Is narcolepsy a risk factor for diabetes?

Obesity is a common feature of narcolepsy. In addition, an increased occurrence of non-insulin dependent diabetes has been reported. So far, it is not known whether glucose metabolism in narcolepsy is disturbed due to, or independently of obesity. In a case-control study at the Sleep medicine clinics in Zurich, Berlin and Beijing 17 patients with narcolepsy/cataplexy were compared to 17 healthy controls matched for age, sex, and body mass index (BMI). A 75-g oral glucose tolerance test was performed and Glucose tolerance was determined by computing plasma glucose curve following oral glucose challenge for 240 minutes; insulin sensitivity and insulin secretion by homeostasis model assessment and minimal model analysis followed. The results were good news for people with narcolepsy. Standard outcome measures and indices of the oral glucose tolerance test did not differ between the patient group and the group of control subjects and in this study, no clinically relevant pathologic findings in the glucose metabolism of narcoleptic patients compared to weight matched controls were found. So, narcolepsy is unlikely to be a risk factor per se for impaired glucose tolerance or diabetes.

The full details are in the January 2012 issue of the journal Sleep.