[A prospective cohort study on the duration of sleep and risk of all-cause mortality among patients with type 2 diabetes].

Objective To investigate the relationship between duration of sleep and all-cause mortality in patients with type 2 diabetes. Methods A total of 17 452 type 2 diabetic patients who were under the National Basic Public Health Service Project, in Changshu county, Qinghe district and Huai’an district in Huai’an city of Jiangsu province, were recruited as participants. Cox proportional hazards regression models were used to estimate the associations between different levels on the duration of sleep and all-cause mortality. Stratified analysis was performed according to factors as gender, age, and lifestyle. Results Among the 67 912 person-years of observation, from the fo1low- up program, the median time of follow-up was 4 years, with 1 057 deaths occurred during the follow-up period. Taking patients with duration of sleep as 7 h/d for reference, the multivariate adjusted hazard ratios (95%CI) of all-cause mortality appeared as ≤6, 8, 9 and ≥10 h/d were 1.14 (0.94-1.37), 1.10 (0.91-1.32), 1.33 (1.05-1.70), and 1.52 (1.24-1.87), respectively which were associated with the duration of sleep. Data from the subgroup analysis showed that this was consistent with the whole population. Longer duration of sleep was associated with the all-cause mortality but no significant association was found between shorter duration of sleep and the all-cause mortality. Conclusion Longer duration of sleep seemed to have increased the risk of all-cause mortality in type 2 diabetic patients. Key words: Diabetes mellitus, type 2; Sleep duration; Mortality; Prospective study