen time, adjusting for the confounding variables.

RESULTS

The sample included 776 adolescents (boys and girls), aged between 11 and 18 years old. Perceived crime was associated with time playing video games among older teenagers (p < 0.05). Pedestrian and traffic safety was inversely associated with time playing video games among adolescents with high socioeconomic status (p < 0.05).

CONCLUSION

The association between PNS and screen time is complex among adolescents and varies according to sociodemographic variables and the screen time outcome (TV/videos/DVDs, video games and the Internet).

Prevalence and correlates of screen time among Brazilian adolescents: findings from a country-wide survey

The purpose of this study was to evaluate the distribution, prevalence, and correlates of excessive screen time (>2 h/day) among Brazilian adolescents. The Study of Cardiovascular Risks in Adolescents (ERICA) is a national, school-based, cross-sectional multicenter study. Information about time spent in front of screens was assessed by questionnaire. Poisson regression models were used to examine the associations between following correlates (region, sex, age, skin color, income, Internet access, and number of TVs at home) and excessive screen time. A total of 66 706 Brazilian adolescents (aged 12–17 years) were included. The overall mean time in front of screens was 3.25 h/day (95% confidence interval (95%CI): 3.20–3.31) and the prevalence of excessive screen time was 57.3% (95%CI: 55.9–58.6). Moreover, excessive screen time also differs across Brazilian regions, being higher in Southeast and South, respectively. In adjusted models stratified by region, the socioeconomic status was associated with excessive screen time in North, Northeast, and Midwest. In all regions, having a computer with Internet access was associated with higher prevalence of excessive screen time. In conclusion, prevalence of excessive screen time in Brazilian adolescents is high. It presents regional variations and facility for Internet access.

Socioeconomic position and sedentary behavior in Brazilian adolescents: A life-course approach

Socioeconomic position (SEP) is a potential correlate of sedentary behavior in adolescents. The aim of this study was to examine the associations between SEP and self-reported and objective measures of sedentary behavior in adolescents, using a life-course approach. Data from the 1993 Pelotas (Brazil) Birth Cohort Study were analyzed (N=5249). Cross-sectional and longitudinal associations between multiple SEP indicators (maternal education, family income, SEP composite, cumulative family income) at birth, 11, 15 and 18years, and five sedentary behavior outcomes (≥4h/day screen time; ≥4h/day TV; ≥2h/day computer; ≥2h/day video game; ≥12.7h/day objectively measured sedentary time) at 11, 15 and 18years, were examined. In cross-sectional analyses, higher SEP was positively associated with more screen time at ages 11 and 15years. There was a consistent and positive association between higher SEP with time spent using a computer, and with sedentary time assessed through accelerometry. SEP at birth had a positive and direct effect on screen, computer and total sedentary time at 18years. Participants in the highest cumulative income group had higher odds of high sedentary behavior in screen (OR: 2.40; 95% CI: 1.50-3.54), computer (OR: 7.35; 95% CI: 4.19-12.89) and total sedentary time (OR: 5.40; 95% CI: 3.53-10.35), respectively, compared with their counterparts with lower cumulative income. Our findings showed that SEP is an early determinant of sedentary behavior in adolescents.

Validation of the Farsi version of the revised Adolescent Sleep Hygiene Scale (ASHSr): a cross-sectional study

BACKGROUND

Restoring sleep is associated with a broad variety of favorable cognitive, emotional, social and behavioral benefits during the day. This holds particularly true for adolescents, as maturational, social, cognitive, emotional and behavioral changes might unfavorably impact on adolescents' sleep. Among adolescents, poor sleep hygiene practices are a potentially modifiable risk factor that can be addressed via appropriate interventions. Accordingly, having reliable and valid self-report measures to assess sleep hygiene practices is essential to gauge individual responses to behavioral interventions and evaluate sleep hygiene recommendations. The aim of the present study therefore was to translate and to test the psychometric properties (internal consistency, test-retest reliability, factorial and concurrent validity) of the Farsi/Persian version of the revised version of the Adolescent Sleep Hygiene Scale (ASHSr).

