Association between smartphone usage and health outcomes of adolescents: A propensity analysis using the Korea youth risk behavior survey.

Objectives: We aimed to investigate the association between smartphone use and adverse behavioral health outcomes using nationwide Korea Youth Risk Behavior Web-based Survey data for 2017 and 2020.
Methods: The 2020 data (N = 54,809) were used to analyze the relationships between daily smartphone usage time (non-user, 0-2 h [hour], 2-4 h, 4-6 h, 6-8 h, and > 8 h), and adverse health outcomes (stress, sleep, depression, suicide, substance use, and smartphone overdependence). A 1:1 propensity score matching (PSM) was used to control for confounding variables.
Results: A total of 40,998 adolescents with < 4 h/day and > 4 h/day of usage were included. Adolescents' mean smartphone usage time in 2020 increased compared to that in 2017 (weighted % of > 2 h/day; 64.3% vs. 85.7%). The curvilinear relationships between smartphone usage time and adverse health outcomes were prominent after > 4 h/day. Adolescents using smartphones 2-4 h/day showed no increased adverse health outcomes compared to non-users, except for smartphone overdependence. Using a smartphone > 4 h/day was significantly associated with stress perception (1.16; 1.11-1.22), suicidal ideation (1.22; 1.13-1.31), and substance use (alcohol, 1.66; 1.57-1.75) after PSM.
Conclusions: Our study demonstrated the curvilinear relationship between smartphone usage time and adverse health outcomes in adolescents. Our findings can help establish smartphone usage guidelines for adolescents.
Competing Interests: The authors have declared that no competing interests exist.
(Copyright: © 2023 Cha et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)