[Prevalence of excessive screen time and associated factors in adolescents]

Nocturnal Smartphone Use Affects Sleep Quality and Cognitive and Physical Performance in Tunisian School-Age Children

Nocturnal smartphone use emits blue light, which can adversely affect sleep, leading to a variety of negative effects, particularly in children. Therefore, the present study aimed to determine the effect of acute (AC) (one night) and repeated (RC) (five nights) nocturnal smartphone exposure on sleep, cortisol, and next-day performance in Tunisian children. Thirteen participants (seven girls and six boys, age 9 ± 0.6, height 1.32 ± 0.06, weight 34.47 ± 4.41) attended six experimental nights. The experiment started with a baseline night (BL) with no smartphone exposure, followed by repeated sessions of nocturnal smartphone exposure lasting 90 minutes (08:00 pm-09:30 pm). Actigraphy; salivary cortisol; the Stroop test (selective attention); choice reaction time (CRT); N-back (working memory); counter-movement jump (CMJ), composed of flight time (time spent in the CMJ flight phase) and jump height; and a 30 m sprint were assessed the morning after each condition. Both AC and RC shortened total sleep time (TST) (p < 0.01), with a greater decrease with RC (-46.7 min, ∆% = -9.46) than AC (-28.8 min, ∆% = -5.8) compared to BL. AC and RC significantly increased waking after sleep onset (3.5 min, ∆% = 15.05, to 9.9 min, ∆% = 43.11%) and number of errors made on the Stroop test (1.8 error, ∆% = 74.23, to 3.07 error, ∆% = 97.56%). Children made 0.15 and 0.8 more errors (∆% = 6.2 to 57.61%) and spent 46.9 s and 71.6 s more time on CRT tasks (∆% = 7.22 to 11.11%) with AC and RC, respectively, compared to BL. The high-interference index of the Stroop task, CMJ performance, and 30 m sprint speed were only altered (p < 0.01) following RC (0.36, Δ% = 41.52%; -34 s, Δ% = -9.29%, for flight time and -1.23 m, -8.72%, for jump height; 0.49 s, Δ% = 6.48, respectively) when compared to BL. In conclusion, one- or five-night exposure to smartphones disturbed the children's sleep quality and their performance, with more pronounced effects following RC.

The Association of Eating Behaviour with Physical Activity and Screen Time among Adolescents in the Klang Valley, Malaysia: A Cross-Sectional Study

Over the last few decades, the time adolescents spend using electronic devices has increased significantly. The aim of this study was to evaluate the impact of screen time and physical activity on eating behaviour in adolescents. This study used the Physical Activity Questionnaire for Adolescents (PAQ-A) Malay version and the Dutch Eating Behaviour Questionnaire (DEBQ) Malay version methods with secondary students around the Klang Valley. The sampling technique used was purposive sampling. With parents' consent, an online survey was conducted among adolescent school children aged between 13 and 17 years during the COVID-19 pandemic in the Klang Valley, Malaysia. There were 372 respondents participating in this study. The results showed that 99.4% of them had more than 4 h screen time a day, and that 38.5% have more than three devices at home. Moreover, there was a significant mean difference in screen time for console games without a handheld device between male and female adolescents (p < 0.05). There was also a significant mean difference in the emotional, restricted and external eating behaviour scores between male and female adolescents (p < 0.001). There was a significant relationship between physical activity and the time duration spent on a television, telephone and laptop during weekends (p < 0.05). There was a significant relationship between eating behaviour and time spent watching television and using laptops during weekends (p < 0.05). Based on the moderation model, gender as a moderator variable indicated that there was a significant relationship between screen time and interaction screen time and gender with emotional eating (p < 0.001). Female adolescents had a stronger relationship between screen time and emotional eating compared to male adolescents (p < 0.05). Meanwhile, for physical activity level as a moderator variable, the results showed that there was a significant interaction between screen time and physical activity for emotional eating behaviour (p < 0.05). In conclusion, this study indicates that screen time was higher among female adolescents and significantly related to emotional eating behaviour. Therefore, the educational sector should emphasise the motivation of adolescents to engage in physical activity, reduce their screen time and eat healthy foods such as fruits and vegetables.

