Excessive screen time among children and adolescents has been associated with physical inactivity, obesity, bullying, sleep disorders and risky sexual behaviors. However, the relation between screen time and different types of high-risk sexual behaviors has not been well explored. The aim of this study was to determine the impact of screen time, (defined as watching television 3 or more hours per day, or playing video or computer games or using a computer 3 or more hours per day) on high-risk sexual behaviors:- early onset of sexual intercourse before the age of 13 years, having sexual intercourse with four or more sexual partners within the last 3 months, alcohol consumption or drug abuse before the last sexual intercourse, or unprotected intercourse without male or female condom use. Methods: Data from the 2015 Youth Risk Behavior Surveillance System (YRBSS), a national survey representative of 9th through 12th grade students in public and private schools in the United States was used. Logistic regression analysis was conducted to determine the association between the predictor variables and the different high-risk sexual behaviors. The model was adjusted for age, sex, and race. Out of 15,624 respondents, about a third (5,770) reported having had “high-risk” sexual intercourse. Results: Analysis showed that students (9th -12thgrade) who watched television 3 or more hours per day were 49% more likely to have been sexually active before the age of 13 years (aOR: 1.49, 95% CI: 1.23-1.80, p Conclusion: The study findings suggest that watching television 3 or more hours per day is more significantly associated with high-risk sexual behaviors than playing video or computer games or using a computer 3 or more hours per day. More research might need to be conducted to determine the ‘protective effect’ of screen time with video or computer games and computer use. In addition, parents, caregivers and all stakeholders should ensure screen time be limited toyouths.

L’épidémie de surpoids et d’obésité concerne également les jeunes enfants, se caractérise par d’importantes inégalités sociales et entraîne des conséquences graves pour la santé à court, moyen et long terme. Les comportements impliqués dans la balance énergétique, à savoir l’activité physique, l’exposition à la télévision et l’alimentation pourraient jouer un rôle déterminant vis-à-vis du risque d’obésité du jeune enfant et sont potentiellement modifiables. Les objectifs de ce travail étaient d’étudier l’association entre ces comportements, considérés isolément mais aussi de manière intégrée sous forme de clusters multi-comportementaux à 2 et 5 ans, et le risque d’obésité et ce, séparément chez les filles et les garçons. Le risque d’obésité a été appréhendé au travers de la masse grasse à 5 ans et de l’âge au rebond d’adiposité. Le travail s’appuie sur les données de la cohorte EDEN. A 2 ans, le temps de jeux extérieurs chez les filles et le temps passé devant la télévision chez les garçons étaient respectivement associés inversement et positivement au pourcentage de masse grasse à 5 ans. A 2 ans, nous avons identifié des clusters multi-comportementaux caractérisés principalement par la fréquence de consommation d’aliments et de boissons à forte densité énergétique. Ces derniers n’étaient pas liés longitudinalement au pourcentage de masse grasse à 5 ans. Les clusters identifiés à 5 ans (4 clusters chez les filles et 2 chez les garçons) étaient principalement différentiés par l’exposition à la télévision ; chez les garçons la surexposition à la télévision était en outre associée à de moins bonnes habitudes alimentaires, tandis que chez les filles toutes les combinaisons possibles de niveaux d’exposition à la télévision et d’activité physique en extérieur (jeux/marche) étaient observées au sein des clusters. Les filles appartenant au cluster « Exposition très élevée à la télévision – Activité physique extérieure élevée » à 5 ans avaient un pourcentage de masse grasse plus élevé que celles du cluster de référence « Exposition modérée à la télévision – Activité physique extérieure plutôt élevée ». Par ailleurs, une plus forte adhésion au profil alimentaire «Aliments transformés, ou type fast-food » (identifié dans des travaux précédents) à 2 ans était associée à un âge plus précoce du rebond d’adiposité, défini comme intervenant en moyenne avant 3,7 ans dans les 2 sexes. Enfin, la position socioéconomique était inversement associée au temps passé devant la télévision ainsi qu’aux clusters caractérisés par une surexposition à la télévision et/ou de moins bonnes habitudes alimentaires ou de repas. Ces travaux montrent que tous les comportements impliqués dans la balance énergétique influencent le risque ultérieur de surpoids et d’obésité, mais avec une temporalité différente, sur des marqueurs de risque distincts et de façon variable en fonction du sexe