Obstructive sleep apnoea and incident diabetes mellitus in a Chinese population

Abstract

Background: Although clinical and epidemiological studies have reported an association between obstructive sleep apnoea (OSA) and diabetes mellitus (DM), the results remain inconsistent. Objective: To evaluate the role of OSA on the incidence of DM in a Chinese cohort. Methods: This is a retrospective cohort study, the eligible subjects were drawn from those who received in-laboratory sleep studies between 01/01/2007 and 31/12/2010 in the Department of Medicine, Queen Mary Hospital. Only those without DM at the time of polysomnogram were included. Follow-up data were drawn from the Hospital Authority Clinical Management System up to the day of data entry in this study. Apnoea-hypopnea index (AHI) was used in the Cox-regression model, adjusting for age, gender, body mass index (BMI), neck, waist and hip circumference, daytime sleepiness (Epworth sleepiness scale score) and prior cardiometabolic comorbidities. Findings: 107 (14.3%) of 749 subjects developed DM over a median follow-up of 87 months, giving an incident rate of 2.0 per 100 person-years. In fully adjusted models, AHI as a categorical variable, severe and mild+moderate OSA patients were observed to have 4.0 (95%CI 1.720-9.298) and 2.7 (95%CI 1.254-5.933) times higher hazard to develop DM, while when AHI was a continuous variable, higher AHI was also associated with increased DM risk (HR=1.014, 95% CI 1.005-1.023). Conclusion: AHI as a measure of OSA severity predicted incident diabetes independent of obesity.