As the planet warms there will be more people suffering from kidney stones most probably due to dehydration that comes by either not drinking enough liquid or losing too much because high heat conditions, US researchers say.

Kidney stone disease or nephrolithiasis is not the only condition scientists have predicted to come together with global warming. Many scientists already think global warming will increase the reach of tropical disease such as malaria. Heart disease is also expected to hit high once temperatures increase.

Kidney stones are formed from dissolved minerals in the urine and can be extremely painful. The disease can be caused by both environmental and metabolic problems. Low volume of urine, which comes from either taking in too little fluid or losing too much through dehydration (due to high temperatures), directly boosts stone risk by increasing the concentration of stone-forming salts.

Currently, kidney stone disease occurs in about 12 percent of US men and 7 percent of women. The disease is more common in the warmer parts of the US, more exactly in the Southeast, a region known as the “kidney-stone belt” because of the high number of people suffering from kidney stones. US states confronting with this situation include Alabama, Tennessee, South Carolina, North Carolina, Mississippi, Louisiana, Georgia, Florida, and Arkansas.

Tom Brikowski, an associate professor with a specialty in hydrology in the department of geosciences at the University of Texas at Dallas and lead author of the study along with colleagues analyzed how common kidney stones are in the US and how much hotter average annual temperature nationwide are expected to get in the coming decades. The UN Intergovernmental Panel on Climate Change reported 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 measures are taken to reduce greenhouse-gas emissions.

The researchers predict that the number of people in the US who suffer from kidney stones at some point in their lives will rise by 1.6 million to 2.2 million by 2050, an increase of up to 30 percent in some areas (the Midwest and the Northeast).

“This is an example of how global warming will affect people directly. We are certain that warming will increase, and that the rate of kidney stone disease will go up. So as a nation, we will have to pay more attention to this problem,” Brikowski said.

He also added that countries in southern Europe, southeastern Europe, and southeast Asia will confront with the same problem, as temperatures will continue to increase due to global warming.

Dr. Margaret Pearle, professor of urology at UT Southwestern and senior author of the paper said the study “is one of the first examples of global warming causing a direct medical consequence for humans.” She added that the increase in the number of people with kidney stones could be noticed when people relocate from areas with moderate temperature to areas with warmer climates. “This has been shown in military deployments to the Middle East for instance,” she said.

The researchers warned that the increased number of kidney stone disease could cost the US up to $1 billion annually.

To avoid kidney stone disease, the researchers urge people to drink more water. However, doctors said making so many people change their drinking habits could prove difficult.

The study was published in the July 14 issue of the Proceedings of the National Academy of Sciences.