Association between sleep disorder and islet α-cell and β-cell function in patients with type 2 diabetes mellitus

Abstract

Objective To investigate the association between sleep disorder and islet α-cell and βcell function in patients with type 2 diabetes. Methods Four hundred and forty patients with type 2 diabetes treated from July 2011 to July 2013 were divided into two groups according to Pittsburgh Sleep Quality Index(PSQI): patients without sleep disorder and patients with sleep disorder. The blood glucose and glycated hemoglobin A1c(HbA1c) was detected in the two groups. Oral glucose tolerance test(OGTT), insulin releasing test and glucagon releasing test were performed to investigate the differences of the β-cell function, glucagon and glucagon/insulin ratio between groups after fasting and glucose-load. The correlation and regression analysis were performed between PSQI and other indicators. Results The level of HbA1c, fasting plasma glucose, fasting plasma insulin and HOMA-IR were significantly higher in patients with sleep disorder compared to those in patients without sleep disorder(8.6%±2.4% vs 7.5%±1.9%, (8.5±2.1) vs (6.7±1.3) mmol/L, (14.4±4.4) vs (12.9±4.6) mU/L, 5.2±1.0 vs 3.8±1.0, t=5.358, 11.085, 3.578,14.448, all P< 0.05). Insulin sensitivity index(ISI) was lower in patients with sleep disorder than that in patients without sleep disorder(-4.3±0.9 vs-4.0±0.6, t=3.379, P<0.05). There was no significant differences in basal and early-phase insulin secretion between the two groups, while the insulin area under curve was higher in patients with sleep disorder than that in petients without(t=2.489, P<0.05). Blood glucagon, area under curve of glucagon and glucagon/insulin ratio were significantly higher in patients with sleep disorder than those in patients without(t=2.047-8.131, P<0.05). Multiple stepwise regression analysis showed that PSQI score was positively related to glucagon/insulin ratio, HOMA-IR and age(β =0.244,0.281,0.307, all P<0.05), and negatively related to ISI (β =-0.105, P<0.05). Conclusions Sleep disorder is associated with the dysfunction of islet α-cells and β-cells. Improving sleep disorder may help to reduce thedawn phenomenonand optimize glycemic control. Key words: Diabetes mellitus, type 2; Sleep disorders; Islet α-cell; Islet β-cell