Patient and Polysomnographic Characteristics
A total of 94 children and adolescents were initially included in the study; afterward, 1 subject was excluded because of an abnormal serum creatinine value of 1.5 mg/dL. Of those subjects, 44% were boys, 58% were prepubertal (mean age, 11.1 ± 2.5 years; age range, 6.3 to 16.3 years). The mean BMI z-score was 2.31 ± 0.50 (range, 1.32 to 3.83); and 25 subjects (27%) were classified as overweight, and 68 subjects (73%) as obese. All subjects were nondiabetic.
All children had a normal UA excretion rate (mean rate, 0.33 ± 0.06 mg/dL; range, 0.20 to 0.47 mg/dL); and the mean urinary UA/creatinine ratio was 0.58 ± 0.13 (range, 0.31 to 0.85). There were 15 subjects (16%) with a total urinary creatinine concentration of < 500 mg/d, possibly suggesting an unreliable 24-h urinary collection. Excluding these 15 subjects did not result in significant changes in any of the subsequent analyses. A fasting measurement of serum UA was available for 62 patients (67%). Mean serum UA was 4.8 ± 1.4 (range, 1.5 to 8.8). The polysomnographic data of the subjects with or without SDB are presented in Table 1. There was no difference in age, sex, pubertal stage distribution, and anthropometric variables between these three groups.