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Topical Area: Obesity

Obesity (Poster Session)

(P31-012-23) Screen Time and Obesity in Adolescents: An Isotemporal Substitution Analysis

Monday, July 24, 2023
12:45 PM – 1:45 PM ET
Location: Poster Board 235

    Presenting Author(s)

  • Yoonkyoung Cho, BA

    MS student in Public Health Sciences (Epidemiology and risk management)
    Department of Public Health Science, Korea University
    Seongbuk-gu, Seoul-t'ukpyolsi, Republic of Korea

    • Co-Author(s)

  • Hajin Jang, MPH in Public Health Sciences

    Researcher
    Interdisciplinary program in precision public health, Department of Public Health Sciences, Korea University
    Seongbukgu, Seoul-t'ukpyolsi, Republic of Korea

  • Hannah Oh, ScD, MPH (she/her/hers)

    Associate Professor
    Department of Public Health Sciences, Korea University
    Seoul, Seoul-t'ukpyolsi, Republic of Korea

Disclosure(s):
Yoonkyoung Cho, BA: No relevant financial relationship(s) with ineligible companies to disclose.


Objectives: While the current guideline recommends < 2 h/d of screen time for children and adolescents, the guideline does not provide specific recommendation on alternative activities (e.g., physical activity, sleeping) that may replace the screen time for better health. Given the finite time, a decrease in screen time indicates an increase in the time spent on other activities (i.e., substitution effect). In this study, we conducted an isotemporal substitution analysis to examine the associations of reallocating screen time for other alternative activities in Korean adolescents, using a 3-year follow-up data.

Methods: This prospective analysis included 4,085 adolescents (2,024 4th grade and 2,061 7th grade students) who were not obese at baseline and participated in the Korean Children and Youth Panel Survey from 2018 to 2021. Participants were asked to report weight, height, the average duration of smartphone use, computer use, TV watching, and other leisure-time and study-time activities. During the follow-up, obesity incidence (294 cases) was defined as having BMI-for-age ≥95th percentiles according to the Korean national growth chart. Isotemporal substitution regression modelling was performed to examine the impact of replacing the amount of time spent using screen devices for another activities (physical activity, sleeping, hanging out with friends, chatting with parents, studying, reading) on obesity risk, adjusting for potential confounders.

Results: Among 4th grade students, reallocating 1-hour of screen time for performing physical activity (odds ratio [OR]=0.78, 95% confidence interval [CI]=0.62-0.99) and reading books (OR=0.67, 95% CI=0.48-0.93) were associated with lower obesity risk. Sleeping, hanging out with friends, chatting with parents, and studying were also inversely associated with obesity risk but the associations were not statistically significant. Among 7th grade students, reallocating 1-hour of screen time for performing physical activity, hanging out with friends, and chatting with parents were inversely associated with obesity risk but none of the association was statistically significant.

Conclusions: Our data suggest that replacing screen time with physical activity is associated with lower risk of obesity in Korean adolescents.

Funding Sources: This work was supported by National Research Foundation of Korea.