de l’enfant et de son origine sociale. Ils montrent aussi que ces comportements se combinent de façon complexe et variable selon le sexe, et suggèrent que certaines typologies comportementales confèrent un risque plus élevé d’accumulation excessive de masse grasse. Ces résultats nous invitent à mettre en place des stratégies de prévention de l’obésité intégrant tous les comportements impliqués dans la balance énergétique et ce dès le plus jeune âge. Les efforts doivent viser à réduire le temps passé devant la télévision, en particulier dans les familles les plus modestes, tout en promouvant l’activité physique, en particulier en encourageant les petites filles aux jeux actifs à l’extérieur. En parallèle, il semble pertinent d’inciter les familles, et ce dès la grossesse, à adopter une alimentation proche des recommandations, en insistant sur l’importance des habitudes de repas, télévision éteinte et sans mise à disposition de boissons sucrées. Compte tenu de son approche holistique de la famille, le médecin généraliste est un vecteur idéal de ces messages de prévention. / The epidemy of obesity concerns also young children, is characterized by important social inequalities and has important consequences on health in the short, medium and long-term. Energy balance-related behaviors, namely physical activity, television exposure and diet, may be important in young children in determining subsequent obesity risk, and are potentially modifiable. The objective of this work was to examine the association between energy balance-related behaviors, considered in isolation or in combination (via cluster analysis) at 2 and 5 years of age, and obesity risk in boys and girls separately. Obesity risk was assessed by the percentage of body fat at 5 years and the age of the adiposity rebound. The work is based on data from the EDEN birth cohort. At 2 years, outdoor play time and television watching time were respectively, inversely and positively associated with the percentage of body fat at 5 years. At 2 years, 2 clusters emerged that were essentially characterized by opposite eating habits, with intake of energy-dense food and sweetened beverages being the most discriminating feature. At 5 years, clusters (2 in boys, 4 in girls) were mainly differentiated by the level of television exposure; in boys, high television exposure combined with unhealthy eating habits, while in girls, all possible combinations of the level of television exposure and time spent in outdoor physical activity (play and walk) were observed within clusters. Girls belonging to the ‘Very high television exposure – High outdoor physical activity’ cluster had a significantly higher percentage of body fat than girls in the reference cluster (labeled ‘Moderate television exposure – rather high outdoor physical activity’). Furthermore, a higher score on the ‘Processed and fast foods’ pattern (identified in a previous Eden analysis) at 2 years was associated with an earlier age of adiposity rebound (here defined as before 3.7 years on the average in both sexes). Maternal education level (taken as a general indicator of socio-economic position (SEP)) was inversely related to television viewing time as well as clusters characterized by a high level of television and/or less favorable eating habits (eating while the television is on and drinking sweetened beverages at mealtimes). These results suggest that all three-energy balance-related behaviors influence the subsequent risk of obesity, but with different timing of influence, on distinct markers of obesity risk, and in a way that differ according to the child’s sex and his/her family’s SEP. Furthermore, results suggest that these behaviors combine in complex ways that differ in boys and girls, and that identification of behavioral typologies based on specific combinations of behaviors may be useful to distinguish groups of children with different levels of risk. These results plead for integrated obesity preventive strategies targeting all three-energy balance-related behaviors, and implemented as early as possible, ideally before the age of 2. Efforts should strive to decrease television viewing time, especially in low SEP families, while simultaneously promoting physical activity, in particular by encouraging young girls to engage in active outdoor play. In parallel, it appears important to encourage mothers, especially from low SEP families, to follow diet guidelines and adopt favorable mealtime routines (e.g., turning off the television during meals, and proposing water rather than sodas at mealtime). Because of their frequent and continued contact with parents and their children throughout childhood, family physicians are particularly well positioned to help parents promote and support the development of early healthful physical activity and diet habits of children, starting in early childhood.