METHOD

A total of 1013 adolescents (mean age: M = 15.4 years; SD = 1.2; range: 12-19 years; 42.9% females) completed the ASHSr and the Pittsburgh Sleep Quality Index (PSQI) in their classroom during an official school lesson. Further, 20% completed the ASHSr 6 weeks later to evaluate the test-retest reliability. Cronbach's alpha coefficients were calculated to examine internal consistency, confirmatory factor analysis (CFA) was used to test factorial validity, whereas concurrent validity and test-retest reliability were examined via correlation analyses.

RESULTS

A first-order confirmatory factor analysis (CFA) corroborated the six-factor structure of the ASHSr, including a physiological, behavioral arousal, cognitive/emotional, daytime sleep, sleep environment, and sleep stability factor. A second-order CFA showed that a higher-order sleep hygiene construct explained sufficient variance in each factor. Cronbach's alpha values ranged between .71 and .75, correlations for test-retest reliability between .82 and .87. Significant correlations were found between most ASHSr scales and the PSQI indices. However, the magnitude of these correlations was weak.

CONCLUSIONS

The Farsi/Persian version of the Adolescent Sleep Hygiene Scale can be used as a reliable and valid tool for evaluation of sleep hygiene practices among Farsi/Persian-speaking adolescents.

Sedentary Behavior During School Recess in Southern Brazil

The aim of this study was to assess sedentary behavior during school recess in Brazilian boys and girls. The study included 455 students (233 boys and 222 girls), aged 8 to 17 years, enrolled in a public school in the city of Londrina, Brazil. All data was collected using questionnaires. Logistic regression with odds ratio and confidence interval (95%) was used to measure the relationship between sedentary behavior and sex, age, weight, screen time, and economic status. There was a high prevalence (40.7%) of sedentary behavior in this sample, with girls (aged 8 to 17 years) more likely than boys (54.5% vs. 27.5%, respectively) and older students (13-17 years) more likely than younger students (8-12 years) to engage in sedentary behavior (49.6% vs. 30.1%, respectively). These findings, and their broad implications for health and for interventions to increase physical activity, are discussed in light of past literature.

An evidence-update on the prospective relationship between childhood sedentary behaviour and biomedical health indicators: a systematic review and meta-analysis

Evidence for adverse health effects of excessive sedentary behaviour in children is predominantly based on cross-sectional studies, measuring TV viewing as proxy for sedentary behaviour. This systematic review and meta-analysis summarizes the evidence on the prospective relationship between childhood sedentary behaviour and biomedical health indicators, overall and stratified by type of sedentary behaviour (TV viewing, computer use/games, screen time and objective sedentary time). PubMed, EMBASE, PsycINFO and Cochrane were systematically searched till January 2015. Methodological quality of all included studies was scored, and a best evidence synthesis was applied. We included 109 studies of which 19 were of high quality. We found moderate-to-strong evidence for a relationship of overall sedentary time with some anthropometrics (overweight/obesity, weight-for-height), one cardiometabolic biomarker (HDL-cholesterol) and some fitness indicators (fitness, being unfit). For other health indicators, we found no convincing evidence because of inconsistent or non-significant findings. The evidence varied by type of sedentary behaviour. The meta-analysis indicated that each additional baseline hour of TV viewing (β = 0.01, 95%CI = [-0.002; 0.02]) or computer use (β = 0.00, 95%CI = [-0.004; 0.01]) per day was not significantly related with BMI at follow-up. We conclude that the evidence for a prospective relationship between childhood sedentary behaviour and biomedical health is in general unconvincing.

