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Racial differences in aldosterone excretion: a longitudinal study in children
J H Pratt1, A K Manatunga, L J Bloem
1Department of Medicine, Indiana University School of Medicine, Indianapolis 46202.
Insights
Black children exhibit significantly lower aldosterone excretion rates compared to white children, a difference that persists longitudinally and is independent of age. This finding highlights potential racial disparities in endocrine function.
Area of Science:
- Endocrinology
- Pediatric Health
- Racial Health Disparities
Background:
- Previous cross-sectional studies indicated lower aldosterone production in Black children compared to White children.
- Aldosterone plays a crucial role in regulating blood pressure and electrolyte balance.
Purpose of the Study:
- To longitudinally assess aldosterone excretion rates in Black and White children.
- To determine if racial differences in aldosterone excretion persist over time.
- To investigate the relationship between aldosterone excretion and factors like age, body weight, and electrolyte levels.
Main Methods:
- Longitudinal urine sample collection every 6 months for up to 5.5 years in 351 White and 170 Black children.
- Measurement of urinary aldosterone, sodium (Na+), and potassium (K+) excretion, normalized to urinary creatinine.
- Statistical analysis to compare excretion rates between racial groups and assess influencing factors.
Main Results:
- No significant difference in Na+ excretion between Black and White children.
- K+ excretion was 18% lower in Black children (P = 0.0001).
- After adjusting for body weight and electrolyte excretion, aldosterone excretion rate was 35% lower in Black children (P = 0.0001), with no change over time or with age.
Conclusions:
- A persistent, age-independent racial difference in aldosterone excretion exists, with Black children exhibiting lower rates.
- Aldosterone excretion rates did not show significant longitudinal trends in either racial group.
- The physiological significance of lower aldosterone excretion in Black children requires further investigation.
Abstract:
Aldosterone production, estimated from urinary excretion of aldosterone and the plasma aldosterone level, was found in a previous cross-sectional study to be lower in black children than white children. The present study examined aldosterone excretion longitudinally to determine whether the aldosterone excretion rate changed with time and if the racial difference in aldosterone excretion persisted. Urine samples were collected every 6 months for up to 5.5 yr in 351 white and 170 black children for measurements of aldosterone, sodium (Na+), and potassium (K+) excretion. Results were expressed per mumol urinary creatinine. Mean values for excretion rates for the total longitudinal period were determined. Na+ excretion was not significantly different in the two groups, whereas K+ excretion was 18% lower in blacks than whites (P = 0.0001). Body weight and urinary Na+ and K+ excretion were significantly related to aldosterone excretion. After adjusting for these variables, the aldosterone excretion rate was 35% lower in blacks than whites (P = 0.0001), a racial difference that did not change with age. Aldosterone excretion rates showed no longitudinal trend to either increase or decrease. The physiological relevance of the lower aldosterone excretion rate in black children remains unknown.