Background. Maternal obesity and physical inactivity have been identified as correlates of overweight and obesity and physical inactivity in older preadolescents; however, no study has explored this relationship in Hispanic preadolescents. Furthermore, the relation between maternal physical activity (PA) and blood pressure (BP) in Hispanic preadolescents has not been examined. Purpose. This study aimed to assess the associations between Hispanic mothers’ PA and body mass index (BMI) and their preadolescents’ PA, screen time, BP, and BMI. Methods. Data of 118 mother-child (aged 2–10 years) dyads enrolled in a crosssectional study of metabolic syndrome in Hispanic preadolescents at a community health center in Johnson City, TN were used. Parent and child questionnaires were used to ascertain mothers’ BMI and PA and preadolescents’ PA and screen time.

Purpose – As screen time per individual increases, more users of digital devices experience ocular related diseases. The purpose of this study is to gather reasons for the vast popularity Dark Mode gained in contemporary society, by investigating previous design eras. As a general lack of trend analysis within user interface design has been identified, the goal of the study is to lay the foundation for further research in the field of user interface design. Method – The study relies on a qualitative literature review. Publications related to Dark Mode, light-on-dark color schemes and digital trends were analyzed for topic-specific content that was then elaborated to give a critically viewed framework of the emerging trend. Findings – The results of our study indicate that various factors led to creation of the hyped trend, known as Dark Mode. It was first and foremost practicality of the light-on-dark color scheme that paved the way for Dark Mode. All operating systems, many apps, platforms and even websites incorporated it in their design. Being an optional feature, Dark Mode makes it more comfortable for users to use their devices outside the light hours or in environments with bad lighting conditions. With Dark Mode users get a far-reaching personalization tool, that visually changes essentially the whole OS or app. From a psychological point of view this improves user satisfaction, as humans naturally are seeking way to be in control. Being in control of own devices is undoubtedly an important aspect of it. Besides that, Dark Mode houses potential to lower energy consumption of devices and provides users with longer battery times. This, however, only applies to devices with display technology like OLED, where backlighting is at least divided into zones, that can be turned off when not in use. Devices with conventional LED displays cannot benefit from lower energy consumption. Implications – The study indicates that individuals use Dark Mode for a more satisfying user experience as they feel e.g. less eye strain with a dark themed user interface. Editing and coding software is mostly designed in a light-on-dark color scheme, as users often work for long continuous hours on screen, surrounded by dark environment. As screen time per individual increases, more users are experiencing ocular diseases. In counteraction, society demanded dark themed interfaces for operating systems, websites, and apps. As individuals were already using unofficial dark themes on different interfaces, tech companies started releasing system updates to make Dark Mode a choice. As Apple released their user interface update just in 2019, Dark Mode is still a relevant trend discussed in the industry and society. Experts indicate that Dark Mode is here to stay, as it satisfies preferences of many users and makes current OLED screens and future digital devices with appropriate display technology more sustainable. Limitations – The time frame of the study, as well as the Covid-19 pandemic greatly limited the possibilities of conducting the study. Due to the novelty of the trend, there is lack of previous research, which limited the view on the subject to only work available. Keywords – Dark Mode, dark-on-light color scheme, retro trends, user interface design, user experience, digital trends, display, screen, screen time, eye strain

Syftet med denna studie var att undersöka samband mellan stress, sömn och skärmtid på smarttelefon. Urvalet bestod av totalt 81 personer på ett universitet i södra Sverige. Två hypoteser testades. 1: hög grad av faktisk skärmtid är relaterat till en hög subjektiv stressupplevelse och hög grad av sömnbesvär. 