May diabetes patients have trouble sleeping despite not having obesity?

Obstructive sleep apnea (OSA) and periodic limb movements during sleep (PLMs) are sleep-related disorders with a high prevalence in type 2 diabetes. Commonly OSA is considered as a consequence of obesity, but several previous studies have shown the presence of OSA in non-obese diabetic patients. A previous study showed higher PLMs prevalence in patients with type 2 diabetes, compared to age-matched controls. We speculated that both OSA and PLMs may reflect the presence of diabetic autonomic neuropathy. To test this hypothesis, we compared a group of 112 non-obese patients with type 2 diabetes with 66 age-, sex-, and body mass index- matched nondiabetic patients. Both groups have been investigated through a set of tests including the Epworth Sleepiness Scale, polysomnography, and the Orthostatic Grading Scale (OGS), a questionnaire to assess the degree of autonomic dysfunction. Diabetic patients with OSA and PLMs scored higher on the OGS than controls. Our results confirm that both OSA and PLMs are related to dysautonomy and may be unrelated to obesity in type 2 diabetes patients.