Obstructive sleep apnoea in obese adolescents and cardiometabolic risk markers.

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT: In paediatric patients, obstructive sleep apnoea is associated with adiposity, especially visceral adiposity. In adults, obstructive sleep apnoea is also associated with a higher prevalence of cardiovascular disease and type 2 diabetes. There are limited and conflicting paediatric studies examining the association between obstructive sleep apnoea and biomarkers of risk for cardiovascular disease and type 2 diabetes in youth. WHAT THIS STUDY ADDS: Obstructive sleep apnoea is linked with greater cardiometabolic risk markers in obese adolescents. Fasting insulin and homeostasis model assessment-insulin resistance may be especially linked with obstructive sleep apnoea among obese male Hispanic adolescents. The relationship between obstructive sleep apnoea and cardiometabolic abnormalities in obese adolescents should be considered when evaluating patients found to have obstructive sleep apnoea. BACKGROUND: Paediatric studies examining the association between obstructive sleep apnoea (OSA) and insulin sensitivity/cardiometabolic risk are limited and conflicting. OBJECTIVE: This study aims to determine if cardiometabolic risk markers are increased among obese youth with obstructive sleep apnoea as compared with their equally obese peers without OSA. METHODS: We performed a retrospective analysis of 96 patients (age 14.2 ± 1.4 years) who underwent polysomnography for suspected OSA. Fasting lipids, glucose, insulin and haemoglobin A1 c (HbA1 c) were performed as part of routine clinical evaluation. Patients were categorized into two groups by degree of OSA as measured by the apnoea-hypopnoea index (AHI): none or mild OSA (AHI < 5) and moderate or severe OSA (AHI ≥ 5). RESULTS: Despite the similar degrees of obesity, patients with moderate or severe OSA had higher fasting insulin (P = 0.037) and homeostasis model assessment-insulin resistance (HOMA-IR [P = 0.0497]) as compared with those with mild or no OSA. After controlling for body mass index, there was a positive association between the AHI and log HOMA-IR (P = 0.005). There was a positive relationship between arousals plus awakenings during the polysomnography and fasting triglycerides. CONCLUSIONS: OSA is linked with greater cardiometabolic risk markers in obese youth.

Experimental investigation of a free-space optical switching network by using symmetric self-electro-optic-effect devices.

A prototype digital free-space photonic switching fabric is demonstrated. It consists of three cascaded 16 x 8 arrays of symmetric self-electro-optic-effect devices that are used as logic gates that implement part of a multistage interconnection network. We discuss architecture, device tolerancing, optical system design, and optomechanical design. This optical circuit is successfully configured as a fully operational array of 32 independent 2 x 2 nodes and operates at 100 kHz.

Six-stage digital free-space optical switching network using symmetric self-electro-optic-effect devices.

We describe the design and demonstration of an extended generalized shuffle interconnection network, centrally controlled by a personal computer. A banyan interconnection pattern is implemented by use of computer-generated Fourier holograms and custom metallization at each 32 × 32 switching node array. Each array of electrically controlled tristate symmetric self-electro-optic-effect devices has 10,240 optical pinouts and 32 electrical pinouts, and the six-stage system occupies a 9 in. × 12.5 in. (22.9 cm × 31.7 cm) area. Details of the architecture, optical and mechanical design, and system alignment and tolerancing are presented.