Urinary Leukotriene E4 Levels in Children with Sleep-Disordered Breathing.

Objective Due to limitations of polysomnography (PSG), novel ways to evaluate pediatric obstructive sleep apnea (OSA) are needed. Urinary leukotriene E4 (LTE4), an inflammatory marker, has been identified as a potential biomarker for pediatric OSA. The objective of the study was to assess whether urinary LTE4 levels correlate with OSA severity, as determined by obstructive apnea-hypopnea index (AHI) and nadir oxygen saturation. Study Design Prospective trial. Setting Tertiary care children's hospital. Subjects and Methods Children (age, 3-16 years) with sleep-disordered breathing (SDB) who were referred for PSG were included. Urine samples were obtained the morning following PSG, and urinary LTE4 levels were quantified with enzyme-linked immunoassay kits. Results A total of 113 children were enrolled, and the mean age was 7.3 years. Thirty-nine percent (n = 44) were obese, and the majority were white (53%, n = 58). Seventy-eight percent (n = 88) were diagnosed with OSA (AHI >1), with 27% (n = 30) having severe disease (AHI >10). The mean urinary LTE4 level was 91.3 ng/mM. Urinary LTE4 levels did not correlate with AHI ( P = .77) or nadir oxygen saturation ( P = .64). There was a significant difference in urinary LTE4 levels between patients with mild SDB and those with moderate to severe OSA ( P = .03). Conclusion Urinary LTE4 levels do not correlate with AHI in children with SDB. Compared with children with severe OSA, children with mild SDB have higher urinary LTE4 levels. Further research is needed determine whether urinary LTE4 is a satisfactory biomarker for pediatric OSA.