Physical Activity, Screen Time, and Sleep Trajectories From Childhood to Adolescence: The Influence of Sex and Body Weight Status

Group-based sleep trajectories in children and adolescents: A systematic review

Sleep is crucial for health and development. Evidence indicates that sleep changes over time and distinct subgroups may experience different longitudinal patterns. This study systematically reviewed the studies that used latent trajectory modeling to investigate sleep trajectories of children and adolescents aged 0-18 years, and summarized the associated determinants and health-related outcomes. We searched PubMed, Embase, CENTRAL, PsycINFO, and Web of Science, identifying 46 articles that met our criteria. To ensure the reliability of the review, only studies rated as good or fair in terms of methodological quality were included, resulting in a total of 36 articles. Group-based trajectories were identified on several sleep dimensions (i.e., sleep duration, general and specific sleep problems, and bed-sharing behavior) and three or four trajectories were reported in most studies. There was a convergence trend across sleep duration trajectories during the first six years of life. Studies on specific sleep problem (i.e., insomnia, night-waking, and sleep-onset difficulties) typically identified two trajectories: consistent, minimal symptoms or chronic yet fluctuating symptoms. Lower socioeconomic status, maternal depression, and night feeding behaviors were the most frequently reported determinants of sleep trajectories. Membership in a group with certain adverse patterns (e.g., persistent short sleep duration) was associated with increased risks of multiple negative health-related conditions, such as obesity, compromised immunity, neurological problems, substance use, or internalizing/externalizing symptoms. Generally, there is potential to improve the quality of studies in this field. Causality is hard to be inferred within the current body of literature. Future studies could emphasize early life sleep, incorporate more assessment timepoints, use objective measures, and employ experimental design to better understand changes of and mechanisms behind the various sleep trajectories and guide targeted interventions for at-risk subpopulations.

Dynamic weight status changes and peer lifestyles in early adolescence: A social network analysis on a longitudinal cohort of Taiwanese youth

BACKGROUND

Friendship networks are relevant to adolescent weight status and lifestyle, but little is known about their relationship in an East Asian setting. Using a longitudinal cohort of Taiwanese adolescents, we studied how weight status and lifestyles might influence friendship. Simultaneously considering the influence of friendship networks, we further examined the effects of peers' lifestyles on the body weight status of adolescents.

METHODS

Data were retrieved from the first three waves of the Taiwan Youth Project (N = 2409; 51 % boys). Participants were asked to nominate their friends at school and to report their lifestyle factors (e.g. sleep habits, internet use, and athletic performance). Weight status was proxied by body mass index calculated from self-reported weight and height. Stochastic actor-based modeling was used for the friendship network analyses.

RESULTS

Considering network structure, adolescents selected friends based on similarities in weight status (β = 0.147 [standard error = 0.044], p < 0.001) and lifestyle factors, such as athletic performance (β = 0.181 [0.034], p < 0.001), internet use (β = 0.156 [0.039], p < 0.001), and social jetlag (β = 0.055 [ ± 0.022], p < 0.05). In the behavior dynamics model, we did not observe any peer influence on changes in adolescents' weight status.

CONCLUSION

These findings suggest a pervasive homophilic friendship selection explained by weight and lifestyle-based similarities, despite no evidence of peer influence on weight status. Stakeholders and care providers of adolescent health should be aware of the social network processes that underlie weight problems.

The Relationships between Physical Activity, Screen Time and Sleep Time According to the Adolescents' Sex and the Day of the Week

This study had two aims: (1) to identify the levels of physical activity, screen time and sleep time of adolescents according to the sex of the participant and the day of the week; (2) to find out the relationships between physical activity, screen time and sleep time according to the sex of the participant and the day of the week. The study design was non-experimental, descriptive-correlational and cross-sectional. The sample consisted of 694 adolescents in Compulsory Secondary Education from Soria (Spain). Four by One-Day Physical Activity Questionnaires were used to measure levels of physical activity, screen time and sleep time. Levene’s test and Student’s t-test were used to calculate the difference between the means of the variables. Pearson’s test was used to calculate bivariate correlations between variables. Results showed higher levels of screen time in males (136.93 min/day ± 81.548). Screen time, sleep time and moderate−vigorous physical activity are higher during the weekend. Positive relationships were found between screen time and light physical activity (rmales = 0.274; p ≤ 0.01; rfemales = 0.065; p > 0.05). The correlations between moderate−vigorous physical activity and screen time were negative (rmales = −0.282; p ≤ 0.01; rfemales = −0.187; p ≤ 0.05). The relationship between screen time and sleep time was negative in males (r = −0.135; p ≤ 0.05). In conclusion, the levels of physical activity, screen time and sleep time vary according to the sex of the participants and the day of the week.

