Uric acid excretion in North American and Southeast European children with obstructive sleep apnea.
OBJECTIVE
Responses to nocturnal hypoxemia accompanying sleep-disordered breathing (SDB) may vary in different populations. Aims of this study were to (1) assess whether severity of SDB is related to uric acid excretion in North American and Southeast European children and (2) evaluate the interaction between nocturnal hypoxemia and country of children's origin in uric acid excretion.


METHODS
Consecutive US and Greek children with snoring who were referred for polysomnography were recruited. Uric acid excretion expressed as uric acid-to-creatinine concentrations ratio in a morning urine specimen was the primary outcome measure.


RESULTS
One hundred and twenty-six US children (6.8+/-0.7years old) and 123 Greek children (6.4+/-2.5years old) were recruited. Forty-three US and 53 Greek participants had moderate-to-severe nocturnal hypoxemia (SpO(2) nadir <90%). Obstructive apnea-hypopnea index and SpO(2) nadir were related to uric acid excretion in Greek (but not US) children after adjustment by age, gender and body mass index z-score (p<0.05). There was a significant interaction between severity of hypoxemia and country of children's origin in uric acid excretion after adjustment by age, gender and body mass index z-score (p=0.036). Greek children with moderate-to-severe hypoxemia had higher uric acid excretion (0.85+/-0.35) than those with mild/no hypoxemia (0.69+/-0.25) (p=0.005). US children with moderate-to-severe hypoxemia (0.41+/-0.20) did not differ in uric acid excretion from those with mild/no hypoxemia (0.42+/-0.22) (p=0.823).


CONCLUSIONS
Uric acid excretion differs in children with SDB and different ethnic backgrounds or environmental exposures.
Kaditis
Athanasios
A
Sleep Disorders Laboratory, University of Thessaly School of Medicine, Larissa, Greece. kaditia@hotmail.com
Gozal
David
D
Snow
Ayelet B
AB
Kheirandish-Gozal
Leila
L
Alexopoulos
Emmanouel
E
Varlami
Vasiliki
V
Papathanasiou
Afroditi A
AA
Capdevila
Oscar Sans
OS
Bhattacharjee
Rakesh
R
Kim
Jinkwan
J
Gourgoulianis
Konstantinos
K
Zintzaras
Elias
E
D002648:Child; D002675:Child, Preschool; D004781:Environmental Exposure / Q000706:statistics & numerical data; D005260:Female; D006115:Greece / Q000453:epidemiology; D006801:Humans; D000860:Hypoxia / Q000208:ethnology* / Q000378:metabolism* / Q000503:physiopathology; D016014:Linear Models; D008297:Male; D009765:Obesity / Q000208:ethnology / Q000378:metabolism / Q000503:physiopathology; D017063:Outcome Assessment, Health Care; D012307:Risk Factors; D012720:Severity of Illness Index; D020181:Sleep Apnea, Obstructive / Q000208:ethnology* / Q000378:metabolism* / Q000503:physiopathology; D012913:Snoring / Q000208:ethnology / Q000503:physiopathology / Q000652:urine; D014481:United States / Q000453:epidemiology; D014527:Uric Acid / Q000652:urine*
D014527:Uric Acid