Kidney punch: Study finds link between climate change, renal stones

A link may exist between hotter days and higher incidences of kidney stones in U.S. adults and children, a study finds. And further climate fluctuations are likely to make the situation worse.

Physicians and researchers looked at the medical records of 60,000 insured people who had kidney stones between 2005 and 2011. The study, published in Environmental Health Perspectives, focused on patients in Atlanta, Chicago, Dallas, Los Angeles and Philadelphia.

When daily temperatures rise—specifically when they get to 86 degrees Fahrenheit—the relative risk of kidney stones increases “significantly” because the hot weather spurs dehydration, one of the most common causes of kidney stone formation, said Dr. Gregory Tasian, a pediatric urologist at Children's Hospital of Philadelphia and the study's lead author. Many people sought treatment for kidney stones within three days of the hot temperatures.

Tasian noted it was important to look at the risk of nephrolithiasis and high daily temperatures—not average annual temperatures. Atlanta and Los Angeles, for instance, had the same average annual temperature of about 63 degrees Fahrenheit, but the prevalence of kidney stones in Atlanta was twice that of L.A. The reason: Atlanta had five times as many individual scorchers above 80 degrees Fahrenheit as did Los Angeles.

Public-health implications could be significant in the future, the authors said, because climate experts predict global average temperatures will increase from two to eight degrees Fahrenheit by 2100.

“As those temperatures increase, there would be an increased associated risk in stones,” Tasian said. “Those implications can be made.”

Dr. Catherine Thomasson, an internist and executive director of Physicians for Social Responsibility, said in an interview the study made sense and is representative of other potentially adverse, climate-related health outcomes.

“Besides kidney stones, people develop symptoms of heat stroke—they can die from overheating,” she said, noting that higher temperatures also exacerbate the chances of heart attacks.

About one in 10 people endure a kidney stone in his or her lifetime. The study doesn't suggest the U.S. is about to experience a renal catastrophe, but it does make a case for new energy policies to be implemented.

“We are already seeing these changes, there's no doubt about it,” Thomasson said. “Do we want to keep seeing more and more of that? The answer should be of course not. Individuals can make some changes, but we really need to be demanding and supporting policy change.”

Climate change, polarizing in the national dialogue despite what some call overwhelming scientific consensus, has increasingly become part of the healthcare conversation. The National Climate Assessment in May said the extreme weather events tied to climate change pose significant threats to public health. A bipartisan group of public officials and business leaders also released a report in June that warned that the U.S. health system is not ready to handle the influx of patients who will need treatment due to hot days, natural disasters and other weather-related events.

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