Effects of a Physical Exercise Program and Health Advice on Sedentary Behavior of Adolescents

Sedentary behavior (SB) is a risk factor for chronic non-communicable diseases. This study aimed to assess the effects of an extracurricular physical exercise program and health advice on SB in adolescents. This was a non-randomized experimental study involving 19 adolescents divided into an intervention group (IG) and a control group (CG), aged 13-16 years from a public school in a Brazilian municipality. SB was measured using self-reports and accelerometers. The intervention included physical exercise and health advice. Repeated measures analysis of variance with a significance level of α = 5% was used. There was a time*group interaction for the subscapular fold ((pre IG = 16.30 mm vs. CG = 13.44 mm, post IG = 14.00 mm vs. CG = 15.89 mm) p = 0.001), and VO2MAX ((pre IG = 32.75 mL/kg/min vs. CG = 30.66 mL/kg/min, post IG = 35.76 mL/kg/min vs. CG = 29.28 mL/kg/min) p = 0.008). The accelerometer showed significant differences between groups in the total SB ((pre IG = 647.49 min/day vs. CG = 535.24 min/day, post IG = 614.02 min/day vs. CG = 586.97 min/day) p = 0.045), with a significant decrease in the IG. In conclusion, an extracurricular physical exercise program and health advice was effective in reducing SB in adolescents.

Gender Differences in Excessive Screen Time among Chinese High School Students in Henan Province

In a technology-driven society, adolescents are particularly vulnerable to the effects of excessive screen time, and gender disparities are notable. However, evidence on the gender difference in excessive screen time among Chinese high school students is scarce. This study examined gender differences in excessive screen time and its impact on mental health and urinary incontinence among 15,055 high school-aged adolescents, including 7514 (49.9%) males and 7541 (50.1%) females with the mean age of 16.72 (SD 0.88) in Henan Province, China. A stratified two-stage cluster sampling design was applied. Mental Health Inventory of Middle School Students and International Consultation on Incontinence Questionnaire-Short Form was used to collect data about mental health and urinary incontinence status. The percentage of students reporting excessive screen time was 9.4%, predominantly male (15.3% versus 3.5%; p < 0.001). Physical disease, living on campus, and cigarette or alcohol consumption were common factors associated with excessive screen time in both genders. Students in their second or third year showed significantly lower rates of excessive screen time than their peers. In males, younger age, active sexual behavior, chronic constipation, and having a mother with a Ph.D. degree were factors associated with a higher probability of reporting excessive screen time, while females living in a rural-urban continuum or whose mothers have a junior college degree were associated with higher odds of reporting excessive screen times. Excessive screen time was significantly positively correlated with mental health problems and urinary incontinence (p < 0.05). Results suggests the need to address excessive screen time and to focus separately on the mechanisms influencing excessive screen time in males and females.

Screen time increases overweight and obesity risk among adolescents: a systematic review and dose-response meta-analysis

Background

Adolescence is a critical period in human life, associated with reduced physical activity and increased sedentary behaviors. In this systematic review and dose-response meta-analysis, we evaluated the association between screen time and risk of overweight/obesity among adolescents.

Methods

A systematic search in electronic databases, including PubMed, Embase, and Scopus was performed up to September 2021. All published studies evaluating the association between screen time and risk of overweight/obesity among adolescents were retrieved. Finally, a total of 44 eligible studies were included in the meta-analysis.

Results

The results of the two-class meta-analysis showed that adolescents at the highest category of screen time were 1.27 times more likely to develop overweight/obesity (OR = 1.273; 95% CI = 1.166–1.390; P < 0.001; I-squared (variation in ES attributable to heterogeneity) = 82.1%). The results of subgrouping showed that continent and setting were the possible sources of heterogeneity. Moreover, no evidence of non-linear association between increased screen time and risk of overweight/obesity among adolescents was observed (P-nonlinearity = 0.311).