2: Låg grad av stress är associerat med låg grad av sömnbesvär. Vid insamlingen av data användes, Perceived stress scale 10 (PSS-10) och Karolinska sleep questionnaire (KSQ). För att mäta skärmtid designades två frågor, en med syfte att mäta individers subjektiva upplevelse av mängden skärmtid och en för att mäta den faktiska mängden som kan utläsas via en funktion på individers smarttelefon. Resultatet för hypotes 1 visade att faktisk skärmtid varken samvarierade med stress eller sömnbesvär. Vidare jämfördes också gruppen hög faktisk skärmtid som översteg 29 h/vecka med stress och sömnbesvär. Resultatet indikerade att en hög faktisk skärmtid och stress inte korrelerade och hög faktisk skärmtid och sömnbesvär inte korrelerade. Resultatet för hypotes 2 visade en negativ signifikant korrelation mellan variablerna stress och sömnbesvär. Det innebar att höga värden på total KSQ, mindre sömnbesvär, korrelerar med låga värden på PSS-10, låg nivå av upplevd stress. Sammanfattningsvis visade studiens resultat att faktisk skärmtid inte samvarierade med varken stress eller sömnbesvär. Dock återfanns en korrelation mellan variablerna stress och sömnbesvär. / The purpose of this study was to investigate the relationship between stress, sleep and screen time on smartphones. The sample consisted of a total of 81 people at a university in southern Sweden. Two hypotheses were tested. 1: High degree of actual screen time is related to a high subjective stress experience and high degree of sleep disturbance. 2: Low levels of stress are associated with low levels of sleep disturbance. In the data collection, Perceived stress scale 10 (PSS-10) and Karolinska sleep questionnaire (KSQ) were used. To measure screen time, two questions were designed, one aimed at measuring individual's subjective experience of the amount of screen time and one to measure the actual amount that can be read through a function on an individual's smartphone. The result for Hypothesis 1 showed that actual screen time did not co-vary with stress or sleep disturbance. Furthermore, the group, high actual screen time exceeding 29 h / week was also compared with the variables stress and sleep disturbance. The result indicated that a high actual screen time and stress did not correlate, and high actual screen time and sleep disturbances did not correlate either. The result for Hypothesis 2 showed a negatively significant correlation between the variables stress and sleep disorders. This meant that high values of total KSQ, less sleep disturbances, correlated with low values of PSS-10, low levels of stress. In summary, the study's results showed that actual screen time did not correlate with neither stress nor sleep disturbance. However, a correlation was found between the variables stress and sleep disturbance.

The increasingly ubiquitous role of smartphones in our everyday lives causes concerns regarding our relationship with the devices. While some raise the question whether smartphones are addictive (Alter 2017; Lopez-Fernandez 2019), others regard this concern as the most recent manifestation of moral panics (Cashmore, Cleland & Dixon 2018; Leick 2019). Meanwhile advocates of the attention economy argument claim that the problem is the design of technology occupying users’ attention (CHT 2019a-d). Somewhere in between, media and communication studies search for empirical evidence. From this vantage point of ideas this study explores the role of Screen Time, shaping and being shaped by this discourse. As a feature of Apple’s iOS software it is supposed to support users in regulating their smartphone use. Applying the walkthrough method as proposed by Light, Burgess & Duguay (2018) combined with an analysis of user experiences, shows how the technology company shapes a concept of self-regulation for users to adopt to. A concept, which first and foremost follows corporate and not the users’ best interest. This thesis poses the the question whether we are slaves to our screens, but arrives at the conclusion that we carry chains of self-regulation. The question remains, how we can create more sustainable and meaningful environments for protecting our attention.

This diploma thesis focuses on the usage of digital technologies by children of early school age (1st to 3rd grade of elementary school). The aim of the thesis is to map in detail the use of screens in children aged 6-9 years and determine the age that would be suitable for the implementation of prevention programs aimed at the healthy use of technologies by children. The research is interested in how much time the children of a given age spend using electronic screens and what type of screens they usually use, what activities they do on the device, how the use differs between boys and girls and whether there are differences in use by children among the first three grades of primary school. The chosen research design is a cross-sectional questionnaire survey in an online form intended for parents. The results of the research showed that the amount of screen time increased with the age of the child and a larger increase was observed mainly in children in the 3rd grade of primary school. Most often, children spend time on mobile devices (smartphone or tablet) and watching TV. We also noticed a slight increase in the use of game consoles for boys in the 3rd grade of primary school, while girls use these devices hardly ever. Thus, prevention programs and education on the safe use and the risks...

