Are kidney stones becoming more prevalent in children?

A recent study indicates that the answer to this question is yes-at least in the state of South Carolina. Using a database in which all emergency department (ED) visits in the state are documented, investigators identified patients from 0 to 18 years of age seen in an ED from 1996 to 2007 with nephrolithiasis or urolithiasis.

During this period, nephrolithiasis was diagnosed in 1,535 children in the state, with an overall incidence during the 12-year period of 12.0 per 100,000 children. By contrast, in 1996, the incidence of nephrolithiasis in children was 7.9 per 100,000 children, a figure that increased steadily to 18.5 per 100,000 in 2007. The incidence of nephrolithiasis was higher in boys than in girls in 1996, but thereafter it increased at a faster rate in girls. By 2007, the incidence was 15.3 per 100,000 for boys compared with 21.9 per 100,000 for girls.

The incidence of kidney stones remained relatively stable in black children over the 12-year period but increased significantly in white children, who were 5.6 times more likely to have stones. The largest increase in incidence was in children from 14 to 18 years old, followed by children from 9 to 13 years old. Incidence remained fairly flat during the study period for children younger than age 9 years.

COMMENTARY

I wonder about the reasons for this increase. Presumably, the genetics of the community haven't changed. Perhaps diet or water intake has. Obesity is a risk factor for some types of kidney stones, reportedly because of hyperinsulinism's decreasing renal ammoniagenesis, resulting in more acidic urine. The interesting observation in this study needs further investigation and explanation. -Michael Burke, MD