Experts say a high-salt diet as well as a lack of hydration may be behind the rising number of cases of kidney stones.

A man in the United States in 1994 had about a 1 in 16 chance of developing a kidney stone. By 2010, those chances had risen to about 1 in 10.

An American woman in 1994 had about a 1 in 25 chance of developing a kidney stone in 1994. By 2010, it was about 1 in 14.

Since then, things have reportedly gotten worse.

The prevalence of kidney stones among adults in the United States has continued to increase since that 2010 Centers for Disease Control and Prevention study.

This trend also has apparently been going on for a while now.

A new study of Minnesotans found that kidney stone incidence increased twofold among men and fourfold among women between 1984 and 2012.

The new findings add to a growing body of research suggesting that not only are kidney stones on the rise, but they’re increasing among demographic groups who have traditionally not been the most at risk.

The most likely causes, researchers suspect, are changes in Americans’ diets — saltier, more processed food, more sugar-sweetened beverages, and less water.

The latest study was published earlier this month in the journal Mayo Clinic Proceedings.

In it, researchers said young women saw the biggest jump in kidney stone incidence. The incidence rate of kidney stones in women ages 18 to 39 jumped more than fourfold, from a 1 in 1,612 chance in 1984 to a 1 in 284 chance in 2012.

The study looked just at residents of Olmsted County, a 90 percent white community in southeastern Minnesota. But other studies elsewhere have found similar jumps.

A 2016 study found the incident of kidney stones increased 16 percent among South Carolina residents between 1997 and 2012.

By group, women saw the largest year-over-year increase at 3 percent per year, followed by African-Americans at 2.9 percent. But children had the biggest jump: 4.7 percent each year on average, and a risk that’s doubled since 1997.

Better detection and increased case reporting could be partly a reason for the jump in incidence rates, but the prime culprit is obesity and the diets that contribute to it, said Dr. Fara Bellows, a urologist at the Ohio State University’s Wexner Medical Center.

Bellows, who wasn’t involved in the recent studies, says today about 9 percent of women and 19 percent of men will get a kidney stone.

Diets high in processed foods and sugar-sweetened beverages are largely to blame, she said, as well as not drinking enough water.

Ingesting high levels of sodium can cause higher levels of calcium in urine, causing the most common type of kidney stone.

Not drinking enough water can also throw off the acid balance in urine, sometimes causing uric acid stones, a type of stone common in men. They can be the result of urine high in acid, which can be caused by a diet rich in purines, found in animal proteins.

Bellows recommends her patients drink 80 ounces of water a day.

“Lack of water in our diets can make those salts more likely to crystallize and form stones,” she told Healthline.

She also recommends a low-salt diet, not restricting calcium below the recommended daily amounts, and limiting animal protein.

Is there a chance kidney stones could become even more frequent or, perhaps, have we seen the worst?

That remains to be seen, Bellows said, but she thinks an increasing focus on preventive medicine, including improving diets, has at least a chance at halting this trend.