Could global warming cause surge in kidney stones? Hot weather increases risk of painful condition, experts claim

A study by experts at The Children's Hospital of Phildelphia examined the medical records of 60,000 adults and children

They focused on five U.S. cities - Atlanta, Chicago, Dallas, LA and Philadephia, analysing the records as well as weather patterns in each city

The risk of kidney stones rose as average temperatures rose above 10 °C

Dehydration brought on by high temperatures leads to a higher concentration of calcium and minerals in the urine, which cause stones

Painful condition causes 500,000 people to visit U.S. hospitals each year

Scientists link rise in cases to global warming, warning children will bear the brunt of the health risks associated with rising temperatures



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Warm weather is causing more patients to be diagnosed with kidney stones, scientists have revealed.

Higher temperatures contribute to dehydration, which increases the risk of kidney stones in those people predisposed to the condition, a new study has found.

Researchers at The Children's Hospital of Philadelphia examined 60,000 patients in several cities across the U.S., with varying climates, discovering a link between hot days and kidney stones.

The study raises the theory that as the planet warms up climate change is taking its toll on human health.

A new study carried out at The Children's Hospital of Philadelphia has found that as average temperatures rise above 10°C a person's risk of developing painful kidney stones increases

Lead researcher and urologist, Gregory Tasian, said: 'We found that as daily temperatures rise, there is a rapid increase in the probability of patients presenting over the next 20 days with kidney stones.

The team analysed medical records of more than 60,000 adults and children with kidney stones between 2005 and 2011 in Atlanta, Chicago, Dallas, Los Angeles and Philadelphia as well as weather records for each city.

They recorded the risk of stone presentation for the full range of temperatures in each city.

As average daily temperatures rose above 10°C, the risk of a person getting kidney stones increased in all cities, except LA.

The delay between a person being out in the hot weather and developing stones was short, peaking within three days of exposure to high temperatures.



'These findings point to potential public health effects associated with global climate change,' said Mr Tasian.

'However, although 11 per cent of the U.S. population has had kidney stones, most people have not.

'It is likely that higher temperatures increase the risk of kidney stones in those people predisposed to stone formation.'

Higher temperatures increase the risk a person will become dehydrated, which leads to a higher concentration of calcium and other minerals in the urine, which cause stones to grow in the kidneys.

It is a painful condition, which causes around 500,000 patients to visit emergency departments across the U.S. each year.

And the number of cases has increased markedly across the world in the last 10 years.

While stones remain more common in adults, the numbers of children developing kidney stones has soared in the last 25 years.

Scientists examined the medical records of 60,000 patients, in five U.S. cities. They compared the prevalence of kidney stones, pictured left on an X-ray and right after extraction from a patient, and weather patterns. The researchers warned global warming could be a factor behind the rising number of cases Lead researcher and urologist, Gregory Tasian, said: 'With some experts predicting that extreme temperatures will become the norm in 30 years, children will bear the brunt of climate change'

The factors causing the increase in kidney stones are currently unknown, but are thought to be influenced by changes in diet and fluid intake.

When stones do not pass on their own, surgery is often necessary.

The new study also found extremely low temperatures increased the risk of kidney stones in three cities - Atlanta, Chicago and Philadelphia.



WHAT ARE KIDNEY STONES?

Kidney stones are stone-like lumps that can develop in one or both kidneys. When stones cause severe pain, it is known as renal colic. Small stones may be passed out painlessly in the urine and may even go undetected. But it is common for a stone to block part of the urinary system, including the: Ureter - the tube connecting the kidney to the bladder

Urethra - the tube urine passes through out of the body

The waste products in the blood can cause crystals to form, collecting inside the kidney. Over time the crystals build up to form a hard, stone-like lump. It is more likely to happen if a person does not drink enough fluid. Some medications also increase the chances of stones developing. Kidney stones are common, affecting people aged 30 to 60 years old. They affect more men than women. While most small stones pass in the urine, larger stones may need to be broken up with X-rays or ultrasound in hospital. In some cases surgery is needed. Source: NHS Choices

The researchers said low temperatures causes more people to stay inside in the warm, causing changes in diet and decreased exercise levels, which could increase risk of stone formation.

They argued that the number of hot days in a year, may better predict the risk of a person suffering kidney stones, compared to the average annual temperature.

Atlanta and LA share the same annual temperature, of 17 °C, but Atlanta has more hot days than LA - as well as twice the prevalence of kidney stones.

Tasian added that while the five cities chosen for their study are representative of those found across the world, more research is needed to explore the current findings.

Future studies should examine how risk patterns vary in different populations, including among children, which only represented a small percentage of those analysed in the current study.

The team's findings have a broader context, in the patterns of global warming.

The authors note that other scientists have reported overall global temperatures between 2000 and 2009 were higher than 82 per cent of temperatures over the last 11,300 years.

Furthermore, increases in greenhouse gas emissions are expected to raise Earth's average temperatures by 1 to 4.5 °C by 2100.

Tasian added: '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.