PEDIATRICS Vol. 100 No. 4 October 1997, pp. 675-681
The Relationship Between Urinary Calcium, Sodium, and Potassium Excretion and the Role of Potassium in Treating Idiopathic Hypercalciuria
Received Dec 16, 1996; accepted Feb 20, 1997.
From the Section of Pediatric Nephrology, Children's Mercy Hospital, University of Missouri at Kansas City, Missouri.
Objectives. 1) To evaluate the relationships between urinary sodium (UNa), potassium (UK), and calcium (UCa) excretion in the pediatric population; and 2) to determine the effect of increasing potassium intake in patients with idiopathic hypercalciuria and investigate whether this intervention can be offered as another mode of therapy in this patient population.
Design. Prospectively, we determined UNa, UK, UCa, and creatinine (Cr) concentrations in randomly collected urine samples from children on initial evaluation for urinary frequency, dysuria, hematuria, enuresis, or kidney stones to identify children with hypercalciuria.
Setting. The outpatient renal clinic of an academic hospital.
Participants. Twenty-three black children (13 girls and 10 boys) and 77 white children (44 girls and 33 boys) 3.92 to 16.67 years of age.
Interventions. Eleven children with hypercalciuria were given potassium supplementation or placed on a high-potassium diet for at least 2 weeks.
Outcome Measures. UNa to UK, UNa to Cr, UK to Cr, and UCa to Cr ratios were calculated from measured levels of urinary minerals. These were repeated in 11 hypercalciuric patients after 2 weeks of increased potassium intake.
Results. A total of 100 urine samples were analyzed. The UCa/Cr ratio in blacks 0.04 ± 0.06 (mean ± standard deviation) was significantly lower than in whites 0.16 ± 0.12. There were 21 hypercalciuric white children versus only 1 black child. Linear regression analysis revealed a positive direct correlation between UNa/Cr and UCa/Cr in all 100 subjects and in whites alone but not in blacks. An inverse relationship existed between UK/Cr and UCa/Cr in all subjects and in whites and showed a strong trend in blacks. A marked direct relationship was found between UNa/K and UCa/Cr in all subjects (r = .43) as well as in whites (r = .59) and blacks (r = .49). One black child and 10 white hypercalciuric children were treated with "extra" K for at least 2 weeks. The UNa/K decreased from 4.73 ± 2.28 to 1.98 ± 1.09, and the UCa/Cr decreased from 0.31 ± 0.10 to 0.14 ± 0.07, with resolution or improvement of the patients' symptoms.
Conclusions. In our patient population with urinary symptoms, the UCa/Cr ratio in black children is lower and hypercalciuria less common than in white children. In both white and black populations, the UNa/K ratio had the strongest association with the UCa/Cr ratio, indicating an opposing role of UNa and UK on the UCa/Cr ratio. Increased potassium intake was found to be beneficial for hypercalciuric children by decreasing the UNa/K ratio and, consequently, the UCa/Cr ratio.
Key words: calcium, diet, hypercalciuria, potassium, sodium.
This article has been cited by other articles:
![]() |
T. Na, W. Zhang, Y. Jiang, Y. Liang, H.-P. Ma, D. G. Warnock, and J.-B. Peng The A563T variation of the renal epithelial calcium channel TRPV5 among African Americans enhances calcium influx Am J Physiol Renal Physiol, May 1, 2009; 296(5): F1042 - F1051. [Abstract] [Full Text] [PDF] |
||||
![]() |
K. Rafferty, K. M. Davies, and R. P. Heaney Potassium Intake and the Calcium Economy J. Am. Coll. Nutr., April 1, 2005; 24(2): 99 - 106. [Abstract] [Full Text] [PDF] |
||||
![]() |
K. E. Marks and C. M. Crill Calcium and Phosphorous in Pediatric Parenteral Nutrition Journal of Pharmacy Practice, December 1, 2004; 17(6): 432 - 446. [Abstract] [PDF] |
||||
![]() |
F. J He and G. A MacGregor Fortnightly review: Beneficial effects of potassium BMJ, September 1, 2001; 323(7311): 497 - 501. [Full Text] [PDF] |
||||
![]() |
S-A Hulton Evaluation of urinary tract calculi in children Arch. Dis. Child., April 1, 2001; 84(4): 320 - 323. [Full Text] |
||||
![]() |
G. VALENTI, A. LAERA, G. PACE, G. ACETO, M. L. LOSPALLUTI, R. PENZA, F. P. SELVAGGI, M. L. CHIOZZA, and M. SVELTO Urinary Aquaporin 2 and Calciuria Correlate with the Severity of Enuresis in Children J. Am. Soc. Nephrol., October 1, 2000; 11(10): 1873 - 1881. [Abstract] [Full Text] |
||||
![]() |
M. Santos-Victoriano, B. H. Brouhard, and R. J. Cunningham III Renal Stone Disease in Children Clinical Pediatrics, October 1, 1998; 37(10): 583 - 599. [Abstract] [PDF] |
||||











