Association of sleep apnea and type II diabetes: a population-based study.

RATIONALE: Cross-sectional association has been reported between sleep-disordered breathing (SDB) and insulin resistance, but no prospective studies have been performed to determine whether SDB is causal in the development of diabetes.

OBJECTIVES: The purpose of our study was to investigate the prevalence and incidence of type II diabetes in subjects with SDB and whether an independent relationship exists between them.

METHODS: A cross-sectional and longitudinal analysis was performed in 1,387 participants of the Wisconsin Sleep Cohort. Full polysomnography was used to characterize SDB. Diabetes was defined in two ways: (1) physician-diagnosis alone or (2) for those with glucose measurements, either fasting glucose > or = 126 mg/dl or physician diagnosis.

MEASUREMENTS AND MAIN RESULTS: There was a greater prevalence of diabetes in subjects with increasing levels of SDB. A total of 14.7% of subjects with an apnea-hypopnea index (AHI) of 15 or more had a diagnosis of diabetes compared with 2.8% of subjects with an AHI of less than 5. The odds ratio for having a physician diagnoses of diabetes mellitus with an AHI of 15 or greater versus an AHI of less than 5 was 2.30 (95% confidence interval, 1.28-4.11; p = 0.005) after adjustment for age, sex, and body habitus. The odds ratio for developing diabetes mellitus within 4 yr with an AHI of 15 or more compared with an AHI of less than 5 was 1.62 (95% confidence interval, 0.67-3.65; p = 0.24) when adjusting for age, sex, and body habitus.

CONCLUSIONS: Diabetes is more prevalent in SDB and this relationship is independent of other risk factors. However, it is not clear that SDB is causal in the development of diabetes.