Climate change: Warming may cause increase in kidney stone cases, say US scientists

Elana Schor in Washington
guardian.co.uk,
Tuesday July 15, 2008

Endangered species. Economic decay. Extreme weather. The list of climate change's destructive costs is long, but US scientists today proposed adding one more: millions of new kidney stone cases.
The proven link between kidney stones and warm temperatures means that climate change could dramatically increase the number of US cases in the coming years, according to a study published today in the renowned journal Proceedings of the National Academy of Sciences.
The increased risk of kidney stones -- which come from painful mineral deposits in the urine -- could lead to as much as $1.3bn in increased medical bills by the year 2050, the team of Texas urologists behind the study estimated.
The study used two competing models to estimate the reach of new kidney stones brought on by global warming, using data from the UN intergovernmental panel on climate change (IPCC).
One model predicted a steady growth in new cases as global temperatures rise, and another predicted that new cases would plateau after temperatures reached 15 degrees Celsius.
The first model projected that stones would become more prevalent in the states of Texas, Florida, California, and the east coast of the US. The second model yielded the bulk of its new cases in the mid-west US, including 100,000 in Chicago alone.
The US would experience between 1.6m and 2.2m new kidney stone afflictions by 2050 under both scenarios. Kidney stones will afflict 10% to 15% of the US population at a total treatment cost of about $2bn per year, according to previous scientific studies. Nearly double that number of cases has been reported in the Middle East, where temperatures are uniformly balmy.
The famously unbearable pain caused by passing a kidney stone through the body can cause nausea, vomiting, and blood in the urine.
But there is an easy way to decrease the risk of climate-induced stones, according to Dr Mark Litwin, a professor of urology and public health at the University of California in Los Angeles.
"The irony is, the cure is fairly simple," Litwin told Science News magazine. "Just drink more water."