Adiposity has unique influence on the renin-aldosterone axis and blood pressure in black children.
OBJECTIVE
To comparatively examine the effects of adiposity on the levels of plasma renin activity (PRA), plasma aldosterone concentration (PAC), and aldosterone-renin ratio (ARR) in young black and white children.


METHODS
We prospectively assessed 248 black and 345 white children and adolescents. A novel analytical technique was used to assess the concurrent influences of age and body mass index (BMI) on PRA, PAC, and ARR. The estimated effects were depicted by colored contour plots.


RESULTS
In contrast to whites, blacks had lower PRA (2.76 vs 3.36 ng/mL/h; P < .001) and lower PAC (9.01 vs 14.59 ng/dL; P < .001). In blacks, BMI was negatively associated with PRA (P = .001), consistent with an association with a more expanded plasma volume; there was no association with PAC. In whites, BMI was positively associated with PAC (P = .005); we did not detect a BMI-PRA association. The effects of BMI on ARR were directionally similar in the two race groups but more pronounced in blacks. Mean systolic blood pressure was greater in blacks with lower PRA (P < .01), higher PAC (P = .015), and higher ARR (P = .49).


CONCLUSIONS
An increase in adiposity was associated with a suppressed PRA in blacks and an increase in PAC in whites. The unique relationship between adiposity and renin-aldosterone axis in blacks suggests the possible existence of a population-specific mechanism characterized by volume expansion, which could in turn enhance the influences of adiposity on blood pressure in black children and adolescents.
Departments of Medicine and Biostatistics, Indiana University School of Medicine, Indianapolis, IN.
Zhangsheng
Z
Yu
George J
GJ
Eckert
Hai
H
Liu
J Howard
JH
Pratt
Wanzhu
W
Tu
D050154:Adiposity / Q000208:ethnology*; D000293:Adolescent; D001741:Black or African American / Q000208:ethnology; D000367:Age Factors; D000450:Aldosterone / Q000097:blood / Q000502:physiology; D001794:Blood Pressure; D015992:Body Mass Index; D005260:Female; D006801:Humans; D008297:Male; D011446:Prospective Studies; D011863:Radioimmunoassay / Q000379:methods; D012083:Renin / Q000097:blood / Q000502:physiology; D012084:Renin-Angiotensin System; D044465:White People / Q000208:ethnology
D000450:Aldosterone; D012083:Renin
ARR; Aldosterone-renin ratio; BMI; BP; Blood pressure; Body mass index; ECFV; Extracellular fluid volume; K; Na; PAC; PRA; Plasma aldosterone concentration; Plasma renin activity; Potassium; SBP; Sodium; Systolic BP