Conclusion

For the first time, the current systematic review and meta-analysis revealed a positive association between screen time and overweight/obesity among adolescents without any dose-response evidence.

Trial registration

The protocol of the current work has been registered in the PROSPERO system (Registration number: CRD42021233899).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12875-022-01761-4.

Individual and Interpersonal Factors Associated with the Incidence, Persistence, and Remission of Internet Gaming Disorders Symptoms in an Adolescents Sample

Video game playing behavior has serious consequences for adolescents on a personal, family, social, and academic level. This research aimed to examine risk and protective factors involving incidence, persistence, and remission of gaming disorders symptoms (IGDs) in Spanish adolescents after nine months of follow-up. Data were drawn from self-administered questionnaires completed on two occasions: at the beginning (T1) and end of the academic year (T2). A total of 950 adolescents aged from 11 to 20 years (M = 14, SD = 1.52, 48.5% female) completed the questionnaire at T1, while 550 adolescents aged from 11 to 18 years (M = 13.43, SD = 1.23, 48.9% female) took part in the follow-up study (T2). The incidence, persistence, and remission rates were 6%, 2.7%, and 4.2%, respectively. Significant relationships with IGDs were found between the male gender and studying at a private school in T1 and T2. The findings show that the time spent playing video games during T1 was positively associated with IGDs in T1 and T2. The incidence of IGDs was associated with emotional problems and low family affection. The persistence of IGDs was linked to higher motor impulsivity, agreeableness, and lower family resolve. Remission was related to a decrease in anxiety and hostility as well as an increase in the emotional stability of adolescents. These findings imply that emotional well-being and family adjustment could be relevant for the effective management of gaming behaviors.

Excess weight in adolescents and associated factors: data from the ERICA study

OBJECTIVE

To estimate the prevalence of excessive weight and to identify associations with socioeconomic, demographic, biological, and lifestyle factors in adolescents.

METHODS

It is a cross-sectional school-based study, with a stratified and complex sample. The evaluated individuals were adolescents (2404), aged 12-17 years old, participating in the Study of Cardiovascular Risk Factors in Adolescents (ERICA). Demographic, socioeconomic, biological, anthropometric, and lifestyle variables were assessed. Poisson regression was used to verify the association between excess weight and independent variables.

RESULTS

The prevalence of excessive weight was 26.3% in the study population, being 16.3% for overweight and 10% for obesity. In the multivariate analysis (hierarchical model), were associated with excessive weight: private education network, a higher number of televisions in the residence, eating habits related to the breakfast consumption, snacks purchase in the canteen, snacks in front to screens consumption and consumption of carbohydrates and lipids, in addition to age group (12-14 years) and sexual maturation (post-pubertal).

CONCLUSIONS

The prevalence of excessive weight among the school adolescents studied is high, with a value higher than the national average and the results of previous studies with adolescents. Its distribution is associated with different factors, which are socioeconomic, demographic, biological, and related to lifestyle, reinforcing the complexity of this condition, which deserves a broad coping approach, involving not only individual efforts but social and public ones as well.

Sleep bruxism in children: relationship with screen-time and sugar consumption

Objective/background

Consumption of added sugar and excessive screen-time is increasing worldwide and is associated with sleeping and behavior disorders, which are related with possible Sleep Bruxism (SB) in children. Therefore, the objective of this investigation was to examine the relationship between screen-time and sugar-consumption and possible SB in children.

Patients/methods

A cross-sectional study, including parents of 460 4- to 8-year-old children, was performed. Frequency of possible SB was assessed with the Children's Sleep Habits Questionnaire; sugar consumption with the Health Behaviour in School-Aged Children Food-Frequency Questionnaire. Comprehensive measures of screen-time (including cell phones, computers, electronic devices, electronic games, and TV) were taken. The time was recorded in hour/day. All data were analyzed with STATA© data analysis and statistical software version 13.0 (Copyright 1996–2016; Stata-Corp LP, College Station, TX, USA). Spearman correlation test and ordinal-multiple-variable regression analyses were used.

