OBJECTIVEFew studies are currently available regarding the influence of sleep duration on glycemic control in diabetic patients. The objective of the current study was to examine the relationship between sleep duration, obesity, and the glycemic level in type 2 diabetic patients.RESEARCH DESIGN AND METHODSA total of 4,870 Japanese type 2 diabetic patients aged ≥20 years were divided into six groups according to their self-reported sleep duration: less than 4.5 h, 4.5–5.4 h, 5.5–6.4 h, 6.5–7.4 h, 7.5–8.4 h, and more than 8.5 h. The associations of sleep duration with obesity and the HbA1c levels were examined in a cross-sectional manner.RESULTSThe HbA1c levels showed a quadratic association with sleep duration; namely, a shorter or longer sleep duration was associated with a higher level compared with a sleep duration of 6.5–7.4 h (P for quadratic trend <0.001). This association remained significant after adjusting for potential confounders, including the total energy intake and depressive symptoms. Furthermore, additional adjustments for obesity, which also showed a U-shaped relationship with sleep duration, did not attenuate the U-shaped sleep-HbA1c association. A significant interaction between sleep duration and age or the use of insulin was observed for the HbA1c levels.CONCLUSIONSSleep duration was shown to have U-shaped associations with obesity and the HbA1c levels in type 2 diabetic patients, independent of potential confounders, and therefore may be an important modifiable factor for the clinical management of patients with type 2 diabetes.

BackgroundDietary fiber is beneficial for the treatment of type 2 diabetes mellitus, although it is consumed differently in ethnic foods around the world. We investigated the association between dietary fiber intake and obesity, glycemic control, cardiovascular risk factors and chronic kidney disease in Japanese type 2 diabetic patients.MethodsA total of 4,399 patients were assessed for dietary fiber intake using a brief self-administered diet history questionnaire. The associations between dietary fiber intake and various cardiovascular risk factors were investigated cross-sectionally.ResultsBody mass index, fasting plasma glucose, HbA1c, triglyceride and high-sensitivity C-reactive protein negatively associated with dietary fiber intake after adjusting for age, sex, duration of diabetes, current smoking, current drinking, total energy intake, fat intake, saturated fatty acid intake, leisure-time physical activity and use of oral hypoglycemic agents or insulin. The homeostasis model assessment insulin sensitivity and HDL cholesterol positively associated with dietary fiber intake. Dietary fiber intake was associated with reduced prevalence of abdominal obesity, hypertension and metabolic syndrome after multivariate adjustments including obesity. Furthermore, dietary fiber intake was associated with lower prevalence of albuminuria, low estimated glomerular filtration rate and chronic kidney disease after multivariate adjustments including protein intake. Additional adjustments for obesity, hypertension or metabolic syndrome did not change these associations.ConclusionWe demonstrated that increased dietary fiber intake was associated with better glycemic control and more favorable cardiovascular disease risk factors including chronic kidney disease in Japanese type 2 diabetic patients. Diabetic patients should be encouraged to consume more dietary fiber in daily life.

Aims/hypothesis Medical nutrition therapy plays a critical role in the prevention and treatment of type 2 diabetes. However, appropriate measures of eating behaviours, such as eating rate, have not yet been clearly established. The aim of the present study was to examine the associations among eating rate, obesity and cardiovascular risk factors. Methods A total of 7,275 Japanese individuals aged ≥40 years who had normal fasting glucose levels, impaired fasting glucose or diabetes were divided into four groups according to self-reported eating rate: slow, medium, relatively fast and very fast. The associations between eating rate and various cardiovascular risk factors were investigated cross-sectionally. Results The proportions of participants who were obese or who had elevated waist circumference levels increased progressively with increases in eating rate (p for trend <0.001), regardless of glucose tolerance status. These associations remained significant after adjustment for potential confounders, namely, age, sex, total energy intake, dietary fibre intake, current smoking, current drinking and regular exercise (p for trend <0.001). Blood pressure and lipid levels also tended to increase in association with eating rate. HbA 1c rose significantly as eating rate increased, even after multivariate adjustment, including BMI, in diabetic patients on insulin therapy (p00.02), whereas fasting plasma glucose did not increase significantly. Conclusions/interpretation Our findings suggest that eating rate is associated with obesity and other cardiovascular risk factors and therefore may be a modifiable risk factor in the management of cardiovascular risk factors and diabetes.

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ObjectiveCigarette smoking is an important modifiable risk factor for cardiovascular diseases. However, the effect of smoking and its cessation on glycemic control in diabetic patients has not been fully examined yet. The aim of the present study was to examine the association of smoking status with glycemic level and markers of insulin resistance and secretion in patients with type 2 diabetes mellitus.Research Design and MethodsA total of 2,490 Japanese male patients with type 2 diabetes mellitus aged ≥20 years were divided according to smoking status, amount of cigarettes smoked and years since quitting. The associations with glycemic level and markers of insulin resistance and secretion were examined cross-sectionally.ResultsHbA1c levels increased progressively with increases in both number of cigarettes per day and pack-years of cigarette smoking compared with never smokers (P for trend = 0.001 and <0.001, respectively), whereas fasting plasma glucose did not. On the other hand, HbA1c, but not fasting plasma glucose, decreased linearly with increase in years after smoking cessation (P for trend <0.001). These graded relationships persisted significantly after controlling for the confounders, including total energy intake, current drinking, regular exercise, depressive symptoms, and BMI. In addition, a homeostasis model assessment of insulin resistance and high-sensitivity C-reactive protein also showed similar trends.ConclusionsSmoking and its cessation showed dose- and time-dependent relationship with glycemic control and insulin resistance in patients with type 2 diabetes mellitus. These findings may highlight the importance of smoking cessation in the clinical management of diabetes mellitus.