July 15 (Bloomberg) -- More Americans may develop kidney stones as global warming raises the risk of dehydration, according to a study in the journal Proceedings of the National Academy of Sciences.

Warmer temperatures predicted by climate scientists may lead to a 30 percent increase in kidney stone cases in some U.S. regions, researchers at the University of Texas wrote in the study published today. That would result in a $1 billion increase in annual treatment costs by 2050, they said.

Dehydration is linked to the condition, which can develop when people don't drink enough water to flush stone-forming salts from the body. Higher temperatures may lead to more dehydration and expand the ``kidney stone belt,'' an area of the Southeast U.S. where men are twice as likely to develop the disease compared with the Northeast, according to the study.

``It's pretty well established that the prevalence of kidney stones increases with annual average temperatures,'' lead author Tom Brikowski, associate professor of geosciences at the University of Texas at Dallas, said in an interview.

The related cost of the predicted increase in kidney stones would be $900 million to $1.3 billion as the kidney stone belt expands northward and westward from warming, the researchers said. Nationwide, cases of kidney stones will rise about 10 percent, with some areas in the Midwest and Northeast seeing as much as a 30 percent jump. About 12 percent of men and 7 percent of women develop the condition during their lifetime.

13 Degrees

Previous studies indicate there's a greater risk of kidney stones when mean average temperatures exceed 13 degrees Celsius (55 degrees Fahrenheit), said Margaret Pearle, a urologist from the University of Texas Southwestern Medical School in Dallas who was involved in the study. The prevalence of kidney stones because of climate change needs further research, she said.

``Clearly with the likelihood of long-term temperature changes, this importance is now greatly enhanced and the issue warrants careful study,'' the researchers said in the study.

Drinking water is the best way to prevent kidney stones, Pearle said.

Health effects of climate change may include increased heat- related deaths, infectious diseases in some areas and more allergies, according to a United Nations panel of scientists.

The UN Intergovernmental Panel on Climate Change said last year that the Earth will likely warm by 1.1 degree to 6.4 degrees Celsius (2 degrees to 11.5 degrees Fahrenheit) by 2100 unless greenhouse-gas emissions are reduced.

To contact the reporter on this story: Adam Satariano in San Francisco at asatariano1@bloomberg.net

Last Updated: July 15, 2008 00:00 EDT