Chest
Volume 132, Issue 1, July 2007, Pages 76-80
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ORIGINAL RESEARCH
SLEEP MEDICINE
Sleep-Disordered Breathing and Uric Acid in Overweight and Obese Children and Adolescents

https://doi.org/10.1378/chest.06-2930Get rights and content

Objective:

The aim of this study was to determine whether the severity of sleep-disordered breathing (SDB) was associated with increased levels of uric acid (UA), both in serum and in urine, as a marker of tissue hypoxia, in a sample of overweight and obese subjects, irrespective of indexes of adiposity.

Methods:

Consecutive subjects underwent polysomnography, fasting blood sampling, and 24-h urine collection. Outcome parameters were serum UA, UA excretion ([24-h urinary UA × serum creatinine]/urine creatinine) and urinary UA/creatinine ratio.

Results:

A total of 93 subjects were included (44% boys; mean [± SD] age = 11.1 ± 2.5; 73% obese). A fasting measurement of serum UA levels was available for 62 patients. The respiratory disturbance index was a significant covariate (β = 0.09 ± 0.03; p = 0.01) in the regression model for serum UA, controlling for sex (β = 0.32 ± 0.29; p = 0.3), puberty (β = 0.87 ± 0.34; p = 0.01), and waist circumference (β = 0.04 ± 0.01; p = 0.005). The percentage of total sleep time with arterial oxygen saturation ≤ 89% (β = 0.94 ± 0.45; p = 0.04) was also significantly associated with serum UA level, controlling for sex (β = 0.22 ± 0.30; p = 0.5), puberty (β = 0.83 ± 0.35; p = 0.02), and waist circumference (β = 0.04 ± 0.02; p = 0.02). None of the SDB variables correlated with UA excretion or with urinary UA/creatinine ratio.

Conclusion:

This study in overweight children and adolescents demonstrated a relationship between the severity of sleep apnea and increased levels of serum UA, independent of abdominal adiposity. In view of the known associations between UA and cardiovascular risk, this finding may contribute to the mechanisms linking SDB with cardiovascular morbidity.

Section snippets

Patient Characteristics

We recruited children and adolescents who were 6 to 17 years of age who presented as overweight or obese between January 2001 and June 2006 at the Pediatric Obesity Clinic of the Antwerp University Hospital. Children were not included when they had any chronic medical condition, or any genetic, neuromuscular or craniofacial syndromes. Patients were classified as prepubertal or pubertal.4 All subjects underwent all measurements as part of their routine clinical evaluation. This case study was

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

Discussion

This is the first study to assess the influence of SDB on UA metabolism in overweight children and adolescents. This study demonstrates is that the severity of sleep apnea was associated with higher serum UA levels after controlling for gender, puberty, and adiposity.

UA metabolism and renal handling in children differ from those in adults. From childhood to adolescence, a child's serum UA level increases linearly; the urinary UA/creatinine ratio is higher in young children and declines to adult

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  • Cited by (0)

    The authors have reported to the ACCP that no significant conflicts of interest exist with any companies/organizations whose products or services may be discussed in this article.

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