The vicious cycle of leptin-insulin resistance predicts impaired glucose metabolism in obese adults with obstructive sleep apnea

Impact of non-apnea sleep disorders on diabetic control and metabolic outcome - A population-based cohort study

OBJECTIVE

There has been a growing recognition that obstructive sleep apnea (OSA) could increase the propensity for type 2 diabetes the metabolic syndrome. However, studies concerning about the impact of non-apnea sleep disorders (NSD) on diabetes control and metabolic outcomes are relatively scarce. Our aim is to investigate the impact of non-apnea sleep disorders (NSD) on diabetic control and associated metabolic outcomes in patients with type 2 diabetes.

METHODS

The data were obtained from two nationwide population-based databases for a period 2007 to 2012. A total 66,992 patients with type 2 diabetes were enrolled and divided into two cohorts based on comorbidity with or without a NSD diagnosis, and were followed up four years. The primary outcomes were to compare rate of change in HbA1c and associated metabolic outcomes during follow-up visits between patients with or without NSD. The secondary outcome is to examine whether NSD were associated with poor glycemic control of the last clinical records while controlling for the baseline HbA1c value.

RESULTS

Of the 66,992 patients with type 2 diabetes, 14.82% had comorbidity with a NSD. HbA1C decreases were significantly lower by 0.04% in the NSD group (P < 0.05), and triglyceride (TG) decreases remained significantly lower by 2.53% in the NSD group (P < 0.05). Furthermore, patients in the NSD group had an 8% higher risk of poor glycemic control (HbA1C >9) (OR = 1.08; 95%CI, 1.01-1.16).

CONCLUSION

Our findings indicated patients with type 2 diabetes comorbid with NSD had a slower improvement in HbA1c compared with the comparison cohort. It may because there may exist potential floor effect given those with NSD having significantly lower HbA1c values at baseline. On the other hand, the poor diabetic control among those with NSD may be also affected by other confounders such as medical treatment or interventions. Nevertheless, given the rapidly increasing prevalence of metabolic diseases and subsequent complications, the results may highlight the importance of sleep in the clinical management of type 2 diabetes.

The correlation of serum levels of leptin, leptin receptor and NO x (NO 2 (-) and NO 3 (-)) in patients with obstructive sleep apnea syndrome

The aim of this study was to investigate the relations between nitric oxide (NO) and leptin levels in a cohort of untreated adult Obstructive sleep apnea syndrome (OSAS) patients. Between June 1, 2012, and January 1, 2013, we evaluated a total of 58 subjects including 36 OSAS patients and 22 healthy controls, both polysomnographically confirmed. Following the completion of polysomnographic evaluation, serum samples were taken at 08:00. Leptin, leptin receptor, NO2 (-) and NO3 (-) levels were analyzed by commercial ELISA kits. Data analysis was performed using the Statistical Package for the Social Sciences (SPSS) version 16.0 (SPSS Inc., Chicago, IL, USA). There was no statistically significant difference between the OSAS patients and control groups with relation to the demographic parameters and body mass index (p > 0.05). Significantly higher serum leptin and plasma NO levels were found in OSAS patients compared to the controls (p < 0.001). In this study, higher leptin levels which were positively correlated with NO levels in OSAS group may indicate a possible link with increased incidence of airway pathologies in these patients.