Insufficient sleep has been recognized to underlie the epidemic of obesity, type 2 diabetes, hypertension, and cardiovascular diseases. Recent evidence indicates that, not only short sleep duration, but also poor sleep quality is associated with obesity, type 2 diabetes, and metabolic syndrome. However, most of the prior studies evaluated sleep quality subjectively by using a questionnaire. In this study, we objectively evaluated sleep quality and investigated its association with obesity in patients with type 2 diabetes. We included 182 patients with type 2 diabetes, of which 113 had obesity (BMI ≥ 25kg/m2). Objective sleep architecture was measured using single-channel electroencephalography, and slow-wave sleep (SWS) was evaluated as a marker of deep sleep. We also measured apnea-hypopnea index (AHI), and nocturnal blood pressure (BP) by 24-h ambulatory BP monitoring. In a total population, the mean value for age was 58 years, duration of diabetes was 12 years, BMI was 27.8 kg/m2, HbA1c was 8.5%, AHI was 15, total sleep time was 345 min, and SWS was 9.8 min. Subjects with obesity (mean BMI 31.2 kg/m2) were younger (56 vs. 62 years) and had higher AHI (18.3 vs. 9.5) than those without obesity (mean BMI 22.2 kg/m2). Neither total sleep time nor SWS was significantly different between the groups. In unadjusted analyses, BMI was significantly correlated with AHI, but not with SWS or total sleep time. Multivariate analysis revealed that AHI (β = 0.423, p < 0.001) was positively, while SWS (β = −0.146, p = 0.042), age, and male sex were negatively associated with BMI, after further adjustment for duration of diabetes, nocturnal systolic BP, serum creatinine, and HbA1c. On the other hand, no significant association was found between total sleep time and BMI. In conclusion, SWS is inversely associated with BMI, independently of AHI and other covariates, in patients with type 2 diabetes. This study indicates an adverse relationship between poor sleep quality and obesity, independent of sleep apnea, in patients with type 2 diabetes.
T. Hirota: None. T. Morioka: Consultant; Self; Ono Pharmaceutical Co., Ltd.. Research Support; Self; Novartis Pharma K.K., MSD K.K., Eli Lilly and Company, Sanofi K.K., Mitsubishi Tanabe Pharma Corporation. Speaker's Bureau; Self; Takeda Pharmaceuticals U.S.A., Inc., Novo Nordisk Inc., Kowa Pharmaceuticals America, Inc., Astellas Pharma US, Inc., Boehringer Ingelheim Pharmaceuticals, Inc., Sumitomo Dainippon Pharma Co., Ltd.. K. Yoda: None. N. Toi: None. N. Hayashi: None. S. Maruo: None. M. Kurajoh: Speaker's Bureau; Self; Sanwa Kagaku Kenkyusho Co., Ltd., Fuji Chemical Industry Co., Ltd., Teijin Pharma Limited, Pfizer Inc.. Other Relationship; Self; Merck Sharp & Dohme Corp.. Speaker's Bureau; Self; Taisho Pharmaceutical Co., Ltd., Novartis Pharma K.K., Daiichi Sankyo Company, Limited. S. Yamada: None. T. Shoji: Speaker's Bureau; Self; Astellas Pharma Inc, Bayer Yakuhin Ltd. Research Support; Self; Bayer Yakuhin Ltd. Speaker's Bureau; Self; Kowa Pharamaceutical Co Ltd, Daiichi Sankyo Company, Limited, MSD K.K., Chugai Pharmaceutical Co., Ltd.. Research Support; Self; Chugai Pharmaceutical Co., Ltd.. Speaker's Bureau; Self; Kyowa Hakko Kirin Co., Ltd., Kissei Pharmaceutical Co., Ltd. M. Emoto: Speaker's Bureau; Self; Eli Lilly and Company, Boehringer Ingelheim Pharmaceuticals, Inc., Sumitomo Dainippon Pharma Co., Ltd.. Research Support; Self; Astellas Pharma Inc, Ono Pharmaceutical Co., Ltd., Kissei Pharmaceutical Co., Ltd., Kowa Pharmaceutical Company Ltd., Taisho Toyama Pharmaceutical Co., Ltd., Mitsubishi Tanabe Pharma Corporation. M. Inaba: None.
