Kidney stones may become more common with climate change: study
Reported July 14, 2008
TORONTO – Some say passing a kidney stone is the closest men will ever come to experiencing the pain of childbirth, and a study released Monday suggests the excruciating experience may become more common with climate change.
Researchers at the University of Texas believe cases of kidney stones could increase by as much as 30 per cent in some regions of the United States by 2050 if temperature increases predicted by the Intergovernmental Panel on Climate Change play out.
The research is one of the first examples of how global warming could have a direct effect on people’s health, said Yair Lotan, who co-authored the study published in the scientific journal Proceedings of the National Academy of Sciences.
“As far as we know this is the first time that climate change has been linked to any human disease directly,” Lotan said in an interview.
The report suggests the region known as the “kidney stone belt” in the southeast United States – which has elevated levels of stone occurrences – will expand with climate change.
It’s “not farfetched” to imagine a similar effect could occur in other parts of the world “if in fact there is an increase in temperature and (if) there’s a link between temperature and stones – which there’s a lot of evidence for,” Lotan said.
There are no estimates of the possible rise in cases in Canada, but several northern U.S. border states could potentially see growth rates as high as five to 15 per cent in some areas, according to the study.
The Kidney Foundation of Canada lists dehydration and living in warmer climates as risk factors to developing a kidney stone. It estimates that about one in 10 Canadians will get one at some point in their lives.
Stones tend to develop in middle age, and men get them more commonly than women.
Dr. Ross Morton, a nephrologist at Kingston General Hospital in Kingston, Ont., said Canada doesn’t have the same kind of regional belt where stones are more common, although some older studies have suggested there are higher risks of developing stones in the Maritimes.
He said the idea of warmer weather leading to more kidney stones makes sense, although he couldn’t comment specifically on the report since he had not yet read it.
“The main thing that protects you against kidney stones is the volume of urine you make, so the more urine you make by volume the less likely you are to make kidney stones,” Morton explained.
“The hotter it is the more likely you are to sweat, and the lower urine volume you’re going to have, so I presume that’s the basis for what they’re saying … and it makes some inherent sense.”
Morton also said there are other known risk factors to developing stones – such as a protein-rich diet and more exposure to sun and vitamin D – so it’s difficult to definitively link the condition to one thing.
“Stones are diseases of affluence – the more animal protein you eat the more likely you are to make kidney stones,” he said.
“The instance of kidney stones in Canada has been on the rise anyway because our animal protein intake has been on the rise.”
But if kidney stones do become more common, it’s bad news because the pain is something no one wants to experience, Morton said.
“Usually patients with kidney stones say it’s one of the worst pains they’ve ever had. In general, women say it’s worse than the pain of childbirth.”
The Kidney Foundation of Canada says stones range in size from a grain of sand to a golf ball and can sometimes be passed through the urinary system without complications.
But larger stones can be agonizing to pass. Some can require surgery to remove, or a treatment involving high-energy shockwaves that break down the stones into small pieces.