Mediating effect of sleep in the association between social media use and mental health among French adolescents during the COVID-19 sanitary crisis.

OBJECTIVE/BACKGROUND: Social media use could have deleterious effects on mental health through short sleep duration and poor sleep quality among adolescents. This study aimed to investigate the mediating role of both sleep duration and sleep quality in the association between social media use and mental health among adolescents. PATIENTS/METHODS: We used cross-sectional data collected from adolescents in the EXIST pilot project conducted during COVID-19 pandemic. Adolescents self-reported wellbeing (WEMWBS), anxiety and depression (HADS) as mental health outcomes. We used ad-hoc questionnaires to assess social media use during weekdays and weekend days, and sleep duration and quality. Mediation analyses were carried out following Baron and Kenny's method, using adjusted linear regression models. RESULTS: A total of 340 adolescents (13.5 ± 0.6 years, 45.3 % girls) were included. Greater social media use, poorer sleep quality, and shorter sleep duration were associated with poorer mental health. Greater social media use was associated with poorer sleep quality only during the weekend days. The total effect of social media use during weekend days on anxiety (ß = 2.54; 95%CI [-1.59; 6.68]) was significantly conveyed through sleep quality (ß = 1.22; 95%CI [0.17; 2.62]; mediated proportion = 48.0 %) and duration (mediated proportion = 46.8 %). Mediated proportions ranged from 12.5 % to 20.6 % for wellbeing and depression. Mediating effects were not evident during weekdays. CONCLUSIONS: Sleep duration and quality mediated the association between social media use and mental health among adolescents during weekend days but not weekdays. Our findings highlight the importance of promoting healthy social media habits, especially during periods of increased reliance on digital platforms, such as COVID-19 pandemic.

Economic evaluation of a school-based strategy to prevent overweight and obesity in French adolescents: insights from the PRALIMAP randomised trial.

OBJECTIVES: This study aimed to provide cost-effectiveness and budget impact analyses of a school-based overweight/obesity screening and care prevention strategy among adolescents. STUDY DESIGN: Cost-effectiveness and budget impact analyses. METHODS: Data from 3538 adolescents who participated in a school-based randomised controlled trial in the Northeast of France were used. Costs (from a public payer's perspective) included screening for overweight and obesity and subsequent care. Effectiveness was measured as the change in body mass index (kilogram per square metre), prevalence of overweight/obesity, moderate physical activity energy expenditure, duration and frequency and total sitting time. The incremental cost-effectiveness ratio was calculated, and a budget impact analysis was conducted. RESULTS: The screening and care strategy resulted in an incremental cost-effectiveness ratio of €1634.48 per averted case of overweight/obesity and €255.43 per body mass index unit decrease. The costs for increasing moderate physical activity by 1000 metabolic equivalent of task-min/week, duration by 60 min/week and frequency 1 day/week were €165.28, €39.21 and €93.66 per adolescent, respectively. Decreasing total sitting time by 60 min/week had a cost of €8.49 per adolescent. The cost of implementing the strategy nationally was estimated to be €50.1 million with a payback period from 3.6 to 7.3 years. CONCLUSIONS: The screening and care strategy could be an efficient way to prevent overweight and obesity among adolescents. Future studies should investigate how the current results could be achieved in schools with different settings and thus justify its relevance for overweight and obesity prevention to policy-makers.