Rebekah Eliason for redOrbit.com – Your Universe Online
According to a new study, as daily temperatures rise, more patients seek treatment for kidney stones. The research team discovered among several US cities with varying climates there is a correlation between hot days and kidney stones in 60,000 people.
“We found that as daily temperatures rise, there is a rapid increase in the probability of patients presenting over the next 20 days with kidney stones,” said study leader Gregory E. Tasian, MD, MSc, MSCE, a pediatric urologist and epidemiologist at The Children’s Hospital of Philadelphia (CHOP), who is on the staff of the Hospital’s Kidney Stone Center as well as the Hospital’s Center for Pediatric Clinical Effectiveness (CPCE).
The research team analyzed medical records of both adults and children with kidney stones. Over 60,000 records between the years of 2005 and 2011 were studied along with weather reports in each patient’s area. The team reviewed patient data from Atlanta, Chicago, Dallas, Los Angeles and Philadelphia.
As the mean daily temperatures rose above 50 F (10 C), the team discovered the risk of kidney stones increased in every city except Los Angeles. There was only a short delay between high daily temperature and kidney stone presentation. Within three days of hot day exposure, the level of kidney stones peaked.
“These findings point to potential public health effects associated with global climate change,” said Tasian.
“However,” he cautions, “although 11 percent of the U.S. population has had kidney stones, most people have not. It is likely that higher temperatures increase the risk of kidney stones in those people predisposed to stone formation.”
Since higher temperatures lead to dehydration, during hot days there are higher levels of calcium and other minerals that lead to the growth of kidneys stones present in people’s urine.
Approximately half a million patients each year in the US seek help in the emergency room for this painful condition. Over the past three decades, the amount of patients with kidney stones has markedly increased. The condition is more common in adults, but the amount of children developing kidney stones in the last 25 years has also dramatically increased. Currently the factors causing the rise in kidney stones are unknown, but suggested theories include changes in diet and fluid intake. If stones do not pass by themselves, surgery becomes necessary.
Additionally, the team discovered that in three cities — Atlanta, Chicago and Philadelphia — extremely low outdoor temperatures also increased the number of kidney stones. According to the authors, this may be a result of people staying indoors among warmer temperatures, diet changes and decreased physical activity.
Tasian added that while the five US cities have climates representative of those found throughout the world, future studies should explore how generalizable the current findings are.
Other studies should analyze how risk patterns vary in different populations, including among children, represented by a small sample size in the current study.
In addition to analyzing kidney stones, this study was intended to see how patterns of global warming affect health. “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,” concluded Tasian. “With some experts predicting that extreme temperatures will become the norm in 30 years, children will bear the brunt of climate change.”
This study was published in Environmental Health Perspectives.