Insomnia and Diabetes Risk

Objective: We examined the joint effects of insomnia and objective short sleep duration, the combination of which is associated with higher morbidity, on diabetes risk.

Research Design and Methods: 1,741 men and women randomly selected from Central Pennsylvania were studied in the sleep laboratory. Insomnia was defined by a complaint of insomnia with duration of ≥ 1 year while poor sleep was defined as a complaint of difficulty falling asleep, staying asleep, or early final awakening. Polysomnographic sleep duration was classified into three categories: ≥ 6 hours of sleep (top 50% of the sample), 5-6 hours (approximately third quartile of the sample), and ≤ 5 hours (approximately the bottom quartile of the sample). Diabetes was defined either based on a fasting blood glucose > 126 mg/dl or using medication. In the logistic regression model we simultaneously adjusted for age, race, sex, body mass index, smoking, alcohol use, depression, sleep disordered breathing (SDB), and periodic limb movement.

Results: Chronic insomnia but not poor sleep was associated with a higher risk for diabetes. Compared to the normal sleeping and ≥ 6 hour sleep duration group, the highest risk of diabetes was in individuals with insomnia and ≤ 5 hour sleep duration group [OR (95% CI) 2.95 (1.2 – 7.0)], and in insomniacs who slept 5-6 hours [OR (95% CI) 2.07 (0.68 – 6.4)].

Conclusions: Insomnia with short sleep duration is associated with increased odds of diabetes. Objective sleep duration may predict cardiometabolic morbidity of chronic insomnia, whose medical impact has been underestimated.