How Does OSAS Severity Affect Glucose Tolerance?

How Does OSAS Severity Affect Glucose Tolerance?
How Does OSAS Severity Affect Glucose Tolerance?

SEATTLE, WA—Severe obstructive sleep apnea syndrome (OSAS) may potentially be associated with pancreatic β-cell functional disorder and glucagon-like peptide-1 (GLP-1) resistance, according to a study conducted at the Division of Behavioral Sleep Medicine, Iwate Medical University School of Medicine, Morioka, Japan, and presented at SLEEP 2015.

Healthy individuals have an increased secretion of GLP-1 with postprandial hyperglycemia followed by a decrease after 30 minutes. However, earlier research has shown that patients with OSAS may have insulin resistance. Tetsuya Kizawa and colleagues aimed to determine the relationship between GLP-1 and the severity of OSAS by studying the time variation of plasma GLP-1 levels in patients with OSAS.

A total of 41 patients with OSAS and HbA1c <6.2% and HOMA-R <2.5 were enrolled.  Patients were stratified into two groups based on their severity of OSAS. Group A (n=19) had AHI≥30 and Group B (n=22) had AHI <30. The team performed glucose tolerance tests and measured plasma glucose, serum insulin, and plasma GLP-1 levels via ELISA before and after 30, 60, 120 minutes of load.

Prior to the glucose load tests, there was a significant difference between Groups A and B in plasma glucose and serum insulin levels. However, there was no similar difference in blood glucose at 30, 60, and 120 minutes. Insulin levels of group A were significantly higher than those of Group B at 30 minutes, but not at 60 or 120 minutes. After 30 minutes, however, plasma GLP-1 levels were significantly higher than pre-load in both groups; no significant difference was found between Group A and B. After 60 minutes, plasma GLP-1 levels in Group B showed a non-significant decline (56.3±0.9pmol/L) but no decline was seen in Group A (10.3 ± 2.6/L). After 120 minutes, plasma GLP-1 levels in Group B dipped significantly lower than Group A (5.5±0.7pmol/L vs. 9.1±1.5pmol/L; P=0.03).

Severe OSAS without insulin resistance and glucose tolerance had prolonged plasma GLP-1 levels after 120 minutes post-glucose load.

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