Abstract
BACKGROUND: Sleep quality is an important factor in adolescents' health; physical as well as psychological. The aim of this study was to determine sleep quality and daytime sleepiness and their effect on the quality of school life (QSL) and achievement. MATERIALS AND METHODS: This cross-sectional study was conducted in high schools. The data collection was done on a random sample of 500 students from 15 to 19 years. The questionnaires included the Pittsburgh Sleep Quality Index (PSQI) to measure sleep quality and the Epworth Sleepiness Scale to measure daytime sleepiness as well as QSL. Data were analyzed by SPSS 25. Linear and logistic regressions were used to obtain adjusted and unadjusted odds ratios as well as predictors. RESULTS: The mean PSQI score was 6.2 ± 2.4. It was realized that 377 participants (75.4%) were poor sleepers; 6.2% had excessive daytime sleepiness. There was a significant association between age and quality of sleep (P < 0.04). No association between gender and quality of sleep or between the quality of sleep and school achievement was found. Linear regression exhibited a significant relationship between the quality of sleep and daytime sleepiness (β = 0.218; t = 4.982, P = 0.000). There was a significant, inverse correlation between sleepiness and the total score of QSL (P = 0.000). Stepwise linear regression analysis exhibited that daytime sleepiness (P = 0.002) and school achievement (P = 0.001) were predictors of QSL. CONCLUSION: According to the study results, sleepiness affects school performance and QSL, and on the other hand, daytime sleepiness is under the effect of sleep quality.