Results

Data of 440 subjects Mean age 6.2 years (S.D. 1.8) were analyzed. Prevalence of possible SB was 35% and screen-time was available for 92.9% of the children. Mean screen-time was 2.1 h/day. Parents reported 73% of the children (n = 319) to consume added sugar once a day every day and 20% more than once every day. Correlations of possible SB were statistically significant with screen-time (Rho = 0.8; p = 0.002) and sugar-consumption (Rho = 0.7; p = 0.03). Associations were found between possible SB and increase-to-increase screen-time and sugar-consumption (OR > 2).

Conclusion

The results of this study demonstrated that as screen-time and sugar consumption increased, the frequency of bruxism in children increased.

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Sleep bruxism is regulated centrally and deals with the reward system, particularly the neurotransmission of dopamine.

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Sugar and the excessive use of screens alter neurotransmission of dopamine.

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Excessive sugar consumption and increased screen time are common behaviors in children.

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Parenting habits affects the consumption of sugar, the use of screens and the occurrence of sleep bruxism.

Screen exposure exacerbates ADHD symptoms indirectly through increased sleep disturbance

OBJECTIVES

The aim of this study was twofold. First, to confirm the deleterious aspect of evening screen exposure in school-aged children, in particular the effect of screens in the bedroom. Second, to explore the three-way association between degree of screen exposure, sleep disturbance, and ADHD symptoms. Solid evidence exists on the link between sleep disturbance and ADHD symptoms, and screen exposure and sleep disturbance. However, no studies have formally assessed the impact of screen exposure on ADHD symptoms in children, as a function of sleep disturbance.

METHODS

Parents of 374 French children (201 girls, 173 boys, mean age of 10.8 ± 2.8 years old) completed the Sleep Disturbance Scale for Children (SDSC), the Attention-Deficit/Hyperactivity Disorder (ADHD) Rating Scale, and a questionnaire about their children's screen habits (total hours in the morning, afternoon, and evening per day). Correlational analyses between evening screen exposure, sleep quality and behavioral problems were conducted. Then, formal mediation analyses were run in order to quantify the relationship between variables.

RESULTS

School-aged children with screens in their bedrooms demonstrated more sleep and behavioral problems. Evening TV exposure was associated with higher SDSC and ADHD scores. Furthermore, the Structural Equation Modelling approach confirmed that evening screen exposure is directly associated with more disrupted sleep, which in turn is directly associated with behavioral problems.

CONCLUSIONS

These findings encourage families to avoid putting screens in their children's bedrooms, and limit evening screen exposure. They furthermore demonstrate the importance of taking into account screen exposure time (morning, afternoon, evening) and location (bedroom or elsewhere) in future studies.

[Association between parental supervision and sedentary behavior and physical inactivity and among Brazilian adolescents]

The scope of this study was to assess the association between parental supervision and sedentary behavior and physical inactivity among Brazilian adolescents. Data of 102,072 students attending 9th grade from public and private school gathered in the 2015 Brazilian National Survey of School Health (PeNSE) were used. Adolescents were sedentary and physical inactive when they spent ≥3 hours/day sitting and practiced less then 60min/day of physical activity, respectively. Frequency of parental supervision (never, sometimes, always) was assessed through checking school homework, knowledge about what the adolescents do in their free time and understanding their problems. Logistic regression was applied and duly adjusted for sociodemographic variables. Among the adolescents, 56.3% were sedentary and 78.1% were inactive. Checking school homework was associated with lower odds of physical inactivity and sedentary behavior. Knowing what adolescents did in their free time and inspecting their belongings was associated with lower odds of physical inactivity. The understanding of problems by parents/guardians was associated with lower odds of sedentary behavior. The conclusion drawn is that greater parental supervision is associated with less physical inactivity and less sedentary behavior.

