Associations among Screen Time and Unhealthy Behaviors, Academic Performance, and Well-Being in Chinese Adolescents

The influence of diet quality and dietary behavior on health-related quality of life in the general population of children and adolescents: a systematic review and meta-analysis

OBJECTIVE

The association between diet quality, dietary behavior and health-related quality of life has been mostly examined in children and adolescents with specific chronic diseases. No systematic review has synthesized the influence of diet quality and dietary behavior on health-related quality of life in the general population of children and adolescents. The purpose of this study was to systematically review the primary studies that evaluated the association between diet quality, dietary behavior and health-related quality of life in the general population of children and adolescents and to synthesize the findings for the association.

METHODS

A computer search in the databases of MEDLINE, EMBASE and PSYCINFO was performed to retrieve English language studies that were published from 1946 up to April 8, 2018. We also screened the PubMed-related articles and the reference lists of the existing relevant literature to identify other eligible studies. We synthesized the association between diet quality, dietary behavior and health-related quality of life using both a qualitative method and meta-analysis. We reported the review following up the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guideline.

RESULTS

Seventeen studies were included in the synthesis including twelve cross-sectional studies and five longitudinal studies. We found that diet quality and dietary behavior were associated with health-related quality of life in children and adolescents. The positive effect of healthy diets on health-related quality of life was observed for multiple domains of health-related quality of life, including physical, school and emotional functioning, and psychosocial quality of life. We observed a dose-response relationship between the diet exposure and health-related quality of life, where an unhealthy dietary behavior or lower diet quality was associated with decreased health-related quality of life among children and adolescents.

CONCLUSION

The findings of the systematic review suggest the importance of promoting healthy diets and nutrition for good health-related quality of life among children and adolescents. Future research is needed to strengthen the evidence for prospective relationships and for the dose-response effect between diet quality, dietary behavior and health-related quality of life among children and adolescents.

The effect of sleep quality on academic performance is mediated by Internet use time: DADOS study

OBJECTIVE

The aims of the present study were to analyze the association of sleep patterns with academic and cognitive performance in adolescents, and to test the potential mediating effect of different activities of screen media usage on this association.

METHODS

A sample of 269 adolescents (140 boys) aged 14 years from the baseline data of the Deporte, ADOlescencia y Salud study completed questionnaires about sleep quality, cognitive performance, and leisure-time sedentary behaviors. Sleep duration was objectively computed using a wrist-worn GENEActiv accelerometer and academic performance was analyzed through school records.

RESULTS

Sleep quality (but not sleep duration) was associated with all the academic performance indicators (all p<0.05). Analysis of covariance revealed higher grades among adolescents with better sleep quality (PSQI≤5; all p<0.05). These analyses showed no differences regarding cognitive performance. Internet use time was revealed as a mediator of the association between sleep quality and academic performance, being significant for all academic performance indicators (P_M ranging from 15.5% to 16.0%).

CONCLUSIONS

The association between sleep quality and academic performance in adolescents is mediated by time of Internet use. Overall, reducing Internet use in adolescents could be an achievable intervention for improving sleep quality, with potentially positive effects on academic performance.

The Prospective Association Between Electronic Device Use Before Bedtime and Academic Attainment in Adolescents

PURPOSE

To examine longitudinal associations between five commonly used technology devices prior to bedtime and real-life academic outcomes in adolescents.

METHODS

A total of 853 adolescents were recruited to a three-year prospective cohort study, with annual assessments. Academic grades/levels for three core subjects (English, Mathematics, and Science) were extracted from school records, and standardized (z-scores) were derived at the end of each academic year. A validated questionnaire was used to determine the frequency of using five types of technology (television viewing, video gaming, mobile telephone use, listening to music, and social networking) before bedtime.

RESULTS

After adjustment, English attainment was the subject most affected by prebedtime technology use, where three of five technologies assessed were negatively and prospectively associated (social networking [β = -.07 and p = .024], video gaming [β = -.10 and p = .008], and mobile telephone [β = -.07 and p=.017]). Social networking (β = -.07and p = .042), television viewing (β = -.08 and p = .044), and mobile telephones (β = -.07 and p = .031) were associated with significant impairment in English for girls whereas attainment in boys was most impaired by video gaming (β = -.12 and p = .014).

CONCLUSIONS

The use of electronic devices by adolescents before bedtime may reduce their academic attainment, but apart from video gaming for boys, the negative impact of near bedtime technology use on academic performance is small.

Prevalence of high screen time and associated factors among students: a cross-sectional study in Zhejiang, China

OBJECTIVE

To investigate the prevalence and correlates of high screen time (ST) among students in Zhejiang, China.

DESIGN

Cross-sectional study.

SETTING

School-based adolescent health survey in Zhejiang Province, China.

PARTICIPANTS

23 543 students in grades 7-12 from 442 different schools.

OUTCOME

High ST.

RESULTS

The mean age of the students was 15.6 years and 49.7% of them were girls. The prevalence of high ST (screen viewing ≥2 hours per day) was 42.4% (95% CI 40.2% to 44.5%), higher in boys than in girls (45.4%(95% CI 42.8% to 48.0%) vs 39.1% (95% CI 36.6% to 41.7%)). No statistically significant difference was found between urban and rural areas (43.0% (95% CI 37.2% to 48.7%) vs 42.1% (95% CI 39.6% to 44.6%)). The prevalence of high ST among middle school, academic high school and vocational high school students was 35.3%, 30.0% and 73.5%, respectively. Multivariable logistic analysis showed that older age, attendance at vocational high school, non-intact family, poor academic performance, bad self-reported health status, loneliness and drinking carbonated beverages ≥3 times every day were positively associated with high ST. Attendance at academic high school, higher parental education and being physically active were negatively associated with high ST.

CONCLUSIONS

High ST was prevalent among students and associated with a cluster of sociodemographic and behavioural risk factors in Zhejiang, China.

Physical activity and park use of youth in Nanchang, China

Physical inactivity is a growing issue in Chinese youth, but parks can facilitate traditional and non-traditional forms of physical activity for little to no cost. Despite this opportunity, very little is known regarding park use among Chinese youth. The purpose of this study was to conduct a cross-sectional observational study of park usage and physical activity of youth in municipal parks in Nanchang, China. Data were collected in June of 2014 in eight parks across Nanchang, Jiangxi a large city in southeast China. Physical activity was measured by a modified version of System for Observing Play and Recreation in Communities. Ordered hierarchic generalized linear models were estimated using a logit link function. The influence of the park was estimated using random effects, with fixed effects and park, environmental, and park user characteristics. Youth were most often seen active in the afternoon, on weekends, and during cooler times (≤ 29 °C). Paradoxically, more children were active when air quality was poorer. Older boys were more active than younger boys, but no differences were observed in girls. More children were seen active in unstructured play compared to structured activities. The results suggest parks are an important setting for physical activity among Chinese youth, and that unstructured activities can play an important role in promoting greater youth physical activity.

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Chinese youth were most often seen engaging in physical activity in the afternoon, on weekends, and during cooler times (< 29 °C).

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Paradoxically, more Chinese youth were physically active when air quality was poorer.

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More Chinese youth were seen physically active in unstructured play compared to structured activities.