Metabolic alterations in adolescents with obstructive sleep apnea

Importance: Obesity is one of the leading health concerns in developed and in developing countries. The risk of obstructive sleep apnea (OSA) is greatly increased by obesity. Obesity is known to be associated with the Metabolic Syndrome and cardiovascular disease in adults. This same association in children is not well defined. Understanding the relationship of obesity, OSA, and metabolic alterations in children would improve understanding of the risks of cardiovascular disease into adulthood.

Objective: To evaluate the association of OSA and metabolic outcomes, including lipid variables and insulin resistance, in obese adolescents.

Methods: Retrospective, case-control series at a tertiary care children's hospital. Obese adolescents aged 12-18 years who underwent overnight polysomnography (PSG) and routine laboratory testing for lipid levels, fasting glucose, and insulin from January 1, 2006 to December 31, 2012.

Results: A total of 42 patients with a mean age of 14.1±1.9 years were analyzed. Nineteen (45.2%) were male. The mean body mass index (BMI) z score was 2.23±0.86, and all patients were obese (BMI z score >95th percentile). Triglyceride, fasting blood glucose, insulin, and homeostasis model assessment-insulin resistance (HOMA-IR) levels were significantly higher in patients with OSA when compared to those with No-OSA (p<0.01). There was incremental worsening of insulin and HOMA-IR with greater severity of OSA. The apnea-hypopnea index (AHI) was positively and significantly correlated with blood glucose and HOMA-IR (p=0.01and p<0.001, respectively). Multiple linear regression analysis showed that the AHI was a predictor of blood glucose (p=0.04) and HOMA-IR (p=0.01) independent of age, gender, total sleep time and BMI z score. Logistic regression analysis showed that elevated levels of blood glucose predicted severe OSA (p=0.02) independent of gender and BMI z score. Elevation in HOMA-IR predicted severe OSA (p=0.004).

Conclusion: OSA severity is associated with increased fasting insulin, blood glucose and HOMA-IR even after controlling for the age, and BMI z score in adolescents.