Activity-Inactivity Patterns, Screen Time, and Physical Activity: The Association with Overweight, Central Obesity and Muscle Strength in Polish Teenagers. Report from the ABC of Healthy Eating Study

Today, the time spent actively is increasingly being replaced by screen-based media, although in some teenagers, a high level of physical activity (PA) and longer time spent in front of a screen (screen time, ST) may coexist as a mixed behavioral pattern. This study aimed to examine the association of the pattern created as activity (low/high ST with high PA) and inactivity patterns (low/high ST with low PA) with overweight, central obesity, and muscle strength in Polish teenagers taking into consideration socioeconomic and demographic factors. Cross-sectional data were collected from elementary school children (n = 1567), aged 11–13 years. Height, weight, waist circumference, and handgrip strength were measured. Body mass index (BMI) was calculated as the overweight measure, and the waist-to-height ratio (WHtR) was calculated as the central obesity measure. Data on ST, PA, socioeconomic status, demographics, and nutrition knowledge were collected by a questionnaire. Activity–inactivity patterns were defined by an a priori approach. Multivariate logistic regression modelling was applied. The most active pattern (lowST-highPA) was found in 17% of the total sample. Teenagers with the most inactive pattern (highST-lowPA) had over four times higher chance of general overweight. No association between WHtR ≥0.5 and highST-highPA pattern was found. Higher muscle strength (>1 SD) was associated only with high physical activity. Urban residence or lower socioeconomic status increased adherence to the most inactive pattern. From a public health perspective, implementing interventions promoting active patterns in 11–13-year-old teenagers is important for obesity prevention and enhanced physical fitness, especially in girls, teenagers living in urban areas, and from families with lower socio-economic status.

Excessive Screen Media Use in Preschoolers Is Associated with Poor Motor Skills

Excessive screen media use exposure is a robust childhood predictor of sedentary behavior. The association between excessive exposure to sedentary behaviors (e.g., screen media use) and motor skills and how this association differs across sociodemographic strata is an important knowledge gap that needs to be addressed. The study aims to investigate the association of motor skills and screen media use in preschool children, taking into account sociodemographic variables, physical activity, and sleep profile. A cross-sectional survey of 926 children from 27 preschools was performed. The main outcome was defined as motor skills assessed using the general motor quotient (GMQ). Independent variables included sociodemographic variables, screen media use, screen habits, physical activity, and sleep duration. Logistic regression models were used to estimate the associations between the children's motor skills and each exposure factor. More than 55 percent of the children ate while watching television and 28 percent spent a long time watching television, playing video games, or using a computer, tablet, or cell phone. Excessive screen media use increased the risk of a low GMQ by 72 percent and inactivity in children increased the odds by 90 percent; sleep duration at night decreased the odds of a low GMQ by 51 percent and daytime sleep decreased the odds by 33 percent. Excessive screen media use has been associated with poor motor skills and increased physical inactivity in children, especially among those with prolonged exposure. Our findings can alert parents to the consequences of excessive screen media use and can motivate policymakers to encourage sports and other health-promotion strategies.

Hábitos alimentares, atividade física e comportamento sedentário entre escolares brasileiros: Pesquisa Nacional de Saúde do Escolar, 2015

RESUMO: Introdução: A urbanização e a industrialização colaboraram para a alteração nos padrões de alimentação, bem como para o surgimento de comportamentos sedentários e a redução da atividade física. Objetivos: Identificar e descrever a prevalência de hábitos alimentares, prática de atividade física e comportamento sedentário em escolares brasileiros e analisar sua associação com as características sociodemográficas. Métodos: Foram utilizados dados da Pesquisa Nacional de Saúde do Escolar de 2015. Foram calculadas prevalências, razões de prevalências e intervalos de 95% de confiança (IC95%). As análises foram ajustadas para idade escolaridade materna. Resultados: A maioria consumia feijão (65,1%) e guloseimas (52,3%), teve mais de três dias de aula de Educação Física escolar (50,7%), realizava atividade física fora da escola por mais de três dias (55,4%), tinha comportamento sedentário (73,3%) e realizava atividade física durante 60 min/dia por menos de quatro dias na semana (72,7%). Em geral, as meninas estavam mais expostas a práticas alimentares não desejáveis e ao comportamento sedentário, e o melhor nível socioeconômico associou-se a maiores prevalências dos indicadores estudados. Elevado consumo de alimentos não saudáveis, aumento do comportamento sedentário e redução na prática de atividade física. Conclusão: Observou-se associação de atitudes não saudáveis com características sociodemográficas entre os escolares. Estratégias que foquem na redução desses comportamentos irão contribuir para ações de promoção da saúde nos ambientes escolar e familiar.

