Investigators identify relationship between climate change and kidney stone occurrence

Gregory Tasian, MD, MSc, MSCE, and Jason Kaufman co-authored a study that investigated the association between kidney stone presentations in South Carolina under 2 different climate change scenarios.

Is there a relationship between climate change and kidney stones? Recent findings suggest so.

Gregory Tasian, MD, MSc, MSCE, and Jason Kaufman co-authored a study that investigated the association between kidney stone presentations in South Carolina under 2 different climate change scenarios.1 The results reflect significant and increasing projections over the next century. Tasian is an associate professor of surgery and epidemiology at the University of Pennsylvania Perelman School of Medicine, a pediatric urologist at the Children’s Hospital of Philadelphia, and Director of Pediatric KIDney Stone (PKIDS) Care Improvement Network and Kaufman is a medical student at the University of Pennsylvania Perelman School of Medicine in Philadelphia, Pennsylvania.

Please discuss the background for this study.

Tasian: We've known for over 30 years that there's been association between high ambient temperatures and kidney stones. A study in the 1980s described the kidney stone belt in the United States extending from the Southeast into the southwest, and that the higher prevalence [was] associated with higher ambient temperatures. However, we didn't fully understand what that precise relationship was between heat and the risk of presenting with stones. Over the last [7 to 8] years, my group has been focused on defining that precise association and relationship, which we've done. Then the natural question became, as the world warms and we're all experiencing more of these extreme daily temperatures, what is that impact going to be on the risk of presenting with kidney stones? [This] led to [the] collaboration with Jason.

Kaufman: The main question we were interested in answering was what the impact of future climate under different scenarios of climate change would have on the incidence of kidney stone disease, using South Carolina as a model state.

What were the notable findings of this study? Were any of them surprising to either of you or your co-authors?

Kaufman: The key findings of this study [were] that we quantified both the incidence of kidney stone disease from 2025 through 2089, as well as the associated costs of that increased disease burden. What's interesting, especially about this study, is that we looked at 2 pathways of climate change: 1 that was more of a 'worst case scenario' pathway without any changes to our current use of greenhouse gases or land, and 1 estimate that was more of a conservative estimate, [taking] into account likely future policies that would mitigate anthropogenic greenhouse gases and climate change.

Tasian: Stepping back from the specific results, I think what we had learned from this study was that climate change is going to have a direct impact on human health. We tend to conceptualize the impact of climate change in somewhat abstract ways. Sea level rise, which certainly can and will be devastating, but it's somewhat of an abstract concept. The loss of polar ice [and] extreme weather events [are] certainly something that we're living through right now, and I think this study just adds to that narrative that the impact of climate change is real. It's going to impact humans, and it's going to impact, in particular, future generations. As a pediatric urologist, where I focus my clinical efforts in the care of children, these children are going to bear the brunt of action, or inaction today.

How does this research build on previous studies on the relationship between kidney stones and climate change?

Kaufman: The group that Dr. Tasian has been working with for the last couple of years has looked at the precise relationship between temperature, humidity, and kidney stone risk. Previous studies had showed that that risk differs slightly in different geographic regions of the US, which can likely be extrapolated to other parts of the world as well. This study builds on those previous studies because we used a similar methodology of determining the precise relationship between ambient climate and kidney stone disease risk in the region of interest. We then projected that risk alongside future projections of temperature and humidity that were provided by a climate scientist who helped us with this study.

Tasian: One of the initiation points for this study was building on the elegant work of Peggy Pearle [, MD, PhD], that was done in 2008.2 She, Tom Brikowski [, PhD], and [Yair Lotan, MD], had published a paper in [the Proceedings of the National Academy of Sciences (PNAS)] that had a similar objective to project the impact of climate change on the prevalence of kidney stones in the United States under different climate change scenarios. That really, I think, brought this question into the national spotlight. What we did was use those relationships that Jason defined to provide some precision to those projections. So, rather than having a hypothesized relationship, we could actually use what that known relationship [between daily temperatures and kidney stone presentations] is.

What is the take-home message for the practicing urologist?

Tasian: Kidney stones are a rapidly growing problem in the United States, and it's a problem that urologists in particular treat. The prevalence of kidney stones has increased over 80% over the last 30 years, and the epidemiology has changed such that it's beginning at a younger age now. That gender gap has all but disappeared. When you add on top of that already increasing prevalence, the impact of climate change will mean that more individuals in the future, probably both children and adults, will be living with kidney stones, many over the course of their lives. So, I think that clinically, this problem that we see all the time now will just become that much more frequent.

Kaufman: As we were [saying] before, an important take-home message for policymakers and the global community in general is that climate change will have a tangible impact on human health in ways that we had not necessarily thought of before.

Is there anything else that either of you feel our audience should know about the findings or this topic in general?

Tasian: I think it adds to the growing body of evidence that human health is directly impacted by climate change. There are a number of groups that have shown an increased risk of death from multiple different causes. A paper just came out in Environmental Health Perspectives just this week that reports climate change is going to increase emergency room visits, particularly among children.3 So, I think there is an urgency for us as urologists who are seeing many of these patients with kidney stones to be advocates, not just for the patients whom we're treating today, but for the population in the future. I do think that that's an important role of us as advocates for patients, to be their voice.

References

1. Kaufman J, Vicedo-Cabrera AM, Tam V, et al. The impact of heat on kidney stone presentations in South Carolina under two climate change scenarios. Sci Rep 12, 369 (2022). Doi:10.1038/s41598-021-04251-2

2. Brikowski TH, Lotan Y, Pearle MS. Climate-related increase in the prevalence of urolithiasis in the United States. Proc Natl Acad Sci U S A. 2008;105(28):9841-6. doi:10.1073/pnas.0709652105

3. Bernstein AS, Sun S, Weinberger KR, et al. Warm season and emergency department visits to U.S. children's hospitals. 2022;130(1):17001. doi:10.1289/EHP8083