About 1 in 10 people in the United States have had a kidney stone, based on the most recent national survey data from 2017–2018. Globally, the picture looks similar: a large meta-analysis covering over 1.2 million participants estimated worldwide prevalence at roughly 11%. That means hundreds of millions of people will deal with a kidney stone at some point in their lives.
Prevalence in the U.S. and Around the World
The 1-in-10 figure for the U.S. comes from self-reported data in the National Health and Nutrition Examination Survey (NHANES), the country’s most comprehensive population health study. That translates to tens of millions of American adults who have passed or been treated for at least one stone.
Globally, rates vary by region. Asia, which contributes the largest body of research, reports a prevalence of about 11.8%. Europe sits slightly lower at 8.7%, and North America at 8.3%. Some regions report notably higher numbers, though these figures often come from fewer studies and may reflect local dietary patterns, climate, or genetic factors rather than a universal trend.
Men, Women, and Age
The old assumption that kidney stones are overwhelmingly a “men’s problem” doesn’t hold up as well as it used to. Among adults under 50, stone prevalence is nearly identical between men and women: 6.3% in men and 6.4% in women, a difference so small it’s statistically meaningless. In the 20–29 age group, women actually have a slightly higher rate (4.1%) than men (3.1%).
Risk climbs with age for both sexes. By the time people reach their 40s, roughly 8–9% have had a stone. After age 50, men begin to pull ahead in overall prevalence, which is why the historical data skewed so heavily male. But for younger generations, the gap has essentially closed.
Recurrence Is Common
One of the most important numbers for anyone who has already passed a stone: about 10% of first-time stone formers will have another episode within five years, and about 22% will have a recurrence within ten years. That comes from a prospective study that tracked patients after their first stone event. The risk isn’t evenly distributed. People who form certain types of stones, who don’t change their fluid intake, or who have underlying metabolic conditions face higher recurrence rates than those averages suggest.
Kidney Stones in Children
Kidney stones were once considered rare in kids. That’s changing. Globally, the number of pediatric stone cases rose from about 2.66 million in 1990 to 3.29 million in 2021. The incidence rate among children has climbed from an estimated 4–6% to around 10% in recent years, a shift that researchers attribute partly to dietary changes and partly to broader epidemiological trends rather than simply better detection.
The increase isn’t uniform. In wealthier countries, pediatric stone rates have actually decreased slightly over the past three decades, while low- and middle-income regions have seen the steepest climbs. Tropical Latin America and parts of Southern Europe, particularly Greece, recorded the largest jumps in pediatric incidence.
How Many People End Up in the ER
Kidney stones generate a significant volume of emergency care. In the most comprehensive U.S. count available, there were approximately 1.3 million emergency department visits for kidney stone disease in a single year, with about 261,000 of those visits resulting in a hospital admission. That works out to roughly 3,600 ER visits per day across the country. Most people who show up to the emergency room with a stone are treated and sent home, but about 1 in 5 require hospitalization for complications like infection, obstruction, or unmanageable pain.
Why Rates Keep Climbing
Several forces are pushing kidney stone numbers upward. The most straightforward is dehydration. Low fluid intake reduces urine volume, which concentrates the calcium, oxalate, and uric acid that form stones. Mean annual temperature accounts for an estimated 70% or more of the geographic variation in stone disease, which is why warmer regions tend to have higher rates.
Climate projections suggest the problem will get worse. One modeling study estimated that the share of the U.S. population living in high-risk zones for kidney stones will grow from 40% in 2000 to 56% by 2050, and potentially 70% by 2095. That translates to an estimated 1.6 to 2.2 million additional lifetime cases by mid-century, with some Midwestern cities like Chicago facing 40–50% increases in prevalence as temperatures rise.
Diet plays a role too, though the connections are more nuanced than commonly assumed. High sodium intake has long been cited as a risk factor because it increases calcium excretion in the urine. However, a recent population-based study in Switzerland found that measured sodium levels in urine were not independently associated with stone formation after adjusting for other variables. Obesity and high blood pressure, both frequently listed as risk factors, also failed to show independent associations in the same analysis. This doesn’t mean these factors are irrelevant, but it suggests the relationship between lifestyle and stone risk is more complex than a simple checklist.
What does consistently matter is fluid intake. Drinking enough water to produce at least 2 to 2.5 liters of urine per day remains the single most effective strategy for reducing stone risk, regardless of body weight, diet, or geography.