Incidence of kidney stone disease in Icelandic children and adolescents from 1985 to 2013: results of a nationwide study

Background: An increase in the incidence of kidney stone disease has been reported for all age groups worldwide. To examine this trend, we conducted a nationwide study of the epidemiology of kidney stones in Icelandic children and adolescents over a 30-year period. Methods: Computerized databases of all major hospitals and medical imaging centers in Iceland were searched for International Classification of Diseases and radiologic and surgical procedure codes indicative of kidney stones in patients aged < 18 years, followed by a thorough medical record review. Age-adjusted incidence was calculated for the time intervals 1985–1989, 1990–1994, 1995–1999, 2000–2004, 2005–2009, and 2010–2013. Time trends in stone incidence were assessed by Poisson regression. The prevalence of stone disease for the years 1999–2013 was also determined. Results: Almost all the 190 patients (97%) that we identified had symptomatic stones, and acute flank or abdominal pain and hematuria were the most common presenting features. The total annual incidence of kidney stones increased from 3.7/100,000 in the first 5-year interval to 11.0/100,000 during the years 1995–2004 (p < 0.001) and decreased thereafter to 8.7/100,000 in 2010–2013 (p = 0.63). The incidence rise was highest in girls aged 13–17 years, in whom it rose from 9.8/100,000 in 1985–1989 to 39.2/100,000 in 2010–2013 (p < 0.001), resulting in an overall female predominance in this age group. The mean annual prevalence of stone disease in 1999–2013 was 48/100,000 for boys and 52/100,000 for girls. Conclusion: We found a significant increase in the incidence of childhood kidney stone disease, driven by a dramatic increase of stone frequency in teenage females which is poorly understood and warrants further study.