Obstructive sleep apnoea and long-term risk of incident diabetes in the middle-aged and older general population.

Background: Obstructive sleep apnoea (OSA) is associated with increased risk of type 2 diabetes. However, results from large population-based prospective cohort studies are rare. The main aim of the present study was to investigate the relative risk of 8-year incident type 2 diabetes in relation to OSA severity in a prospective cohort study of middle-aged and older adults.

Methods: A total of 2918 participants (mean age 59 years) of the Korean Genome and Epidemiology Study (KoGES), who underwent home-based overnight polysomnography at baseline examination between 2011 and 2014, were followed up 4-yearly between 2015-2018 and 2019-2021. A total of 1697 participants were present in both follow-ups. After excluding participants who had diabetes at baseline (n=481), a total of 1216 participants were eligible for the analyses.

Results: OSA at baseline was categorised by apnoea-hypopnoea index levels as non-OSA (0-4.9 events·h), mild OSA (5.0-14.9 events·h) and moderate-severe OSA (≥15.0 events·h). Incident type 2 diabetes was identified at each follow-up. Compared with non-OSA, participants with moderate-severe OSA had 1.5 times higher risk of developing type 2 diabetes at the end of the 8-year follow-up after adjusting for potential covariates (relative risk 1.50, 95% CI 1.02-2.21). In the same analytical models for 4-year relative risk of incident type 2 diabetes, none of the OSA groups were at significantly higher risk compared with the non-OSA group.

Conclusion: Moderatesevere OSA, a modifiable risk factor, poses a higher risk of incident type 2 diabetes compared with non-OSA over an 8-year period in general middle-aged and older adults.