0850 Association Between Smart Device Usage And Accelerometer-measured Sleep Efficiency Among Children And Adolescents In Hong Kong: A Cross-sectional Survey

Abstract

Introduction: Over the last few years, the use of smart devices, including smartphone and tablets, has been increasing rapidly. Several studies showed that excessive use of smart device among children and adolescents may affect sleep quality. However, most existing studies relied on self-report sleep quality with questionable validity. Here, we examined the association between smart device usage and objectively- measured sleep efficiency in a cross-sectional study conducted in Hong Kong. Method(s): In 2016, 198 children and adolescents aged 7-16 (mean 11.9, 47.5% boys) were recruited in three schools. They have completed a self-administered questionnaire about their smart device usage and worn an ActiGraph GT3X accelerometer for seven consecutive days. Sleeping time was determined using Sadeh's algorithm and sleep efficiency was defined as total sleep time divided by total sleeping period. Multiple linear regression (adjusted for age, sex, parental educational level, and family income) was used to examine the association between smart device usage and sleep efficiency. Result(s): On average, participants spent 128.7 minutes per school day and 230.7 minutes per holiday using a smartphone, and spent 37.3 minutes per school day and 78.2 minutes per holiday using a tablet. The participants had a good sleep efficiency with mean of 95.3%. Regression results showed that (1) one additional hour spent on tablet per school day was associated with 0.64% decrease in sleep efficiency (95% CI 0.23%-1.05%, p=0.02); (2) one additional hour spent on tablet per holiday was associated with 0.24% decrease in sleep efficiency (95% CI 0.01%-0.47%, p=0.04); (3) time spent on smartphone, regardless of per school day or per holiday, had insignificant association with sleep efficiency (ps>;0.05). Conclusion(s): Tablet usage was negatively associated with sleep efficiency among Hong Kong Children and adolescents.