PHILADELPHIA, Jan. 15 (UPI) -- Middle-aged white men have historically been considered at greatest risk for kidney stones, but a new study conducted in South Carolina shows the risk for children, women and African Americans has increased.
Researchers at the Children's Hospital of Philadelphia and the University of Pennsylvania did not find a cause for the increases, but the author's previous research has linked high daily temperatures to an increase in patients seeking treatment for kidney stones.
Dehydration, possibly caused in part by higher temperatures, can cause the stones, as can a poor diet high in sodium or low in calcium, though researchers said they had not focused their research on diet differences. Higher numbers of young women with kidney stones is especially concerning, the researchers said, because they can significantly increase the risk for other health conditions.
"The fact that stones were once rare and are now increasingly common could contribute to the inappropriate use of diagnostic tests such as CT scans for children with kidney stones, since healthcare providers historically have not been accustomed to evaluating and treating children with kidney stones," said Dr. Gregory Tasian, a pediatric urologist and epidemiologist at Children's Hospital of Philadelphia, in a press release. "These trends of increased frequency of kidney stones among adolescents, particularly females, are also concerning when you consider that kidney stones are associated with a higher risk of chronic kidney disease, cardiovascular and bone disease, particularly among young women."
In the study, published in the Clinical Journal of the American Society of Nephrology, researchers analyzed data on 4.6 million people in South Carolina gathered between 1997 and 2012.
The researchers found 152,925 incidents of kidney stones during the time per, with the overall number of annual kidney stone patients increasing by 16 percent during the 15-year period. Among groups, adolescent incidence went up 4.7 percent per year, women saw a 3 percent increase per year, and kidney stones among blacks went up 2.9 percent per year.
The risk for kidney stones in children doubled from 1997 to 2012, and women saw a 45 percent lifetime increase in risk for stones.
Researchers suggested diet should be considered as a factor, but did not examine dietary differences in the new study.
Dehydration, however, is already known to contribute to the growth of kidney stones, which may also explain the increase in cases as temperatures have risen in South Carolina in recent years.
"Kidney stone prevalence has already been on the rise over the last 30 years, and we can expect this trend to continue, both in greater numbers and over a broader geographic area, as daily temperatures increase," Tasian said of his 2014 study. "With some experts predicting that extreme temperatures will become the norm in 30 years, children will bear the brunt of climate change."