Objective Our objective was to identify factors associated with sleep pattern in school age children living in Tehran city.

Study Design This was a cross-sectional study of 6–9 year olds children (n=270) who recruited by multistage sampling among primary school in Tehran city. Sleep pattern and efficiency was measured for 7 consecutive days using Actigraph accelerometer. Height and weight were directly measured using standardized equipment. Other factors including age, gender, history of preterm birth, birth weight, playing video game, watching TV, family income and parental educational level gathered by standard questionnaire.

Results 7days and weekdays sleep duration was significantly shorter (p<0.05) in older children while there was not the same for weekend sleep duration. After adjusting for age we found no significant associations between measured factors and sleep pattern. There was no significant gender difference for sleep pattern, but girls had better (p<0.05) sleep efficiency during 7 days and weekdays compared to boys.

Conclusions Sleep efficiency showed an inverse correlation with sleep duration. No significant relationship was found between sleep efficiency during 7 days, weekdays and weekend with the personal and the environmental factors.