Sleep Duration and Body Mass Index in Korean Children

ABSTRACT

OBJECTIVES: We conducted this study to investigate the relationship between sleep duration and body mass index (BMI), in Korean children. METHODS: We performed a cross-sectional analysis of data collected on 3,639 boys and girls (aged 7-12) in Daegu, Korea. The data included each child's age, sex, weight, height, extracurricular activities, bedtime, wake-up time, sleep latency, total sleep duration, parents' occupations, and parents' educational levels. The relationship between sleep duration and each variable was examined via analysis of variance (ANOVA). RESULTS: The analysis showed an association between short sleep duration and high BMI. Boys showed a graded inverse relationship between sleep duration and BMI. However, there was no significant corresponding result for girls. In the total sample, hours of computer use, time when the computer was turned off, time when the television was turned off, mother's bedtime, and hours of extracurricular activity were associated with longer sleep duration. No association was found between sleep duration and hours of watching television, child's wake-up time, or educational level of the parents. CONCLUSION: The results of this study show an inverse relationship between a child's sleep duration and BMI;thus, children with shorter sleep duration tend to have higher BMIs.