Thirty years ago, kidney stones were considered a middle-aged white man’s disease. Now, doctors are increasingly seeing a different breed of patients suffering from the extremely painful condition, especially in the summer.
New data shows that kidney stones, hard deposits of minerals and salts that can become lodged in the urinary tract, are now occurring in younger people, particularly teenage girls.
Experts aren’t sure why more children and adolescents are getting the disease, but they speculate that a combination of factors are responsible, including a diet high in highly processed foods, increased use of antibiotics at a young age, and climate change , leading to more cases of dehydration.
Doctors speaking to NBC News said they see more children with kidney stones in the summer than at any other time of the year.
Kidney stones are a metabolic disorder, also called nephrolithiasis, that occurs when minerals such as calcium, oxalate, and phosphorus build up in the urine, forming hard yellowish crystals that are as small as a grain of sand or, in severe cases, as large as a golf ball. Some stones pass out of the urinary tract easily, but others can get stuck, blocking the flow of urine and causing severe pain and bleeding.
In recent years, hospitals across the country have opened pediatric “stone clinics” to keep up with demand. There, children can meet with urologists, nephrologists, and nutritionists to receive the care they need to treat and prevent future kidney stones.
Kidney stones in adults are associated with conditions such as metabolic syndrome, obesity, high blood pressure and diabetes.
“We don’t see that in children,” said Dr. Gregory Tasian, a pediatric urologist at Children’s Hospital of Philadelphia. “They are otherwise healthy and simply get their first kidney stone for unclear reasons.”
Much of the nephrolithiasis research in children in the United States has been directed by Tasian and his colleagues and focuses on finding the cause. “Obviously something has changed in our environment that is causing this rapid change,” he said.
According to the National Kidney Foundation, about 10% of people in the US will have a kidney stone at some point in their lives. Stones can be found in children as young as 5 years old.
Chloe Carroll, now 14, was just 8 years old when she discovered blood in her urine during a dance. Doctors diagnosed her with her first kidney stone – a surprise for a young athlete with no previous illnesses.
Less than a year later, she was hit by a second rock. At the age of 11, she developed another stone – all three stones had to be surgically removed.
“It’s still nerve-wracking going through this over and over again,” Carroll, now 14, said through tears as she recalled the fear of surgery. “But I know it’s a part of life and I have to move on.”
How many children develop kidney stones?
Kidney stones are not common in children, although frequency is unclear as most research has focused on adults.
One estimate comes from a 2016 study led by Tasian, which included nearly 153,000 South Carolina adults and children receiving emergency, hospitalization, or surgical care for nephrolithiasis.
The study, published in the Clinical Journal of the American Society of Nephrology, found that the annual incidence of kidney stone disease increased by 16% from 1997 to 2012, with 15- to 19-year-olds seeing the largest increase. In this age group, the incidence of kidney stones was 52% higher in girls and women. The disease was more common in men over the age of 25.
Overall, the risk of childhood kidney stone disease doubled in boys and girls, while there was a 45% increase in risk in women over the 16-year study period. Black adults and children in the study were also more likely to develop kidney stones than whites.
Similar trends have been reported in other studies, including a study conducted in Olmsted County, Minnesota, which found that the kidney stone incidence rate in children ages 12 to 17 increased by 6% per year from 1984 to 2008.
Is Diet Linked to Kidney Stones?
Experts believe that the deteriorating diet of children could play a role.
High levels of sodium from potato chips, sandwich meats, sports drinks, and packaged meals can introduce extra minerals into the urine, which can clump together into kidney stones. This is especially likely if a child doesn’t drink enough water or drinks too many sweetened beverages high in fructose corn syrup.
It’s like trying to dissolve sugar in an almost empty cup of coffee, said Dr. David Chu, a pediatric urologist at Ann & Robert H. Lurie Children’s Hospital in Chicago who is conducting research with Tasian.
Hotter summers cause more kidney stones
The hotter and wetter it is, the more you sweat and the less you urinate, causing minerals to bind in the kidneys and urinary tract. Children are particularly vulnerable to heat.
dr Christina Carpenter, interim chief of pediatric urology at New York-Presbyterian Morgan Stanley Children’s Hospital, said she has treated more children with kidney stones over the summer.
Studies have found that the number of people seeking medical help for kidney stones increases as average daily temperatures rise. Other research shows that in the US Southeast – known as the “Kidney Stone Belt” – the prevalence of kidney stone disease is up to 50% higher than in the Northwest.
A 2008 study predicted that the “belt” will inevitably expand upwards, with the proportion of the US population living in “high-risk zones” rising from 40% in 2000 to 70% in 2095.
An antibiotic connection with kidney stones
Antibiotics could change the gut microbiome in a way that promotes the formation of kidney stones, Tasian said.
In 2018, Tasian’s team found that people who took any of the five commonly prescribed oral antibiotics had a 1.3 to 2.3-fold increase in the likelihood of developing kidney stones. The risk decreased over time but remained high for up to five years after taking the drug — and was greatest when it was given at an earlier age.
Because many antibiotics are unnecessarily prescribed in the US, Tasian called this a “leading theory” for the increase in the development of kidney stones in children.
The earlier a person develops kidney stones, the more time they have to develop a more severe form of the disease and related long-term health problems, Tasian said. Consequences include loss of kidney function, reduced bone mineral density that can lead to fractures, and a higher risk of heart disease in adulthood.
According to the National Kidney Foundation, children who develop a stone have about a 50 percent chance of developing another stone within five to seven years.
Any stone that passes through the urinary tract increases the risk of developing a ureteral stricture, which is a narrowing of the tube that drains urine from the kidneys into the bladder, Carpenter said.
When this happens, children may need to undergo invasive surgery to fix the problem.
The trend is also concerning because there is limited evidence on how best to treat children with kidney stone disease, experts say.
Symptoms of Kidney Stones
According to the National Institute of Diabetes and Digestive and Kidney Disease, symptoms include:
- Lancinating pains in the back, lower abdomen and groin.
- Pink, brown, or red blood in the urine.
- Constant urge to urinate.
- Cloudy or foul-smelling urine.
- Irritability, especially in younger children.
Some children may not have any symptoms. However, symptoms in children, especially younger ones, can sometimes be more “non-specific,” Carpenter said, so they may complain of abdominal pain rather than back pain or nausea.
To avoid kidney stones
Drink plenty of water, especially in the warmer months, experts say.
Not sure if you’re drinking enough? Make sure your urine resembles a light lemonade color, Carpenter said. If it’s darker, moisturize more.