Factors associated with sleep duration among pupils

BACKGROUND: Sleep shortage has been pervasive among pupils. METHODS: By multiple regression analysis, 2722 questionnaires obtained from grade 5 to 12 pupils were analyzed to determine factors associated with sleep duration. RESULTS: Significant regression formulae for sleep duration were obtained for all school types: adjusted R(2) / p value were 0.14 / <0.001 for elementary school; 0.11 / <0.001 for junior high school; 0.06 / <0.001 for high school. Longer after-school activity (standardized regression coefficient / p value were -0.22 / <0.001 for elementary school; -0.10 / <0.01 for junior high school; -0.18 / <0.001 for high school) and more sleepiness (-0.09 / <0.001 for elementary school; -0.07 / <0.05 for junior high school; -0.07 / <0.05 for high school) were significantly associated with reduced sleep duration for all school types. In both elementary and junior high schools, the higher grade (-0.53 / <0.001 for elementary school; -0.10 / <0.01 for junior high school), and longer weekday screen time (-0.15 / <0.001 for elementary school; -0.19 / <0.001 for junior high school) were also significantly associated with sleep loss. In elementary school, irregular dinner (-0.07 / <0.05), breakfast skipping (-0.11 / <0.001), longer weekend screen time (-0.09 / <0.05) and better self-reported academic performance (0.07 / <0.05) also revealed significant associations with sleep loss. In high school, reduction of sleep duration was also significantly associated with higher standardized body mass index (-0.08 / <0.05). CONCLUSIONS: Excessive after-school activity might be paid more attention in association with pupils' sleep reduction.