Association between psychological distress and elevated use of electronic devices among U.S. adolescents: Results from the youth risk behavior surveillance 2009-2017

OBJECTIVE

The purpose of this study was to provide updated information about the prevalence and temporal trends of elevated use of electronic devices (EUED) in leisure time (i.e., 3 h or more on an average school day) in nationally representative samples of U.S. adolescents in recent years and to determine whether there is a significant association between EUED and psychological distress.

METHODS

We used the national Youth Risk Behavior Survey (YRBS) data from 2009, 2011, 2013, 2015, and 2017 (N = 75,807). Propensity score matching was used to reduce selection bias due to potential confounding factors with EUED. Ordinal logistic regression analyses were performed for the matched samples to predict the association between EUED and psychological distress.

RESULTS

The prevalence of EUED in U.S. youth has substantially increased from 24.9% in 2009 to 43.1% in 2017 (p < .001). Boys had higher rates of EUED than girls only in 2009 and 2011 but not in 2013, 2015, and 2017. A significant association between EUED and psychological distress was identified throughout all the five survey years. The odds of having a higher level of psychological distress increased approximately 1.5 times among youth with EUED than those without.

CONCLUSIONS

The prevalence of U.S. youth with psychological distress and EUED has increased simultaneously in the past several years. Future longitudinal studies are warranted to examine causal and/or reciprocal relationship between the two.

Screen time, body mass index and neck circumference: is there an association with social class in children?

Abstract Life habits during childhood are decisive for future health conditions. The aim of this study was to evaluate screen time and anthropometry of children enrolled in municipal schools in the interior of the State of São Paulo. A cross-sectional study was carried out with students from 9 to 10 years of age from a city in the State of São Paulo, Brazil. A socioeconomic questionnaire validated by the Brazilian Association of Research Companies was used, containing also the determination of screen time (TV, video game, computer and cell phone), recommended by the Pediatrics Society. Anthropometry data was collected according to the Lohmam Anthropometric Standardization Reference Manual and compared to the z-score level with the WHO 2007. For the statistical analysis, Kruskal-Wallis, Chi-square or Fisher’s Exact tests were used.The confidence level was at 95%. Out of the 703 schoolchildren assessed, 97.44% had adequate height, 59.17% eutrophy BMI and 30.44% overweight. There was a correlation between BMI and non-stratified social class (p=0.038) and BMI and neck circumference (NC) (p<0.001).The z-score of the BMI showed that children with weight loss stayed longer watching TV (p=0.0486). The gender comparison showed that girls of higher social class stayed longer at the computer (p=0.0351) and using the cell phone (p<0.0001),and boys playing videogame (p=0.0005). Overweight and weight loss shown in the positive correlation between BMI and NC, although on opposite sides, were associated with screen time and especially with TV in children of higher social class.

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.

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.

Physical activity but not sedentary time is associated with vitamin D status in adolescents: study of cardiovascular risk in adolescents (ERICA)

BACKGROUND/OBJECTIVES

The association between active lifestyle components and vitamin D status in adolescents remains relatively unexplored. We aimed to investigate independent and joint associations of moderate-to-vigorous physical activity (MVPA) and screen time with serum 25-hydroxyvitamin D [25(OH)D] concentrations in adolescents.

METHODS

This multicenter cross-sectional study involved 1152 Brazilian adolescents (age 12-17 years). Serum 25(OH)D was measured in a single laboratory and categorized as ≤20, 21-29, or ≥30 ng/mL. Demographic and lifestyle characteristics were assessed by self-reports. Ordered logistic regression was used to investigate potential associations of being physically active (MVPA ≥ 300 min/week) and excessive screen time (>2 h/day) with serum 25(OH)D concentrations.