The global average screen time on smartphones reaches up to 4 hours, revealed App Annie. In recent years, there have also been increasing concerns about the problematic use of smartphones and its impact on public health, such as sleep hygiene, cognitive capacity, and mental health. According to Tristan Harris, a former Design Ethicist at Google, enabling grayscale is a possible way to reduce screen time, because it makes the smartphone less attractive. Therefore, the aim of this thesis is to perform an experiment to confirm or reject the functionality of this recommendation and at the same time, through in-depth interviews with its participants, to describe how they perceive it and how it affects them.

Contexte. Les symptômes dépressifs et anxieux font partie des problèmes de santé mentale les plus courants chez les adolescents et peuvent entraîner d’importantes conséquences. Bien qu’il ait été suggéré que la pratique d’activité physique peut en réduire le risque, l’inactivité des jeunes Canadiens tend à augmenter à l’adolescence. Toutefois, la nature de ces liens, ainsi que les différences entre les filles et les garçons, demeurent mal comprises. Si les bénéfices de l’activité physique sur les symptômes dépressifs et anxieux pourraient dépendre des autres habitudes de vie, dont le temps d’écran et de sommeil, les mécanismes sous-jacents à ces associations ont été peu explorés. Objectifs. (1) Examiner les associations bidirectionnelles existant entre l’activité physique et les symptômes dépressifs et anxieux chez les adolescents québécois à 13, 15 et 17 ans en contrôlant pour le temps d’écran et de sommeil. (2) Examiner si ces associations sont médiées par le temps d’écran et de sommeil. (3) Examiner comment elles diffèrent chez les participants en fonction de leur sexe. Méthodologie. Les données sont tirées de l’Étude longitudinale du développement des enfants du Québec et sont majoritairement autorapportées par les participants à l’âge de 13, 15 et 17 ans (N = 1556). Des analyses à décalage croisé avec intercepte aléatoire et des analyses multigroupes ont été réalisées. Résultats. Un niveau plus élevé d’activité physique est faiblement associé à un niveau de symptômes dépressifs plus faible de 13 à 15 ans chez les filles et de 15 à 17 ans chez tous les adolescents. Les résultats sont plus inconstants pour l’anxiété, mais davantage de symptômes anxieux à 13 ans sont associés à moins d’activité physique à 15 ans chez les garçons. Un niveau plus élevé de sommeil à 15 ans s’est révélé être un deuxième prédicteur spécifique d’un niveau plus faible de symptômes dépressifs à 17 ans. Aucun effet médiateur du temps d’écran ou du temps de sommeil n’a pu être détecté. Implications. Des interventions préventives visant à promouvoir la pratique d’activité physique dès l’enfance, particulièrement chez les filles, ainsi qu’un temps de sommeil suffisant chez les adolescents plus âgés devraient être mises en place. / Context. Depressive and anxious symptoms in adolescents are prevalent and can have serious consequences. Although it has been suggested that physical activity may reduce the risk of developing these symptoms, inactivity among young Canadians tends to increase during adolescence. However, the nature of the associations between physical activity and depressive and anxious symptoms, as well as the differences between girls and boys, remain poorly understood. Moreover, the benefits of physical activity may depend on other lifestyle habits, including screen time and sleep time, but the mechanisms underlying these associations have not often been explored. Objectives. (1) Examine the bidirectional associations between physical activity and depressive and anxious symptoms in Quebec adolescents at ages 13, 15 and 17 by controlling for screen and sleep time. (2) Examine whether these associations are mediated by screen and sleep time. (3) Examine how these associations differ among participants based on sex. Method. The data are drawn from the Quebec Longitudinal Study of Child Development and are mostly self-reported by participants at ages 13, 15 and 17 (N = 1556). Random intercept cross-lagged panel models and multigroup analyses were conducted. Results. A higher level of physical activity is significantly but weakly associated with a lower level of depressive symptoms at ages 13 to 15 in girls and at ages 15 to 17 in all adolescents. Results for anxious symptoms are more mixed, but higher anxious symptoms at age 13 are associated with less physical activity at age 15 in boys. Higher sleep time at age 15 was found to be a second specific predictor of a lower level of depressive symptoms at age 17. No mediating effect of screen or sleep time was detected. Implications. Preventive interventions should promote physical activity from childhood, particularly among girls, as well as sufficient sleep in older adolescents.

