A new study warned that kidney stones may be added to the growing list of possible consequences of global warming, according to media reports Wednesday.

The study said that as many as 2.3 million more people in U.S. may develop kidney stones by the year 2050 because the more sultry climes could cause more dehydration, which is believed to be a major contributor to stone formation.

"I think the reality of this study is accurate as temperatures do play a great role in stone diseases," said Stephen Nakada, chair of urology at the University of Wisconsin–Madison.

In the United States, the rate of kidney stones cases has been rising in recent decades, increasing from 3.6 percent of the overall population in 1976 to 5.2 percent by the mid-1990s.

The study noted that the increase rate correlates with an increase of half a degree Fahrenheit (0.28 degree Celsius) during the same period.

Most kidney stones form from minerals deposited in the two fist-size organs as they filter urea, mineral salts, toxins and other products from the blood; others form from too much acid in the urine.

Study co-author Yair Lotan, an assistant professor of urology, acknowledged that the study was based on estimates that may change.

"This means that things may not get as bad as we predict," he said, "or it could be that there will be even more cases of kidney stones than our models tell us."

(Agencies via Xinhua July 16, 2008)