[Epidemiological characteristics and changes of screen time among students aged 6-14 years in Beijing in 2015 and...

To analyze the characteristics and changes in screen time among students aged 6-14 years in Beijing in 2015 and 2019.

A multistage cluster sampling approach was adopted. A survey on after-school screen time was conducted among students in grades 1, 3, 5, and 7 (first year of junior high school) in 7 districts of Beijing in 2015 and 2019, using the Nutrition and Health Status Questionnaire developed by the Beijing Center for Disease Prevention and Control. A total of 4152 primary and secondary school students were surveyed in 2015, and 4202 in 2019. The Mann-Whitney U test and chi-square test were employed to analyze differences in daily average screen time and the prevalence of exceeding the daily screen time limit among respondents with different demographic characteristics. Using a generalized linear mixed model (GLMMs) to analyze the association between different years, gender, age, residential areas, and whether screen time exceeds the limit.

Survey result showed that the median screen time of respondents was 54 (31, 84) min/d in 2015 and 41 (26, 69) min/d in 2019, representing a decrease of 13 min/d (P<0.01). The prevalence of exceeding the daily screen time limit (≥2 h/d) was 10.06% (403/4005) in 2015 and 5.01% (203/4052) in 2019, a reduction of 5.05 percentage points (P<0.01). Compared with 2015, the daily average screen time (school days, weekends, and the entire week) of respondents across different genders, age groups, and regions all decreased in 2019 (male：Z=-6.95, Z=-9.37, Z=-9.55；female：Z=-4.63, Z=-10.77, Z=-8.94；6-9 years：Z=-4.12, Z=-8.38, Z=-7.06；10-14 years：Z=-7.63, Z=-11.89, Z=-11.63；urban：Z=-5.37, Z=-10.48, Z=-9.11；suburban：Z=-6.13, Z=-10.02, Z=-9.62；P <0.01). GLMMs analysis revealed that the daily average screen time exceeding rate among survey subjects in 2019 was lower than in 2015 (β = -0.74, OR=0.48，95% CI 0.40-0.57). Compared with their counterparts with the same characteristics, respondents who were male (β = 0.26, OR=1.29, 95%CI 1.09-1.53), aged 10-14 years(β=0.67，OR=1.95，95%CI 1.64-2.32), and residing in suburban areas (β=0.57, OR=1.77, 95%CI 1.47-2.12) had a significantly higher rates of excessive screen time (P<0.01).

The daily average screen time and prevalence of excessive screen time among primary and secondary school students in Beijing decreased significantly overall in 2019 compared with 2015. However, male students, age 10-14 years, and those residing in suburban areas consistently had higher screen time and a higher prevalence of excessive screen time than their counterparts within the same categories.