Kidney Stones on the Rise in the United States

Diana Phillips

January 27, 2016

More Americans than ever are developing kidney stones, and the demographics of those at increased risk are changing, a study published online January 14 in the Clinical Journal of the American Society of Nephrology has shown.

In an analysis of data from 152,925 child and adult patients with kidney stones in South Carolina, the annual incidence of nephrolithiasis increased 16% between 1997 and 2012, with the greatest rates of increase observed among adolescents, females, and blacks.

The cumulative risk of developing kidney stones during childhood nearly doubled, at 87% among girls and 90% for boys, during the course of the study, "although the risk in 2012 was modest at 0.9% and 0.6% in girls and boys, respectively," Gregory E. Tasian, MD, from the Division of Pediatric Urology at the Children's Hospital of Philadelphia in Pennsylvania, and colleagues report.

"The emergence of kidney stones in children is particularly worrisome, because there is limited evidence on how to best treat children for this condition," said Dr Tasian in a press release.

As a result, "there is unwanted variability in evaluation and treatment practices for children with nephrolithiasis, including poor adherence to guidelines aimed at reducing radiation exposure among children with suspected nephrolithiasis and use of surgical interventions that are dependent more on local availability and ease of use than clinical indications," the study authors explain.

The researchers hypothesize that the increased risk for kidney stones among youth may be attributable to increased sodium intake, decreased calcium intake, or dehydration.

When considered by sex, the lifetime risk for kidney stones in men remained stable, at approximately 23%, during the study period but increased 45% between 1997 and 2012 among women, going from 10.5% to 15.2%. After adjusting for age and race, the incidence among females increased an estimated 15% per 5 years, the authors note.

The highest rate of increased incidence was observed among 15- to 19-year-olds, at 26% per 5 years after adjustment for age and sex, the authors report.

The changes in kidney stone incidence over time were significantly modified by race, with an estimated 15% increase per 5 years observed among blacks compared with an estimated 3% per 5 years among whites, the authors observe.

The study findings point to a reversal of historical trends that warrants further research, the authors write. "Understanding modifiable risk factors that account for the age, sex, and race differences in incidence rates will facilitate targeted secondary prevention strategies, particularly for those groups in which nephrolithiasis were once rare but are now increasing."

The study was supported by the Children's Hospital of Philadelphia and the National Institutes of Health. The authors have disclosed no relevant financial relationships.

Clin J Am Soc Nephrol. Published online January 14, 2016. Abstract


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