Table of Contents

HK J Paediatr (New Series)
Vol 13. No. 2, 2008

HK J Paediatr (New Series) 2008;13:82-89

Original Article

Hypothalamic-Pituitary-Adrenal Axis in Obese Chinese Children

ACH Ho, AM Li, MHM Chan, EMC Wong, IHS Chan, DFY Chan, HK So, CC Fu, Ssk Chan, CWK Lam, EAS Nelson


Abstract

Aims: To evaluate the correlation between hypothalamic-pituitary-adrenal (HPA) axis activity with degree of obesity, severity of obstructive sleep apnoea (OSA) and laboratory parameters in a group of obese Chinese children. Methods: Consecutive children with primary obesity were recruited from the Obesity & Lipid Disorder Clinic of a university teaching hospital. Degree of obesity was assessed by anthropometric measurements. Those with habitual snoring (snoring for >3 nights per week) underwent overnight sleep study. Laboratory measurements included fasting plasma glucose, lipid profile, and serum insulin. Twenty-four-hour urinary free cortisol (UFC) excretion was used as a surrogate marker of HPA axis activity. Results: One hundred ninety-six children were studied and their median age and body mass index (BMI) were 12.1 (IQR 9.9-13.9) years and 29.5 (26.2-33.4), respectively. Boys were more obese and had significantly higher UFC than girls (160.0 vs 132.4 nmol/day, p=0.016). Spearman's rank correlation revealed significant positive association between UFC and anthropometric markers of obesity, namely, BMI, waist circumference, and skinfold thickness. There was also negative association between UFC and plasma high-density lipoprotein concentrations. In boys, a positive correlation was demonstrated between UFC and serum insulin concentrations. However, unlike previous publications, only age and male gender were significant independent factors associated with UFC excretion in multivariate analysis. Eighteen children had OSA but no correlation was found between UFC and severity of OSA. Conclusion: Twenty-four-hour urinary free cortisol is not able to delineate any HPA axis dys-regulation in this cohort, further studies will be required to investigate the relationship between obesity and cortisol pathway in children.

Keyword : Hypothalamic-Pituitary-Adrenal Axis; Insulin; Obesity; Obstructive Sleep Apnoea; Urinary Free Cortisol Excretion


Abstract in Chinese

 
 

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