Body image dissatisfaction, physical activity and screen-time in Spanish adolescents

This cross-sectional study contributes to the literature on whether body dissatisfaction is a barrier/facilitator to engaging in physical activity and to investigate the impact of mass-media messages via computer-time on body dissatisfaction. High-school students ( N = 1501) reported their physical activity, computer-time (homework/leisure) and body dissatisfaction. Researchers measured students’ weight and height. Analyses revealed that body dissatisfaction was negatively associated with physical activity on both genders, whereas computer-time was associated only with girls’ body dissatisfaction. Specifically, as computer-homework increased, body dissatisfaction decreased; as computer-leisure increased, body dissatisfaction increased. Weight-related interventions should improve body image and physical activity simultaneously, while critical consumption of mass-media interventions should include a computer component.

Associations between parent-child relationship quality and obesogenic risk in adolescence: a systematic review of recent literature

Adolescence is a period of significant cognitive, social and physiological change, presenting unique risk factors for weight gain. Childhood obesity research has traditionally focused on the influence of parent-level factors on children's eating and weight status. Increasingly, emphasis is turning towards the reciprocal nature of the parent-child relationship and its influence on health behaviour. A systematic literature review was conducted to investigate the relationship between parent-child relationship quality (defined as the felt emotional bond between parent and child) and obesogenic risk (weight status, eating attitudes and behaviours, level of physical activity and sedentary behaviour) in adolescence; 26 papers were included in the review. The results neither support nor challenge an association between parent-child relationship quality and weight, with study design flaws and limited measurement of the parent-child relationship precluding robust conclusions. The review does however suggests that several aspects of the parent-child relationship are important in understanding eating attitudes and behaviours, including the felt emotional bond between the parent and child, the child's perception of how much the parent cares for them and the mother's sensitivity towards the child. The need for further longitudinal research into the association between parent-child relationship quality and obesity risk across this developmental period is discussed.

Systematic review of sedentary behaviour and health indicators in school-aged children and youth: an update

This systematic review is an update examining the relationships between objectively and subjectively measured sedentary behaviour and health indicators in children and youth aged 5–17 years. EMBASE, PsycINFO, and Medline were searched in December 2014, and date limits were imposed (≥February 2010). Included studies were peer-reviewed and met the a priori-determined population (apparently healthy children and youth, mean age: 5–17 years), intervention (durations, patterns, and types of sedentary behaviours), comparator (various durations, patterns, and types of sedentary behaviours), and outcome (critical: body composition, metabolic syndrome/cardiovascular disease risk factors, behavioural conduct/pro-social behaviour, academic achievement; important: fitness, self-esteem) study criteria. Quality of evidence by outcome was assessed using the Grading of Recommendations Assessment, Development, and Evaluation framework. Due to heterogeneity, a narrative analysis was conducted. A total of 235 studies (194 unique samples) were included representing 1 657 064 unique participants from 71 different countries. Higher durations/frequencies of screen time and television (TV) viewing were associated with unfavourable body composition. Higher duration/frequency of TV viewing was also associated with higher clustered cardiometabolic risk scores. Higher durations of TV viewing and video game use were associated with unfavourable behavioural conduct/pro-social behaviour. Higher durations of reading and doing homework were associated with higher academic achievement. Higher duration of screen time was associated with lower fitness. Higher durations of screen time and computer use were associated with lower self-esteem. Evidence ranged from “very low” to “moderate” quality. Higher quality studies using reliable and valid sedentary behaviour measures should confirm this largely observational evidence.

Sedentary behavior in Brazilian children and adolescents: a systematic review

OBJECTIVE

To describe the methodological characteristics of the studies selected and assess variables associated with sedentary behavior in Brazilian children and adolescents.

METHODS

For this systematic review, we searched four electronic databases: PubMed, Web of Knowledge, LILACS, SciELO. Also, electronic searches were applied in Google Scholar. A supplementary search was conducted in the references lists of the included articles and in non-indexed journals. We included observational studies with children and adolescents aged from three to 19 years developed in Brazil, presenting analyses of associations based on regression methods and published until September 30, 2014.

