Obstructive Sleep Apnea, Glucose Tolerance, and β-Cell Function in Adults With Prediabetes or Untreated Type 2 Diabetes in the Restoring Insulin Secretion (RISE) Study

<b>Objective:</b> Obstructive sleep apnea (OSA) is associated with insulin resistance and has been described as a risk factor for type 2 diabetes. Whether OSA adversely impacts pancreatic islet beta-cell function remains unclear. We aimed to investigate the association of OSA and short sleep duration with beta-cell function in overweight/obese adults with prediabetes or recently-diagnosed, treatment-naïve type 2 diabetes. <p><b>Research Design and Methods:</b> 221 adults (57.5% men, age 54.5±8.7 years, BMI 35.1±5.5 kg/m²) completed one week of wrist actigraphy and one night of polysomnography before undergoing a 3-h oral glucose tolerance test (OGTT) and a two-step hyperglycemic clamp. Associations of measures of OSA and actigraphy-derived sleep duration with HbA1c, OGTT-derived and clamp-derived outcomes were evaluated with adjusted regression models.</p> <p><b>Results:</b> Mean±SD objective sleep duration by actigraphy was 6.6±1.0 hours/night. OSA defined as an apnea-hypopnea index (AHI) ≥5 events per hour was present in 89% of the participants; 20% mild, 28% moderate and 41% severe. Higher AHI was associated with higher HbA1c (p =0.007). However, OSA severity, measured by either AHI as a continuous variable or by categories of OSA severity, and sleep duration (continuous or <6 h vs. ≥6 h) were not associated with fasting glucose, 2-h glucose, insulin sensitivity or beta-cell responses.</p> <p><b>Conclusion:</b> In this baseline cross-sectional analysis of the RISE clinical trial of adults with prediabetes or recently-diagnosed, untreated type 2 diabetes, the prevalence of OSA was high. Although some measures of OSA severity were associated with HbA1c, OSA severity and sleep duration were not associated with measures of insulin sensitivity or beta-cell responses.</p>