RESULTS

The prevalence of higher serum 25(OH)D concentrations (≥30 ng/mL) was 36.4%. In adjusted models, being physically active was associated with higher serum 25(OH)D concentrations only in boys [proportional odds ratio (POR) = 2.04, 95% CI 1.42-2.93], while excessive screen time was not associated with serum 25(OH)D. Adolescents who were physically active and limited their screen time had higher odds of a higher serum 25(OH)D concentration, but the association was significant only for boys (POR = 2.11, 95% CI 1.19-3.74).

CONCLUSIONS

MVPA may play an important role in increasing serum 25(OH)D concentrations in adolescence, especially for boys, regardless of screen time.

Socioeconomic inequality in screen time frequency in children and adolescents: the weight disorders survey of the CASPIAN IV study

BACKGROUND

This study aimed to assess the socioeconomic inequality and determinants of screen time (ST) frequency in Iranian children and adolescents.

METHODS

This nationwide study was conducted as part of a national school-based surveillance program among 36,486 students consisting of 50.79% boys and 74.23% urban inhabitants, aged 6-18 years, living in urban and rural areas of 30 provinces of Iran. Socioeconomic inequality in ST, including the time spent for ST, watching TV and leisure-time working with computer, was assessed across quintiles of SES using concentration index (C) and slope index of inequality (SII).

RESULTS

Overall, 36,486 students completed the study (response rate 91.25%). Their mean (SD) age was 12.14 (3.36) years. The national estimation of frequency of ST was 31.66% (95% CI 31.16-32.17) with ascending change from 20.80% (95% CI 19.81-21.82) to 36.66% (95% CI 35.47-37.87) from the first to the last quintal of SES. Estimated C value at national level was positive (0.08), which indicate inequality was in favor of low SES groups. Considering the SII values, at national level [- 0.16 (- 0.39, 0.06)], the absolute difference in ST frequency between the bottom and top of the socioeconomic groups had descending trends. In multivariate logistic regression model, family history of obesity, generalized obesity and age were the main significant determinants of prolonged ST, watching TV, and computer working (P < 0.001).

CONCLUSIONS

Socioeconomic inequality in ST frequency was in favor of low SES groups. These findings are useful for health policies, better programming and future complementary analyses.

Factors Associated with Screen Time in Iranian Children and Adolescents: The CASPIAN-IV Study

BACKGROUND

Prolonged screen time is frequent in children and adolescents. Implementing interventions to reduce physical inactivity needs to assess related determinants. This study aims to assess factors associated with screen time in a national sample of children and adolescents.

METHODS

This nationwide study was conducted among 14,880 students aged 6-18 years. Data collection was performed using questionnaires and physical examination. The World Health Organization-Global School Health Survey questionnaire was used. Logistic regression analysis was used to examine the relationship between demographic variables, socioeconomic status (SES), family structure, physical activity, unhealthy eating habits, body mass index, and mental distress with screen time.

RESULTS

The participation rate was 90.6% (n = 13,486), 50.8% were male, and 75.6% lived in urban areas. Mean (standard deviation) age of participants was 12.47 (3.36) years. The SES, eating junk foods, urban residence, and age had significant association with screen time, watching television (TV), and computer use (P < 0.05). With increasing number of children, the odds ratio of watching TV reduced (P < 0.001). Statistically, significant association existed between obesity and increased time spent watching TV (P < 0.001). Girls spent less likely to use computer and to have prolonged screen time (P < 0.001). Participants in the sense of worthlessness were less likely to watch TV (P = 0.005). Screen time, watching TV, and using computer were higher in students with aggressive behaviors (P < 0.001); screen time was higher in those with insomnia.

CONCLUSIONS

In this study, higher SES, unhealthy food habits, and living in urban areas, as well as aggressive behaviors and insomnia increased the risk of physical inactivity.