Will climate change lead to more people having kidney stones?

PHILADELPHIA, Pa. — The climate crisis will cause more people to suffer from kidney stones, a new study predicts.

Researchers from the Children’s Hospital of Philadelphia (CHOP) say kidney stones is a condition in which hard deposits of minerals build up in the urine, causing great pain as they pass through the urinary tract. Their study finds the incidence of this condition has increased in the last 20 years and is more prevalent among women and children.

“While it is impossible to predict with certainty how future policies will slow or hasten greenhouse gas emission and anthropogenic climate change, and to know exactly what future daily temperatures will be, our analysis suggests that a warming planet will likely cause an increased burden of kidney stone disease on healthcare systems,” says study senior author and urologist Dr. Gregory Tasian in a media release.

Heat and kidney stones don’t mix

Past studies have demonstrated that high room temperatures increase the risk of developing kidney stones and, particularly in the United States, more people develop the condition after hot days. With this in mind, the researchers wanted to understand how climate change would impact any future cases of kidney stones.

To do so, the team created a model to estimate the impact of heat on future kidney stone cases in South Carolina. They chose the southern state as a model because it lies within the “kidney stone belt” of the U.S. — a region in the southeast with a greater number of kidney stone disease cases than other areas.

The state’s healthcare system also uses an all-payer claims database, which means that researchers can easily capture stone diagnoses across the population, regardless of payer status.

Big differences between 2 possible futures

The team first looked at the relationship between historic daily state-wide mean temperatures and the number of kidney stone diagnoses between 1997 to 2014. They then used wet-bulb temperatures (WBT) – a moist heat metric that accounts for both room heat and humidity – as an accurate metric for predicting the presence of kidney stones.

Using the data to forecast the heat-related number of kidney stones, study authors were able to forecast what the associated costs would be in the year 2089 based on two climate change scenarios.

The first climate change scenario (RCP 4.5) represented an “intermediate” future with a shift towards lower emissions, the use of carbon capture technology, taxes on CO2 emissions, and an expansion of forest lands from the present day to 2100. The second scenario (RCP 8.5) represented a future with mostly uninhibited greenhouse gas emissions.

The first scenario projected a 4.1-degree increase in mean temperature (Fahrenheit) using the five-year period from 2010 to 2014 to model what the outcome would look like in the years 2085 to 2089. While the second scenario projected a much higher 6.5-degree increase within the same time frame.

Using their model, the researchers found that by 2089, heat-caused kidney stones would increase across the state by 2.2 percent in the intermediate future and by 3.9 percent in the bleaker future.

More kidney stone cases will be expensive for the healthcare system

Based on the average cost of treatment — which can be more than $9,000 — the researchers forecasted that from 2025 to 2089, the total cost attributable to these excess kidney stone cases would be $56.6 million for the first scenario and $99.4 million for the second.

“Our analysis is a model to conceptualize how the burden of kidney stone disease is expected to progress with climate change, and also how mitigations to greenhouse gas emissions can offset some of this burden,” explains first author Jason Kaufman, a fourth-year medical student at the University of Pennsylvania Perelman School of Medicine.

“With climate change, we don’t often talk about the impact on human health, particularly when it comes to children, but a warming planet will have significant effects on human health,” adds Dr. Tasian. “As pediatric researchers, we have a duty to explore the burden of climate change on human health, as the children of today will be living this reality in the future.”

The findings are published in the journal Scientific Reports.

South West News Service writer Georgia Lambert contributed to this report.