RESULTS

Of the 255 potential references retrieved by the searches, 49 met the inclusion criteria and composed the descriptive synthesis. In this set, we identified a great number of cross-sectional studies (n = 43; 88.0%) and high methodological variability on the types of sedentary behavior assessed, measurement tools and cut-off points used. The variables most often associated with sedentary behavior were "high levels of body weight" (in 15 out of 27 studies; 55.0%) and "lower level of physical activity" (in eight out of 16 studies; 50.0%).

CONCLUSIONS

The findings of this review raise the following demands to the Brazilian agenda of sedentary behavior research geared to children and adolescents: development of longitudinal studies, validation of measuring tools, establishment of risk cut-offs, measurement of sedentary behavior beyond screen time and use of objective measures in addition to questionnaires. In the articles available, the associations between sedentary behavior with "high levels of body weight" and "low levels of physical activity" were observed in different regions of Brazil.

The association between time spent in sedentary behaviors and blood pressure: a systematic review and meta-analysis

BACKGROUND AND OBJECTIVE

Sedentary behaviors, defined as waking behaviors with low energy expenditure while sitting, are positively associated with several adverse health outcomes. However, the association between sedentary behaviors and blood pressure (BP) is inconclusive. This study aimed to conduct a systematic review and meta-analysis on the association between time spent in sedentary behaviors and BP.

METHODS

We searched PubMed, MEDLINE, and Web of Science for papers published before August 2014 that assessed the association between time spent in sedentary behaviors and BP. Studies on both adults and children were included. Only good quality studies were included. The pooled estimates of systolic BP (SBP) and diastolic BP (DBP) increase per hour of time spent in sedentary behaviors a day were computed using a fixed-effects model and a random-effects model, respectively. Another pooled estimate of odds ratio per hour of time spent in sedentary behaviors a day on having high BP was computed using a fixed-effects model. A sub-group analysis was conducted for studies using self-reported and objectively assessed time spent in sedentary behaviors separately.

RESULTS

A total of 31 papers of good quality were included in the systematic review, 18 of which found no association between time spent in sedentary behaviors and BP (58.1%). A total of 28 papers were included in the meta-analysis. Pooled effects showed that an additional hour of time spent in sedentary behaviors per day was associated with an increase of 0.06 mmHg (108,228 participants, 95% CI 0.01-0.11, p = 0.01) of SBP and 0.20 mmHg (107,791 participants, 95% CI 0.10-0.29, p < 0.001) of DBP. Accelerometer-assessed time spent in sedentary behaviors was not associated with either SBP (p = 0.06) or DBP (p = 0.33). The odds ratio (OR) of having high BP with an additional hour of time spent in sedentary behaviors per day was 1.02 (98,798 participants, 95% CI 1.003-1.03, p = 0.02).

CONCLUSIONS

Self-reported but not accelerometer-assessed time spent in sedentary behaviors was associated with BP. Further studies are warranted to determine the preventive effect of reducing sedentary behaviors on high BP.

Regional Disparities in Sedentary Behaviors and Meal Frequency in Iranian Adolescents: The CASPIAN-III Study

BACKGROUND

The prevalence of obesity is increasing among Iranian youngsters like other developing countries.

OBJECTIVES

This study was conducted to assess regional disparities in sedentary behaviors and meal frequency in Iranian adolescents.

PATIENTS AND METHODS

In this national survey, 5682 students aged 10 - 18 years from urban and rural districts of 27 provinces of Iran were selected via stratified multi-stage sampling method. The country was classified into four sub-national regions, based on criteria of the combination of geography and socioeconomic status (SES). Mean of meal frequency and physical activity levels as well as prevalence of omitting meals and sedentary behavior were compared across regions with different SES after stratifying with sex and age group.

