Ma Junqi, Sheng Li
School of Public Administration, Chongqing Technology and Business University, Chongqing, China.
School of Foreign Languages, Chongqing Technology and Business University, Chongqing, China.
PLoS One. 2024 Dec 16;19(12):e0311996. doi: 10.1371/journal.pone.0311996. eCollection 2024.
The prevalence of overweight and obesity among adolescents has been increasing steadily. This study aims to investigates the causal effect and underlying mechanisms between Internet use and body weight among Chinese adolescents. Using data from China Health and Nutrition Survey (CHNS) spanning from 2004 to 2015, the analytical sample includes 3054 participants (aged 11-19, 48% females). We exploit ordinary least squares (OLS) and two-stage least squares (2SLS) models, obtained causal effect of Internet use on body mass index (BMI), overweight and obesity among adolescents. We find a significant positive effect of Internet use on BMI (β = 0.499, p < 0.05) and probability of overweight (β = 0.061, p < 0.05). Specifically, Internet use increases BMI by 2.56%, and increases the probability of being overweight by 6.1%. But no evidence shows that Internet use significantly increases the probability of obesity (p > 0.1). The mechanism is that Internet use increases sedentary activities (mainly screen time) and food consumption behavior, which results in an imbalance between energy intake and expenditure that in turn increases BMI and overweight. Furthermore, the longer the time spent playing games online, the greater the probability of adolescents being overweight (β = 0.012, p < 0.1), whereas time spent watching movies online, surfing online, and chatting online is not significantly associated with body weight. Heterogeneity analyses show that the adverse effects of Internet use on adolescents' body weight is more pronounced in rural areas and among the male group. This study suggests that reducing time spent playing games online, and increasing physical activity and cultivating healthy eating behaviour can reduce the risk of overweight and obesity in adolescents.
青少年中超重和肥胖的患病率一直在稳步上升。本研究旨在探讨中国青少年上网与体重之间的因果关系及潜在机制。利用2004年至2015年中国健康与营养调查（CHNS）的数据，分析样本包括3054名参与者（年龄在11 - 19岁，48%为女性）。我们采用普通最小二乘法（OLS）和两阶段最小二乘法（2SLS）模型，得出上网对青少年体重指数（BMI）、超重和肥胖的因果效应。我们发现上网对BMI有显著的正向影响（β = 0.499，p < 0.05）以及超重概率（β = 0.061，p < 0.05）。具体而言，上网使BMI增加2.56%，使超重概率增加6.1%。但没有证据表明上网会显著增加肥胖概率（p > 0.1）。其机制是上网增加了久坐活动（主要是屏幕时间）和食物消费行为，这导致能量摄入与消耗失衡，进而增加BMI和超重。此外，在线玩游戏的时间越长，青少年超重的概率就越大（β = 0.012，p < 0.1），而在线看电影、上网冲浪和在线聊天的时间与体重没有显著关联。异质性分析表明，上网对青少年体重的不利影响在农村地区和男性群体中更为明显。本研究表明，减少在线玩游戏的时间，增加体育活动并培养健康的饮食行为，可以降低青少年超重和肥胖的风险。
