Short sleep duration and adiposity in Chinese adolescents

Objective: To investigate the relationship between sleep duration and adiposity measurements in rural Chinese adolescents. Methods: This report is based on a cross-sectional analysis of 500 Chinese adolescent twins. Anthropometric measurements and direct adiposity measurements using dual-energy X-ray absorptiometry (DEXA) were taken for all subjects. Standard sleep questionnaires and a 7-day diary were administered to assess sleep duration. Results: Sleep duration decreased with increasing age during adolescence, reaching a nadir at approximately 15 years of age. While BMI and body fat increased through the entire range of adolescence for both genders, after the age of 12, females had much higher amounts of total and truncal fat than males. Graphic plots showed that among females, both long and short sleepers tended to have higher adiposity measures than medium duration sleepers. The association of short sleep duration with higher adiposity measures was significant even after adjustment for covariates. This association was stronger for total and truncal fat and waist circumference (P <0.05) than for BMI (P = 0.06). In contrast, consistent relationships between sleep duration and adiposity measures were not seen in males. Conclusion: Even in this relatively lean Chinese adolescent cohort, short sleep duration was significantly associated with higher adiposity measures and lower lean body mass in females. The results of this study indicate that the observed association between short sleep duration and higher BMI is most likely mediated by factors associated with total and central adiposity rather than lean body mass.