YI12 / 175P Blood Pressure in Chinese Children with Obstructive Sleep Apnea/Hypopnea Syndrome

YI12 / 175P – Blood pressure in Chinese children with obstructive sleep apnea/hypopnea syndrome.

ZFXu, JQAn2, KLShen1.

1Beijing Children's Hospital, Capital Medical University Respiratory Department - Beijing (China)

2Beijing Children's Hospital, Capital Medical University ENT Department - Beijing (China)

Objective: Obstructive sleep apnea/hypopnea syndrome (OSAHS) is a common sleep problem. Adult studies have showed that OSAHS is associated with hypertension. Few pediatric studies have been performed on the role of OSAHS in childhood hypertension, although the etiology, clinical features and natural history of childhood OSAHS are different from adults. The aim of this study is to investigate the association between sleep breathing disorders and increased blood pressure in children.

Methods: Snoring children were recruited from January 2007 to December 2007. A clinical questionnaire was administered and a physical examination (including blood pressure at awake and sleep) and polysomnography were performed. A child with an apnea hypopnea index greater than 5 or obstructive apnea index greater than 1 was diagnosed as having OSAHS. To control for age and sex differences when assessing obesity and blood pressure, body mass index (BMI) Z scores and blood pressure indices were calculated for each child.

Result: Two hundred and one children with snoring were recruited, of which 133 were diagnosed with OSAHS. There were no differences between the two groups in age and gender distribution. The mean wake and sleep blood pressures were higher in the OSAHS group compared to the non-OSAHS group (awake SBP: P<0.001, awake DBP：P=0.007；sleep SBP P<0.001；sleep DBP P=0.014). Spearman correlation test showed that blood pressure correlated to BMI Z score and LgAHI, but not to minimum oxygen desaturation. After control for age, sex, BMI Z score and family history of hypertension, LgAHI correlated to systolic blood pressure (awake P=0.009，sleep P=0.043), and BMI score correlated to diastolic blood pressure (awake P<0.001，sleep P=0.043). After an overnight sleep, both OSAHS and non-OSAHS children had a decreased blood pressure in the early morning.

Conclusion: OSAHS children had a higher blood pressure than non-OSAHS children. AHI and obesity, but not minimum oxygen saturation, were correlated to blood pressure. Frequent sleep apneas and hypopneas might play a role in the pathogenesis of increased blood pressure.