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

Objectives: 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.

Methods: 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.