Nephrol Dial Transplant (2004) 19: 1660
Nephrol Dial Transplant Vol. 19 No. 6 © ERA-EDTA 2004; all rights reserved
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Sir,We recently reported that in children with vesicoureteral reflux (VUR), the prevalence of hypercalciuria was greater than in the general population and that, at the same time, their family members have a high hypercalciuria prevalence and/or urolithiasis. Conversely, the question that we addressed in our article is intriguing: are adult patients with hypercalciuria, whether symptomatic or not, at a higher risk of conceiving children affected by VUR? [1].
Ristoska-Bojkovska et al. have speculated that this is a chance association. Their reasoning was based on the observation that hypercalciuria frequency was similar in a group of children with urinary tract infection (UTI) and VUR (18.7%) and in another group of children with UTI but without VUR (15.1%). Therefore, the hypercalciuria in children with VUR would be a chance association since these two entities are relatively common in the general population.
First, the association between hypercalciuria and UTI has been known for years. One possibility for the occurrence of hypercalciuria in childhood is in the form of a UTI, with a prevalence considered to be between 13 and 48.9% [2,3]. This is in contrast to the observed frequency of UTI in the population without hypercalciuria, considered to be 
1–2% in children and 3–5% in girls [4]. The reason for the association between these two relatively common entities in the general population is unknown.
Secondly, Ristoska-Bojkovska et al. have observed that hypercalciuria prevalence in children with VUR is higher that in the healthy population, which confirms our own data. The prevalence of hypercalciuria in control children on the island of Tenerife is 3.8% [5]. In other countries, the reported prevalence is between 2.2 and 6.4% [6]. In the study of Ristoska-Bojkovska et al., neither urinary calcium excretion of the patients’ parents nor family history of urolithiasis were determined. Therefore, the authors cannot affirm or reject our hypothesis on the genetic origin of hypercalciuria in children with VUR.
We agree that our hypothesis is controversial, and more studies in families of children with VUR are needed. However, it is possible that an association exists between urolithiasis and other renal malformations. We have already suggested this association in patients with unilateral multicystic dysplastic kidney [7] and with ureteropelvic junction obstruction [8].
Conflict of interest statement. None declared.
Pediatric Nephrology Unit Nuestra Señora de Candelaria University Hospital Santa Cruz de Tenerife Spain Email: vgarcia{at}comtf.es
References
- García-Nieto V, Siverio B, Monge M, Toledo C, Molini N. Urinary calcium excretion in children with vesicoureteral reflux. Nephrol Dial Transplant 2003; 18: 507–511
[Abstract/Free Full Text] - García Nieto V, Muros de Fuentes M, Quintero Quintero M, Gómez de la Rosa JL. Estudio de la clínica de presentación de la hipercalciuria idiopática en la infancia. Act Pediatr Esp 1991; 49: 413–416
- Cervera A, Corral MJ, Gómez Campdera FJ, De Lecea AM, Luque A, López Gómez JM. Idiopathic hypercalciuria in children. Classification, clinical manifestations and outcome. Acta Paediatr Scand 1987; 76: 271–278[Medline]
- Jodal U, Winberg J. Management of children with unobstructed urinary tract infection. Pediatr Nephrol 1987; 1: 647–656[CrossRef][Web of Science][Medline]
- Melián JS, García-Nieto V, Sosa AM. Herencia y prevalencia de hipercalciuria en la población infantil de la isla de La Gomera. Nefrología 2000; 20: 510–516[Medline]
- Moore ES, Coe FL, McMann BJ, Favus MJ. Idiopathic hypercalciuria in children: prevalence and metabolic characteristics. J Pediatr 1978; 92: 906–910[CrossRef][Web of Science][Medline]
- Molini Menchón N, García Nieto V. Displasia renal multiquística en la infancia. Trastornos asociados. BSCP Can Ped 2001; 26: 51–57
- Luis Yanes MI, García Nieto V, Callejón A, Fernández González LM, León JS. Anomalías metabólicas causantes de cálculos en niños diagnosticados de estenosis pieloureteral. An Esp Pediatr 2000; 52 [Suppl 4]: 140A
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