Body image and health-related behaviors among fitspirit participants

Background

Body image variables such as body size perception (BSP) and body size dissatisfaction (BSD) can influence health-related behaviors. However, few studies have investigated these body image variables in adolescent girls participating in a physical activity intervention. Therefore, the study objectives were to examine the 1) associations between health-related behaviors (physical activity, screen-time, eating habits and sleep duration) and BSP and BSD among girls participating in FitSpirit, a physical activity intervention for girls; and 2) influence of weight control practices on the association between health-related behaviors and BSP and BSD.

Methods

This cross-sectional study assessed a sample of 545 adolescent girls (mean age: 15.0±1.5 years) from 240 schools. Body mass index, health-related behaviors, perceived actual body size and desired body size variables were self-reported and collected via an online questionnaire at the end of the FitSpirit intervention. A negative BSP score [perceived actual body size – calculated BMI z-score] indicates an underestimation of body size. A positive BSD score [perceived actual body size – desired body size] indicates a desire to reduce body size. A multiple linear regression analysis examined the effects of age, zBMI and health behaviors on BSP and BSD. A second multiple linear regression analysis examined the independent associations between BSP and BSD by weight control practice. The linear relationships between BSP and BSD were evaluated with Pearson’s correlations.

Results

Underestimation and dissatisfaction of body size are more prevalent in participants living with overweight/obesity. Screen-time and sleep duration were independently associated with BSP score (Beta=0.02; P<0.05 and Beta=-0.07; P<0.05, respectively), whereas only screen-time was associated with the BSD score (Beta=0.07; P<0.001). Physical activity was independently associated with the BSP score only in participants trying to control (maintain) their weight (Beta=-0.18; P<0.05).

Conclusions

Body size overestimation and dissatisfaction are associated with health-related behaviors, specifically with more screen-time and less optimal sleeping habits. Physical activity level does not appear to be associated with body image in girls engaged in a physical activity intervention and who want to lose or gain weight. Health promotion interventions could include screen-time and sleep components as they may influence body image.

Anthropometric Measurements, Sociodemographics, and Lifestyle Behaviors among Saudi Adolescents Living in Riyadh Relative to Sex and Activity Energy Expenditure: Findings from the Arab Teens Lifestyle Study 2 (ATLS-2)

The aim of the study was to examine the anthropometric measurements, sociodemographics, and lifestyle behaviors among Saudi adolescents relative to sex and physical activity (PA). A random cross-sectional survey conducted on Saudi adolescents from secondary schools in Riyadh, using a multistage stratified cluster sampling technique. Measurements included demographics, weight, height, waist circumference, PA, sedentary behaviors (SB), sleep duration, and dietary habits using a validated questionnaire. A total of 1262 adolescents (16.4 ± 0.95 years; 52.4% males) were studied. Overweight/obesity was more than 40%. Physical inactivity among adolescents was 53%, which indicates some improvement over the past years, especially among females. More than 80% of adolescents had over three hours/day of screen time, with no significant sex differences. Insufficient sleep was highly prevalent with gender differences. A large proportion of the participants did not consume daily breakfast (65.7%), vegetables (73.2%), fruits (84.2%), or milk/dairy products (62.4%), whereas significant proportions of the adolescents consumed sugar-sweetened drinks, fast food, French fries/potato chips, cake/donuts, and chocolates/candy on at least three days or more per week. It was concluded that non-daily intake of breakfast and vegetables was significantly associated with lower PA. The updated information can aid in effectively planning and implementing promotional programs toward improving the lifestyle behaviors of Saudi adolescent.