Background/Aims: Dietary factors can modify calciuria. We aim to investigate urinary calcium excretion in healthy infants according to their protein. Methods: Secondary data analysis from a randomized clinical trial where healthy term infants were randomized after birth to a higher (HP) or lower (LP) protein content formula that was consumed until age 1 year. A non-randomized group of breastfed (BF) infants was used for reference. Anthropometry, dietary intakes and calciuria (calcium/creatinine ratios) from spot urine samples were assessed at ages 3 and 6 months. At 6 months, the kidney volumes were assessed using ultrasonography, and the serum urea and creatinine levels were determined. Results: BF infants showed the highest calciuria levels, followed by the HP and the LP groups (p < 0.001 for all comparisons). Either protein intakes or formula types modulated the calciuria in linear regression models adjusted for other influencing dietary factors. The usual cut-off values classified 37.8% (BF), 16.8% (HP) and 4.9% (LP) of the infants as hypercalciuric. Conclusions: Feeding types during the first months of life affect calciuria, with BF infants presenting the highest levels. We propose new cut-off values, based on feeding types, to prevent the overestimation in hypercalciuria diagnoses among BF infants.

Keywords:
Calciuria, Feeding type, Infants, Protein intake
1.
Escribano J, Rubio-Torrents C, Ferré N, et al: Reduced bone mass in 7-year-old children with asymptomatic idiopathic hypercalciuria. Ann Nutr Metab 2014;64:304-313.
2.
Coe FL: Treated and untreated recurrent calcium nephrolithiasis in patients with idiopathic hypercalciuria, hyperuricosuria, or no metabolic disorder. Ann Intern Med 1977;87:404-410.
3.
Escribano J, Balaguer A, Martin R, et al: Childhood idiopathic hypercalciuria - clinical significance of renal calyceal microlithiasis and risk of calcium nephrolithiasis. Scand J Urol Nephrol 2004;38:422-426.
4.
Stapleton FB: Hematuria associated with hypercalciuria and hyperuricosuria: a practical approach. Pediatr Nephrol 1994;8:756-761.
5.
Sargent JD, Stukel TA, Kresel J, Klein RZ: Normal values for random urinary calcium to creatinine ratios in infancy. J Pediatr 1993;123:393-397.
6.
Butani L, Kalia A: Idiopathic hypercalciuria in children - how valid are the existing diagnostic criteria? Pediatr Nephrol 2004;19:577-582.
7.
Matos V, van Melle G, Boulat O, et al: Urinary phosphate/creatinine, calcium/creatinine, and magnesium/creatinine ratios in a healthy pediatric population. J Pediatr 1997;131:252-257.
8.
Melian JS, Garcia Nieto V, Sosa AM: [Inheritance and prevalence of hypercalciuria in the children from the island of La Gomera]. Nefrologia 2000;20:510-516.
9.
Srivastava T, Alon US: Pathophysiology of hypercalciuria in children. Pediatr Nephrol 2007;22:1659-1673.
10.
Noble S, Emmett P: Differences in weaning practice, food and nutrient intake between breast- and formula-fed 4-month-old infants in England. J Hum Nutr Diet 2006;19:303-313.
11.
Amanzadeh J, Gitomer WL, Zerwekh JE, et al: Effect of high protein diet on stone-forming propensity and bone loss in rats. Kidney Int 2003;64:2142-2149.
12.
Breslau NA, Brinkley L, Hill KD, Pak CY: Relationship of animal protein-rich diet to kidney stone formation and calcium metabolism. J Clin Endocrinol Metab 1988;66:140-146.
13.
Escribano J, Luque V, Ferre N: Increased protein intake augments kidney volume and function in healthy infants. Kidney Int 2011;79:783-790.
14.
Bonny O, Rubin A, Huang CL, et al: Mechanism of urinary calcium regulation by urinary magnesium and pH. J Am Soc Nephrol 2008;19:1530-1537.
15.
Cha SK, Jabbar W, Xie J, Huang CL: Regulation of TRPV5 single-channel activity by intracellular pH. J Membr Biol 2007;220:79-85.
16.
Koletzko B, von Kries R, Closa R, et al: Lower protein in infant formula is associated with lower weight up to age 2 y: a randomized clinical trial. Am J Clin Nutr 2009;89:1836-1845.
17.
Comission E: Commission Directive 91/321/EEC of 14 May 1991 on infant and follow-on formulae. Off J Eur Comm 1991;175:35-49.
18.
Verwied-Jorky S, Schiess S, Luque V, et al: Methodology for longitudinal assessment of nutrient intake and dietary habits in early childhood in a transnational multicenter study. J Pediatr Gastroenterol Nutr 2011;52:96-102.
19.
Luque V, Escribano J, Mendez-Riera G, et al: Methodological approaches for dietary intake assessment in formula-fed infants. J Pediatr Gastroenterol Nutr 2013;56:320-327.
20.
Dinkel E, Ertel M, Dittrich M, et al: Kidney size in childhood. Sonographical growth charts for kidney length and volume. Pediatr Radiol 1985;15:38-43.
21.
Schwartz GJ, Brion LP, Spitzer A: The use of plasma creatinine concentration for estimating glomerular filtration rate in infants, children, and adolescents. Pediatr Clin North Am 1987;34:571-590.
22.
World Medical Association Declaration of Helsinki: ethical principles for medical research involving human subjects. JAMA 2000;284:3043-3045.
23.
Hess B, Ackermann D, Essig M, et al: Renal mass and serum calcitriol in male idiopathic calcium renal stone formers: role of protein intake. J Clin Endocrinol Metab 1995;80:1916-1921.
24.
Hillman LS, Salmons SS, Erickson MM, et al: Calciuria and aminoaciduria in very low birth weight infants fed a high-mineral premature formula with varying levels of protein. J Pediatr 1994;125:288-294.
25.
Góes HC, Torres AG, Donangelo CM, Trugo NM: Nutrient composition of banked human milk in Brazil and influence of processing on zinc distribution in milk fractions. Nutrition 2002;18:590-594.
26.
Yamawaki N, Yamada M, Kan-no T, et al: Macronutrient, mineral and trace element composition of breast milk from Japanese women. J Trace Elem Med Biol 2005;19:171-181.
27.
Fomon SJ, Nelson SE: Calcium, phosphorus, magnesium, and sulfur; in Fomon SJ (ed): Nutrition Normal Infants. St. Louis, Mosby-Year Book, 1993, pp 192-218.
28.
Erol I, Buyan N, Ozkaya O, et al: Reference values for urinary calcium, sodium and potassium in healthy newborns, infants and children. Turk J Pediatr 2009;51:6-13.
29.
European Food Safety Authority (EFSA) Panel on Dietetic Products, Nutrition and Allergies (NDA): Scientific opinion on the essential composition of infant and follow-on formulae. EFSA J 2014;12:3760.
© 2017 S. Karger AG, Basel
2017
Copyright / Drug Dosage / Disclaimer
Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.
You do not currently have access to this content.