Urolithiasis in children

Abstract

Urolithiasis is a common health disorder in all parts of the world with an estimated lifetime prevalence of approximately 10–12 % in men and 5–6 % in women [1, 2]. In the 1950s to the 1970s, the estimated incidence of pediatric urolithiasis in the United States was 1–2 % that of adults [3, 4], and other earlier studies found stones to account for 1 in 7,600 to 1 in 1,000 pediatric US hospital admissions [5–7]. A recently published study of patients younger than 18 years hospitalized between 2002 and 2007, based on a validated collection of pediatric hospital data (the Pediatric Health Information System database), found childhood stone disease to account for 1 in 685 pediatric hospitalizations in the United States [8]. Although the epidemiology of urolithiasis in children and adolescents has to date been less well defined than in the adult population, two recent population-based studies [9, 10] have suggested a significant increase in the frequency of childhood kidney stone diagnosis. A study by Sas et al. [9] conducted in the state of South Carolina found an increase in the incidence of symptomatic kidney stones in children and adolescents less than 18 years of age, from 7.9 per 100,000 children in 1996 to 18.5 per 100,000 in 2007. In that study the highest incidence increase was seen in females aged 14–18 years, followed by the age group 9–13 years. The incidence rate, however, did not significantly change in children aged less than 9 years. Another population-based pediatric study, based on the Rochester Epidemiology Project, reported an increase in the incidence of urolithiasis from 7.2 per 100,000 in the years 1984–1990 to 14.5 per 100,000 in the years 2003–2008 [10]. The greatest incidence rise in both of the above studies was observed in teenagers where it reached approximately 35 per 100,000 children while only a limited increase was seen in children under the age of 10 years [9, 10]. In the South Carolina study, the risk of developing clinical stone events was 10 times greater in children aged 14–18 years than for children aged 0–3 years [9]. Male preponderance for kidney stone disease has in multiple studies been reported for both pediatric [11, 12] and adult [1, 13] stone disease. Interestingly, a number of recent studies clearly show childhood kidney stone disease to be more common in the female gender [8, 9, 14], particularly in the age group 10–17 years [9, 15]. Furthermore, a number of pediatric studies have shown a more rapid incidence rise in girls than boys [9, 15, 16], and in the study by Sas et al. [9], the overall male–female ratio changed from approximately 1:1 in the year 1996 to 1:1.4 in the year 2007. Interestingly, our group [13] and others [17, 18] have shown a decreasing male predominance of kidney stone disease in the adult population, particularly the youngest age groups where the male–female ratio is now close to 1:1. Thus, kidney stone disease is becoming more common in the female gender.