Bedtime and its correlates among secondary school children in Karachi, Pakistan

To determine the demographic and lifestyle predictors of bedtime among secondary school children in Karachi, Pakistan, and to assess what variables of daytime functioning correlate with bedtimes.

The cross-sectional study was conducted between September and October 2007, among secondary school students aged 10-16 years, in the socio-economically diverse city of Karachi. Data was collected using a pre-tested self-reporting questionnaire, and analysed by univariate and multivariate logistic regression analysis on SPSS version 15. A p value of <0.05 was considered significant. All odds ratio were recorded with a 95% confidence interval.

Of the 539 students in the study, 102 (18.92%) were male and 437 (81.07%) were female. Of the total, 401 (74.4%) slept late (after 10pm). Homework and TV shows were more frequent reasons of bedtime among the late-sleepers, whereas parental influence was reported more by the early-sleepers. Advancing grade at school, father's profession as doctor or engineer and sleeping alone in the room were independent predictors of late bedtime on multivariate analysis (p<0.05). Students who were older, did not share a bed, or slept for >3 hours during the afternoon, were more likely to sleep after 10pm on univariate analysis only (p<0.05). Students sleeping late were more likely to get less daily and nocturnal sleep, wake-up later, require multiple wake up reminders in the morning, fall asleep in a morning class and feel tired during the day (p<0.05). They were also 2.42 times less likely to feel that they got adequate sleep to be fresh in the morning (p<0.001; 95% CI 1.58-3.72).

More than three-fourth of our secondary school children sleep late. Parents and teachers should foster healthy sleeping habits and early bedtimes among students to allow optimal daytime functioning.