The relationship of glucose tolerance to sleep disorders and daytime sleepiness

The purpose of the study was to find out if snoring, sleep apnea and daytime sleepiness are independent indices of obesity related to type two diabetes (T2D), and whether depression is independently associated with features of sleep apnea. A population-based cohort study was conducted among 593 subjects (245 men and 348 women) born in 1935 and living in Oulu in 1996-1998. Glucose status was determined with a standard 2h oral glucose tolerance test, and sleeping disorders were recorded on the Epworth sleepiness scale (ESS) and in a questionnaire of five questions about sleeping and snoring. Depression was measured by the Zung self-rated depression scale. Insulin sensitivity was measured by quantitative insulin sensitivity check index. Habitual snoring was more common in diabetic subjects than in subjects with impaired glucose regulation (IGR) or normal glucose tolerance (NGT). All sleep disorders associated with neck circumference, waist circumference and body mass index (BMI). There was also a relationship between impaired insulin sensitivity and habitual snoring in bivariate analysis. In multiple logistic regression analysis, depression associated independently with daytime sleepiness (OR 3.00, 95% CI 1.40-6.46). Type 2 diabetes (T2D) (OR 1.93, 95% CI 1.04-3.57) and smoking (OR 1.69, 95% CI 1.00-2.84) associated independently with habitual snoring. BMI (OR 1.20, 95% CI 1.09-1.34) and male gender (OR 2.61, 95% CI 1.05-6.72) associated independently with sleep apnea. In a multiple regression model, BMI, neck circumference and habitual snoring associated independently with T2D. Habitual snoring was associated with T2D and impaired insulin sensitivity. Daytime sleepiness seemed to be linked with depression but not with using sleep medication, IGR and T2D.