Introduction : Seulement 7% des Canadiens de 17 ans et moins pratiquent 60 minutes d’activité physique modérée à vigoureuse quotidiennement. La majorité dépasse le temps d’écran quotidien recommandé de deux heures. Plusieurs études transversales indiquent que les deux comportements évoluent indépendamment et ne seraient que faiblement corrélés. Objectifs et hypothèses : Les objectifs de ce mémoire est d’identifier des trajectoires d’activité physique et des trajectoires de temps devant l’écran durant l’adolescence, par sexe, et de décrire la distribution des individus selon l’appartenance simultanée aux deux trajectoires. Nos hypothèses stipulent que des trajectoires différentes seront observées pour les deux sexes et que les deux comportements ne s’influenceront pas. Méthodes : Les données proviennent d’une étude prospective de 1294 adolescents de la région de Montréal, recrutés en 1999 à l’âge de 12-13 ans. Des questionnaires ont été remplis en classe à chaque 3 mois, de la première à la cinquième année du secondaire. Des modélisations de trajectoires de groupe ont identifié des trajectoires d’activité physique et de temps devant l’écran. Une modélisation de trajectoires jointes a rapporté des probabilités d’appartenance aux trajectoires des deux variables. Résultats : Cinq groupes ont été identifiés pour les trajectoires d’activité physique pour les deux sexes. Quatre groupes ont été identifiés pour les garçons et 5 pour les filles concernant le temps passé devant l’écran. 57% des garçons et 46% des filles ont fait des activités physiques pendant 6-7 jours par semaine, durant toute l’adolescence. Toutes les trajectoires de temps devant l’écran accumulent plus de deux heures d’écran quotidiennement. Les probabilités conditionnelles suggèrent une relation entre l’activité physique et le temps devant l’écran. Conclusion : Le développement de l’activité physique et du temps devant l’écran est hétérogène durant l’adolescence. Leur coévolution doit être prise en compte par les professionnels en santé publique. / Introduction: Only 7% of Canadians age ≤ 17 years engage in the recommended 60 minutes or more of moderate-to-vigorous physical activity (PA) daily. Further, most youth surpass the recommended screen time maximum of 2-hours daily. Many cross-sectional studies suggest that PA and screen time are only weakly correlated and that they evolve independently. Objectives and hypotheses: The first objective of this MSc thesis was to model PA and screen time trajectories during adolescence, in boys and girls. The second objective was to describe the distribution of participants according to concurrent membership in the two sets of trajectories. Our hypotheses were that trajectories differ by sex and that PA trajectories are independent of screen time trajectories. Methods: Data were drawn from an ongoing longitudinal study of 1294 adolescents age 12-13 years recruited in 1999-2000 in 10 Montreal-area high schools. Self-report questionnaires were completed during class time, every 3 months from grade 7 to 11. Group-based trajectory modeling identified PA and screen time trajectories. Joint trajectory models provided membership probabilities in both PA and screen time trajectories. Results: Five groups of PA trajectories were identified in both sexes. Four and five screen time trajectory groups were identified in boys and girls, respectively. Half (57%) of boys and 46% of girls engaged in PA 6-7 days weekly during the entire 5-year follow-up. All screen time trajectories were above the recommended 2-hours daily. Conditional probabilities suggested weak associations between PA and screen time. Conclusion: Patterns of PA and screen time are heterogeneous during adolescence. Their co- evolution may need to be considered by public health practitioners.