Urinary electrolytes, body weight, and blood pressure. Pooled cross-sectional results among four groups of adolescent females.

Results of blood pressures (BP) and urinary electrolyte excretion studies are reported among several groups of adolescent and young adult females, both black and white, who were initially examined in high school and restudied at home 3--4 years later. Pooling of the data from the several cross-sectional studies (n = 662) revealed a weak but statistically significant positive correlation systolic blood pressure (SBP) and the urinary sodium (Na) excretion rate. Three of four correlations between SBP and potassium (K) were of an inverse nature. Although not statistically significant in their own right, when coupled with the Na/K excretion ratio, which was significantly associated with SBP, a moderating role for K is suggested. The urinary Na, K, and creatinine (Cr) excretion rates were highly intercorrelated and were correlated with weight. As measured by R2 in a stepwise regression analysis, weight contributed approximately 3% to the BP variance, and the urinary electrolytes accounted for approximately 2% of the SBP variance. Statistically significant partial correlation coefficients between SBP and Na, and Na/K, remained after adjusting for body weight.