RESULTS

Meal frequency in lower socio-economic regions was significantly higher than two other regions in 10 - 13 and 10 - 18 years old groups (P trend < 0.001). However, the mean of working hours with computer was linearly increased with increasing the SES in studied regions (P trend < 0.001), whereas the corresponding figure was not significant for the mean of watching TV (P trend > 0.05). Frequency of adolescents omitting their meals was higher in higher SES regions especially in West Iran (P < 0.001) in 10 - 13 years old age group. Having personal computer and working with it more than two hours per day mainly was observed in central Iran which ranked as the highest SES group.

CONCLUSIONS

Efforts to ensure Iranian youth meet healthy food habits and screen time guidelines include limiting access to screen technologies and encouraging parents to monitor their own screen time is required.

Age and time effects on children's lifestyle and overweight in Sweden

BACKGROUND

High physical activity, low sedentary behavior and low consumption of sugar-sweetened beverages can be markers of a healthy lifestyle. We aim to observe longitudinal changes and secular trends in these lifestyle variables as well as in the prevalence of overweight and obesity in 7-to-9-year-old schoolchildren related to gender and socioeconomic position.

METHODS

Three cross-sectional surveys were carried out on schoolchildren in grades 1 and 2 (7-to-9-year-olds) in 2008 (n = 833), 2010 (n = 1085), and 2013 (n = 1135). Information on children's level of physical activity, sedentary behavior, diet, and parent's education level was collected through parental questionnaires. Children's height and weight were also measured. Longitudinal measurements were carried out on a subsample (n = 678) which was included both in 2008 (7-to-9-year-olds) and 2010 (9-to-11-year-olds). BMI was used to classify children into overweight (including obese) and obese based on the International Obesity Task Force reference. Questionnaire reported maternal education level was used as a proxy for socioeconomic position (SEP).

RESULTS

Longitudinally, consumption of sugar-sweetened beverages ≥ 4 days/week increased from 7% to 16% in children with low SEP. Overall, sedentary behavior > 4 hours/day doubled from 14% to 31% (p < 0.001) and sport participation ≥ 3 days/week increased from 17% to 37% (p < 0.001). No longitudinal changes in overweight or obesity were detected. In the repeated cross-sectional observations sedentary behavior increased (p = 0.001) both in high and low SEP groups, and overweight increased from 13.8% to 20.9% in girls (p < 0.05). Overall, children with high SEP were less-often overweight (p < 0.001) and more physically active (p < 0.001) than children with low SEP.

CONCLUSIONS

Children's lifestyles changed longitudinally in a relatively short period of two years. Secular trends were also observed, indicating that 7-9-year-olds could be susceptible to actions that promote a healthy lifestyle. Socioeconomic differences were consistent and even increasing when it came to sugar-sweetened beverage consumption. Decreasing the socioeconomic gap in weight status and related lifestyle variables should be prioritized. Primary school is an arena where most children could be reached and where their lifestyle could be influenced by health promoting activities.

Television time among Brazilian adolescents: correlated factors are different between boys and girls

Objective. The aim of this study was to identify the prevalence of excess television time and verify correlated factors in adolescent males and females. Methods. This cross-sectional study included 2,105 adolescents aged from 13 to 18 years from the city of Aracaju, Northeastern Brazil. Television time was self-reported, corresponding to the time spent watching television in a typical week. Several correlates were examined including age, skin color, socioeconomic status, parent education, physical activity level, consumption of fruits and vegetables, smoking status, alcohol use, and sports team participation. Results. The prevalence excess television time (≥2 hours/day) in girls and boys was 70.9% and 66.2%, respectively. Girls with low socioeconomic status or inadequate consumption of fruits and vegetables were more likely to have excess television time. Among boys, those >16 years of age or with black skin color were more likely to have excess television time. Conclusions. Excess television time was observed in more than two-thirds of adolescents, being more evident in girls. Correlated factors differed according to sex. Efforts to reduce television time among Brazilian adolescents, and replace with more active pursuits, may yield desirable public health benefits.

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.