Short sleep duration is associated with insulin resistance independent of adiposity in Chinese adult twins

Objective: To investigate the association between sleep duration and insulin resistance in rural Chinese adults and examine whether any such associations are independent of adiposity. Methods: This is a cross-sectional analysis of 854 men and 640 women aged 20 to 70 years from the Anqing Twin Cohort. The following measures were obtained for each subject: Body mass index (BMI) and percentage of trunk fat (%TF), fasting plasma glucose, homeostatic model assessment of insulin resistance index (HOMA-IR), self-reported sleep duration and measures of snoring and sleep disturbance from the Pittsburgh Sleep Quality Indices (PSQI) questionnaire were modified for a Chinese population. Multivariate linear regressions were applied to examine the association of sleep duration with HOMA-IR, with and without adjustment for adiposity variables, along with other relevant covariates. Results: In this sample of relatively lean rural Chinese adults, short sleep duration was associated with HOMA-IR in women but not in men. In women, short (<= 7 h/night) sleep duration was associated with a higher HOMA-IR (p = 0.003) compared with normal sleep duration (>7 to <= 8 h/night) after adjustment for all the covariates except adiposity. Further adjustment for BMI or %TF attenuated the sleep-HOMA-IR association, but the association remained significant upon adjustment for BMI (p = 0.013): and upon adjustment for %TF (p = 0.026). Long sleep duration (>8 h/night) was not significantly associated with HOMA-IR. Conclusion: In this rural Chinese cohort, short sleep duration is independently associated with increased insulin resistance among women only, even after adjusting for adiposity and other potential confounders. (C) 2011 Elsevier B.V. All rights reserved.