Urinary sodium excretion: association with hyperinsulinaemia, hypertension and sympathetic nervous system activity in obese and control children.
The aim of the present study was to evaluate the association between 24 h urinary excretion of sodium and blood pressure, fasting plasma insulin, renin, aldosterone and serum norepinephrine concentrations in 45 obese and 15 control children. Urinary sodium excretion was significantly lower in obese subjects (1.3 +/- 0.6 mmol/kg/24 h, P < 0.01) than in controls (2.8 +/- 1.3 mmol/kg/24 h). Hyperinsulinaemia did not affect sodium excretion of obese children. Plasma renin and aldosterone levels did not correlate with sodium excretion and were significantly higher in overweight children. Serum norepinephrine levels were also significantly higher in the obese group (0.66 +/- 0.89 microgram/100 ml) as compared to the controls (0.11 +/- 0.03 microgram/100 ml, P < 0.01) and showed significant negative correlation with urinary sodium excretion (r = 0.43, P < 0.05).


CONCLUSIONS
Hyperinsulinaemia and the consequently increased sympathetic nervous system activity might be involved in the development of high blood pressure in obese children by decreasing urinary sodium excretion.
Csábi
G
G
Department of Paediatrics, University Medical School of Pécs, Hungary.
Molnár
D
D
Hartmann
G
G
D000293:Adolescent; D015992:Body Mass Index; D002648:Child; D015331:Cohort Studies; D006801:Humans; D006946:Hyperinsulinism / Q000503:physiopathology*; D006973:Hypertension / Q000503:physiopathology*; D009318:Natriuresis; D009638:Norepinephrine / Q000097:blood; D009765:Obesity / Q000503:physiopathology*; D012084:Renin-Angiotensin System; D013564:Sympathetic Nervous System / Q000503:physiopathology*
D009638:Norepinephrine