The South's painful kidney-climate connection

If your kidneys are killing you, our warming climate may be partly to blame.

A number of papers being presented at this week's 103rd Annual Scientific Meeting of the American Urological Association taking place in Orlando, Fla. link urinary tract diseases and environmental conditions -- including global warming.

"Predicted Climate-Related Increase in the Prevalence and Cost of Nephrolithiasis in the U.S." links rising global temperatures to kidney stones, which occur when salts build up in the kidneys. Published earlier this year in the Journal of Urology, the study was conducted by Tom Brikowski, a geosciences professor at the University of Texas at Dallas, and Margaret Pearle and Yair Lotan, urologists with the University of Texas Southwestern Medical School in Dallas. According to an AUA announcement:

Using published data to determine the temperature-dependence of stone disease, researchers applied predictions of temperature increase to determine the impact of global warming on the incidence and cost of stone disease in the United States. The Intergovernmental Panel on Climate Change indicates a 1-20 C increase in temperature by 2050 for much of the United States. These findings place a greater significance on the harmful effects of global warming, an ongoing economic and political issue.

The southern United States is considered "the stone belt" because these states have higher incidences of kidney stones. Rising global temperatures could expand this region; the fraction of the U.S. population living in high-risk stone zones is predicted to grow from 40 percent in 2000 to 50 percent by 2050. This could lead to an increase of one to two million lifetime cases of stone disease. The impact of climate-related changes in stone disease will be non-uniformly distributed and likely concentrated in the southern half of the country (linear model) or upper Midwest (non-linear model). The cost associated with treating stone disease could climb as high as one $1 billion annually by 2050, representing a 10-20 percent increase over present-day estimates.

Dehydration has been linked to kidney stones, especially in warmer climes, and global warming will worsen this effect, Environmental News Services reports. To prevent kidney stones from forming in the first place, doctors recommend increasing fluid intake, particularly in hot weather. Lemonade made with real lemons or liquid or frozen concentrate may be especially helpful because it increases levels of citrate, which prevents stone formation.