More people are reporting kidney stones than ever and one study has found the possible cause for this rise.

The study, headed by Gregory Tasian and published in the journal Environmental Health Perspectives found that as the average temperature in a region rose, so did the rate of kidney stones. This is a trend that has been happening for the last 30 years. Once temperatures rose above an average of 50 degrees, people were more likely to develop the stones. The number of stones reported typically increased three days after an especially warm day.

This conclusion was reached after Tasian and his team reviewed records for 60,433 patients who had been treated for kidney stones between 2005 and 2011. They then compared the number of kidney stones treated with the average temperatures in various regions of the United States over a period of 20 days.

Their findings indicate that the increasing temperatures associated with global warming could be a possible cause for the rise in cases of kidney stones over the last three decades. They estimate that the rate of kidney stones will continue to increase as average temperatures increase in the future.

Kidney stones are comprised of calcium deposits that accumulate in the kidneys. They are thought to be influenced by temperature largely because the rate of dehydration goes up when it is hot outside. Dehydration is associated with less urine production, which means there are higher levels of calcium in the urine that then form the stones.

Tasian expects kidney stones to become an increasingly common problem as more climates experience more severe heat. “Kidney stone prevalence has already been on the rise over the last 30 years, and we can expect this trend to continue, both in greater numbers and over a broader geographic area, as daily temperatures increase. With some experts predicting that extreme temperatures will become the norm in 30 years, children will bear the brunt of climate change,” he said.