Time spent on social media use and BMI z-score: A cross-sectional explanatory pathway analysis of 10798 14-year-old boys and girls.

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Foubister, Campbell  ORCID logo  https://orcid.org/0000-0002-2625-8478
Jago, Russell 
Sharp, Stephen J 
van Sluijs, Esther MF 

BACKGROUND: The association between adolescent time spent on social media use and body mass index z-score (BMI z-score) is unclear. Pathways of association and sex differences are also unclear. This study examined the association between time spent on social media use and BMI z-score (primary objective) and potential explanatory pathways (secondary objective) for boys and girls. METHODS: Data are from 5332 girls and 5466 boys aged 14 years in the UK Millennium Cohort Study. BMI z-score was regressed on self-reported time spent on social media use (h/day). Potential explanatory pathways explored included dietary intake, sleep duration, depressive symptoms, cyberbullying, body-weight satisfaction, self-esteem, and well-being. Sex-stratified multivariable linear regression and structural equation modelling were used to examine potential associations and explanatory pathways. RESULTS: Using social media for ≥5 h/day (vs. <1 h/day) was positively associated with BMI z-score for girls (β [95% CI]) (0.15 [0.06, 0.25]) (primary objective, multivariable linear regression). For girls, the direct association was attenuated when sleep duration (0.12 [0.02, 0.22]), depressive symptoms (0.12 [0.02, 0.22]), body-weight satisfaction (0.07 [-0.02, 0.16]), and well-being (0.11 [0.01, 0.20]) were included (secondary objective, structural equation modelling). No associations were observed for boys and potential explanatory pathway variables were not examined. CONCLUSIONS: In girls, high time spent on social media use (≥5 h/day) was positively associated with BMI z-score, and this association was partially explained by sleep duration, depressive symptoms, body-weight satisfaction, and well-being. Associations and attenuations between a self-reported summary variable of time spent on social media use and BMI z-score were small. Further research should examine whether time spent on social media use is related to other adolescent health metrics.

adolescent, obesity, social media use, Adolescent, Humans, Male, Female, Body Mass Index, Cohort Studies, Cross-Sectional Studies, Social Media, Body Weight
Journal Title
Pediatr Obes
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MRC (MC_UU_00006/5)
Medical Research Council (MR/K023187/1)
Medical Research Council (MC_UU_12015/7)
Campbell Foubister is funded by a NIHR SPHR PhD studentship (Grant Reference Number PD-SPH-2015). The work of EvS is supported by the UK Medical Research Council (Unit Programme number MC_UU_12015/7). This study was undertaken under the auspices of the Centre for Diet and Activity Research (CEDAR), a UKCRC Public Health Research Centre of Excellence. Funding from the British Heart Foundation, Cancer Research UK, Economic and Social Research Council, Medical Research Council, the National Institute for Health Research, and the Wellcome Trust, under the auspices of the UK Clinical Research Collaboration, is gratefully acknowledged [MR/K023187/1]. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. I am grateful to the Centre for Longitudinal Studies (CLS), UCL Social Research Institute, for the use of these data and to the UK Data Service for making them available. However, neither CLS nor the UK Data Service bear any responsibility for the analysis or interpretation of these data.