Washington, July 15 : In a new study, researchers at UT Southwestern Medical Center and UT Dallas, have predicted that Global warming may increase the number of people affected by kidney stones. The researchers predicted that by 2050, higher temperatures will cause an additional 1.6 million to 2.2 million kidney-stone cases, representing up to a 30 percent growth in some areas.
It is known that kidney-stone disease or nephrolithiasis is caused due to dehydration and the new research suggests global warming will worsen this effect.
"This study is one of the first examples of global warming causing a direct medical consequence for humans," said Dr. Margaret Pearle, professor of urology at UT Southwestern and senior author of the paper, which
She added: "There is a known geographic variation in stone disease that has been attributed to regional differences in temperature. When people relocate from areas of moderate temperature to areas with warmer climates, a rapid increase in stone risk has been observed. This has been shown in military deployments to the Middle East for instance."
Kidney stones, which are solid crystals that form from dissolved minerals in urine, can be caused by both environmental and metabolic problems. Low volume of urine directly increases stone risk by increasing the concentration of stone-forming salts. They can arise from either taking in too little fluid or losing too much through dehydration.
Kidney-stones are more common in the warmer parts of the U.S. The Southeast is known as the "kidney-stone belt" because of the high incidence of kidney stones in the population living in Alabama, Arkansas, Florida, Georgia, Louisiana, Mississippi, North Carolina, South Carolina and Tennessee.
In order to forecast climate change, Dr. Tom Brikowski, lead author of the study and associate professor of geosciences at UT Dallas, used models of global warming obtained from the Intergovernmental Panel on Climate Change's 2007 Fourth Assessment Report, in which predicted temperature increases are based on expectations of future greenhouse gases.
The investigators were able to derive two mathematical models relating temperature to kidney-stone risk by using two studies that reported kidney-stone rates in various geographic regions and correlating regional stone rates with local mean annual temperatures.
Both models of kidney-stone risk predicted that the current kidney-stone belt will expand with global warming, although the exact extent and location of the change was different.
The study appeared in the latest issue of Proceedings of the National Academy of Sciences.