Study: global warming may increase kidney stones

Global warming could do more than hurt polar bears: It could force a rise in kidney stones, scientists warned Monday.

"We see a relationship between kidney stones and temperatures everywhere," says study co-author Margaret Pearle of the University of Texas Southwestern Medical School in Dallas. "Even in places with air conditioning, warmer temperatures mean more stones."

Kidney stones result from salts crystallizing in the kidneys, often triggered by dehydration, causing famously painful blockages. Warm Southeastern states get 50 percent more cases than Northeastern states. The new research says global warming will drive this kidney-stone "belt" north and cause at least 1.6 million new cases by 2050.

The U.N.-sponsored Intergovernmental Panel on Climate Change warned last year that industrial emissions of greenhouse gases very likely would raise average global temperatures 3 to 7 degrees this century. That would increase the risks for heat stroke and expand tropical diseases such as malaria.

The kidney-stone finding, reported Monday by the Proceedings of the National Academy of Sciences, combines the panel's projections of higher U.S. temperatures with Medicare and Veterans Administration health records to estimate how many extra U.S. kidney-stone cases will result.