The association of obstructive sleep apnea (OSA) and nocturnal hypoxemia with the development of abnormal HbA1c in a population cohort of men without diabetes

Aim: To examine the relationship between indices of undiagnosed OSA and the development of abnormal glycaemic control in community-dwelling men free of diabetes. Methods: The Men, Androgens, Inflammation, Lifestyle, Environment, and Stress (MAILES) Study is a population-based cohort study in Adelaide, South Australia. Clinic visits at baseline (2002-06) and follow-up (2007-10) identified abnormal glycaemic metabolism [HbA1c 6.0 to <6.5% (42 to <48 mmol/mol)] in men without diabetes. At follow-up (2010-11), n = 837 underwent assessment of OSA by full in-home unattended polysomnography (Embletta X100). Results: Development of abnormal glycaemic metabolism over 4-6 years (n = 103 "incident" cases, 17.0%) showed adjusted associations [odds ratio (95% CI)] with the 1st [1.7 (0.8-3.8)], 2nd [2.4 (1.1-4.9)], and 3rd [2.3 (1.1-4.8)] quartiles of mean oxygen saturation (SaO₂) compared to the highest quartile. Prevalent abnormal glycaemic metabolism (n = 140, 20.8%) was independently associated with the third and fourth quartiles of percentage of sleep time with oxygen saturation <90% and lowest quartile of mean SaO₂. Linear regression analysis showed a significant reduction in HbA1c [unstandardized B, 95% CI: -0.02 (-0.04, -0.002), p = 0.034] per percentage point increase in mean SaO₂. OSA as measured by the apnea-hypopnea index showed no adjusted relationship with abnormal glycaemic metabolism. Conclusions: Development of abnormal glycaemic metabolism was associated with nocturnal hypoxemia. Improved management of OSA and glycaemic control may occur if patients presenting with one abnormality are assessed for the other.